Exploring the Midgut Transcriptome and Brush Border Membrane Vesicle Proteome of the Rice Stem Borer, Chilo suppressalis (Walker)

PubMed Central

Peng, Chuanhua; Wang, Xiaoping; Li, Fei; Lin, Yongjun

2012-01-01

The rice stem borer, Chilo suppressalis (Walker) (Lepidoptera: Pyralidae), is one of the most detrimental pests affecting rice crops. The use of Bacillus thuringiensis (Bt) toxins has been explored as a means to control this pest, but the potential for C. suppressalis to develop resistance to Bt toxins makes this approach problematic. Few C. suppressalis gene sequences are known, which makes in-depth study of gene function difficult. Herein, we sequenced the midgut transcriptome of the rice stem borer. In total, 37,040 contigs were obtained, with a mean size of 497 bp. As expected, the transcripts of C. suppressalis shared high similarity with arthropod genes. Gene ontology and KEGG analysis were used to classify the gene functions in C. suppressalis. Using the midgut transcriptome data, we conducted a proteome analysis to identify proteins expressed abundantly in the brush border membrane vesicles (BBMV). Of the 100 top abundant proteins that were excised and subjected to mass spectrometry analysis, 74 share high similarity with known proteins. Among these proteins, Western blot analysis showed that Aminopeptidase N and EH domain-containing protein have the binding activities with Bt-toxin Cry1Ac. These data provide invaluable information about the gene sequences of C. suppressalis and the proteins that bind with Cry1Ac. PMID:22666467

Changes in intestinal absorption of nutrients and brush border glycoproteins after total parenteral nutrition in rats.

PubMed Central

Miura, S; Tanaka, S; Yoshioka, M; Serizawa, H; Tashiro, H; Shiozaki, H; Imaeda, H; Tsuchiya, M

1992-01-01

The effect of total parenteral nutrition on nutrients absorption and glycoprotein changes of brush border membrane was examined in rat small intestine. In total parenteral nutrition rats, a marked decrease in activity of brush border enzymes was observed mainly in the proximal and middle segments of the intestine. Galactose perfusion of jejunal segment showed that hexose absorption was significantly inhibited, while intestinal absorption of glycine or dipeptide, glycylglycine was not significantly affected by total parenteral nutrition treatment. When brush border membrane glycoprotein profile was examined by [3H]-glucosamine or [3H]-fucose incorporation into jejunal loops, significant changes were observed in the glycoprotein pattern of brush border membrane especially in the high molecular weight range over 120 kDa after total parenteral nutrition treatment, suggesting strong dependency of glycoprotein synthesis on luminal substances. Molecular weight of sucrase isomaltase in brush border membrane detected by specific antibody showed no significant difference, however, in total parenteral nutrition and control rats. Also, molecular weight of specific sodium glucose cotransporter of intestinal brush border membrane detected by selective photoaffinity labelling was not altered in total parenteral nutrition rats. It may be that prolonged absence of oral food intake may produce significant biochemical changes in brush border membrane glycoprotein and absorptive capacity of small intestine, but these changes were not observed in all brush border membrane glycoproteins. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:1582592

Saccharomyces boulardii upgrades cellular adaptation after proximal enterectomy in rats

PubMed Central

Buts, J; De Keyser, N; Marandi, S; Hermans, D; Sokal, E; Chae, Y; Lambotte, L; Chanteux, H; Tulkens, P

1999-01-01

BACKGROUND—Saccharomyces boulardii is a non-pathogenic yeast which exerts trophic effects on human and rat small intestinal mucosa.
AIMS—To examine the effects of S boulardii on ileal adaptation after proximal enterectomy in rats.
METHODS—Wistar rats, aged eight weeks, underwent 60% proximal resection or transection and received by orogastric intubation either 1 mg/g body wt per day lyophilised S boulardii or the vehicle for seven days. The effects on ileal mucosal adaptation were assessed eight days after surgery.
RESULTS—Compared with transection, resection resulted in mucosal hyperplasia with significant decreases in the specific and total activities of sucrase, lactase, and maltase. Treatment of resected animals with S boulardii had no effect on mucosal hyperplasia but did upgrade disaccharidase activities to the levels of the transected group. Enzyme stimulation by S boulardii was associated with significant increases in diamine oxidase activity and mucosal polyamine concentrations. Likewise, sodium dependent D-glucose uptake by brush border membrane vesicles, measured as a function of time and glucose concentration in the incubation medium, was significantly (p<0.05) increased by 81% and three times respectively in the resected group treated with S boulardii. In agreement with this, expression of the sodium/glucose cotransporter-1 in brush border membranes of resected rats treated with S boulardii was enhanced twofold compared with resected controls.
CONCLUSION—Oral administration of S boulardii soon after proximal enterectomy improves functional adaptation of the remnant ileum.


Keywords: Saccharomyces boulardii; intestine; adaptation; polyamines; brush border membrane enzymes; glucose uptake PMID:10369710

Hypoglycemic property of soy isoflavones from hypocotyl in Goto-Kakizaki diabetic rats.

PubMed

Jin, Ming; Shen, Ming-Hua; Jin, Mei-Hua; Jin, Ai-Hua; Yin, Xue-Zhe; Quan, Ji-Shu

2018-03-01

The present study was carried out to investigate the hypoglycemic effect of soy isoflavones from hypocotyl in GK diabetic rats. A single administration and long-term administration tests were conducted in GK diabetic rats to test the hypoglycemic effect of soy isoflavones. At the end of long-term administration trial, blood protein, cholesterol, triglyceride, glycosylated serum protein, C-reactive protein, insulin, aminotransferase, lipid peroxide, interleukin-6, tumor necrosis factor-α were estimated. Inhibition of soy isoflavones against α-amylase and α-glucosidase, as well as on glucose uptake into brush border membrane vesicles or Caco-2 cells were determined in vitro . In single administration experiment, soy isoflavones reduced postprandial blood glucose levels in GK rats. In long-term administration, hypoglycemic effect of soy isoflavones was first observed at week 12 and maintained till week 16. A significant reduction in fasting blood glucose, C-reactive protein, and lipid peroxide was noted at week 16. However, there was no significant treatment effect on blood insulin. Furthermore, soy isoflavone administration resulted in significant decreases in glycosylated serum protein, tumor necrosis factor-α, and interleukin-6. Other biochemical parameters, such as protein, cholesterol, triglyceride and aminotransferases were not modified, however. The results in vitro showed that soy isoflavones showed a potent inhibitory effect on intestinal α-glucosidase, but not on pancreatic α-amylase. Soy isoflavones also decreased glucose transport potency into brush border membrane vesicles or Caco-2 cells. It is concluded that soy isoflavones from hypocotyl, performs hypoglycemic function in GK rats with type 2 diabetes, maybe via suppression of carbohydrate digestion and glucose uptake in small intestine.

Efficient entrapment of large and small compounds during vesiculation of intestinal microvilli.

PubMed Central

van Dommelen, F S; Hamer, C M; De Jonge, H R

1986-01-01

An efficient method is described permitting the encapsulation of membrane-impermeable compounds at the interior of intestinal microvilli during vesicle formation. Rat intestinal epithelial cells were isolated by high-frequency vibration and exposed transiently to iso-osmotic medium containing 5 mM-EDTA. Vesiculation of microvilli was effected by freeze-thawing instead of mechanical fragmentation or hypo-osmotic lysis. Solutes to be entrapped were mixed with the extracellular medium before freezing in liquid N2. Microvillous vesicles were isolated from thawed cell suspensions by Ca2+- or Mg2+-aggregation of contaminants and differential centrifugation. The yield, purity, orientation and transport properties of the vesicles were similar, or superior, to preparations described in the literature. A high loading efficiency was demonstrated for small impermeants (cyclic GMP, ATP, Arsenazo III) as well as proteins (albumin); in contrast, loading of isolated vesicles by hypo-osmotic shock was only partially effective (cyclic GMP, ATP) or ineffective (albumin). Entrapment of an ATP-regenerating system could partially block a Mg2+-dependent conversion of intravesicular ATP into ADP. No evidence was obtained for the contribution of a proton pump to the intrinsic Mg2+-ATPase of the vesicle. Potential applications of the vesicle-loading technique in studies of brush-border transport regulation by intramicrovillar factors are discussed. Images Fig. 1. Fig. 2. PMID:3024625

Apolipoprotein A-1 (apoA-1) deposition in, and release from, the enterocyte brush border: a possible role in transintestinal cholesterol efflux (TICE)?

PubMed

Danielsen, E Michael; Hansen, Gert H; Rasmussen, Karina; Niels-Christiansen, Lise-Lotte; Frenzel, Franz

2012-03-01

Transintestinal cholesterol efflux (TICE) has been proposed to represent a non-hepatobiliary route of cholesterol secretion directly "from blood to gut" and to play a physiologically significant role in excretion of neutral sterols, but so far little is known about the proteins involved in the process. We have previously observed that apolipoprotein A-1 (apoA-1) synthesized by enterocytes of the small intestine is mainly secreted apically into the gut lumen during fasting where its assembly into chylomicrons and basolateral discharge is at a minimal level. In the present work we showed, both by immunomicroscopy and subcellular fractionation, that a fraction of the apically secreted apoA-1 in porcine small intestine was not released from the cell surface but instead deposited in the brush border. Cholesterol was detected in immunoisolated microvillar apoA-1, and it was partially associated with detergent resistant membranes (DRMs), indicative of localization in lipid raft microdomains. The apolipoprotein was not readily released from microvillar vesicles by high salt or by incubation with phosphatidylcholine-specific phospholipase C or trypsin, indicating a relatively firm attachment to the membrane bilayer. However, whole bile or taurocholate efficiently released apoA-1 at low concentrations that did not solubilize the transmembrane microvillar protein aminopeptidase N. Based on these findings and the well known role played by apoA-1 in extrahepatic cellular cholesterol removal and reverse cholesterol transport (RCT), we propose that brush border-deposited apoA-1 in the small intestine acts in TICE by mediating cholesterol efflux into the gut lumen. Copyright © 2011 Elsevier B.V. All rights reserved.

Environmental cues and symbiont microbe-associated molecular patterns function in concert to drive the daily remodelling of the crypt-cell brush border of the Euprymna scolopes light organ

PubMed Central

Heath-Heckman, Elizabeth A.C.; Foster, Jamie; Apicella, Michael A.; Goldman, William E.; McFall-Ngai, Margaret

2016-01-01

Summary Recent research has shown that the microbiota affects the biology of associated host epithelial tissues, including their circadian rhythms, although few data are available on how such influences shape the microarchitecture of the brush border. The squid-vibrio system exhibits two modifications of the brush border that supports the symbionts: effacement and repolarization. Together these occur on a daily rhythm in adult animals, at the dawn expulsion of symbionts into the environment, and symbiont colonization of the juvenile host induces an increase in microvillar density. Here we sought to define how these processes are related and the roles of both symbiont colonization and environmental cues. Ultrastructural analyses showed that the juvenile-organ brush borders also efface concomitantly with daily dawn-cued expulsion of symbionts. Manipulation of the environmental light cue and juvenile symbiotic state demonstrated that this behaviour requires the light cue, but not colonization. In contrast, symbionts were required for the observed increase in microvillar density that accompanies post dawn brush-border repolarization; this increase was induced solely by host exposure to phosphorylated lipid A of symbiont cells. These data demonstrate that a partnering of environmental and symbiont cues shapes the brush border and that microbe-associated molecular patterns play a role in the regulation of brush-border microarchitecture. PMID:27062511

Sulfate-bicarbonate exchange in brush-border membranes from rat renal cortex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pritchard, J.B.

1987-02-01

Under Na/sup +/-free conditions /sup 35/SO/sub 4//sup 2 -/ uptake by rat renal brush-border membrane (BBM) vesicles could be driven by imposition of a HCO/sup -//sub 3/ gradient (in greater than out). The initial rate of /sup 35/SO/sub 4//sup 2 -/ uptake was stimulated 10-fold, and peak overshoot exceeded equilibrium uptake by 2-3 times. Cl/sup -/, SCN/sup -/, NO/sub 3//sup -/, I/sup -/, and OH/sup -/ were able to substitute for HCO/sub 3//sup -/. Divalent anions, including /sup 35/SO/sub 4//sup 2 -/ itself, were less effective as counterions. HCO/sub 3//sup -/-SO/sub 4//sup 2 -/ exchange was cis-inhibited by disulfonic stilbenes,more » ((SITS)(DIDS)), phloretin, Hg, and S/sub 2/O/sub 3//sup 2 -/. HCO/sub 3//sup -/-driven /sup 35/SO/sub 4//sup 2 -/ uptake was saturable, with an apparent K/sub m/ of 0.4 mM for SO/sub 4//sup 2 -/. Simultaneous imposition of Na/sup +/ and HCO/sub 3//sup -/ gradients produced approximately additive stimulation of /sup 35/SO/sub 4//sup 2 -/ uptake. The HCO/sub 3//sup -/-driven component of /sup 35/SO/sub 4//sup 2 -/ uptake, but not the component driven by Na/sup +/, was inhibited by SITS. Finally, Na/sup +/-driven SO/sub 4//sup 2 -/ accumulation could be reduced by imposing an out greater than in HCO/sub 3//sup +/ gradient, conditions accelerating exchange driven SO/sub 4//sup 2 -/ efflux. These findings indicate the presence of separate Na/sup +/-SO/sub 4//sup 2 -/ cotransport and SO /sub 4//sup 2 -/-anion exchange pathways in the same BBM vesicles.« less

Identification of a New cry1I-Type Gene as a Candidate for Gene Pyramiding in Corn To Control Ostrinia Species Larvae

PubMed Central

Zhao, Can; Abdelgaffar, Heba M.; Pan, Hongyu; Song, Fuping

2015-01-01

Pyramiding of diverse cry toxin genes from Bacillus thuringiensis with different modes of action is a desirable strategy to delay the evolution of resistance in the European corn borer (Ostrinia nubilalis). Considering the dependency of susceptibility to Cry toxins on toxin binding to receptors in the midgut of target pests, a diverse mode of action is commonly defined as recognition of unique binding sites in the target insect. In this study, we present a novel cry1Ie toxin gene (cry1Ie2) as a candidate for pyramiding with Cry1Ab or Cry1Fa in corn to control Ostrinia species larvae. The new toxin gene encodes an 81-kDa protein that is processed to a protease-resistant core form of approximately 55 kDa by trypsin digestion. The purified protoxin displayed high toxicity to Ostrinia furnacalis and O. nubilalis larvae but low to no activity against Spodoptera or heliothine species or the coleopteran Tenebrio molitor. Results of binding assays with 125I-labeled Cry1Ab toxin and brush border membrane vesicles from O. nubilalis larvae demonstrated that Cry1Ie2 does not recognize the Cry1Ab binding sites in that insect. Reciprocal competition binding assays with biotin-labeled Cry1Ie2 confirmed the lack of shared sites with Cry1Ab or Cry1Fa in O. nubilalis brush border membrane vesicles. These data support Cry1Ie2 as a good candidate for pyramiding with Cry1Ab or Cry1Fa in corn to increase the control of O. nubilalis and reduce the risk of resistance evolution. PMID:25795679

Effect of dietary fatty acids on jejunal and ileal oleic acid uptake by rat brush border membrane vesicles.

PubMed

Prieto, R M; Stremmel, W; Sales, C; Tur, J A

1996-04-18

To test the effect of dietary fatty acids on fatty acid uptake, the influx kinetics of a representative long-chain fatty acid, 3H-oleic acid, in both the jejunum and ileum of rats has been studied using brush border membrane vesicles (BBMV). Animals were fed with semipurified diets containing 5 g fat/100 g diet, as corn oil (control group), safflower oil (unsaturated group) and coconut oil hydrogenated (saturated group). With increasing unbound oleate concentration in the medium, the three dietary groups showed saturable kinetics in both jejunal and ileal BBMV (controls: Vmax = 0.15 +/- 0.01 nmol x mg protein-1 x 5 min-1 and Km = 136 +/- 29.1 nmol for jejunum, and Vmax = 0.23 +/- 0.03 nmol x mg protein-1 x 5 min-1 and Km = 196 +/- 50.3 nmol for ileum; unsaturated: Vmax = 0.28 +/- 0.05 nmol x mg protein-1 x 5 min-1 and Km = 242.7 +/- 91.8 nmol for jejunum, and Vmax = 1.29 +/- 0.06 nmol x mg protein-1 x 5 min-1 and Km = 509.8 +/- 97.5 nmol for ileum; saturated: Vmax = 0.03 +/- 0.01 nmol x mg protein-1 x 5 min-1 and Km = 124.5 +/- 72.6 nmol for jejunum, and Vmax = 0.04 +/- 0.01 nmol x mg protein -1.5 min-1 and Km = 205.6 +/- 85.3 nmol for ileum). These results support the theory that feeding an isocaloric diet containing only unsaturated fatty acids enhanced oleic acid uptake, and feeding an isocaloric diet containing only saturated fatty acids decreased oleic acid uptake. The results obtained in the present work also show the adaptative ability of jejunum and ileum to the type of dietary fat.

Identification of a New cry1I-Type Gene as a Candidate for Gene Pyramiding in Corn To Control Ostrinia Species Larvae.

PubMed

Zhao, Can; Jurat-Fuentes, Juan Luis; Abdelgaffar, Heba M; Pan, Hongyu; Song, Fuping; Zhang, Jie

2015-06-01

Pyramiding of diverse cry toxin genes from Bacillus thuringiensis with different modes of action is a desirable strategy to delay the evolution of resistance in the European corn borer (Ostrinia nubilalis). Considering the dependency of susceptibility to Cry toxins on toxin binding to receptors in the midgut of target pests, a diverse mode of action is commonly defined as recognition of unique binding sites in the target insect. In this study, we present a novel cry1Ie toxin gene (cry1Ie2) as a candidate for pyramiding with Cry1Ab or Cry1Fa in corn to control Ostrinia species larvae. The new toxin gene encodes an 81-kDa protein that is processed to a protease-resistant core form of approximately 55 kDa by trypsin digestion. The purified protoxin displayed high toxicity to Ostrinia furnacalis and O. nubilalis larvae but low to no activity against Spodoptera or heliothine species or the coleopteran Tenebrio molitor. Results of binding assays with (125)I-labeled Cry1Ab toxin and brush border membrane vesicles from O. nubilalis larvae demonstrated that Cry1Ie2 does not recognize the Cry1Ab binding sites in that insect. Reciprocal competition binding assays with biotin-labeled Cry1Ie2 confirmed the lack of shared sites with Cry1Ab or Cry1Fa in O. nubilalis brush border membrane vesicles. These data support Cry1Ie2 as a good candidate for pyramiding with Cry1Ab or Cry1Fa in corn to increase the control of O. nubilalis and reduce the risk of resistance evolution. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Structural specificity of mucosal-cell transport and metabolism of peptide drugs: implication for oral peptide drug delivery

NASA Technical Reports Server (NTRS)

Bai, J. P.; Amidon, G. L.

1992-01-01

The brush border membrane of intestinal mucosal cells contains a peptide carrier system with rather broad substrate specificity and various endo- and exopeptidase activities. Small peptide (di-/tripeptide)-type drugs with or without an N-terminal alpha-amino group, including beta-lactam antibiotics and angiotensin-converting enzyme (ACE) inhibitors, are transported by the peptide transporter. Polypeptide drugs are hydrolyzed by brush border membrane proteolytic enzymes to di-/tripeptides and amino acids. Therefore, while the intestinal brush border membrane has a carrier system facilitating the absorption of di-/tripeptide drugs, it is a major barrier limiting oral availability of polypeptide drugs. In this paper, the specificity of peptide transport and metabolism in the intestinal brush border membrane is reviewed.

Proteomic analysis of the enterocyte brush border

PubMed Central

McConnell, Russell E.; Benesh, Andrew E.; Mao, Suli; Tabb, David L.

2011-01-01

The brush border domain at the apex of intestinal epithelial cells is the primary site of nutrient absorption in the intestinal tract and the primary surface of interaction with microbes that reside in the lumen. Because the brush border is positioned at such a critical physiological interface, we set out to create a comprehensive list of the proteins that reside in this domain using shotgun mass spectrometry. The resulting proteome contains 646 proteins with diverse functions. In addition to the expected collection of nutrient processing and transport components, we also identified molecules expected to function in the regulation of actin dynamics, membrane bending, and extracellular adhesion. These results provide a foundation for future studies aimed at defining the molecular mechanisms underpinning brush border assembly and function. PMID:21330445

Jejunal brush border microvillous alterations in Giardia muris-infected mice: role of T lymphocytes and interleukin-6.

PubMed

Scott, K G; Logan, M R; Klammer, G M; Teoh, D A; Buret, A G

2000-06-01

Intestinal colonization with the protozoan Giardia causes diffuse brush border microvillous alterations and disaccharidase deficiencies, which in turn are responsible for intestinal malabsorption and maldigestion. The role of T cells and/or cytokines in the pathogenesis of Giardia-induced microvillous injury remains unclear. The aim of this study was to assess the role of T cells and interleukin-6 (IL-6) in the brush border pathophysiology of acute murine giardiasis in vivo. Athymic nude (nu(-)/nu(-)) CD-1 mice and isogenic immunocompetent (nu(+)/nu(+)) CD-1 mice (4 weeks old) received an axenic Giardia muris trophozoite inoculum or vehicle (control) via orogastric gavage. Weight gain and food intake were assessed daily. On day 6, segments of jejunum were assessed for parasite load, brush border ultrastructure, IL-6 content, maltase and sucrase activities, villus-crypt architecture, and intraepithelial lymphocyte (IEL) infiltration. Despite similar parasitic loads on day 6, infected immunocompetent animals, but not infected nude mice, showed a diffuse loss of brush border microvillous surface area, which was correlated with a significant reduction in maltase and sucrase activities and a decrease in jejunal IL-6 concentration. In both athymic control and infected mice, jejunal brush border surface area and disaccharidases were high, but levels of tissue IL-6 were low and comparable to the concentration measured in immunocompetent infected animals. In both immunocompetent and nude mice, infection caused a small but significant increase in the numbers of IELs. These findings suggest that the enterocyte brush border injury and malfunction seen in giardiasis is, at least in part, mediated by thymus-derived T lymphocytes and that suppressed jejunal IL-6 does not necessarily accompany microvillous shortening.

Generation of stable lipid raft microdomains in the enterocyte brush border by selective endocytic removal of non-raft membrane.

PubMed

Danielsen, E Michael; Hansen, Gert H

2013-01-01

The small intestinal brush border has an unusually high proportion of glycolipids which promote the formation of lipid raft microdomains, stabilized by various cross-linking lectins. This unique membrane organization acts to provide physical and chemical stability to the membrane that faces multiple deleterious agents present in the gut lumen, such as bile salts, digestive enzymes of the pancreas, and a plethora of pathogens. In the present work, we studied the constitutive endocytosis from the brush border of cultured jejunal explants of the pig, and the results indicate that this process functions to enrich the contents of lipid raft components in the brush border. The lipophilic fluorescent marker FM, taken up into early endosomes in the terminal web region (TWEEs), was absent from detergent resistant membranes (DRMs), implying an association with non-raft membrane. Furthermore, neither major lipid raft-associated brush border enzymes nor glycolipids were detected by immunofluorescence microscopy in subapical punctae resembling TWEEs. Finally, two model raft lipids, BODIPY-lactosylceramide and BODIPY-GM1, were not endocytosed except when cholera toxin subunit B (CTB) was present. In conclusion, we propose that constitutive, selective endocytic removal of non-raft membrane acts as a sorting mechanism to enrich the brush border contents of lipid raft components, such as glycolipids and the major digestive enzymes. This sorting may be energetically driven by changes in membrane curvature when molecules move from a microvillar surface to an endocytic invagination.

The epidermal growth factor receptor (EGF-R) is present on the basolateral, but not the apical, surface of enterocytes in the human gastrointestinal tract.

PubMed Central

Playford, R J; Hanby, A M; Gschmeissner, S; Peiffer, L P; Wright, N A; McGarrity, T

1996-01-01

BACKGROUND: While it is clear that luminal epidermal growth factor (EGF) stimulates repair of the damaged bowel, its significance in maintaining normal gut growth remains uncertain. If EGF is important in maintaining normal gut growth, the EGF receptor (EGF-R) should be present on the apical (luminal) surface in addition to the basolateral surface. AIMS/SUBJECTS/METHODS: This study examined the distribution of the EGF-R in the epithelium throughout the human gastro-intestinal tract using immunohistochemistry, electron microscopy, and western blotting of brush border preparations. RESULTS: Immunostaining of the oesophagus showed circumferential EGF-R positivity in the cells of the basal portions of the stratified squamous epithelium but surface cells were EGF-R negative. In the normal stomach, small intestine, and colon, immunostaining localised the receptor to the basolateral surface with the apical membranes being consistently negative. EGF-R positivity within the small intestine appeared to be almost entirely restricted to the proliferative (crypt) region. Western blotting demonstrated a 170 kDa protein in whole tissue homogenates but not in the brush border vesicle preparations. CONCLUSIONS: As the EGF-R is located only on the basolateral surfaces in the normal adult gastrointestinal tract, the major role of luminal EGF is probably to stimulate repair rather than to maintain normal gut growth. Images Figure 1 Figure 2 Figure 3 PMID:8977341

In Vivo and In Vitro Binding of Vip3Aa to Spodoptera frugiperda Midgut and Characterization of Binding Sites by 125I Radiolabeling

PubMed Central

Chakroun, Maissa

2014-01-01

Bacillus thuringiensis vegetative insecticidal proteins (Vip3A) have been recently introduced in important crops as a strategy to delay the emerging resistance to the existing Cry toxins. The mode of action of Vip3A proteins has been studied in Spodoptera frugiperda with the aim of characterizing their binding to the insect midgut. Immunofluorescence histological localization of Vip3Aa in the midgut of intoxicated larvae showed that Vip3Aa bound to the brush border membrane along the entire apical surface. The presence of fluorescence in the cytoplasm of epithelial cells seems to suggest internalization of Vip3Aa or a fragment of it. Successful radiolabeling and optimization of the binding protocol for the 125I-Vip3Aa to S. frugiperda brush border membrane vesicles (BBMV) allowed the determination of binding parameters of Vip3A proteins for the first time. Heterologous competition using Vip3Ad, Vip3Ae, and Vip3Af as competitor proteins showed that they share the same binding site with Vip3Aa. In contrast, when using Cry1Ab and Cry1Ac as competitors, no competitive binding was observed, which makes them appropriate candidates to be used in combination with Vip3A proteins in transgenic crops. PMID:25002420

Mechanisms of zinc transport into pig small intestine brush-border membrane vesicles.

PubMed Central

Tacnet, F; Lauthier, F; Ripoche, P

1993-01-01

1. The purpose of the present work was to examine certain membrane transport mechanisms likely to carry zinc across the brush-border membrane of pig small intestine, isolated in a vesicular form. 2. In initial velocity conditions, saturation kinetics revealed a great effect of pH on zinc transport: optimal conditions were observed with an intravesicular pH of around 6.6 with or without a H+ gradient; however, this did not allow us to conclude the existence of a neutral exchange between Zn2+ and H+ ions. 3. By measuring 36Cl uptakes, the presence of the Cl(-)-HCO3- or Cl(-)-OH-antiporter with typical 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) sensitivity was detected in vesicles; zinc did not alter this anionic exchange activity. A 65Zn time course, performed in conditions identical with those for 36Cl uptake, was DIDS insensitive and was greatly inhibited by an outward OH- gradient. This could argue against a transport of zinc as a complex with Cl- and HCO3- through the anion antiporter. 4. When external Cl- and HCO3- were replaced by SCN-, able to form a Zn(SCN)4(2-) complex, we observed a stimulating effect of outward HCO3- gradients on 65Zn uptake but neither DIDS nor diphenylamine-2-carboxylate (DPC) inhibited the transport in these conditions. This suggested that the intestinal anion antiporter was not a major route for zinc reabsorption. 5. The tripeptide Gly-Gly-His at low concentrations stimulated 65Zn uptake, then inhibited it in a dose-dependent manner either in the presence of an inward H+ gradient or in the presence of a membrane potential 'negative inside' or in both situations. These conditions are necessary for the active transport of the peptide and this strongly suggests that zinc can be transported as a [Gly-Gly-His-Zn] complex, utilizing the peptide carrier system. PMID:8229851

Bacillus thuringiensis delta-endotoxin binding to brush border membrane vesicles of rice stem borers.

PubMed

Alcantara, Edwin P; Aguda, Remedios M; Curtiss, April; Dean, Donald H; Cohen, Michael B

2004-04-01

The receptor binding step in the molecular mode of action of five delta-endotoxins (Cry1Ab, Cry1Ac, Cry1C, Cry2A, and Cry9C) from Bacillus thuringiensis was examined to find toxins with different receptor sites in the midgut of the striped stem borer (SSB) Chilo suppressalis (Walker) and yellow stem borer (YSB) Scirpophaga incertulas (Walker) (Lepidoptera: Pyralidae). Homologous competition assays were used to estimate binding affinities (K(com)) of (125)I-labelled toxins to brush border membrane vesicles (BBMV). The SSB BBMV affinities in decreasing order was: Cry1Ab = Cry1Ac > Cry9C > Cry2A > Cry1C. In YSB, the order of decreasing affinities was: Cry1Ac > Cry1Ab > Cry9C = Cry2A > Cry1C. The number of binding sites (B(max)) estimated by homologous competition binding among the Cry toxins did not affect toxin binding affinity (K(com)) to both insect midgut BBMVs. Results of the heterologous competition binding assays suggest that Cry1Ab and Cry1Ac compete for the same binding sites in SSB and YSB. Other toxins bind with weak (Cry1C, Cry2A) or no affinity (Cry9C) to Cry1Ab and Cry1Ac binding sites in both species. Cry2A had the lowest toxicity to 10-day-old SSB and Cry1Ab and Cry1Ac were the most toxic. Taken together, the results of this study show that Cry1Ab or Cry1Ac could be combined with either Cry1C, Cry2A, or Cry9C for more durable resistance in transgenic rice. Cry1Ab should not be used together with Cry1Ac because a mutation in one receptor site could diminish binding of both toxins. Copyright 2004 Wiley-Liss, Inc.

Cation-dependent nutrient transport in shrimp digestive tract.

PubMed

Simmons, Tamla; Mozo, Julie; Wilson, Jennifer; Ahearn, Gregory A

2012-02-01

Purified epithelial brush border membrane vesicles (BBMV) were produced from the hepatopancreas of the Atlantic White shrimp, Litopeneaus setiferus, using standard methods originally developed for mammalian tissues and previously applied to other crustacean and echinoderm epithelia. These vesicles were used to study the cation dependency of sugar and amino acid transport across luminal membranes of hepatopancreatic epithelial cells. (3)H-D: -glucose uptake by BBMV against transient sugar concentration gradients occurred when either transmembrane sodium or potassium gradients were the only driving forces for sugar accumulation, suggesting the presence of a possible coupled transport system capable of using either cation. (3)H-L: -histidine transport was only stimulated by a transmembrane potassium gradient, while (3)H-L: -leucine uptake was enhanced by either a sodium or potassium gradient. These responses suggest the possible presence of a potassium-dependent transporter that accommodates either amino acid and a sodium-dependent system restricted only to L: -leucine. Uptake of (3)H-L: -leucine was significantly stimulated (P < 0.05) by several metallic cations (e.g., Zn(2+), Cu(2+), Mn(2+), Cd(2+), or Co(2+)) at external pH values of 7.0 or 5.0 (internal pH 7.0), suggesting a potential synergistic role of the cations in the transmembrane transfer of amino acids. (3)H-L: -histidine influxes (15 suptakes) were hyperbolic functions of external [zinc] or [manganese], following Michaelis-Menten kinetics. The apparent affinity constant (e.g., K (m)) for manganese was an order of magnitude smaller (K (m) = 0.22 μM Mn) than that for zinc (K (m) = 1.80 μM Zn), while no significant difference (P > 0.05) occurred between their maximal transport velocities (e.g., J (max)). These results suggest that a number of cation-dependent nutrient transport systems occur on the shrimp brush border membrane and aid in the absorption of these important dietary elements.

Plastin 1 Binds to Keratin and Is Required for Terminal Web Assembly in the Intestinal Epithelium

PubMed Central

Grimm-Günter, Eva-Maria S.; Revenu, Céline; Ramos, Sonia; Hurbain, Ilse; Smyth, Neil; Ferrary, Evelyne; Louvard, Daniel; Robine, Sylvie

2009-01-01

Plastin 1 (I-plastin, fimbrin) along with villin and espin is a prominent actin-bundling protein of the intestinal brush border microvilli. We demonstrate here that plastin 1 accumulates in the terminal web and interacts with keratin 19, possibly contributing to anchoring the rootlets to the keratin network. This prompted us to investigate the importance of plastin 1 in brush border assembly. Although in vivo neither villin nor espin is required for brush border structure, plastin 1-deficient mice have conspicuous ultrastructural alterations: microvilli are shorter and constricted at their base, and, strikingly, their core actin bundles lack true rootlets. The composition of the microvilli themselves is apparently normal, whereas that of the terminal web is profoundly altered. Although the plastin 1 knockout mice do not show any overt gross phenotype and present a normal intestinal microanatomy, the alterations result in increased fragility of the epithelium. This is seen as an increased sensitivity of the brush border to biochemical manipulations, decreased transepithelial resistance, and increased sensitivity to dextran sodium sulfate-induced colitis. Plastin 1 thus emerges as an important regulator of brush border morphology and stability through a novel role in the organization of the terminal web, possibly by connecting actin filaments to the underlying intermediate filament network. PMID:19321664

Preparation of plasmonic vesicles from amphiphilic gold nanocrystals grafted with polymer brushes

PubMed Central

Song, Jibin; Huang, Peng; Chen, Xiaoyuan

2016-01-01

Gold nanovesicles contain multiple nanocrystals within a polymeric coating. The strong plasmonic coupling between adjacent nanoparticles in their vesicular shell makes ultrasensitive biosensing and bioimaging possible. In our laboratory, multifunctional plasmonic vesicles are assembled from amphiphilic gold nanocrystals (such as gold nanoparticles and gold nanorods) coated with mixed hydrophilic and hydrophobic polymer brushes or amphiphilic diblock co-polymer brushes. To fulfill the different requirements of biomedical applications, different polymers that are either pH=responsive, photoactive or biodegradable can be used to form the hydrophobic brush, while the hydrophilicity is maintained by polyethylene glycol (PEG). This protocol covers the preparation, surface functionalization and self-assembly of amphiphilic gold nanocrystals grafted covalently with polymer brushes. The protocol can be completed within 2 d. The preparation of amphiphilic gold nanocrystals, coated with amphiphilic diblock polymer brushes using a ‘grafting to’ method or mixed hydrophilic and hydrophobic polymer brushes using tandem ‘grafting to’ and ‘grafting from’ methods, is described. We also provide detailed procedures for the preparation and characterization of pH-responsive plasmonic gold nanovesicles from amphiphilic gold nanocrystals using a film-rehydration method that can be completed within ~3 d. PMID:27763624

Intestinal surfactant permeation enhancers and their interaction with enterocyte cell membranes in a mucosal explant system.

PubMed

Danielsen, E Michael; Hansen, Gert H

2017-07-03

Intestinal permeation enhancers (PEs) are agents aimed to improve oral delivery of therapeutic drugs with poor bioavailability. The main permeability barrier for oral delivery is the intestinal epithelium, and PEs act to increase the paracellular and/or transcellular passage of drugs. Transcellular passage can be achieved by cell membrane permeabilization and/or by endocytic uptake and subsequent transcytosis. One broad class of PEs is surfactants which act by inserting into the cell membrane, thereby perturbing its integrity, but little is known about how the dynamics of the membrane are affected. In the present work, the interaction of the surfactants lauroyl-L-carnitine, 1-decanoyl-rac-glycerol, and nonaethylene glycol monododecyl ether with the intestinal epithelium was studied in organ cultured pig jejunal mucosal explants. As expected, at 2 mM, these agents rapidly permeabilized the enterocytes for the fluorescent polar tracer lucifer yellow, but surprisingly, they all also blocked both constitutive -and receptor-mediated pathways of endocytosis from the brush border, indicating a complete arrest of apical membrane trafficking. At the ultrastructural level, the PEs caused longitudinal fusion of brush border microvilli. Such a membrane fusogenic activity could also explain the observed formation of vesicle-like structures and large vacuoles along the lateral cell membranes of the enterocytes induced by the PEs. We conclude that the surfactant action of the PEs selected in this study not only permeabilized the enterocytes, but profoundly changed the dynamic properties of their constituent cell membranes.

DREW-UCLA Breast Cancer Research and Training Program: Molecular/Cellular Pathogenesis Model

DTIC Science & Technology

2007-03-01

system in bovine renal brush- border [13] and in a bovine renal epithelial cell line NBL -1 [14]. In order to highlight the substrate difference with an... NBL -1 expresses a broad specificity Na(+)-dependent neu- tral amino acid transport system (System B0) similar to that in bovine renal brush border

Local pH domains regulate NHE3-mediated Na+ reabsorption in the renal proximal tubule

PubMed Central

Burford, James L.; McDonough, Alicia A.; Holstein-Rathlou, Niels-Henrik; Peti-Peterdi, Janos

2014-01-01

The proximal tubule Na+/H+ exchanger 3 (NHE3), located in the apical dense microvilli (brush border), plays a major role in the reabsorption of NaCl and water in the renal proximal tubule. In response to a rise in blood pressure NHE3 redistributes in the plane of the plasma membrane to the base of the brush border, where NHE3 activity is reduced. This NHE3 redistribution is assumed to provoke pressure natriuresis; however, it is unclear how NHE3 redistribution per se reduces NHE3 activity. To investigate if the distribution of NHE3 in the brush border can change the reabsorption rate, we constructed a spatiotemporal mathematical model of NHE3-mediated Na+ reabsorption across a proximal tubule cell and compared the model results with in vivo experiments in rats. The model predicts that when NHE3 is localized exclusively at the base of the brush border, it creates local pH microdomains that reduce NHE3 activity by >30%. We tested the model's prediction experimentally: the rat kidney cortex was loaded with the pH-sensitive fluorescent dye BCECF, and cells of the proximal tubule were imaged in vivo using confocal fluorescence microscopy before and after an increase of blood pressure by ∼50 mmHg. The experimental results supported the model by demonstrating that a rise of blood pressure induces the development of pH microdomains near the bottom of the brush border. These local changes in pH reduce NHE3 activity, which may explain the pressure natriuresis response to NHE3 redistribution. PMID:25298526

In vivo antibody-mediated modulation of aminopeptidase A in mouse proximal tubular epithelial cells.

PubMed

Mentzel, S; Dijkman, H B; van Son, J P; Wetzels, J F; Assmann, K J

1999-07-01

Aminopeptidase A (APA) is one of the many renal hydrolases. In mouse kidney, APA is predominantly expressed on the brush borders and sparsely on the basolateral membranes of proximal tubular epithelial cells. However, when large amounts of monoclonal antibodies (MAbs) against APA were injected into mice, we observed strong binding of the MAbs to the basolateral membranes, whereas the MAbs bound only transiently to the brush borders of the proximal tubular epithelial cells. In parallel, APA itself disappeared from the brush borders by both endocytosis and shedding, whereas it was increasingly expressed on the basolateral sides. Using ultrastructural immunohistology, we found no evidence for transcellular transport of endocytosed APA to the basolateral side of the proximal tubular epithelial cells. The absence of transcellular transport was confirmed by experiments in which we used a low dose of the MAbs. Such a low dose did not result in binding of the MAbs to the brush borders and had no effect on the presence of APA in the brush borders of the proximal tubular epithelial cells. In these experiments we still could observe binding of the MAbs to the basolateral membranes in parallel with the local appearance of APA. In addition, treatment of mice with chlorpromazine, a calmodulin antagonist that interferes with cytoskeletal function, largely inhibited the MAb-induced modulation of APA. Our studies suggest that injection of MAbs to APA specifically interrupts the normal intracellular traffic of this enzyme in proximal tubular epithelial cells. This intracellular transport is dependent on the action of cytoskeletal proteins.

Induction of a gradual, reversible morphogenesis of its host's epithelial brush border by Vibrio fischeri.

PubMed

Lamarcq, L H; McFall-Ngai, M J

1998-02-01

Bacteria exert a variety of influences on the morphology and physiology of animal cells whether they are pathogens or cooperative partners. The association between the luminous bacterium Vibrio fischeri and the sepiolid squid Euprymna scolopes provides an experimental model for the study of the influence of extracellular bacteria on the development of host epithelia. In this study, we analyzed bacterium-induced changes in the brush borders of the light organ crypt epithelia during the initial hours following colonization of this tissue. Transmission electron microscopy of the brush border morphology in colonized and uncolonized hosts revealed that the bacteria effect a fourfold increase in microvillar density over the first 4 days of the association. Estimates of the proportions of bacterial cells in contact with host microvilli showed that the intimacy of the bacterial cells with animal cell surfaces increases significantly during this time. Antibiotic curing of the organ following colonization showed that sustained interaction with bacteria is essential for the retention of the induced morphological changes. Bacteria that are defective in either light production or colonization efficiency produced changes similar to those by the parent strain. Conventional fluorescence and confocal scanning laser microscopy revealed that the brush border is supported by abundant filamentous actin. However, in situ hybridization with beta-actin probes did not show marked bacterium-induced increases in beta-actin gene expression. These experiments demonstrate that the E. scolopes-V. fischeri system is a viable model for the experimental study of bacterium-induced changes in host brush border morphology.

Induction of a Gradual, Reversible Morphogenesis of Its Host’s Epithelial Brush Border by Vibrio fischeri

PubMed Central

Lamarcq, Laurence H.; McFall-Ngai, Margaret J.

1998-01-01

Bacteria exert a variety of influences on the morphology and physiology of animal cells whether they are pathogens or cooperative partners. The association between the luminous bacterium Vibrio fischeri and the sepiolid squid Euprymna scolopes provides an experimental model for the study of the influence of extracellular bacteria on the development of host epithelia. In this study, we analyzed bacterium-induced changes in the brush borders of the light organ crypt epithelia during the initial hours following colonization of this tissue. Transmission electron microscopy of the brush border morphology in colonized and uncolonized hosts revealed that the bacteria effect a fourfold increase in microvillar density over the first 4 days of the association. Estimates of the proportions of bacterial cells in contact with host microvilli showed that the intimacy of the bacterial cells with animal cell surfaces increases significantly during this time. Antibiotic curing of the organ following colonization showed that sustained interaction with bacteria is essential for the retention of the induced morphological changes. Bacteria that are defective in either light production or colonization efficiency produced changes similar to those by the parent strain. Conventional fluorescence and confocal scanning laser microscopy revealed that the brush border is supported by abundant filamentous actin. However, in situ hybridization with β-actin probes did not show marked bacterium-induced increases in β-actin gene expression. These experiments demonstrate that the E. scolopes-V. fischeri system is a viable model for the experimental study of bacterium-induced changes in host brush border morphology. PMID:9453641

Is there a tripeptidyl peptidase in the renal brush-border membrane?

PubMed Central

Kenny, A J; Ingram, J

1988-01-01

A recent claim that the renal brush border contains a tripeptidyl peptidase [Andersen & McDonald (1987) Am. J. Physiol. 253, F649-F655] was examined. In a fluorescent assay, the hydrolysis of Gly-Pro-Met-2-naphthylamide (-NH-Nap) and Gly-Pro-Leu-NH-Nap by pig kidney microvilli was strongly inhibited by amastatin or di-isopropyl phosphorofluoridate (inhibitors of aminopeptidases and dipeptidyl peptidase IV). The products formed were shown to be Gly-Pro and Met-NH-Nap (or Leu-NH-Nap) and free 2-naphthylamine. Specific antibodies to pig and rat aminopeptidase N abolished the apparent tripeptidyl peptidase activity. We conclude that these substrates are hydrolysed by the sequential attack of dipeptidyl peptidase IV and aminopeptidase N and that pig and rat brush borders lack a detectable tripeptidyl peptidase. Images Fig. 1. PMID:3058122

Isolation and partial characterization of gypsy moth BTR-270, an anionic brush border membrane glycoconjugate that binds Bacillus thuringiensis Cry1A toxins with high affinity

Treesearch

Algimantas P. Valaitis; Jeremy L. Jenkins; Mi Kyong Lee; Donald H. Dean; Karen J. Garner

2001-01-01

BTR-270, a gypsy moth (Lymantria dispar) brush border membrane molecule that binds Bacillus thuringiensis (Bt) Cry1A toxins with high affinity, was purified by preparative gel electrophoresis. Rabbit antibodies specific for the Bt toxin-binding molecule were raised. Attempts to label BTR-270 by protein-directed techniques were...

Influence of exocrine and endocrine pancreatic function on intestinal brush border enaymatic activities.

PubMed Central

Caspary, W F; Winckler, K; Lankisch, P G; Creutzfeldt, W

1975-01-01

Digestive enzymatic activities (disaccharidases, alkaline phosphatase, peptide hydrolases) have been determined in the mucosa of 14 patients with chronic pancreatitis. All had an abnormal secretin-pancreozymin test. Four patients had insulin-dependent diabetes mellitus, four a pathological glucose tolerance test. Nine patients had steatorrhoea. Maltase, sucrase, and alkaline phosphatase activity was significantly elevated in patients with exocrine pancreatic insufficiency, whereas those of lactase, trehalase, and peptide hydrolase were normal. Patients with steatorrhoea had higher maltase and sucrase activity than those without steatorrhoea, whereas decreased glucose tolerance had no effect on brush border enzymatic activity. It is suggested thatdecreased exocrine rather than decreased endocrine pancreatic function is responsible for the increase in intestinal disaccharidase and alkaline phosphatase activity, possible by the influence of pacreatic enzymes on the turnover of brush border enzymes from the luminal side of the mucosal membranes or by direct hormonal stimulation though cholecystokinin. PMID:1092602

A specific binding protein from Tenebrio molitor for the insecticidal toxin of Bacillus thuringiensis subsp. tenebrionis.

PubMed

Belfiore, C J; Vadlamudi, R K; Osman, Y A; Bulla, L A

1994-04-15

Biopesticides based on the bacterium Bacillus thuringiensis have attracted wide attention as safe alternatives to chemical insecticides. In this paper, we report, for the first time, the identification of a single binding protein from a coleopteran insect, Tenebrio molitor, that is specific for the cryIII toxin of B. thuringiensis. The protein appeared as a single band of 144 kDa on radioligand and immunoblots of total proteins extracted from brush border membrane vesicles of the midgut of T. molitor. Radiolabelled cryIIIA toxin bound to the protein with a Kd value of 17.5 nM and could be specifically blocked by unlabelled toxin but not by toxins from other subspecies of B. thuringiensis. This study lays the groundwork to clone the cryIIIA toxin binding protein and to determine the molecular mechanism(s) of toxin action.

Effect of proinflammatory interleukins on jejunal nutrient transport

PubMed Central

Hardin, J; Kroeker, K; Chung, B; Gall, D

2000-01-01

AIM—We examined the effect of proinflammatory and anti-inflammatory interleukins on jejunal nutrient transport and expression of the sodium-glucose linked cotransporter (SGLT-1).
METHODS—3-O-methyl glucose and L-proline transport rates were examined in New Zealand White rabbit stripped, short circuited jejunal tissue. The effects of the proinflammatory cytokines interleukin (IL)-1α, IL-6, and IL-8, IL-1α plus the specific IL-1 antagonist, IL-1ra, and the anti-inflammatory cytokine IL-10 were investigated. In separate experiments, passive tissue permeability was assessed and brush border SGLT-1 expression was measured by western blot in tissues exposed to proinflammatory interleukins.
RESULTS—The proinflammatory interleukins IL-6, IL-1α, and IL-8 significantly increased glucose absorption compared with control levels. This increase in glucose absorption was due to an increase in mucosal to serosal flux. IL-1α and IL-8 also significantly increased L-proline absorption due to an increase in absorptive flux. The anti-inflammatory IL-10 had no effect on glucose transport. The receptor antagonist IL-1ra blocked the ability of IL-1α to stimulate glucose transport. IL-8 had no effect on passive tissue permeability. SGLT-1 content did not differ in brush border membrane vesicles (BBMV) from control or interleukin treated tissue.
CONCLUSIONS—These findings suggest that intestinal inflammation and release of inflammatory mediators such as interleukins increase nutrient absorption in the gut. The increase in glucose transport does not appear to be due to changes in BBMV SGLT-1 content.


Keywords: glucose transport; small intestine; intestinal inflammation; inflammation PMID:10896908

Functional Regulation of Sugar Assimilation by N-Glycan-specific Interaction of Pancreatic α-Amylase with Glycoproteins of Duodenal Brush Border Membrane*

PubMed Central

Asanuma-Date, Kimie; Hirano, Yuki; Le, Na; Sano, Kotone; Kawasaki, Nana; Hashii, Noritaka; Hiruta, Yoko; Nakayama, Ken-ichi; Umemura, Mariko; Ishikawa, Kazuhiko; Sakagami, Hiromi; Ogawa, Haruko

2012-01-01

Porcine pancreatic α-amylase (PPA) binds to N-linked glycans of glycoproteins (Matsushita, H., Takenaka, M., and Ogawa, H. (2002) J. Biol Chem., 277, 4680–4686). Immunostaining revealed that PPA is located at the brush-border membrane (BBM) of enterocytes in the duodenum and that the binding is inhibited by mannan but not galactan, indicating that PPA binds carbohydrate-specifically to BBM. The ligands for PPA in BBM were identified as glycoprotein N-glycans that are significantly involved in the assimilation of glucose, including sucrase-isomaltase (SI) and Na+/Glc cotransporter 1 (SGLT1). Binding of SI and SGLT1 in BBM to PPA was dose-dependent and inhibited by mannan. Using BBM vesicles, we found functional changes in PPA and its ligands in BBM due to the N-glycan-specific interaction. The starch-degrading activity of PPA and maltose-degrading activity of SI were enhanced to 240 and 175%, respectively, while Glc uptake by SGLT1 was markedly inhibited by PPA at high but physiologically possible concentrations, and the binding was attenuated by the addition of mannose-specific lectins, especially from Galanthus nivalis. Additionally, recombinant human pancreatic α-amylases expressed in yeast and purified by single-step affinity chromatography exhibited the same carbohydrate binding specificity as PPA in binding assays with sugar-biotinyl polymer probes. The results indicate that mammalian pancreatic α-amylases share a common carbohydrate binding activity and specifically bind to the intestinal BBM. Interaction with N-glycans in the BBM activated PPA and SI to produce much Glc on the one hand and to inhibit Glc absorption by enterocytes via SGLT1 in order to prevent a rapid increase in blood sugar on the other. PMID:22584580

Oral administration of thymoquinone mitigates the effect of cisplatin on brush border membrane enzymes, energy metabolism and antioxidant system in rat intestine.

PubMed

Shahid, Faaiza; Farooqui, Zeba; Abidi, Subuhi; Parwez, Iqbal; Khan, Farah

2017-10-01

Cisplatin (CP) is a widely used chemotherapeutic agent that elicits severe gastrointestinal toxicity. Nigella sativa, a member of family Ranunculaceae, is one of the most revered medicinal plant known for its numerous health benefits. Thymoquinone (TQ), a major bioactive component derived from the volatile oil of Nigella sativa seeds, has been shown to improve gastrointestinal functions in animal models of acute gastric/intestinal injury. In view of this, the aim of the present study was to investigate the protective effect of TQ on CP induced toxicity in rat intestine and to elucidate the mechanism underlying these effects. Rats were divided into four groups viz. control, CP, TQ and CP+TQ. Animals in CP+TQ and TQ groups were orally administered TQ (1.5mg/kg bwt) with and without a single intraperitoneal dose of CP (6mg/kg bwt) respectively. The effect of TQ was determined on CP induced alterations in the activities of brush border membrane (BBM), carbohydrate metabolism, and antioxidant defense enzymes in rat intestine. TQ administration significantly mitigated CP induced decline in the specific activities of BBM marker enzymes, both in the mucosal homogenates and in the BBM vesicles (BBMV) prepared from intestinal mucosa. Furthermore, TQ administration restored the redox and metabolic status of intestinal mucosal tissue in CP treated rats. The biochemical results were supported by histopathological findings that showed extensive damage to intestine in CP treated rats and markedly preserved intestinal histoarchitecture in CP and TQ co-treated group. The biochemical and histological data suggest a protective effect of TQ against CP-induced gastrointestinal damage. Thus, TQ may have a potential for clinical application to counteract the accompanying gastrointestinal toxicity in CP chemotherapy. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Angiotensin 2 directly increases rabbit renal brush-border membrane sodium transport: Presence of local signal transduction system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morduchowicz, G.A.; Sheikh-Hamad, D.; Dwyer, B.E.

1991-05-01

In the present study, the authors have examined the direct actions of angiotensin II (AII) in rabbit renal brush border membrane (BBM) where binding sites for AII exist. Addition of AII (10(-11)-10(-7) M) was found to stimulate 22Na+ uptake by the isolated BBM vesicles directly. All did not affect the Na(+)-dependent BBM glucose uptake, and the effect of AII on BBM 22Na+ uptake was inhibited by amiloride, suggesting the involvement of Na+/H+ exchange mechanism. BBM proton permeability as assessed by acridine orange quenching was not affected by AII, indicating the direct effect of AII on Na+/H+ antiport system. In searchmore » of the signal transduction mechanism, it was found that AII activated BBM phospholipase A2 (PLA) and that BBM contains a 42-kDa guanine nucleotide-binding regulatory protein (G-protein) that underwent pertussis toxin (PTX)-catalyzed ADP-ribosylation. Addition of GTP potentiated, while GDP-beta S or PTX abolished, the effects of AII on BBM PLA and 22Na+ uptake, suggesting the involvement of G-protein in AII's actions. On the other hand, inhibition of PLA by mepacrine prevented AII's effect on BBM 22Na+ uptake, and activation of PLA by mellitin or addition of arachidonic acid similarly enhanced BBM 22Na+ uptake, suggesting the role of PLA activation in mediating AII's effect on BBM 22Na+ uptake. In summary, results of the present study show a direct stimulatory effect of AII on BBM Na+/H+ antiport system, and suggest the presence of a local signal transduction system involving G-protein mediated PLA activation.« less

Influence of time, storage temperature and freeze/thaw cycles on the activity of digestive enzymes from gilthead sea bream (Sparus aurata).

PubMed

Solovyev, Mikhail; Gisbert, Enric

2016-10-01

In this study, we tested the effects of long-term storage (2 years) at -20 °C and short-term storage (several hours) in ice and freeze/thaw cycles on the activities of pancreatic, gastric and intestinal (brush border and cytosolic) digestive enzymes in a teleost fish species. The results revealed a significant lose in activity of pancreatic (trypsin, chymotrypsin, total alkaline proteases and α-amylase) and intestinal cytosolic (leucine-alanine peptidase) enzymes between 140 and 270 days of storage at -20 °C, whereas in contrast, the activity of all the assayed brush border enzymes remained constant during the first 2 years of storage at -20 °C. During short-term storage conditions, the most stable enzymes assayed were those of the enterocytes of the brush border, which did not show any change in activity after being held for 5 h in ice. Five freezing and thawing cycles did not affect the activity of the intestinal brush border enzymes and the cytosolic ones, whereas the activity of trypsin, α-amylase and bile-salt-activated lipase was significantly affected by the number of freezing and thawing cycles. No changes in pepsin activity were found in samples exposed to 1 and 2 freezing and thawing cycles.

Exposure to Engineered Nanomaterial Results in Disruption of Brush Borders in Epithelia Models in vitro

NASA Astrophysics Data System (ADS)

Faust, James J.

Engineered nanoparticles (NP; 10-9 m) have found use in a variety of consumer goods and medical devices because of the unique changes in material properties that occur when synthesized on the nanoscale. Although many definitions for nanoparticle exist, from the perspective of size, nanoparticle is defined as particles with diameters less than 100 nm in any external dimension. Examples of their use include titanium dioxide added as a pigment in products intended to be ingested by humans, silicon dioxide NPs are used in foods as an anticaking agent, and gold or iron oxide NPs can be used as vectors for drug delivery or contrast agents for specialized medical imaging. Although the intended use of these NPs is often to improve human health, it has come to the attention of investigators that NPs can have unintended or even detrimental effects on the organism. This work describes one such unintended effect of NP exposure from the perspective of exposure via the oral route. First, this Dissertation will explain an event referred to as brush border disruption that occurred after nanoparticles interacted with an in vitro model of the human intestinal epithelium. Second, this Dissertation will identify and characterize several consumer goods that were shown to contain titanium dioxide that are intended to be ingested. Third, this Dissertation shows that sedimentation due to gravity does not artifactually result in disruption of brush borders as a consequence of exposure to food grade titanium dioxide in vitro. Finally, this Dissertation will demonstrate that iron oxide nanoparticles elicited similar effects after exposure to an in vitro brush border expressing model of the human placenta. Together, these data suggest that brush border disruption is not an artifact of the material/cell culture model, but instead represents a bona fide biological response as a result of exposure to nanomaterial.

Sugar uptake by intestinal basolateral membrane vesicles.

PubMed

Wright, E M; van Os, C H; Mircheff, A K

1980-03-27

A high yield of membrane vesicles was prepared from the basolateral surface of rat intestinal cells using an N2 cavitation bomb and density gradient centrifugation. The membranes were enriched 10-fold and were free of significatn contamination by brush border membranes and mitochondria. The rate of D-E114C]glucose and L-E13H]glucose uptake into the vesicle was measured using a rapid filtration technique. D-Glucose equilibrated within the vesicles with a half-time 1/25th that for L-glucose. The stereospecific uptake exhibited saturation kinetics with a Km of approx. 44 mM and a V of approx. 110 nmol . mg-1 min-1 at 10 degrees C. The activation energy for the process was 14 kcal . mol-1 below 15 degrees C and it approached 3 kcal . mol-1 above 22 degrees C. Carrier-mediated uptake was eliminated in the presence of 1 mM HgCl2 and 0.5 mM phloretin. The rate of transport was unaffected by the absence or presence of sodium concentration gradients. Competition studies demonstrated that all sugars with the D-glucose pyranose ring chair conformation shared the transport system, and that, with the possible exception of the -OH group at carbon No. 1, there were no specific requirements for an equatorial -OH group at any position in the pyranose ring. In the case of alpha-methyl-D-glucoside its inability to share the D-glucose transport system may be due to steric hindrance posed by the -OCH3 group rather than by a specific requirement for a free hydroxyl group at the position in the ring. It is concluded that sugars are transported across the basolateral membrane of the intestinal epithelium by a facilitated diffusion system reminiscent of that in human red blood cells.

Bacillus thuringiensis Cry1A toxin-binding glycoconjugates present on the brush border membrane and in the peritrophic membrane of the Douglas-fir tussock moth are peritrophins

Treesearch

Algimantas P. Valaitis; John D. Podgwaite

2013-01-01

Bacillus thuringiensis (Bt) Cry1A toxin-binding sites in the Douglas fir tussock moth (DFTM) larval gut were localized using immunofluorescence microscopy. Cry1Aa, Cry1Ab and Cry1Ac all bound strongly to the DFTM peritrophic membrane (PM); weaker binding of the Cry1A toxins was observed along the apical brush border of the midgut epithelium....

Effect of chronic hypo and hypervitaminosis C on the brush border enzymes and the intestinal uptake of glucose and alanine.

PubMed

Mahmood, A; Chauhan, V P; Lyall, V; Sarkar, A K

1979-08-15

Brush border sucrase and alkaline phosphatase activities are considerably enhanced in the intestine of ascorbic acid deficient guinea-pigs. Similar increase in the uptake of D-glucose and L-alanine also occurs in chronic vitamin C deficiency. However the permeability of D-glucose and L-alanine in the intestine of animals fed with large doses of vitamin C is severely depressed, with a reduction in the levels of sucrase and alkaline phosphatase activities.

Trafficking Ion Transporters to the Apical Membrane of Polarized Intestinal Enterocytes.

PubMed

Engevik, Amy Christine; Goldenring, James R

2018-01-02

Epithelial cells lining the gastrointestinal tract require distinct apical and basolateral domains to function properly. Trafficking and insertion of enzymes and transporters into the apical brush border of intestinal epithelial cells is essential for effective digestion and absorption of nutrients. Specific critical ion transporters are delivered to the apical brush border to facilitate fluid and electrolyte uptake. Maintenance of these apical transporters requires both targeted delivery and regulated membrane recycling. Examination of altered apical trafficking in patients with Microvillus Inclusion disease caused by inactivating mutations in MYO5B has led to insights into the regulation of apical trafficking by elements of the apical recycling system. Modeling of MYO5B loss in cell culture and animal models has led to recognition of Rab11a and Rab8a as critical regulators of apical brush border function. All of these studies show the importance of apical membrane trafficking dynamics in maintenance of polarized epithelial cell function. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

In Vivo, Villin Is Required for Ca2+-Dependent F-Actin Disruption in Intestinal Brush Borders

PubMed Central

Ferrary, Evelyne; Cohen-Tannoudji, Michel; Pehau-Arnaudet, Gérard; Lapillonne, Alexandre; Athman, Rafika; Ruiz, Tereza; Boulouha, Lilia; El Marjou, Fatima; Doye, Anne; Fontaine, Jean-Jacques; Antony, Claude; Babinet, Charles; Louvard, Daniel; Jaisser, Frédéric; Robine, Sylvie

1999-01-01

Villin is an actin-binding protein localized in intestinal and kidney brush borders. In vitro, villin has been demonstrated to bundle and sever F-actin in a Ca2+-dependent manner. We generated knockout mice to study the role of villin in vivo. In villin-null mice, no noticeable changes were observed in the ultrastructure of the microvilli or in the localization and expression of the actin-binding and membrane proteins of the intestine. Interestingly, the response to elevated intracellular Ca2+ differed significantly between mutant and normal mice. In wild-type animals, isolated brush borders were disrupted by the addition of Ca2+, whereas Ca2+ had no effect in villin-null isolates. Moreover, increase in intracellular Ca2+ by serosal carbachol or mucosal Ca2+ ionophore A23187 application abolished the F-actin labeling only in the brush border of wild-type animals. This F-actin disruption was also observed in physiological fasting/refeeding experiments. Oral administration of dextran sulfate sodium, an agent that causes colonic epithelial injury, induced large mucosal lesions resulting in a higher death probability in mice lacking villin, 36 ± 9.6%, compared with wild-type mice, 70 ± 8.8%, at day 13. These results suggest that in vivo, villin is not necessary for the bundling of F-actin microfilaments, whereas it is necessary for the reorganization elicited by various signals. We postulate that this property might be involved in cellular plasticity related to cell injury. PMID:10459016

Expression of Mucin-Type Glycoprotein K88 Receptors Strongly Correlates with Piglet Susceptibility to K88+ Enterotoxigenic Escherichia coli, but Adhesion of This Bacterium to Brush Borders Does Not

PubMed Central

Francis, David H.; Grange, Philippe A.; Zeman, David H.; Baker, Diane R.; Sun, Ronggai; Erickson, Alan K.

1998-01-01

Three antigenic variants of the K88 fimbrial adhesin exist in nature, K88ab, K88ac, and K88ad. Enterotoxigenic Escherichia coli (ETEC) strains that produce these fimbriae cause life-threatening diarrhea in some but not all young pigs. The susceptibility of pigs to these organisms has been correlated with the adherence of bacteria to isolated enterocyte brush borders. Whether that correlation holds for multiple K88 variants and over a broad genetic base of pigs is unknown and was the impetus for this study. We also desired to examine the correlation of the expression of a porcine intestinal brush border mucin-type glycoprotein (IMTGP) which binds K88ab and K88ac with the susceptibility of piglets to K88+ ETEC. Of 31 neonatal gnotobiotic pigs inoculated with K88ab+ or K88ac+ ETEC, 13 developed severe diarrhea, became dehydrated, and died or became moribund. Another pig became severely lethargic but not dehydrated. In vitro brush border adherence analysis was not possible for 10 of the severely ill pigs due to colonization by challenge strains. However, of the 17 pigs that did not become severely ill, 8 (47%) had brush borders that supported the adherence of K88ab+ and K88ac+ bacteria in vitro, suggesting a poor correlation between in vitro brush border adherence and piglet susceptibility to K88+ ETEC. By contrast, the expression of IMTGP was highly correlated with susceptibility to K88+ ETEC. Of the 12 pigs that produced IMTGP, 11 developed severe diarrhea. The other pig that produced IMTGP became lethargic but not severely diarrheic. Only 2 of 18 pigs that did not produce IMTGP became severely diarrheic. Colonizing bacteria were observed in histologic sections of intestines from all pigs that expressed IMTGP except for the one that did not develop severe diarrhea. However, colonizing bacteria were observed in histologic sections from only one pig that did not produce IMTGP. The bacterial concentration in the jejuna and ilea of pigs expressing IMTGP was significantly greater (P < 0.005) than that in pigs not expressing IMTGP. These observations suggest the IMTGP is a biologically relevant receptor for K88ab+ and K88ac+ E. coli or a correlate for expression for such a receptor. PMID:9712746

Experimental type II diabetes and related models of impaired glucose metabolism differentially regulate glucose transporters at the proximal tubule brush border membrane.

PubMed

Chichger, Havovi; Cleasby, Mark E; Srai, Surjit K; Unwin, Robert J; Debnam, Edward S; Marks, Joanne

2016-06-01

What is the central question of this study? Although SGLT2 inhibitors represent a promising treatment for patients suffering from diabetic nephropathy, the influence of metabolic disruption on the expression and function of glucose transporters is largely unknown. What is the main finding and its importance? In vivo models of metabolic disruption (Goto-Kakizaki type II diabetic rat and junk-food diet) demonstrate increased expression of SGLT1, SGLT2 and GLUT2 in the proximal tubule brush border. In the type II diabetic model, this is accompanied by increased SGLT- and GLUT-mediated glucose uptake. A fasted model of metabolic disruption (high-fat diet) demonstrated increased GLUT2 expression only. The differential alterations of glucose transporters in response to varying metabolic stress offer insight into the therapeutic value of inhibitors. SGLT2 inhibitors are now in clinical use to reduce hyperglycaemia in type II diabetes. However, renal glucose reabsorption across the brush border membrane (BBM) is not completely understood in diabetes. Increased consumption of a Western diet is strongly linked to type II diabetes. This study aimed to investigate the adaptations that occur in renal glucose transporters in response to experimental models of diet-induced insulin resistance. The study used Goto-Kakizaki type II diabetic rats and normal rats rendered insulin resistant using junk-food or high-fat diets. Levels of protein kinase C-βI (PKC-βI), GLUT2, SGLT1 and SGLT2 were determined by Western blotting of purified renal BBM. GLUT- and SGLT-mediated d-[(3) H]glucose uptake by BBM vesicles was measured in the presence and absence of the SGLT inhibitor phlorizin. GLUT- and SGLT-mediated glucose transport was elevated in type II diabetic rats, accompanied by increased expression of GLUT2, its upstream regulator PKC-βI and SGLT1 protein. Junk-food and high-fat diet feeding also caused higher membrane expression of GLUT2 and its upstream regulator PKC-βI. However, the junk-food diet also increased SGLT1 and SGLT2 levels at the proximal tubule BBM. Glucose reabsorption across the proximal tubule BBM, via GLUT2, SGLT1 and SGLT2, is not solely dependent on glycaemic status, but is also influenced by diet-induced changes in glucose metabolism. We conclude that different metabolic disturbances result in complex adaptations in renal glucose transporter protein levels and function. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Role of human placental apical membrane transporters in the efflux of glyburide, rosiglitazone, and metformin

PubMed Central

HEMAUER, Sarah J.; PATRIKEEVA, Svetlana L.; NANOVSKAYA, Tatiana N.; HANKINS, Gary D.V.; AHMED, Mahmoud S.

2010-01-01

Objective Substrates of placental efflux transporters could compete for a single transporter, which could result in an increase in the transfer of each substrate to the fetal circulation. Our aim was to determine the role of placental transporters in the biodisposition of oral hypoglycemic drugs that could be used as monotherapy or in combination therapy for gestational diabetes. Study design Inside-out brush border membrane vesicles from term placentas were used to determine the efflux of glyburide, rosiglitazone, and metformin by P-gp, Breast Cancer Resistance Protein (BCRP), and Multidrug Resistance Protein (MRP1). Results Glyburide was transported by MRP1 (43 ± 4%); BCRP (25 ± 5%); and P-gp (9 ± 5%). Rosiglitazone was transported predominantly by P-gp (71 ± 26%). Metformin was transported by P-gp (58 ± 20%) and BCRP (25 ± 14%). Conclusion Multiple placental transporters contribute to efflux of glyburide, rosiglitazone, and metformin. Administration of drug combinations could lead to their competition for efflux transporters. PMID:20350646

New Poly(amino acid methacrylate) Brush Supports the Formation of Well-Defined Lipid Membranes

PubMed Central

2015-01-01

A novel poly(amino acid methacrylate) brush comprising zwitterionic cysteine groups (PCysMA) was utilized as a support for lipid bilayers. The polymer brush provides a 12-nm-thick cushion between the underlying hard support and the aqueous phase. At neutral pH, the zeta potential of the PCysMA brush was ∼−10 mV. Cationic vesicles containing >25% DOTAP were found to form a homogeneous lipid bilayer, as determined by a combination of surface analytical techniques. The lipid mobility as measured by FRAP (fluorescence recovery after photobleaching) gave diffusion coefficients of ∼1.5 μm2 s–1, which are comparable to those observed for lipid bilayers on glass substrates. PMID:25746444

Heat-Induced Structural Changes Affect OVA-Antigen Processing and Reduce Allergic Response in Mouse Model of Food Allergy

PubMed Central

Wallner, Michael; Kverka, Miloslav; Kozakova, Hana; Srutkova, Dagmar; Klimesova, Klara; Sotkovsky, Petr; Palova-Jelinkova, Lenka; Ferreira, Fatima; Tuckova, Ludmila

2012-01-01

Background and Aims The egg protein ovalbumin (OVA) belongs to six most frequent food allergens. We investigated how thermal processing influences its ability to induce allergic symptoms and immune responses in mouse model of food allergy. Methodology/Principal Findings Effect of increased temperature (70°C and 95°C) on OVA secondary structure was characterized by circular dichroism and by the kinetics of pepsin digestion with subsequent HPLC. BALB/c mice were sensitized intraperitoneally and challenged with repeated gavages of OVA or OVA heated to 70°C (h-OVA). Levels of allergen-specific serum antibodies were determined by ELISA (IgA and IgGs) or by β-hexosaminidase release test (IgE). Specific activities of digestive enzymes were determined in brush border membrane vesicles of jejunal enterocytes. Cytokine production and changes in regulatory T cells in mesenteric lymph nodes and spleen were assessed by ELISA and FACS. Heating of OVA to 70°C caused mild irreversible changes in secondary structure compared to boiling to 95°C (b-OVA), but both OVA treatments led to markedly different digestion kinetics and Tregs induction ability in vitro, compared to native OVA. Heating of OVA significantly decreased clinical symptoms (allergic diarrhea) and immune allergic response on the level of IgE, IL-4, IL-5, IL-13. Furthermore, h-OVA induced lower activities of serum mast cell protease-1 and enterocyte brush border membrane alkaline phosphatase as compared to native OVA. On the other hand h-OVA stimulated higher IgG2a in sera and IFN-γ secretion by splenocytes. Conclusions Minor irreversible changes in OVA secondary structure caused by thermal processing changes both its digestion and antigenic epitopes formation, which leads to activation of different T cell subpopulations, induces shift towards Th1 response and ultimately reduces its allergenicity. PMID:22629361

Glucose transporters and enzymes related to glucose synthesis in small intestinal mucosa of mid-lactation dairy cows fed 2 levels of starch.

PubMed

Lohrenz, A-K; Duske, K; Schönhusen, U; Losand, B; Seyfert, H M; Metges, C C; Hammon, H M

2011-09-01

Diets containing corn starch may improve glucose supply by providing significant amounts of intestinal starch and increasing intestinal glucose absorption in dairy cows. Glucose absorption in the small intestine requires specific glucose transporters; that is, sodium-dependent glucose co-transporter-1 (SGLT1) and facilitated glucose transporter (GLUT2), which are usually downregulated in the small intestine of functional ruminants but are upregulated when luminal glucose is available. We tested the hypothesis that mRNA and protein expression of intestinal glucose transporters and mRNA expression of enzymes related to gluconeogenesis are affected by variable starch supply. Dairy cows (n=9/group) were fed for 4 wk total mixed rations (TMR) containing either high (HS) or low (LS) starch levels in the diet. Feed intake and milk yield were measured daily. After slaughter, tissue samples of the small intestinal mucosa (mid-duodenum and mid-jejunum) were taken for determination of mRNA concentrations of SGLT1 and GLUT2 as well as pyruvate carboxylase, cytosolic phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase by real-time reverse transcription PCR relative to a housekeeping gene. Protein expression of GLUT2 in crude mucosal membranes and of SGLT1 and GLUT2 in brush-border membrane vesicles was quantified by sodium dodecyl sulfate-PAGE and immunoblot. A mixed model was used to examine feeding and time-related changes on feed intake and milk yield and to test feeding and gut site effects on gene or protein expression of glucose transporters and enzymes in the intestinal mucosa. Dry matter intake, but not energy intake, was higher in cows fed HS compared with LS. Abundance of SGLT1 mRNA tended to be higher in duodenal than in jejunal mucosa, and mRNA abundances of pyruvate carboxylase tended to be higher in jejunal than in duodenal mucosa. In brush-border membrane vesicles, SGLT1 and GLUT2 protein expression could be demonstrated. No diet-dependent differences were found concerning mRNA and protein contents of glucose transporter or mRNA level of gluconeogenic enzymes. In conclusion, our investigations on glucose transporters and gluconeogenic enzymes in the small intestinal mucosa of dairy cows did not show significant diet regulation when TMR with different amounts of intestinal starch were fed. Therefore, predicted intestinal glucose absorption after enhanced starch feeding is probably not supported by changes of intestinal glucose transporters in dairy cows. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Role of Sphingolipids in Infant Gut Health and Immunity.

PubMed

Nilsson, Åke

2016-06-01

Sphingomyelin (SM), glycosphingolipids, and gangliosides are important polar lipids in the milk fat globule membrane but are not found in standard milk replacement formulas. Because digestion and absorption of SM and glycosphingolipids generate the bioactive metabolites ceramide, sphingosine, and sphingosine-1-phosphate (S1P), and because intact gangliosides may have beneficial effects in the gut, this may be important for gut integrity and immune maturation in the neonate. The brush border enzymes that hydrolyze milk SM, alkaline sphingomyelinase (nucleotide phosphodiesterase pyrophosphatase 7), and neutral ceramidase are expressed at birth in both term and preterm infants. Released sphingosine is absorbed, phosphorylated to S1P, and converted to palmitic acid via S1P-lyase in the gut mucosa. Hypothetically, S1P also may be released from absorptive cells and exert important paracrine actions favoring epithelial integrity and renewal, as well as immune function, including secretory IgA production and migration of T lymphocyte subpopulations. Gluco-, galacto-, and lactosylceramide are hydrolyzed to ceramide by lactase-phlorizin hydrolase, which also hydrolyzes lactose. Gangliosides may adhere to the brush border and is internalized, modified, and possibly transported into blood, and may exert protective functions by their interactions with bacteria, bacterial toxins, and the brush border. Copyright © 2016 Elsevier Inc. All rights reserved.

Binding of glycated ovocystatin to rat renal brush border membranes.

PubMed

Golab, Krzysztof; Gburek, Jakub; Konopska, Bogusława; Krotkiewski, Hubert; Warwas, Maria

2013-10-01

Glycated proteins are considered as one of the factors involved in the pathogenesis of diabetic complications, including nephropathy. These proteins are formed endogenously under conditions of hyperglycemia, as well as being provided with food containing sugars, which was subjected to high temperature. Examples are egg products. One of the proteins found in eggs in a relatively high concentration is chicken cystatin (ovocystatin). It is now believed that some proteins can passage the intestinal epithelium by transcytosis directly into the bloodstream. Thus, glycated protein present in food can be an additional source of glycotoxins. The aim of this study was to compare the affinity of native and glycated cystatin to the brush border membranes of rat kidney. Kinetic analysis was performed with surface plasmon resonance technique using sensor chip L1. Dissociation constants for native and glycated cystatin (Kd ) were 2.76 μmol/L and 3.82 μmol/L, respectively. The results of our study indicate that glycation only slightly affects binding of cystatin to brush border membranes. This suggests that glycated cystatin and other glycated proteins may also be efficiently taken up in the kidney proximal tubule. The observation may be important for understanding the mechanisms involved in the development of diabetic nephropathy. © 2013 Japanese Society of Animal Science.

Short-term fasting induces intra-hepatic lipid accumulation and decreases intestinal mass without reduced brush-border enzyme activity in mink (Mustela vison) small intestine.

PubMed

Bjornvad, C R; Elnif, J; Sangild, P T

2004-11-01

For many mammalian species short-term fasting is associated with intestinal atrophy and decreased digestive capacity. Under natural conditions, strictly carnivorous animals often experience prey scarcity during winter, and they may therefore be particularly well adapted to short-term food deprivation. To examine how the carnivorous gastrointestinal tract is affected by fasting, small-intestinal structure, brush-border enzyme activities and hepatic structure and function were examined in fed mink (controls) and mink that had been fasted for 1-10 days. During the first 1-2 days of fasting, intestinal mass decreased more rapidly than total body mass and villus heights were reduced 25-40%. In contrast, tissue-specific activity of the brush-border enzymes sucrase, maltase, lactase, aminopeptidase A and dipeptidylpeptidase IV increased 0.5- to 1.5-fold at this time, but returned to prefasting levels after 6 days of fasting. After 6-10 days of fasting there was a marked increase in the activity of hepatic enzymes and accumulation of intra-hepatic lipid vacuoles. Thus, mink may be a useful model for studying fasting-induced intestinal atrophy and adaptation as well as mechanisms involved in accumulation of intra-hepatic lipids following food deprivation in strictly carnivorous domestic mammals, such as cats and ferrets.

Intestinal epithelial cell surface glycosylation in mice. I. Effect of high-protein diet.

PubMed

Gupta, R; Jaswal, V M; Meenu Mahmood, A

1992-01-01

The effects of variation in dietary protein content have been investigated on brush border glycosylation and enzyme activities in mice small intestine. The comparison of different parameters was made between the mice fed 30% (high protein, HP) and 18% protein (pair-fed, PF, and ad libitum-fed) for 21 days. The activities of brush border sucrase, lactase, p-nitrophenyl (PNP)-beta-D-glucosidase and PNP-beta-D-galactosidase were reduced in the HP diet-fed mice compared to PF and ad libitum-fed controls. Alkaline phosphatase and leucine amino-peptidase activities were significantly enhanced while gamma-glutamyl transpeptidase activity was unaltered under these conditions. Total hexoses and sialic acid content in the brush borders were reduced significantly in the test group compared to the controls while hexosamine and fucose contents remained essentially similar in different groups. The results on the binding of wheat germ agglutinin and Ulex europaeus agglutininI to microvillus membranes corroborated the chemical analysis data on sialic acid and fucose contents of the membranes. Peanut agglutinin binding was enhanced in mice from the HP group. Incorporation of (14C)-mannose into membranes was significantly less in HP diet-fed mice. These results indicate that the feeding of HP diet to mice brings about marked alterations in small intestinal epithelial cell surface glycosylation and enzyme functions.

Role of specific activators of intestinal amino acid transport in Bombyx mori larval growth and nutrition.

PubMed

Leonardi, M G; Casartelli, M; Fiandra, L; Parenti, P; Giordana, B

2001-12-01

Nutrient absorption and its modulation are critical for animal growth. In this paper, we demonstrate that leucine methyl ester (Leu-OMe) can greatly increase the activity of the transport system responsible for the absorption of most essential amino acids in the larval midgut of the silkworm Bombyx mori. We investigated leucine uptake activation by Leu-OMe in brush border membrane vesicles and in the apical membrane of epithelial cells in the midgut incubated in vitro. Moreover, the addition of this strong activator of amino acid absorption to diet significantly affected larval growth. Silkworms fed on artificial diet supplemented with Leu-OMe reached maximum body weight 12-18 h before control larvae, and produced cocoon shells up to 20% heavier than those of controls. The activation of amino acid absorption plays an essential role in larval development so that larval growth and cocoon production similar to controls reared on an artificial diet with 25% of dry mulberry leaf powder were observed in silkworms fed on an artificial diet with only 5% of mulberry powder. Arch. Copyright 2001 Wiley-Liss, Inc.

Presence of the storage seed protein vicilin in internal organs of larval Callosobruchus maculatus (Coleoptera: Bruchidae).

PubMed

Uchôa, Adriana F; DaMatta, Renato A; Retamal, Claudio A; Albuquerque-Cunha, José M; Souza, Sheila M; Samuels, Richard I; Silva, Carlos P; Xavier-Filho, José

2006-02-01

Variant vicilins (7S storage globulins) of cowpea seeds (Vigna unguiculata) are considered as the main resistance factor present in some African genotypes against the bruchid Callosobruchus maculatus. It has been suggested that the toxic properties of vicilins may be related to their recognition and interaction with glycoproteins and other membrane constituents along the digestive tract of the insect. However, the possibility of a systemic effect has not yet been investigated. The objective of this work was to study the fate of 7S storage globulins of V. unguiculata in several organs of larvae of the cowpea weevil C. maculatus. Results demonstrated binding of vicilins to brush border membrane vesicles, suggesting the existence of specific receptors. Vicilins were detected in the haemolymph, in the midgut, and in internal organs, such as fat body and malpighian tubules. There is evidence of accumulation of vicilins in the fat body of both larvae and adults. The absorption of vicilins and their presence in insect tissues parallels classical sequestration of secondary compounds.

Compatibility of garlic (Allium sativum L.) leaf agglutinin and Cry1Ac δ-endotoxin for gene pyramiding.

PubMed

Upadhyay, Santosh Kumar; Singh, Seema; Chandrashekar, Krishnappa; Tuli, Rakesh; Singh, Pradhyumna Kumar

2012-03-01

δ-Endotoxins produced by Bacillus thuringiensis (Bt) have been used as bio-pesticides for the control of lepidopteran insect pests. Garlic (Allium sativum L.) leaf agglutinin (ASAL), being toxic to several sap-sucking pests and some lepidopteran pests, may be a good candidate for pyramiding with δ-endotoxins in transgenic plants for enhancing the range of resistance to insect pests. Since ASAL shares the midgut receptors with Cry1Ac in Helicoverpa armigera, there is possibility of antagonism in their toxicity. Our study demonstrated that ASAL increased the toxicity of Cry1Ac against H. armigera while Cry1Ac did not alter the toxicity of ASAL against cotton aphids. The two toxins interacted and increased binding of each other to brush border membrane vesicle (BBMV) proteins and to the two important receptors, alkaline phosphatase (ALP) and aminopeptidase N (APN). The results indicated that the toxins had different binding sites on the ALP and APN but influenced mutual binding. We conclude that ASAL can be safely employed with Cry1Ac for developing transgenic crops for wider insect resistance.

The In Ovo Feeding Administration (Gallus Gallus)—An Emerging In Vivo Approach to Assess Bioactive Compounds with Potential Nutritional Benefits

PubMed Central

2018-01-01

In recent years, the in ovo feeding in fertilized broiler (Gallus gallus) eggs approach was further developed and currently is widely applied in the evaluation process of the effects of functional foods (primarily plant origin compounds) on the functionality of the intestinal brush border membrane, as well as potential prebiotic properties and interactions with the intestinal microbial populations. This review collates the information of potential nutrients and their effects on the mineral absorption, gut development, brush border membrane functionality, and immune system. In addition, the advantages and limitations of the in ovo feeding method in the assessment of potential prebiotic effects of plant origin compounds is discussed. PMID:29597266

Electroneutral, HCO3(-)-independent, pH gradient-dependent uphill transport of Cl- by ileal brush-border membrane vesicles. Possible role in the pathogenesis of chloridorrhea.

PubMed Central

Vasseur, M; Caüzac, M; Alvarado, F

1989-01-01

By applying a rapid filtration technique to isolated brush border membrane vesicles from guinea pig ileum, 36Cl uptake was quantified in the presence and absence of electrical, pH and alkali-metal ion gradients. A mixture of 20 mM-Hepes and 40 mM-citric acid, adjusted to the desired pH with Tris base, was found to be the most suitable buffer. Malate and Mes could be used to replace the citrate, but succinate, acetate and maleate proved to be unsuitable. In the absence of a pH gradient (pHout:pHin = 7.5:7.5), Cl- uptake increased slightly when an inside-positive membrane potential was applied, but uphill transport was never observed. A pH gradient (pHout:pHin = 5.0:7.5) induced both a 400% increase in the initial Cl- influx rate and a long-lasting (20 to 300 s) overshoot, indicating that a proton gradient can furnish the driving force for uphill Cl- transport. Under pH gradient conditions, initial Cl- entry rates had the following characteristics. (1) They were unaffected by cis-Na+ and/or -K+, indicating the absence of Cl-/K+, Cl-/Na+ or Cl-/K+/Na+ symport activity. (2) Inhibition by 20-100 mM-trans-Na+ and/or -K+ occurred, independent of the existence of an ion gradient. (3) Cl- entry was practically unaffected by short-circuiting the membrane potential with equilibrated potassium and valinomycin. (4) Carbonyl cyanide m-chlorophenylhydrazone was strongly inhibitory and so, to a lesser extent, was 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid [(SITS)], independent of the sign and size of the membrane potential. (5) Cl- entry was negligibly increased (less than 30%) by either trans-Cl- or -HCO3-, indicating the absence of an obligatory Cl-/anion antiport activity. In contrast, the height of the overshoot at 60 s was increased by trans-Cl-, indicating time-dependent inhibition of 36Cl efflux. That competitive inhibition of 36Cl fluxes by anions is involved here is supported by initial influx rate experiments demonstrating: (1) the saturability of Cl- influx, which was found to exhibit Michaelis-Menten kinetics; and (2) competitive inhibition of influx by cis-Cl- and -Br-. Quantitatively, the conclusion is warranted that over 85% of the total initial Cl- uptake energized by a pH gradient involves an electroneutral Cl-/H+ symporter or its physicochemical equivalent, a Cl-/OH- antiporter, exhibiting little Cl- uniport and either Cl-/Cl- or Cl-/HCO3- antiport activities.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2597129

Phosphorous digestibility and activity of intestinal phytase in hybrid tilapia, Oreochromis niloticus X O. aureus

USGS Publications Warehouse

La Vorgna, M.W.; Hafez, Y.; Hughes, S.G.; Handwerker, T.

2003-01-01

Experiments were conducted to determine the degree to which phytate-bound phosphorus from plant protein sources could be used by hybrid tilapia (Oreochromis niloticus X O. aureus). Utilizing an inert marker technique with chromic oxide, hybrid tilapia in our study were effective at utilizing both inorganic and phytate phosphorus as evidenced by average apparent digestibility values of 93.2% and 90.0% for total and phytate phosphorus, respectively. Analysis of the intestinal brush border membrane of the tilapia revealed enzyme activity that was capable of hydrolyzing phytic acid. The presence of phytic acid hydrolyzing enzyme activity in the intestinal brush border provides a probable mechanism by which these hybrid tilapia are able to utilize phytate phosphorus effectively. ?? 2003 by The Haworth Press, Inc. All rights reserved.

Intestinal lactoferrin receptor: presence and specificity during development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, L.A.; Lonnerdal, B.L.

1986-03-01

As the major iron-binding protein in breast milk, lactoferrin (Lf) has been suggested to play a role in Fe absorption from milk. The authors previous work has validated the use of the Rhesus monkey as a model for studying this role of Lf. They have identified a specific Lf receptor on the brush border (BB) of juvenile Rhesus small intestine (s.i.) which may facilitate Fe uptake into the mucosal cell. In this study the authors examined the presence and specificity of the Lf receptor during development. BB membrane vesicles were prepared from fetal (113 d gestation), infant (3 m), andmore » adult (12 y) Rhesus s.i.; Binding assays were performed by incubating BB vesicles with 59-Fe-Lf and filtering through a 0.22 ..mu..m filter. The fetal and infant tissues were found to possess receptors with a high affinity for Lf. This early ontogeny indicates the importance of the receptor to the infant. Adult s.i. contained Lf receptors in all regions. Since the adult has no dietary intake of Lf, the receptor may play a role in Fe homeostasis via biliary Lf excretion or may simply continue to be expressed throughout life. The receptors were examined for their affinity for purified bovine Lf and human transferrin, both of which are similar in structure to Lf. No binding was found for either, demonstrating the specificity of the receptor for Lf. The presence of the Lf receptor in fetal tissue and its specificity for Lf implies it is essential for adequate Fe nutrition of the suckling infant.« less

Role of the Na+/H+ antiporter in rat proximal tubule bicarbonate absorption.

PubMed Central

Preisig, P A; Ives, H E; Cragoe, E J; Alpern, R J; Rector, F C

1987-01-01

Amiloride and the more potent amiloride analog, 5-(N-t-butyl) amiloride (t-butylamiloride), were used to examine the role of the Na+/H+ antiporter in bicarbonate absorption in the in vivo microperfused rat proximal convoluted tubule. Bicarbonate absorption was inhibited 29, 46, and 47% by 0.9 mM or 4.3 mM amiloride, or 1 mM t-butylamiloride, respectively. Sensitivity of the Na+/H+ antiporter to these compounds in vivo was examined using fluorescent measurements of intracellular pH with (2', 7')-bis(carboxyethyl)-(5,6)-carboxyfluorescein (BCECF). Amiloride and t-butylamiloride were shown to be as potent against the antiporter in vivo as in brush border membrane vesicles. A model of proximal tubule bicarbonate absorption was used to correct for changes in the luminal profiles for pH and inhibitor concentration, and for changes in luminal flow rate in the various series. We conclude that the majority of apical membrane proton secretion involved in transepithelial bicarbonate absorption is mediated by the Na+-dependent, amiloride-sensitive Na+H+ antiporter. However, a second mechanism of proton secretion contributes significantly to bicarbonate absorption. This mechanism is Na+-independent and amiloride-insensitive. PMID:2888788

Phosphatidylethanolamine N-methyltransferase activity is increased in rat intestinal brush-border membrane by chronic ethanol ingestion.

PubMed

Furtado, Valéria Cristina Soares; Takiya, Christina Maeda; Braulio, Valeria Bender

2002-01-01

Phosphatidylethanolamine N-methyltransferase (PEMT) catalyses the synthesis of phosphatidylcholine from phosphatidylethanolamine. The aim of this study was to evaluate the effect of chronic ethanol ingestion on PEMT activity in the jejunal brush-border membrane (BBM) of adequately nourished rats. For this purpose, rats were fed a liquid diet containing ethanol [ethanol-fed group (EFG)] or an isocaloric liquid diet without ethanol [pair-fed group (PFG)] for 4 weeks. Diet ingestion, body weight, nitrogen balance and urinary creatinine excretion were monitored during the experimental period, and serum transferrin levels were determined at the end. BBM was isolated for the determination of PEMT activity. PEMT activity was significantly increased in the jejunal BBM of the EFG. Nutritional parameters, however, did not differ between groups. The increase in PEMT activity may be attributed exclusively to chronic ethanol ingestion, since a major nutritional deficit was excluded.

Differential interaction of Escherichia coli heat-labile toxin and cholera toxin with pig intestinal brush border glycoproteins depending on their ABH and related blood group antigenic determinants.

PubMed

Balanzino, L E; Barra, J L; Monferran, C G; Cumar, F A

1994-04-01

The ability of glycoproteins from pig intestinal brush border membranes (BBM) to bind cholera toxin (CT) or heat-labile toxins from strains of Escherichia coli isolated from human (LTh) or pig (LTp) intestines was studied. Glycoproteins capable of binding the toxins are also recognized by antibodies or lectins specific for ABO(H) blood group and related antigens. Pigs expressing A, H, or I antigenic determinants were used for comparison. The toxin-binding capacity of a glycoprotein depends on the toxin type and the blood group epitope borne by the glycoprotein. LTh and LTp preferably bound to several blood group A-active glycoproteins rather than H-active glycoproteins. By contrast, CT practically did not recognize either blood group A- or blood group H-active glycoproteins, while glycoproteins from pigs expressing I antigenic determinants were able to interact with LTh, LTp, and CT. LTh, LTp, or CT glycoprotein binding was selectively inhibited by specific lectins or monosaccharides. Affinity purification of the toxin binding brush border glycoproteins on the basis of their blood group reactivity suggests that such glycoproteins are hydrolytic enzymes. BBM from A+ pigs contain about 27 times more LTh binding sites, in addition to those recognized by CT, than an equivalent membrane preparation from H+ pigs. The present findings may help clarify some previous unclear results on LTh binding to intestinal BBM glycoproteins obtained by use of animals not typed by their ABO(H) blood group phenotype.

Microimaging of Bacillus thuringiensis Toxin-binding proteins in gypsy moth larval gut using confocal fluorescence microscopy

Treesearch

Daniel J. Krofcheck; Algimantas P. Valaitis

2010-01-01

After ingestion by susceptible insect larvae, Bacillus thuringiensis (Bt) insecticidal proteins bind to the brush border membranes of gut epithelial cells and disrupt the integrity of the plasma membrane by forming...

The mRNA expression of amino acid and sugar transporters, aminopeptidase, as well as the di- and tri-peptide transporter PepT1 in the intestines of Eimeria infected broiler chickens.

PubMed

Miska, K B; Fetterer, R H

2017-02-01

Coccidiosis in chickens is caused by infection of gut epithelial cells with protozoan parasites of the genus Eimeria This disease causes losses to the poultry industry since infected birds fail to gain weight as rapidly as non-infected birds and efficiency of feed conversion is compromised. For the present study the effect of Eimeria on expression of components of amino acid and sugar uptake mechanisms was determined. Broiler chicks were infected with Eimeria maxima, which infects the jejunum; Eimeria acervulina, which infects the duodenum; or Eimeria tenella, which infects the ceca. Sections of the jejunum, duodenum, and ceca (depending on species of Eimeria) were taken at several time points between d zero and 14 post infection (PI) for mRNA expression analysis. Genes examined included one digestive enzyme, 7 peptide and amino acid transporters located on the brush border, 8 transporters located at the basolateral surface of the gut epithelium, and 5 sugar transporters. All 3 Eimeria species examined caused decrease in expression of brush border transporters particularly at d 5 to 7 PI, which corresponds to the time when pathology is greatest. The same pattern was seen in expression of sugar transporters. However, the expression of basolateral transporters differed among species. Eimeria tenella infection resulted in decreased expression of all basolateral transporters, while E. maxima infection caused increased expression of 2 genes and slight decrease in expression of the remaining 5 genes. Infection with E. acervulina resulted in increased expression at the height of infection of all but one basolateral transporter. In conclusion, Eimeria infection causes a general decrease in gene expression of sugar transporter and brush border AATs at the height of infection. However the expression of basolateral transporters is increased in E. maxima and E. acervulina infected birds. It is possible that decreased expression of brush border transporters in combination with increased expression of basolateral transporters leads to decrease of nutrients available for the parasite, thus limiting parasite reproduction. Published by Oxford University Press on behalf of Poultry Science Association 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Sulfate-chloride exchange by lobster hepatopancreas is regulated by pH-sensitive modifier sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cattey, M.A.; Ahearn, G.A.; Gerencser, G.A.

1991-03-15

{sup 35}SO{sub 4}{sup 2{minus}} uptake by Atlantic lobster (Homarus americanus) hepatopancreatic epithelial brush border membrane vesicles (BBMV) was stimulated by internal Cl{sup {minus}}, but not internal HCO{sub 3}{sup {minus}}, or external Na{sup +}. Sulfate-chloride exchange was stimulated by inside positive, and inhibited by inside negative, trans-membrane K diffusion potentials. {sup 35}SO{sub 4}{sup 2{minus}}-Cl{sup {minus}} exchange was strongly inhibited by 4,4{prime} diisothiocyanostilbene-2,2{prime}-disulfonic acid (DIDS), 4-acetamido-4{prime}-isotheocynaostilbene-2,2{prime}-disulfonic acid, (SITS), and thiosulfate. Chloride, bicarbonate, furosamide, and bumetanide slightly, yet significantly, cis-inhibited {sup 35}SO{sub 4}{sup 2{minus}}-Cl{sup {minus}} exchange. Altering bilateral pH from 8.0 to 5.4 stimulated {sup 35}SO{sub 4}{sup 2{minus}}-Cl{sup {minus}} exchange when vesicles weremore » loaded with Cl{sup {minus}}, but reduced bilateral pH alone or the presence of pH gradients did not affect {sup 35}SO{sub 4}{sup 2{minus}} transport in the absence of internal Cl{sup {minus}}. {sup 36}Cl uptake into SO{sub 4}{sup 2{minus}}-loaded BBMV was stimulated by an internal negative membrane potential and inhibited when the interior was electrically positive. A model is proposed which suggests that SO{sub 4}{sup 2{minus}}-Cl{sup {minus}} exchange is regulated by internal and external pH-sensitive modifier sites on the anion antiporter and by coupling to the electrogenic 2 Na{sup +}/1 H{sup +} antiporter and by coupling to the electrogenic 2 Na{sup +}/1 H{sup +} antiporter on the same membrane.« less

A fluorescence method for determination of glucose transport by intestinal BBMV of common carp.

PubMed

Yang, Li-Ping; Yan, Xiao; Zheng, Wen-Jia; Hu, Jun-Yi; Zhang, Yu-Ru; Qin, Chao-Bin; Meng, Xiao-Lin; Lu, Rong-Hua; Chen, Fang; Xie, Di-Zhi; Nie, Guo-Xing

2017-11-15

Epithelial brush-border membrane vesicles (BBMVs) were isolated from the intestine of common carp and studied systematically by enzyme activity, transmission electron microscopy and immunoblotting. The uptake time course and the substrate concentration effect were assessed, and then, the ability of phlorizin and cytochalasin B to inhibit uptake was analyzed. The results show that sucrase, alkaline phosphatase and Na + -K + -ATPase activities in these vesicles were enriched 7.94-, 6.74- and 0.42-fold, respectively, indicating a relatively pure preparation of apical membrane with little basolateral contamination. The vesicular structure was in complete closure, as confirmed by electron microscopy. The presence of SGLT1 on the BBMVs was confirmed by Western blot analysis. In the time course experiment, the glucose uptake by BBMVs in Na + medium displayed an initial accumulation (overshoot) at 5 min followed by a rapid return to equilibrium values at 60 min. Over the 2-NBDG concentration range selected, the external 2-NBDG concentration in NaSCN medium graphed as a curved line. Phlorizin and cytochalasin B had an obvious inhibitory effect on 2-NBDG transport in carp BBMVs, and the detected fluorescence intensity decreased. The inhibition rate in the 1000 μM group was the strongest at 64.18% and 63.61% of phlorizin and cytochalasin B, respectively, indicating the presence of carriers other than SGLT1. This study is the first to demonstrate that 2-NBDG can be used as a convenient and sensitive probe to detect glucose uptake in fish BBMVs. This technology will provide a convenient method to discover new effects and factors in glucose metabolism. Copyright © 2017. Published by Elsevier Inc.

Acetylated sialic acid residues and blood group antigens localise within the epithelium in microvillous atrophy indicating internal accumulation of the glycocalyx

PubMed Central

Phillips, A D; Brown, A; Hicks, S; Schüller, S; Murch, S H; Walker-Smith, J A; Swallow, D M

2004-01-01

Background: Microvillous atrophy, a disorder of intractable diarrhoea in infancy, is characterised by the intestinal epithelial cell abnormalities of abnormal accumulation of periodic acid-Schiff (PAS) positive secretory granules within the apical cytoplasm and the presence of microvillous inclusions. The identity of the PAS positive material is not known, and the aim of this paper was to further investigate its composition. Methods: Formaldehyde fixed sections were stained with alcian blue/PAS to identify the acidic or neutral nature of the material, phenylhydrazine blocking was employed to stain specifically for sialic acid, and saponification determined the presence of sialic acid acetylation. The specificity of sialic acid staining was tested by digestion with mild sulphuric acid. Expression of blood group related antigens was tested immunochemically. Results: Alcian blue/PAS staining identified a closely apposed layer of acidic material on the otherwise neutral (PAS positive) brush border in controls. In microvillous atrophy, a triple layer was seen with an outer acidic layer, an unstained brush border region, and accumulation within the epithelium of a neutral glycosubstance that contained acetylated sialic acid. Blood group antigens were detected on the brush border, in mucus, and within goblet cells in controls. In microvillous atrophy they were additionally expressed within the apical cytoplasm of epithelial cells mirroring the PAS abnormality. Immuno electron microscopy localised expression to secretory granules. Conclusions: A neutral, blood group antigen positive, glycosubstance that contains acetylated sialic acid accumulates in the epithelium in microvillous atrophy. Previous studies have demonstrated that the direct and indirect constitutive pathways are intact in this disorder and it is speculated that the abnormal staining pattern reflects accumulation of glycocalyx related material. PMID:15542511

Intestinal alkaline phosphatase regulates protective surface microclimate pH in rat duodenum.

PubMed

Mizumori, Misa; Ham, Maggie; Guth, Paul H; Engel, Eli; Kaunitz, Jonathan D; Akiba, Yasutada

2009-07-15

Regulation of localized extracellular pH (pH(o)) maintains normal organ function. An alkaline microclimate overlying the duodenal enterocyte brush border protects the mucosa from luminal acid. We hypothesized that intestinal alkaline phosphatase (IAP) regulates pH(o) due to pH-sensitive ATP hydrolysis as part of an ecto-purinergic pH regulatory system, comprised of cell-surface P2Y receptors and ATP-stimulated duodenal bicarbonate secretion (DBS). To test this hypothesis, we measured DBS in a perfused rat duodenal loop, examining the effect of the competitive alkaline phosphatase inhibitor glycerol phosphate (GP), the ecto-nucleoside triphosphate diphosphohydrolase inhibitor ARL67156, and exogenous nucleotides or P2 receptor agonists on DBS. Furthermore, we measured perfusate ATP concentration with a luciferin-luciferase bioassay. IAP inhibition increased DBS and luminal ATP output. Increased luminal ATP output was partially CFTR dependent, but was not due to cellular injury. Immunofluorescence localized the P2Y(1) receptor to the brush border membrane of duodenal villi. The P2Y(1) agonist 2-methylthio-ADP increased DBS, whereas the P2Y(1) antagonist MRS2179 reduced ATP- or GP-induced DBS. Acid perfusion augmented DBS and ATP release, further enhanced by the IAP inhibitor l-cysteine, and reduced by the exogenous ATPase apyrase. Furthermore, MRS2179 or the highly selective P2Y(1) antagonist MRS2500 co-perfused with acid induced epithelial injury, suggesting that IAP/ATP/P2Y signalling protects the mucosa from acid injury. Increased DBS augments IAP activity presumably by raising pH(o), increasing the rate of ATP degradation, decreasing ATP-mediated DBS, forming a negative feedback loop. The duodenal epithelial brush border IAP-P2Y-HCO(3-) surface microclimate pH regulatory system effectively protects the mucosa from acid injury.

Binding specificity of Bacillus thuringiensis Cry1Aa for purified, native Bombyx mori aminopeptidase N and cadherin-like receptors

PubMed Central

Jenkins, Jeremy L; Dean, Donald H

2001-01-01

Background To better understand the molecular interactions of Bt toxins with non-target insects, we have examined the real-time binding specificity and affinity of Cry1 toxins to native silkworm (Bombyx mori) midgut receptors. Previous studies on B. mori receptors utilized brush border membrane vesicles or purifed receptors in blot-type assays. Results The Bombyx mori (silkworm) aminopeptidase N (APN) and cadherin-like receptors for Bacillus thuringiensis insecticidal Cry1Aa toxin were purified and their real-time binding affinities for Cry toxins were examined by surface plasmon resonance. Cry1Ab and Cry1Ac toxins did not bind to the immobilized native receptors, correlating with their low toxicities. Cry1Aa displayed moderate affinity for B. mori APN (75 nM), and unusually tight binding to the cadherin-like receptor (2.6 nM), which results from slow dissociation rates. The binding of a hybrid toxin (Aa/Aa/Ac) was identical to Cry1Aa. Conclusions These results indicate domain II of Cry1Aa is essential for binding to native B. mori receptors and for toxicity. Moreover, the high-affinity binding of Cry1Aa to native cadherin-like receptor emphasizes the importance of this receptor class for Bt toxin research. PMID:11722800

Ontogeny of NHE8 in the rat proximal tubule

PubMed Central

Becker, Amy M.; Zhang, Jianning; Goyal, Sunita; Dwarakanath, Vangipuram; Aronson, Peter S.; Moe, Orson W.; Baum, Michel

2014-01-01

Proximal tubule bicarbonate reabsorption is primarily mediated via the Na+/H+ exchanger, identified as NHE3 in adults. Previous studies have demonstrated a maturational increase in rat proximal tubule NHE3 expression, with a paucity of NHE3 expression in neonates, despite significant Na+-dependent proton secretion. Recently, a novel Na+/H+ antiporter (NHE8) was identified and found to be expressed on the apical membrane of the proximal tubule. To determine whether NHE8 may be the antiporter responsible for proton secretion in neonates, the present study characterized the developmental expression of NHE8 in rat proximal tubules. RNA blots and real-time RT-PCR demonstrated no developmental difference in the mRNA of renal NHE8. Immunoblots, however, demonstrated peak protein abundance of NHE8 in brush border membrane vesicles of 7- and 14-day-old compared with adult rats. In contrast, the level of NHE8 expression in total cortical membrane protein was higher in adults than in neonates. Immunohistochemistry confirmed the presence of NHE8 on the apical membrane of the proximal tubules of neonatal and adult rats. These data demonstrate that NHE8 does undergo maturational changes on the apical membrane of the rat proximal tubule and may account for the Na+-dependent proton flux in neonatal proximal tubules. PMID:17429030

Possible Insecticidal Mechanisms Mediated by Immune-Response-Related Cry-Binding Proteins in the Midgut Juice of Plutella xylostella and Spodoptera exigua.

PubMed

Lu, Keyu; Gu, Yuqing; Liu, Xiaoping; Lin, Yi; Yu, Xiao-Qiang

2017-03-15

Cry toxins are insecticidal toxin proteins produced by a spore-forming Gram-positive bacterium Bacillus thuringiensis. Interactions between the Cry toxins and the receptors from midgut brush border membrane vesicles (BBMVs), such as cadherin, alkaline phosphatase, and aminopeptidase, are key steps for the specificity and insecticidal activity of Cry proteins. However, little is known about the midgut juice proteins that may interfere with Cry binding to the receptors. To validate the hypothesis that there exist Cry-binding proteins that can interfere with the insecticidal process of Cry toxins, we applied Cry1Ab1-coupled Sepharose beads to isolate Cry-binding proteins form midgut juice of Plutella xylostella and Spodoptera exigua. Trypsin-like serine proteases and Dorsal were found to be Cry1Ab1-binding proteins in the midgut juice of P. xylostella. Peroxidase-C (POX-C) was found to be the Cry1Ab1-binding protein in the midgut juice of S. exigua. We proposed possible insecticidal mechanisms of Cry1Ab1 mediated by the two immune-related proteins: Dorsal and POX-C. Our results suggested that there exist, in the midgut juice, Cry-binding proteins, which are different from BBMV-specific receptors.

Impaired nutrient signaling and body weight control in a Na+ neutral amino acid cotransporter (Slc6a19)-deficient mouse.

PubMed

Bröer, Angelika; Juelich, Torsten; Vanslambrouck, Jessica M; Tietze, Nadine; Solomon, Peter S; Holst, Jeff; Bailey, Charles G; Rasko, John E J; Bröer, Stefan

2011-07-29

Amino acid uptake in the intestine and kidney is mediated by a variety of amino acid transporters. To understand the role of epithelial neutral amino acid uptake in whole body homeostasis, we analyzed mice lacking the apical broad-spectrum neutral (0) amino acid transporter B(0)AT1 (Slc6a19). A general neutral aminoaciduria was observed similar to human Hartnup disorder which is caused by mutations in SLC6A19. Na(+)-dependent uptake of neutral amino acids into the intestine and renal brush-border membrane vesicles was abolished. No compensatory increase of peptide transport or other neutral amino acid transporters was detected. Mice lacking B(0)AT1 showed a reduced body weight. When adapted to a standard 20% protein diet, B(0)AT1-deficient mice lost body weight rapidly on diets containing 6 or 40% protein. Secretion of insulin in response to food ingestion after fasting was blunted. In the intestine, amino acid signaling to the mammalian target of rapamycin (mTOR) pathway was reduced, whereas the GCN2/ATF4 stress response pathway was activated, indicating amino acid deprivation in epithelial cells. The results demonstrate that epithelial amino acid uptake is essential for optimal growth and body weight regulation.

Sirolimus Induced Phosphaturia is Not Caused by Inhibition of Renal Apical Sodium Phosphate Cotransporters

PubMed Central

Haller, Maria; Amatschek, Stefan; Wilflingseder, Julia; Kainz, Alexander; Bielesz, Bernd; Pavik, Ivana; Serra, Andreas; Mohebbi, Nilufar; Biber, Jürg; Wagner, Carsten A.; Oberbauer, Rainer

2012-01-01

The vast majority of glomerular filtrated phosphate is reabsorbed in the proximal tubule. Posttransplant phosphaturia is common and aggravated by sirolimus immunosuppression. The cause of sirolimus induced phosphaturia however remains elusive. Male Wistar rats received sirolimus or vehicle for 2 or 7 days (1.5mg/kg). The urine phosphate/creatinine ratio was higher and serum phosphate was lower in sirolimus treated rats, fractional excretion of phosphate was elevated and renal tubular phosphate reabsorption was reduced suggesting a renal cause for hypophosphatemia. PTH was lower in sirolimus treated rats. FGF 23 levels were unchanged at day 2 but lower in sirolimus treated rats after 7 days. Brush border membrane vesicle phosphate uptake was not altered in sirolimus treated groups or by direct incubation with sirolimus. mRNA, protein abundance, and subcellular transporter distribution of NaPi-IIa, Pit-2 and NHE3 were not different between groups but NaPi-IIc mRNA expression was lower at day 7. Transcriptome analyses revealed candidate genes that could be involved in the phosphaturic response. Sirolimus caused a selective renal phosphate leakage, which was not mediated by NaPi-IIa or NaPi-IIc regulation or localization. We hypothesize that another mechanism such as a basolateral phosphate transporter may be responsible for the sirolimus induced phosphaturia. PMID:22859939

Evidence of native starch degradation with human small intestinal maltase-glucoamylase (recombinant)

USDA-ARS?s Scientific Manuscript database

Action of human small intestinal brush border carbohydrate digesting enzymes is thought to involve only final hydrolysis reactions of oligosaccharides to monosaccharides. In vitro starch digestibility assays use fungal amyloglucosidase to provide this function. In this study, recombinant N-terminal ...

The PDZ domain of the guanine nucleotide exchange factor PDZGEF directs binding to phosphatidic acid during brush border formation.

PubMed

Consonni, Sarah V; Brouwer, Patricia M; van Slobbe, Eleonora S; Bos, Johannes L

2014-01-01

PDZGEF is a guanine nucleotide exchange factor for the small G protein Rap. It was recently found that PDZGEF contributes to establishment of intestinal epithelial polarity downstream of the kinase Lkb1. By binding to phosphatidic acid enriched at the apical membrane, PDZGEF locally activates Rap2a resulting in induction of brush border formation via a pathway that includes the polarity players TNIK, Mst4 and Ezrin. Here we show that the PDZ domain of PDZGEF is essential and sufficient for targeting PDZGEF to the apical membrane of polarized intestinal epithelial cells. Inhibition of PLD and consequently production of phosphatidic acid inhibitis targeting of PDZGEF to the plasma membrane. Furthermore, localization requires specific positively charged residues within the PDZ domain. We conclude that local accumulation of PDZGEF at the apical membrane during establishment of epithelial polarity is mediated by electrostatic interactions between positively charged side chains in the PDZ domain and negatively charged phosphatidic acid.

The PDZ Domain of the Guanine Nucleotide Exchange Factor PDZGEF Directs Binding to Phosphatidic Acid during Brush Border Formation

PubMed Central

Consonni, Sarah V.; Brouwer, Patricia M.; van Slobbe, Eleonora S.; Bos, Johannes L.

2014-01-01

PDZGEF is a guanine nucleotide exchange factor for the small G protein Rap. It was recently found that PDZGEF contributes to establishment of intestinal epithelial polarity downstream of the kinase Lkb1. By binding to phosphatidic acid enriched at the apical membrane, PDZGEF locally activates Rap2a resulting in induction of brush border formation via a pathway that includes the polarity players TNIK, Mst4 and Ezrin. Here we show that the PDZ domain of PDZGEF is essential and sufficient for targeting PDZGEF to the apical membrane of polarized intestinal epithelial cells. Inhibition of PLD and consequently production of phosphatidic acid inhibitis targeting of PDZGEF to the plasma membrane. Furthermore, localization requires specific positively charged residues within the PDZ domain. We conclude that local accumulation of PDZGEF at the apical membrane during establishment of epithelial polarity is mediated by electrostatic interactions between positively charged side chains in the PDZ domain and negatively charged phosphatidic acid. PMID:24858808

[Kinetic properties of the fructose influx across the brush border of the rat jejunum. Effects of a diet rich in fructose].

PubMed

Crouzoulon, G

1978-10-01

The unidirectional influx (i.e. initial rate of uptake) of D-fructose across the brush border of rat jejunum is a saturable function of concentration, with a Kt of 125 mM, which implicates a carrier mechanism. This mechanism appears to be very specific for fructose in view of the lack of influx inhibition observed in the presence of large concentrations of the sugars or polyols, D-glucose, D-galactose, D-mannose, D-xylose, L-sorbose, D-tagatose, sorbitol or mannitol. D-Fructose uptake is inhibited by incubation, preceded by a 30-min preincubation in the same inhibitory conditions, in the absence of Na, or in the presence of metabolic poisons, NaF, 2,4-dinitrophenol, monoiodoacetate. Phloridzin (10-3 M), with or without preincubation, has no effect on uptake. D-Fructose influx is stimulated by fructose feeding, mainly because the augmentation of the number of active sites of transfer: Jmax is increased two-fold, Kt is more weakly affected.

Kinetic Measurements of Di- and Tripeptide and Peptidomimetic Drug Transport in Different Kidney Regions Using the Fluorescent Membrane Potential-Sensitive Dye, DiS-C3-(3).

PubMed

Alghamdi, Othman A; King, Nicola; Jones, Graham L; Moens, Pierre D J

2017-12-01

Tri- and dipeptides are transported in the kidney by PEPT1 and PEPT2 isoforms. The aim of this study was to investigate differences in transport kinetics between renal brush border (BBMV) and outer medulla (OMMV) membrane vesicles (where PEPT1 and PEPT2 are sequentially available) for a range of di- and tripeptides and peptidomimetic drugs. This was accomplished through the use of the potential-sensitive fluorescent dye 3,3'-dipropylthiacarbocyanine iodide [DiS-C 3 -(3)]. BBMV and OMMV were prepared from the rat kidney using standard techniques. The presence of PEPT1 in BBMV and PEPT2 in OMMV was confirmed using Western blotting. Fluorescence changes were measured when extravesicular medium at pH 6.6 containing 0-1 mM substrates was added to a cuvette containing vesicles pre-equilibrated at pH 7.4 and 2.71 μM DiS-C 3 -(3). An increase in fluorescence intensity occurred upon substrate addition reflecting the expected positive change in membrane potential difference. Of the range of substrates studied, OMMV manifested the highest affinity to cefadroxil and valacyclovir (K m 4.3 ± 1.2 and 11.7 ± 3.2 µM, respectively) compared to other substrates, whilst the BBMV showed a higher affinity to Gly-His (K m 15.4 ± 3.1 µM) compared to other substrates. In addition, OMMV showed higher affinity and capacity to Gly-Gln (K m 47.1 ± 9.8 µM, 55.5 ± 2.8 ΔF/s/mg protein) than BBMV (K m 78.1 ± 13.3 µM and 35.5 ± 1.7 ΔF/s/mg protein, respectively). In conclusion, this study successfully separated the expression of PEPT1 and PEPT2 into different vesicle preparations inferring their activity in different regions of the renal proximal tubule.

Alterations in gut microflora populations and brush border functionality following intra-amniotic daidzein administration

USDA-ARS?s Scientific Manuscript database

Daidzein is an isoflavone found primarily in soybean and various soy-based products such as tofu. In the intestines, daidzein is reductively transformed to its constituent metabolites equol and O-desmethylangolensin. Although the ingestion of daidzein has been associated with marked physiological im...

CHARACTERIZATION OF A BRUSH BORDER FERRIREDUCTASE IN LOBSTER HEPATOPANCREATIC EPITHELIAL CELLS AND ITS POSSIBLE ROLE IN IRON TRANSPORT. (R823068)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

New sterically stabilized vesicles based on nonionic surfactant, cholesterol, and poly(ethylene glycol)-cholesterol conjugates.

PubMed Central

Beugin, S; Edwards, K; Karlsson, G; Ollivon, M; Lesieur, S

1998-01-01

Monomethoxypoly(ethylene glycol) cholesteryl carbonates (M-PEG-Chol) with polymer chain molecular weights of 1000 (M-PEG1000-Chol) and 2000 (M-PEG2000-Chol) have been newly synthesized and characterized. Their aggregation behavior in mixture with diglycerol hexadecyl ether (C16G2) and cholesterol has been examined by cryotransmission electron microscopy, high-performance gel exclusion chromatography, and quasielastic light scattering. Nonaggregated, stable, unilamellar vesicles were obtained at low polymer levels with optimal shape and size homogeneity at cholesteryl conjugate/ lipids ratios of 10 mol% M-PEG1000-Chol or 5 mol% M-PEG2000-Chol, corresponding to the theoretically predicted brush conformational state of the PEG chains. At 20 mol% M-PEG1000-Chol or 10 mol% M-PEG2000-Chol, the saturation threshold of the C16G2/cholesterol membrane in polymer is exceeded, and open disk-shaped aggregates are seen in coexistence with closed vesicles. Higher levels up to 30 mol% lead to the complete solubilization of the vesicles into disk-like structures of decreasing size with increasing PEG content. This study underlines the bivalent role of M-PEG-Chol derivatives: while behaving as solubilizing surfactants, they provide an efficient steric barrier, preventing the vesicles from aggregation and fusion over a period of at least 2 weeks. PMID:9635773

Flexibility contra Stiffness: The Phragmoplast as a Physical Barrier for Beads But Not for Vesicles[OA

PubMed Central

Esseling-Ozdoba, Agnieszka; Kik, Richard A.; van Lammeren, André A.M.; Kleijn, J. Mieke; Emons, Anne Mie C.

2010-01-01

In plant cells, Golgi vesicles are transported to the division plane to fuse with each other, forming the cell plate, the initial membrane-bordered cell wall separating daughter cells. Vesicles, but not organelles, move through the phragmoplast, which consists of two opposing cylinders of microtubules and actin filaments, interlaced with endoplasmic reticulum membrane. To study physical aspects of this transport/inhibition process, we microinjected fluorescent synthetic 1,2-dioleoyl-sn-glycero-3-phospho-rac-1-glycerol (DOPG) vesicles and polystyrene beads into Tradescantia virginiana stamen hair cells. The phragmoplast was nonselective for DOPG vesicles of a size up to 150 nm in diameter but was a physical barrier for polystyrene beads having a diameter of 20 and 40 nm and also when beads were coated with the same DOPG membrane. We conclude that stiffness is a parameter for vesicle transit through the phragmoplast and discuss that cytoskeleton configurations can physically block such transit. PMID:19939943

Histochemical study of lectin binding sites in fourth and fifth instar gypsy moth larval midgut epithelium

Treesearch

Algimantas P. Valaitis

2011-01-01

There is evidence that the gypsy moth, Lymantria dispar, midgut epithelial brush border membrane has membrane-bound glycoconjugates, such as BTR-270 and aminopeptidase N (APN), which function as high affinity binding sites (receptors) for the insecticidal proteins produced by Bacillus thuringiensis (Bt). As gypsy...

Tracking the fate of pasta (T. Durum semolina) immunogenic proteins by in vitro simulated digestion.

PubMed

Mamone, Gianfranco; Nitride, Chiara; Picariello, Gianluca; Addeo, Francesco; Ferranti, Pasquale; Mackie, Alan

2015-03-18

The aim of the present study was to identify and characterize the celiacogenic/immunogenic proteins and peptides released during digestion of pasta (Triticum durum semolina). Cooked pasta was digested using a harmonized in vitro static model of oral-gastro-duodenal digestion. The course of pasta protein digestion was monitored by SDS-PAGE, and gluten proteins were specifically analyzed by Western blot using sera of celiac patients. Among the allergens, nonspecific lipid-transfer protein was highly resistant to gastro-duodenal hydrolysis, while other digestion-stable allergens such as α-amylase/trypsin inhibitors were not detected being totally released in the pasta cooking water. To simulate the final stage of intestinal degradation, the gastro-duodenal digesta were incubated with porcine jejunal brush-border membrane hydrolases. Sixty-one peptides surviving the brush-border membrane peptidases were identified by liquid chromatography-mass spectrometry, including several gluten-derived sequences encrypting different motifs responsible for the induction of celiac disease. These results provide new insights into the persistence of wheat-derived peptides during digestion of cooked pasta samples.

Localization of the action of cholera toxin on adenyl cyclase in mucosal epithelial cells of rabbit intestine

PubMed Central

Parkinson, David K.; Ebel, Hans; DiBona, Donald R.; Sharp, Geoffrey W. G.

1972-01-01

Brush borders and plasma membranes have been purified from mucosal epithelial cells of rabbit ileum under control conditions and after treatment for 3 hr with cholera toxin in vivo. The activity of several enzymes in these preparations was measured. It was concluded that adenyl cyclase, like NaK-ATPase, seems not to be a normal constituent of brush borders. Both these enzymes are present in plasma membrane preparations derived largely from the basal and lateral margins of the epithelial cells, both may be phospholipid dependent enzymes and both are affected by cholera toxin. Adenyl cyclase activity is increased while NaK-ATPase is decreased. The activities of alkaline phosphatase, leucineaminopeptidase, 5′-nucleotidase, glucose-6-phosphatase, and Mg-ATPase were not found to be affected by the toxin. Cholera toxin, which makes contact with the luminal side of the epithelial cells, in the natural disease and in the experimental model, would appear to exert its pathologic effect on adenyl cyclase at the opposite (basal and lateral) side of the cells. Images PMID:4344729

Regulation of protein expression and function of octn2 in forskolin-induced syncytialization in BeWo Cells.

PubMed

Huang, F-D; Kung, F-L; Tseng, Y-C; Chen, M-R; Chan, H-S; Lin, C-J

2009-02-01

Placental OCTN2 is a high-affinity carnitine transporter that can interact with a number of therapeutic agents. The process of syncytialization is associated with the expression of a variety of genes. However, the association between syncytialization and OCTN2 expression is not yet clear. Given that forskolin induces BeWo cells to undergo biochemical and morphological differentiation, the purpose of the present study was to investigate whether the function and expression of OCTN2 are influenced by forskolin treatment during syncytialization. The forskolin-induced differentiation of BeWo cells was validated by secretion of beta-human chorionic gonadotropin (beta-hCG) and syncytin expression. Cellular localization of OCTN2 was analyzed by confocal microscopy. Expression of OCTN2 and the modular proteins PDZK1, PDZK2, NHERF1 and NHERF2 was analyzed by Western blotting and carnitine uptake by BeWo cells was estimated and the kinetic properties of uptake measured. The results showed that forskolin treatment increased beta-hCG secretion and syncytin expression, suggesting induction of syncytialization. Confocal images of BeWo cells showed the localization of OCTN2 in the brush-border membrane. OCTN2 protein expression was upregulated in isolated brush-border membranes by long-term forskolin treatment, but the V(m) for carnitine uptake was unchanged, although the K(m) increased. PDZK1, NHERF1 and NHERF2 protein expression in the brush-border membrane was downregulated by forskolin treatment, whereas PDZK2 levels remained unchanged. In conclusion, protein expression and function of OCTN2 in BeWo cells can be regulated by forskolin treatment. While the presence of forskolin results in an increase in OCTN2 protein expression, the increase in uptake capacity may be compensated by the decreased expression of PDZK1, NHERF1 or NHERF2.

Differential Association of the Na+/H+ Exchanger Regulatory Factor (NHERF) Family of Adaptor Proteins with the Raft-and the Non-Raft Brush Border Membrane Fractions of NHE3

PubMed Central

Sultan, Ayesha; Luo, Min; Yu, Qin; Riederer, Brigitte; Xia, Weiliang; Chen, Mingmin; Lissner, Simone; Gessner, Johannes E.; Donowitz, Mark; Yun, C. Chris; deJonge, Hugo; Lamprecht, Georg; Seidler, Ursula

2014-01-01

Background/Aims Trafficking, brush border membrane (BBM) retention, and signal-specific regulation of the Na+/H+ exchanger NHE3 is regulated by the Na+/H+ Exchanger Regulatory Factor (NHERF) family of PDZ-adaptor proteins, which enable the formation of multiprotein complexes. It is unclear, however, what determines signal specificity of these NHERFs. Thus, we studied the association of NHE3, NHERF1 (EBP50), NHERF2 (E3KARP), and NHERF3 (PDZK1) with lipid rafts in murine small intestinal BBM. Methods Detergent resistant membranes (“lipid rafts”) were isolated by floatation of Triton X-incubated small intestinal BBM from a variety of knockout mouse strains in an Optiprep step gradient. Acid-activated NHE3 activity was measured fluorometrically in BCECF-loaded microdissected villi, or by assessment of CO2/HCO3− mediated increase in fluid absorption in perfused jejunal loops of anethetized mice. Results NHE3 was found to partially associate with lipid rafts in the native BBM, and NHE3 raft association had an impact on NHE3 transport activity and regulation in vivo. NHERF1, 2 and 3 were differentially distributed to rafts and non-rafts, with NHERF2 being most raft-associated and NHERF3 entirely non-raft associated. NHERF2 expression enhanced the localization of NHE3 to membrane rafts. The use of acid sphingomyelinase-deficient mice, which have altered membrane lipid as well as lipid raft composition, allowed us to test the validity of the lipid raft concept in vivo. Conclusions The differential association of the NHERFs with the raft-associated and the non-raft fraction of NHE3 in the brush border membrane is one component of the differential and signal-specific NHE3 regulation by the different NHERFs. PMID:24297041

Differential association of the Na+/H+ Exchanger Regulatory Factor (NHERF) family of adaptor proteins with the raft- and the non-raft brush border membrane fractions of NHE3.

PubMed

Sultan, Ayesha; Luo, Min; Yu, Qin; Riederer, Brigitte; Xia, Weiliang; Chen, Mingmin; Lissner, Simone; Gessner, Johannes E; Donowitz, Mark; Yun, C Chris; deJonge, Hugo; Lamprecht, Georg; Seidler, Ursula

2013-01-01

Trafficking, brush border membrane (BBM) retention, and signal-specific regulation of the Na+/H+ exchanger NHE3 is regulated by the Na+/H+ Exchanger Regulatory Factor (NHERF) family of PDZ-adaptor proteins, which enable the formation of multiprotein complexes. It is unclear, however, what determines signal specificity of these NHERFs. Thus, we studied the association of NHE3, NHERF1 (EBP50), NHERF2 (E3KARP), and NHERF3 (PDZK1) with lipid rafts in murine small intestinal BBM. Detergent resistant membranes ("lipid rafts") were isolated by floatation of Triton X-incubated small intestinal BBM from a variety of knockout mouse strains in an Optiprep step gradient. Acid-activated NHE3 activity was measured fluorometrically in BCECF-loaded microdissected villi, or by assessment of CO2/HCO3(-) mediated increase in fluid absorption in perfused jejunal loops of anethetized mice. NHE3 was found to partially associate with lipid rafts in the native BBM, and NHE3 raft association had an impact on NHE3 transport activity and regulation in vivo. NHERF1, 2 and 3 were differentially distributed to rafts and non-rafts, with NHERF2 being most raft-associated and NHERF3 entirely non-raft associated. NHERF2 expression enhanced the localization of NHE3 to membrane rafts. The use of acid sphingomyelinase-deficient mice, which have altered membrane lipid as well as lipid raft composition, allowed us to test the validity of the lipid raft concept in vivo. The differential association of the NHERFs with the raft-associated and the non-raft fraction of NHE3 in the brush border membrane is one component of the differential and signal-specific NHE3 regulation by the different NHERFs. © 2013 S. Karger AG, Basel.

Drug-nutrient interactions: inhibition of amino acid intestinal absorption by fluoxetine.

PubMed

Urdaneta, E; Idoate, I; Larralde, J

1998-05-01

Fluoxetine is one of the most widely used antidepressants and nowadays it is also being used to manage obesity problems. In our laboratory we demonstrated that the drug inhibited sugar absorption (Monteiro et al. 1993). The aim of the present work was to determine the effect of fluoxetine on intestinal leucine absorption. Using a procedure of successive absorptions in vivo the drug diminished amino acid absorption by 30% (P < 0.001). Experiments in vitro in isolated jejunum also revealed a reduction in leucine uptake of 37% (P < 0.001). In both cases fluoxetine only affected mediated transport without altering diffusion. In a preparation enriched in basolateral membrane, fluoxetine inhibited the Na+,K(+)-ATPase (EC 3.6.1.37) activity (55%; P < 0.001) in a non-competitive manner with an inhibition constant (Ki) value of 0.92 mM. Leucine uptake by brush-border membrane vesicles was diminished by the drug (a reduction of 48% was observed at 30s, P < 0.001); only the apical Na(+)-dependent transport system of the amino acid was modified and the inhibition was non-competitive. Leucine uptake in the presence of lysine indicated that transporter B was involved. These results suggest that fluoxetine reduces leucine absorption by its action on the basolateral and apical membrane of the enterocyte; the nutritional status of the patients under drug treatment may be affected as neutral amino acid absorption is decreased.

Effects of glucocorticoid-induced stress on absorption of glycylsarcosine in jejunum of broilers.

PubMed

Chang, W H; Li, J J; Zhang, S; Zheng, A J; Yuan, J L; Cai, H Y; Liu, G H

2015-04-01

This study was conducted to investigate the effects of stress on the absorption of glycylsarcosine in the jejunum of broilers, as well as the underlying mechanisms. A glucocorticoid analogue, dexamethasone (DEX), was chosen to simulate the effects of endogenous glucocorticoids. Two hundred 21-day-old male Arbor Acre broilers were randomly allotted to 4 groups with 5 replicates in each group and 10 birds per replicate by a completely randomized assignment involving a single factorial arrangement of injection dose DEX. The broilers were injected with 1-mL DEX (0.1-, 0.5-, and 2.5-mg/kg BW) or saline subcutaneously in the abdomen 1×/d for 7 d. The broilers were weighed, killed, and sampled at 28 days old. The results showed that DEX dose-dependently reduced growth and endogenous corticosterone content in the plasma of the broilers (P<0.05). DEX decreased absorption of glycylsarcosine by jejunum brush border membrane vesicles and gut sacs (P<0.05). DEX treatment increased the crypt depth of the jejunum, decreased the villus height, absorption area, and ratio of villus height to crypt depth (P<0.05). Effect of dexamethasone on villus width was not obvious (P>0.05). It was concluded that DEX reduced the absorption of glycylsarcosine in the jejunum of broilers. © The Author 2015. Published by Oxford University Press on behalf of Poultry Science Association.

Acute and chronic exposure of rat intestinal mucosa to dextran promotes SGLTI-mediated glucose transport.

PubMed

Debnam, E S; Denholm, E E; Grimble, G K

1998-08-01

The intestinal handling of dextran, an alpha-1,6-linked glucose polymer, is poor compared with starch, and some ingested dextran might therefore reach the lower small intestine. As luminal sugar up-regulates SGLT1 (sodium-dependent glucose transporter) locally, we report the effects of a dextran-enriched diet on jejunal and ileal brush border membrane (BBM) glucose uptake. Rats were maintained on a diet containing 65% maltodextrin or 32.5% maltodextrin + 32.5% dextran (10 kD or 40 kD) for 8-10 days, and the kinetics of phlorizin-sensitive [3H]-glucose uptake by purified BBM vesicles was determined. Ingestion of 40-kD but not 10-kD dextran increased Vmax for jejunal and ileal glucose uptake (+64.3% and +61.8% respectively, both P < 0.02). The transport response to 40-kD dextran was in keeping with lower levels of expired H2 at the end of the feeding period. High-performance liquid chromatography (HPLC) analysis of luminal contents indicated extensive hydrolysis of ingested dextran. Finally, 3-h jejunal exposure to 40-kD dextran in vivo increased the Vmax for glucose uptake by jejunal BBM. It is likely that increased SGLT1-mediated glucose uptake after short or longer term mucosal exposure to dextran results from luminal dextran per se or a hydrolysis product. The clinical implications of this up-regulation are discussed.

Identification of Bacillus thuringiensis Cry1AbMod binding-proteins from Spodoptera frugiperda.

PubMed

Martínez de Castro, Diana L; García-Gómez, Blanca I; Gómez, Isabel; Bravo, Alejandra; Soberón, Mario

2017-12-01

Bacillus thuringiensis Cry toxins are currently used for pest control in transgenic crops but evolution of resistance by the insect pests threatens the use of this technology. The Cry1AbMod toxin was engineered to lack the alpha helix-1 of the parental Cry1Ab toxin and was shown to counter resistance to Cry1Ab and Cry1Ac toxins in different insect species including the fall armyworm Spodoptera frugiperda. In addition, Cry1AbMod showed enhanced toxicity to Cry1Ab-susceptible S. frugiperda populations. To gain insights into the mechanisms of this Cry1AbMod-enhanced toxicity, we isolated the Cry1AbMod toxin binding proteins from S. frugiperda brush border membrane vesicles (BBMV), which were identified by pull-down assay and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS results indicated that Cry1AbMod toxin could bind to four classes of aminopeptidase (N1, N3, N4 y N5) and actin, with the highest amino acid sequence coverage acquired for APN 1 and APN4. In addition to these proteins, we found other proteins not previously described as Cry toxin binding proteins. This is the first report that suggests the interaction between Cry1AbMod and APN in S. frugiperda. Copyright © 2017 Elsevier Inc. All rights reserved.

Molecular identification and functional characterization of rabbit MATE1 and MATE2-K.

PubMed

Zhang, Xiaohong; Cherrington, Nathan J; Wright, Stephen H

2007-07-01

An electroneutral organic cation (OC)/proton exchanger in the apical membrane of proximal tubules mediates the final step of renal OC excretion. Two members of the multidrug and toxin extrusion family, MATE1 and MATE2-K, were recently identified in human and rodent kidney and proposed to be the molecular basis of renal OC/H(+) exchange. To take advantage of the comparative value of the large database on the kinetic and selectivity characteristics of OC/H(+) exchange that exists for rabbit kidney, we cloned rbMATE1 and rbMATE2-K. The rabbit homologs have 75% (MATE1) and 74% (MATE2-K) amino acid identity to their human counterparts (and 51% identity with each other). rbMATE1 and rbMATE2-K exhibited H(+) gradient-dependent uptake and efflux of tetraethylammonium (TEA) when expressed in Chinese hamster ovary cells. Both transporters displayed similar affinities for selected compounds [IC(50) values within 2-fold for TEA, 1-methyl-4-phenylpyridinium, and quinidine] and very different affinities for others (IC(50) values differing by 8- to 80-fold for choline and cimetidine, respectively). These results indicate that rbMATE1 and rbMATE2-K are multispecific OC/H(+) exchangers with similar, but distinct, functional characteristics. Overall, the selectivity of MATE1 and MATE2-K correlated closely with that observed in rabbit renal brush-border membrane vesicles.

Role of rat sodium/phosphate cotransporters in the cell membrane transport of arsenate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villa-Bellosta, Ricardo; Sorribas, Victor

2008-10-01

Inorganic arsenate (As{sup V}) is a common contaminant of underground water. Following oral exposure, it is assumed that As{sup V} is distributed and crosses cell membranes through inorganic phosphate (Pi) transporters. We have tested this hypothesis by studying the inhibition of rat Na/Pi cotransporters by As{sup V} in Xenopus laevis oocytes and in several rat tissues. The ubiquitously expressed type III Pi transporters (PiT-1 and PiT-2) showed a low affinity for As{sup V} (K{sub i} {approx} 3.8 mM), similar to the Pi transport system in aortic vascular smooth muscle cells (K{sub i} 1.5 mM). The type II renal isoforms, NaPi-IIamore » and NaPi-IIc, were also poorly inhibited by As{sup V} (K{sub i} {approx} 1 mM), similar to the Pi transport from kidney cortex brush-border membrane (BBM) vesicles. Conversely, the high-affinity intestinal transporter, NaPi-IIb, was very efficiently inhibited with a K{sub i} of 51 {mu}M, similar to the Pi transport from intestinal BBM vesicles. Taking into account the 1.1 mM Pi in blood and renal ultrafiltrate, and the nanomolar range of As{sup V} exposures, we have determined that the contribution by Na/Pi cotransporters to As{sup V} membrane transport is negligible, given that 10-15 mM As{sup V} would be necessary in these fluids to be significantly transported. Intestinal transport is an exception, because Pi competition is weak, thereby considering that its concentration in lumen mainly depends on low Pi levels from ingested fresh water, and because As{sup V} very efficiently inhibits Pi intestinal transport. Our data agree with current toxicokinetic knowledge, and they explain the asymmetric excretion of trivalent and pentavalent arsenic species into bile and urine.« less

Sodium-coupled electrogenic transport of pyroglutamate (5-oxoproline) via SLC5A8, a monocarboxylate transporter.

PubMed

Miyauchi, Seiji; Gopal, Elangovan; Babu, Ellappan; Srinivas, Sonne R; Kubo, Yoshiyuki; Umapathy, Nagavedi S; Thakkar, Santoshanand V; Ganapathy, Vadivel; Prasad, Puttur D

2010-06-01

Pyroglutamate, also known as 5-oxoproline, is a structural analog of proline. This amino acid derivative is a byproduct of glutathione metabolism, and is reabsorbed efficiently in kidney by Na(+)-coupled transport mechanisms. Previous studies have focused on potential participation of amino acid transport systems in renal reabsorption of this compound. Here we show that it is not the amino acid transport systems but instead the Na(+)-coupled monocarboxylate transporter SLC5A8 that plays a predominant role in this reabsorptive process. Expression of cloned human and mouse SLC5A8 in mammalian cells induces Na(+)-dependent transport of pyroglutamate that is inhibitable by various SLC5A8 substrates. SLC5A8-mediated transport of pyroglutamate is saturable with a Michaelis constant of 0.36+/-0.04mM. Na(+)-activation of the transport process exhibits sigmoidal kinetics with a Hill coefficient of 1.8+/-0.4, indicating involvement of more than one Na(+) in the activation process. Expression of SLC5A8 in Xenopuslaevis oocytes induces Na(+)-dependent inward currents in the presence of pyroglutamate under voltage-clamp conditions. The concentration of pyroglutamate necessary for induction of half-maximal current is 0.19+/-0.01mM. The Na(+)-activation kinetics is sigmoidal with a Hill coefficient of 2.3+/-0.2. Ibuprofen, a blocker of SLC5A8, suppressed pyroglutamate-induced currents in SLC5A8-expressing oocytes; the concentration of the blocker necessary for causing half-maximal inhibition is 14+/-1microM. The involvement of SLC5A8 can be demonstrated in rabbit renal brush border membrane vesicles by showing that the Na(+)-dependent uptake of pyroglutamate in these vesicles is inhibitable by known substrates of SLC5A8. The Na(+) gradient-driven pyroglutamate uptake was stimulated by an inside-negative K(+) diffusion potential induced by valinomycin, showing that the uptake process is electrogenic.

Comprehensive fire prevention legislation enacted by the California legislature in 1992 after the East Bay firestorm

Treesearch

Rachel Richman

1995-01-01

Legislation was enacted by the California Legislature in 1992 after the East Bay firestorm on the Oakland/Berkeley border; it included roofing standards, brush clearance, and other safety requirements. Fire safety personnel and local government officials all participated in developing these measures and presenting them to the California Legislature.

Intra amniotic administration of raffinose and stachyose affects the intestinal brush border functionality and alters gut microflora populations

USDA-ARS?s Scientific Manuscript database

This study investigates the effectiveness of two types of prebiotics, stachyose and raffinose, which are present in staple food crops that are widely consumed in regions where dietary Fe deficiency is a health concern. The hypothesis is that these prebiotics will improve Fe status, intestinal functi...

The in ovo feeding administration (gallus gallus)-an emerging in vivo approach to assess bioactive compounds with potential nutritional benefits

USDA-ARS?s Scientific Manuscript database

In recent years, the in ovo feeding in fertilized broiler (Gallus gallus) eggs approach was further developed and currently is widely applied in the evaluation process of the effects of functional foods (primarily plant origin compounds) on the functionality of the intestinal brush border membrane, ...

Bacillus thuringiensis pore-forming toxins trigger massive shedding of GPI-anchored aminopeptidase N from gypsy moth midgut epithelial cells

Treesearch

Algimantas P. Valaitis

2008-01-01

The insecticidal Cry proteins produced by Bacillus thuringiensis strains are pore-forming toxins (PFTs) that bind to the midgut brush border membrane and cause extensive damage to the midgut epithelial cells of susceptible insect larvae. Force-feeding B. thuringiensis PFTs to Lymantria dispar larvae elicited...

Localization of Bacillus thuringiensis Cry1A toxin-binding molecules in gypsy moth larval gut sections using fluorescence microscopy

Treesearch

Algimantas P. Valaitis

2011-01-01

The microbial insecticide Bacillus thuringiensis (Bt) produces Cry toxins, proteins that bind to the brush border membranes of gut epithelial cells of insects that ingest it, disrupting the integrity of the membranes, and leading to cell lysis and insect death. In gypsy moth, Lymantria dispar, two toxin-binding molecules for the...

Diagnostic and Research Aspects of Small Intestinal Disaccharidases in Coeliac Disease

PubMed Central

Ciclitira, Paul J.

2017-01-01

Disaccharidases (DS) are brush border enzymes embedded in the microvillous membrane of small intestinal enterocytes. In untreated coeliac disease (CD), a general decrease of DS activities is seen. This manuscript reviews different aspects of DS activities in CD: their utility in the diagnosis and their application to in vitro toxicity testing. The latter has never been established in CD research. However, with the recent advances in small intestinal organoid techniques, DS might be employed as a biomarker for in vitro studies. This includes establishment of self-renewing epithelial cells raised from tissue, which express differentiation markers, including the brush border enzymes. Determining duodenal DS activities may provide additional information during the diagnostic workup of CD: (i) quantify the severity of the observed histological lesions, (ii) provide predictive values for the grade of mucosal villous atrophy, and (iii) aid diagnosing CD where minor histological changes are seen. DS can also provide additional information to assess the response to a gluten-free diet as marked increase of their activities occurs four weeks after commencing it. Various endogenous and exogenous factors affecting DS might also be relevant when considering investigating the role of DS in other conditions including noncoeliac gluten sensitivity and DS deficiencies. PMID:28512643

The effect of amino acids and dipeptides on sodium-ion transport in rat enterocytes.

PubMed

Cheeseman, C I; Devlin, D

1985-02-14

Sodium efflux from isolated intestinal epithelial cells was measured during incubation with several different free amino acids and dipeptides. L-Leucine, which is cotransported with sodium across the brush border membrane, significantly stimulated the total sodium efflux and almost all of this increase involved the ouabain-sensitive flux, i.e., the active component. In contrast, glycyl-L-leucine had little or no effect on active sodium efflux either in the presence or absence of 0.1 mM bestatin, a peptide hydrolase inhibitor. A second dipeptide L-carnosine (beta-alanyl-L-histidine) which is poorly hydrolysed by enterocytes also had no effect upon sodium efflux. However, glycylglycine, which has been shown to be cotransported with sodium, did stimulate the ionic efflux. In addition, measurement of sodium uptake by sheets of small intestine showed that glycyl-L-leucine, carnosine and glycyl-L-proline failed to increase the uptake of the ion, while glycylglycine did significantly stimulate sodium uptake. These data indicate that some dipeptides are not cotransported with sodium, while others are. This suggests that there may well be multiple peptide transporters with very different characteristics in the brush border membrane of enterocytes.

Kidney and Phosphate Metabolism

PubMed Central

2008-01-01

The serum phosphorus level is maintained through a complex interplay between intestinal absorption, exchange intracellular and bone storage pools, and renal tubular reabsorption. The kidney plays a major role in regulation of phosphorus homeostasis by renal tubular reabsorption. Type IIa and type IIc Na+/Pi transporters are important renal Na+-dependent inorganic phosphate (Pi) transporters, which are expressed in the brush border membrane of proximal tubular cells. Both are regulated by dietary Pi intake, vitamin D, fibroblast growth factor 23 (FGF23) and parathyroid hormone. The expression of type IIa Na+/Pi transporter result from hypophosphatemia quickly. However, type IIc appears to act more slowly. Physiological and pathophysiological alteration in renal Pi reabsorption are related to altered brush border membrane expression/content of the type II Na+/Pi cotransporter. Many studies of genetic and acquired renal phosphate wasting disorders have led to the identification of novel genes. Two novel Pi regulating genes, PHEX and FGF23, play a role in the pathophysiology of genetic and acquired renal phosphate wasting disorders and studies are underway to define their mechanism on renal Pi regulation. In recent studies, sodium-hydrogen exchanger regulatory factor 1 (NHERF1) is reported as another new regulator for Pi reabsorption mechanism. PMID:24459526

An unusual presentation of pseudocowpox associated with an outbreak of pustular ulcerative vulvovaginitis in a Swedish dairy herd.

PubMed

Blomqvist, Gunilla; Ullman, Karin; Segall, Thomas; Hauzenberger, Elenor; Renström, Lena; Persson-Waller, Karin; Leijon, Mikael; Valarcher, Jean-Francois

2018-03-01

Species Pseudocowpox virus (PCPV; family Poxviridae) is known to cause pustular cutaneous disease in cattle. We describe an outbreak of pseudocowpox with an unusual clinical picture in a free-stall dairy herd of ~80 cows. Approximately 90% of the cows had vesicles, erosions, papules, and scabs on the vulva and vaginal mucosa. Histologic analysis of biopsy tissues indicated a primary, although not specified, viral infection. Transmission electron microscopy revealed parapoxvirus particles in both tissue and vesicular materials. Deep sequencing analysis of extracted DNA from swabbed vesicle areas gave a contig of nearly 120,000 nucleotides, matching the PCPV strain VR 634 with 100% identity. Analyses confirmed the absence of other potential causes of pustular vulvovaginitis such as bovine herpesvirus 1 and Ureaplasma diversum. A rolling cow brush was suspected to be the fomite.

Comparative analysis of Bacillus thuringiensis toxin binding to gypsy moth, browntail moth, and douglas-fir tussock moth midgut tissue sections using fluorescence microscopy

Treesearch

Algimantas P. Valaitis; John D. Podgwaite

2011-01-01

Many strains of Bacillus thuringiensis (Bt) produce insecticidal proteins, also referred to as Cry toxins, in crystal inclusions during sporulation. When ingested by insects, the Cry toxins bind to receptors on the brush border midgut epithelial cells and create pores in the epithelial gut membranes resulting in the death of...

Proximal tubule proteins are significantly elevated in bladder urine of patients with ureteropelvic junction obstruction and may represent novel biomarkers: A pilot study.

PubMed

Gerber, Claire; Harel, Miriam; Lynch, Miranda L; Herbst, Katherine W; Ferrer, Fernando A; Shapiro, Linda H

2016-04-01

Ureteropelvic junction obstruction (UPJO) is the major cause of hydronephrosis in children and may lead to renal injury and early renal dysfunction. However, diagnosis of the degree of obstruction and severity of renal injury relies on invasive and often inconclusive renal scans. Biomarkers from voided urine that detect early renal injury are highly desirable because of their noninvasive collection and their potential to assist in earlier and more reliable diagnosis of the severity of obstruction. Early in response to UPJO, increased intrarenal pressure directly impacts the proximal tubule brush border. We hypothesize that single-pass, apically expressed proximal tubule brush border proteins will be shed into the urine early and rapidly and will be reliable noninvasive urinary biomarkers, providing the tools for a more reliable stratification of UPJO patients. We performed a prospective cohort study at Connecticut Children's Medical Center. Bladder urine samples from 12 UPJO patients were obtained prior to surgical intervention. Control urine samples were collected from healthy pediatric patients presenting with primary nocturnal enuresis. We determined levels of NGAL, KIM-1 (previously identified biomarkers), CD10, CD13, and CD26 (potentially novel biomarkers) by ELISA in control and experimental urine samples. Urinary creatinine levels were used to normalize the urinary protein levels measured by ELISA. Each of the proximal tubule proteins outperformed the previously published biomarkers. No differences in urinary NGAL and KIM-1 levels were observed between control and obstructed patients (p = 0.932 and p = 0.799, respectively). However, levels of CD10, CD13, and CD26 were significantly higher in the voided urine of obstructed individuals when compared with controls (p = 0.002, p = 0.024, and p = 0.007, respectively) (Figure). Targeted identification of reliable, noninvasive biomarkers of renal injury is critical to aid in diagnosing patients at risk, guiding therapeutic decisions and monitoring treatment efficacy. Proximal tubule brush border proteins are reliably detected in the urine of obstructed patients and may be more effective at predicting UPJO. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Hepatectomy-Related Hypophosphatemia: A Novel Phosphaturic Factor in the Liver-Kidney Axis

PubMed Central

Nomura, Kengo; Miyagawa, Atsumi; Shiozaki, Yuji; Sasaki, Shohei; Kaneko, Ichiro; Ito, Mikiko; Kido, Shinsuke; Segawa, Hiroko; Sano, Mitsue; Fukuwatari, Tsutomu; Shibata, Katsumi

2014-01-01

Marked hypophosphatemia is common after major hepatic resection, but the pathophysiologic mechanism remains unknown. We used a partial hepatectomy (PH) rat model to investigate the molecular basis of hypophosphatemia. PH rats exhibited hypophosphatemia and hyperphosphaturia. In renal and intestinal brush-border membrane vesicles isolated from PH rats, Na+-dependent phosphate (Pi) uptake decreased by 50%–60%. PH rats also exhibited significantly decreased levels of renal and intestinal Na+-dependent Pi transporter proteins (NaPi-IIa [NaPi-4], NaPi-IIb, and NaPi-IIc). Parathyroid hormone was elevated at 6 hours after PH. Hyperphosphaturia persisted, however, even after thyroparathyroidectomy in PH rats. Moreover, DNA microarray data revealed elevated levels of nicotinamide phosphoribosyltransferase (Nampt) mRNA in the kidney after PH, and Nampt protein levels and total NAD concentration increased significantly in the proximal tubules. PH rats also exhibited markedly increased levels of the Nampt substrate, urinary nicotinamide (NAM), and NAM catabolites. In vitro analyses using opossum kidney cells revealed that NAM alone did not affect endogenous NaPi-4 levels. However, in cells overexpressing Nampt, the addition of NAM led to a marked decrease in cell surface expression of NaPi-4 that was blocked by treatment with FK866, a specific Nampt inhibitor. Furthermore, FK866-treated mice showed elevated renal Pi reabsorption and hypophosphaturia. These findings indicate that hepatectomy-induced hypophosphatemia is due to abnormal NAM metabolism, including Nampt activation in renal proximal tubular cells. PMID:24262791

Effect of Npt2b deletion on intestinal and renal inorganic phosphate (Pi) handling.

PubMed

Ikuta, Kayo; Segawa, Hiroko; Sasaki, Shohei; Hanazaki, Ai; Fujii, Toru; Kushi, Aoi; Kawabata, Yuka; Kirino, Ruri; Sasaki, Sumire; Noguchi, Miwa; Kaneko, Ichiro; Tatsumi, Sawako; Ueda, Otoya; Wada, Naoko A; Tateishi, Hiromi; Kakefuda, Mami; Kawase, Yosuke; Ohtomo, Shuichi; Ichida, Yasuhiro; Maeda, Akira; Jishage, Kou-Ichi; Horiba, Naoshi; Miyamoto, Ken-Ichi

2018-06-01

Hyperphosphatemia is common in chronic kidney disease and is associated with morbidity and mortality. The intestinal Na + -dependent phosphate transporter Npt2b is thought to be an important molecular target for the prevention of hyperphosphatemia. The role of Npt2b in the net absorption of inorganic phosphate (Pi), however, is controversial. In the present study, we made tamoxifen-inducible Npt2b conditional knockout (CKO) mice to analyze systemic Pi metabolism, including intestinal Pi absorption. Although the Na + -dependent Pi transport in brush-border membrane vesicle uptake levels was significantly decreased in the distal intestine of Npt2b CKO mice compared with control mice, plasma Pi and fecal Pi excretion levels were not significantly different. Data obtained using the intestinal loop technique showed that Pi uptake in Npt2b CKO mice was not affected at a Pi concentration of 4 mM, which is considered the typical luminal Pi concentration after meals in mice. Claudin, which may be involved in paracellular pathways, as well as claudin-2, 12, and 15 protein levels were significantly decreased in the Npt2b CKO mice. Thus, Npt2b deficiency did not affect Pi absorption within the range of Pi concentrations that normally occurs after meals. These findings indicate that abnormal Pi metabolism may also be involved in tight junction molecules such as Cldns that are affected by Npt2b deficiency.

Domain III of Cry1Ac Is Critical to Binding and Toxicity against Soybean Looper (Chrysodeixis includens) but Not to Velvetbean Caterpillar (Anticarsia gemmatalis).

PubMed

Mushtaq, Rubina; Shakoori, Abdul Rauf; Jurat-Fuentes, Juan Luis

2018-02-27

Insecticidal proteins Cry1Ac and Cry2Ac7 from the bacterium Bacillus thuringiensis (Bt) belong to the three-domain family of Bt toxins. Commercial transgenic soybean hybrids produce Cry1Ac to control the larvae of the soybean looper ( Chrysodeixis includens ) and the velvet bean caterpillar ( Anticarsia gemmatalis ). The specificity of Cry1Ac is determined by loops extending from domain II and regions of domain III in the three-dimensional structure of the toxin. In this study, we constructed a hybrid toxin (H1.2Ac) containing domains I and II of Cry1Ac and domain III of Cry2Ac7, in an attempt to obtain a protein with enhanced toxicity compared to parental toxins. Bioassays with H1.2Ac revealed toxicity against the larvae of A. gemmatalis but not against C. includens . Saturation binding assays with radiolabeled toxins and midgut brush border membrane vesicles demonstrated no specific H1.2Ac binding to C. includens , while binding in A. gemmatalis was specific and saturable. Results from competition binding assays supported the finding that Cry1Ac specificity against A. gemmatalis is mainly dictated by domain II. Taken together, these distinct interactions with binding sites may help explain the differential susceptibility to Cry1Ac in C. includens and A. gemmatalis , and guide the design of improved toxins against soybean pests.

Differential protection of Cry1Fa toxin against Spodoptera frugiperda larval gut proteases by cadherin orthologs correlates with increased synergism.

PubMed

Rahman, Khalidur; Abdullah, Mohd Amir F; Ambati, Suresh; Taylor, Milton D; Adang, Michael J

2012-01-01

The Cry proteins produced by Bacillus thuringiensis (Bt) are the most widely used biopesticides effective against a range of crop pests and disease vectors. Like chemical pesticides, development of resistance is the primary threat to the long-term efficacy of Bt toxins. Recently discovered cadherin-based Bt Cry synergists showed the potential to augment resistance management by improving efficacy of Cry toxins. However, the mode of action of Bt Cry synergists is thus far unclear. Here we elucidate the mechanism of cadherin-based Cry toxin synergism utilizing two cadherin peptides, Spodoptera frugiperda Cad (SfCad) and Manduca sexta Cad (MsCad), which differentially enhance Cry1Fa toxicity to Spodoptera frugiperda neonates. We show that differential SfCad- and MsCad-mediated protection of Cry1Fa toxin in the Spodoptera frugiperda midgut correlates with differential Cry1Fa toxicity enhancement. Both peptides exhibited high affinity for Cry1Fa toxin and an increased rate of Cry1Fa-induced pore formation in S. frugiperda. However, only SfCad bound the S. frugiperda brush border membrane vesicle and more effectively prolonged the stability of Cry1Fa toxin in the gut, explaining higher Cry1Fa enhancement by this peptide. This study shows that cadherin fragments may enhance B. thuringiensis toxicity by at least two different mechanisms or a combination thereof: (i) protection of Cry toxin from protease degradation in the insect midgut and (ii) enhancement of pore-forming ability of Cry toxin.

Cry1Ac and Vip3Aa proteins from Bacillus thuringiensis targeting Cry toxin resistance in Diatraea flavipennella and Elasmopalpus lignosellus from sugarcane

PubMed Central

2017-01-01

The biological potential of Vip and Cry proteins from Bacillus is well known and widely established. Thus, it is important to look for new genes showing different modes of action, selecting those with differentiated entomotoxic activity against Diatraea flavipennella and Elasmopalpus lignosellus, which are secondary pests of sugarcane. Therefore, Cry1 and Vip3 proteins were expressed in Escherichia coli, and their toxicities were evaluated based on bioassays using neonate larvae. Of those, the most toxic were Cry1Ac and Vip3Aa considering the LC50 values. Toxins from E. coli were purified, solubilized, trypsinized, and biotinylated. Brush Border Membrane Vesicles (BBMVs) were prepared from intestines of the two species to perform homologous and heterologous competition assays. The binding assays demonstrated interactions between Cry1Aa, Cry1Ac, and Vip3Aa toxins and proteins from the BBMV of D. flavipennella and E. lignosellus. Homologous competition assays demonstrated that binding to one of the BBMV proteins was specific for each toxin. Heterologous competition assays indicated that Vip3Aa was unable to compete for Cry1Ac toxin binding. Our results suggest that Cry1Ac and Vip3Aa may have potential in future production of transgenic sugarcane for control of D. flavipennella and E. lignosellus, but more research is needed on the potential antagonism or synergism of the toxins in these pests. PMID:28123906

Does apical membrane GLUT2 have a role in intestinal glucose uptake?

PubMed

Naftalin, Richard J

2014-01-01

It has been proposed that the non-saturable component of intestinal glucose absorption, apparent following prolonged exposure to high intraluminal glucose concentrations, is mediated via the low affinity glucose and fructose transporter, GLUT2, upregulated within the small intestinal apical border. The evidence that the non-saturable transport component is mediated via an apical membrane sugar transporter is that it is inhibited by phloretin, after exposure to phloridzin. Since the other apical membrane sugar transporter, GLUT5, is insensitive to inhibition by either cytochalasin B, or phloretin, GLUT2 was deduced to be the low affinity sugar transport route. As in its uninhibited state, polarized intestinal glucose absorption depends both on coupled entry of glucose and sodium across the brush border membrane and on the enterocyte cytosolic glucose concentration exceeding that in both luminal and submucosal interstitial fluids, upregulation of GLUT2 within the intestinal brush border will usually stimulate downhill glucose reflux to the intestinal lumen from the enterocytes; thereby reducing, rather than enhancing net glucose absorption across the luminal surface. These states are simulated with a computer model generating solutions to the differential equations for glucose, Na and water flows between luminal, cell, interstitial and capillary compartments. The model demonstrates that uphill glucose transport via SGLT1 into enterocytes, when short-circuited by any passive glucose carrier in the apical membrane, such as GLUT2, will reduce transcellular glucose absorption and thereby lead to increased paracellular flow. The model also illustrates that apical GLUT2 may usefully act as an osmoregulator to prevent excessive enterocyte volume change with altered luminal glucose concentrations.

Does apical membrane GLUT2 have a role in intestinal glucose uptake?

PubMed Central

Naftalin, Richard J

2014-01-01

It has been proposed that the non-saturable component of intestinal glucose absorption, apparent following prolonged exposure to high intraluminal glucose concentrations, is mediated via the low affinity glucose and fructose transporter, GLUT2, upregulated within the small intestinal apical border. The evidence that the non-saturable transport component is mediated via an apical membrane sugar transporter is that it is inhibited by phloretin, after exposure to phloridzin. Since the other apical membrane sugar transporter, GLUT5, is insensitive to inhibition by either cytochalasin B, or phloretin, GLUT2 was deduced to be the low affinity sugar transport route. As in its uninhibited state, polarized intestinal glucose absorption depends both on coupled entry of glucose and sodium across the brush border membrane and on the enterocyte cytosolic glucose concentration exceeding that in both luminal and submucosal interstitial fluids, upregulation of GLUT2 within the intestinal brush border will usually stimulate downhill glucose reflux to the intestinal lumen from the enterocytes; thereby reducing, rather than enhancing net glucose absorption across the luminal surface. These states are simulated with a computer model generating solutions to the differential equations for glucose, Na and water flows between luminal, cell, interstitial and capillary compartments. The model demonstrates that uphill glucose transport via SGLT1 into enterocytes, when short-circuited by any passive glucose carrier in the apical membrane, such as GLUT2, will reduce transcellular glucose absorption and thereby lead to increased paracellular flow. The model also illustrates that apical GLUT2 may usefully act as an osmoregulator to prevent excessive enterocyte volume change with altered luminal glucose concentrations. PMID:25671087

Expression of nutrient transporters in duodenum, jejunum, and ileum of Eimeria maxima-infected broiler chickens.

PubMed

Fetterer, Raymond H; Miska, Katarzyna B; Jenkins, Mark C; Wong, Eric A

2014-10-01

The uptake of amino acids is mediated by active transporters located on the basolateral and brush border membranes of intestinal epithelial cells. The current study investigated the expression of amino acid transporters (AAT) and other genes in the intestine of chicks infected with Eimeria maxima. At 7-day postinfection (PI), tissue from each intestinal segment (duodenum, jejunum, and ileum) was taken from birds inoculated with 3 × 10(3) oocysts/bird and processed to recover RNA. Analysis of gene expression was performed using real-time reverse transcription polymerase chain reaction (qRT-PCR). Results were given as relative expression using β₂-microglobulin as an endogenous control. All the genes studied were expressed in three segments of the intestines, and expression of the genes was altered by infection with E. maxima. Even though the jejunum is considered the parasite's primary predilection site, there was no segment-related difference in expression of most of the genes studied. The antimicrobial peptide (LEAP2) was downregulated in all three segments of the intestine. The results also demonstrate that transporters associated with brush border membranes were downregulated while transporters associated with the basolateral membranes were upregulated and that E. maxima alters the expression of AAT and LEAP2 throughout the small intestine.

Human neutral brush border endopeptidase EC 3.4.24.11 in urine, its isolation, characterisation and activity in renal diseases.

PubMed

Vlaskou, D; Hofmann, W; Guder, W G; Siskos, P A; Dionyssiou-Asteriou, A

2000-07-01

Human neutral brush border endopeptidase (NEP) was purified from the urine of patients suffering from acute toxic tubulointerstitial nephropathy. An enzyme preparation with specific activity of 102 Ug(-1) protein was obtained. The urinary activities of neutral endopeptidase and alanine aminopeptidase were measured in patients with renal disease and in 30 control patients, resulting in a reference range from 0.1 to 0.7 Ug(-1) creatinine and 1.4-14.1 Ug(-1) creatinine, respectively. Urine enzyme activities were highest in patients with acute tubulotoxic renal diseases. Neutral endopeptidase and alanine aminopeptidase activities were found to be 6.5- and 10-fold higher than the upper value of the reference range, respectively. Smaller increases in the rate of excretion of these enzymes (2.5- and 3.5-fold), respectively, were observed in patients suffering from acute tubular insufficiency and even lower increases, 2- and 1.5-fold, respectively, were observed in patients with chronic renal diseases. In diabetics and kidney transplant patients the enzyme excretion rates were within the reference range. Assay of both transmembrane metalloproteinases in urine may prove valuable in serving as markers for renal toxicity. Together with beta-NAG these enzymes could be employed as differentiation markers between acute and chronic tubular insufficiency.

Fermented soya bean (tempe) extracts reduce adhesion of enterotoxigenic Escherichia coli to intestinal epithelial cells.

PubMed

Roubos-van den Hil, P J; Nout, M J R; Beumer, R R; van der Meulen, J; Zwietering, M H

2009-03-01

This study aimed to investigate the effect of processed soya bean, during the successive stages of tempe fermentation and different fermentation times, on adhesion of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal brush border cells as well as Caco-2 intestinal epithelial cells; and to clarify the mechanism of action. Tempe was prepared at controlled laboratory scale using Rhizopus microsporus var. microsporus as the inoculum. Extracts of raw, soaked and cooked soya beans reduced ETEC adhesion to brush border cells by 40%. Tempe extracts reduced adhesion by 80% or more. ETEC adhesion to Caco-2 cells reduced by 50% in the presence of tempe extracts. ETEC K88 bacteria were found to interact with soya bean extracts, and this may contribute to the observed decrease of ETEC adhesion to intestinal epithelial cells. Fermented soya beans (tempe) reduce the adhesion of ETEC to intestinal epithelial cells of pig and human origin. This reduced adhesion is caused by an interaction between ETEC K88 bacteria and soya bean compounds. The results strengthen previous observations on the anti-diarrhoeal effect of tempe. This effect indicates that soya-derived compounds may reduce adhesion of ETEC to intestinal cells in pigs as well as in humans and prevent against diarrhoeal diseases.

Exploring the Margin Recipe for Online Adaptive Radiation Therapy for Intermediate-Risk Prostate Cancer: An Intrafractional Seminal Vesicles Motion Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, Yang, E-mail: Yang.Sheng@duke.edu; Medical Physics Graduate Program, Duke University, Durham, North Carolina; Li, Taoran

Purpose: To provide a benchmark for seminal vesicle (SV) margin selection to account for intrafractional motion and to investigate the effectiveness of 2 motion surrogates in predicting intrafractional SV coverage. Methods and Materials: Fifteen prostate patients were studied. Each patient had 5 pairs (1 patient had 4 pairs) of pretreatment and posttreatment cone beam CTs (CBCTs). Each pair of CBCTs was registered on the basis of prostate fiducial markers. All pretreatment SVs were expanded with 1-, 2-, 3-, 4-, 5-, and 8-mm isotropic margins to form a series of planning target volumes, and their intrafractional coverage to the posttreatment SVmore » determined the “ground truth” for exact coverage. Two motion surrogates, the center of mass (COM) and the border of contour, were evaluated by the use of Pearson product-moment correlation coefficient and exponential fitting for predicting SV underdosage. Action threshold of each surrogate was calculated. The margin for each surrogate was calculated according to a traditional margin recipe. Results: Ninety-five percent posttreatment SV coverage was achieved in 9%, 53%, 73%, 86%, 95%, and 97% of fractions with 1-, 2-, 3-, 4-, 5-, and 8-mm margins, respectively. The 5-mm margins provided 95% intrafractional SV coverage in over 90% of fractions. The correlation between the COM and border was weak, moderate, and strong in the left-right (L-R), anterior-posterior (A-P), and superior-inferior (S-I) directions, respectively. Exponential fitting gave the underdosage threshold of 4.5 and 7.0 mm for the COM and border. The Van Herk margin recipe recommended 0-, 0.5-, and 0.8-mm margins in the L-R, A-P, and S-I directions based on the COM, and 1.2-, 3.9-, and 2.5-mm margins based on the border. Conclusions: Five-millimeter isotropic margins for the SV constitute the minimum required to mitigate the intrafractional motion. Both the COM and the border are acceptable predictors for SV underdosage with 4.5- and 7.0-mm action threshold. Traditional margin based on the COM or border underestimates the margin.« less

SGLT5 Reabsorbs Fructose in the Kidney but Its Deficiency Paradoxically Exacerbates Hepatic Steatosis Induced by Fructose

PubMed Central

Fukuzawa, Taku; Fukazawa, Masanori; Ueda, Otoya; Shimada, Hideaki; Kito, Aki; Kakefuda, Mami; Kawase, Yosuke; Wada, Naoko A.; Goto, Chisato; Fukushima, Naoshi; Jishage, Kou-ichi; Honda, Kiyofumi; King, George L.; Kawabe, Yoshiki

2013-01-01

Although excessive fructose intake is epidemiologically linked with dyslipidemia, obesity, and diabetes, the mechanisms regulating plasma fructose are not well known. Cells transfected with sodium/glucose cotransporter 5 (SGLT5), which is expressed exclusively in the kidney, transport fructose in vitro; however, the physiological role of this transporter in fructose metabolism remains unclear. To determine whether SGLT5 functions as a fructose transporter in vivo, we established a line of mice lacking the gene encoding SGLT5. Sodium-dependent fructose uptake disappeared in renal brush border membrane vesicles from SGLT5-deficient mice, and the increased urinary fructose in SGLT5-deficient mice indicated that SGLT5 was the major fructose reabsorption transporter in the kidney. From this, we hypothesized that urinary fructose excretion induced by SGLT5 deficiency would ameliorate fructose-induced hepatic steatosis. To test this hypothesis we compared SGLT5-deficient mice with wild-type mice under conditions of long-term fructose consumption. Paradoxically, however, fructose-induced hepatic steatosis was exacerbated in the SGLT5-deficient mice, and the massive urinary fructose excretion was accompanied by reduced levels of plasma triglycerides and epididymal fat but fasting hyperinsulinemia compared with fructose-fed wild-type mice. There was no difference in food consumption, water intake, or plasma fructose between the two types of mice. No compensatory effect by other transporters reportedly involved in fructose uptake in the liver and kidney were indicated at the mRNA level. These surprising findings indicated a previously unrecognized link through SGLT5 between renal fructose reabsorption and hepatic lipid metabolism. PMID:23451068

Hypoglycemic Effect of Opuntia ficus-indica var. saboten Is Due to Enhanced Peripheral Glucose Uptake through Activation of AMPK/p38 MAPK Pathway.

PubMed

Leem, Kang-Hyun; Kim, Myung-Gyou; Hahm, Young-Tae; Kim, Hye Kyung

2016-12-09

Opuntia ficus-indica var. saboten (OFS) has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, detailed mechanisms underlying hypoglycemic effects remain unclear. In this study, the mechanism underlying the hypoglycemic activity of OFS was evaluated using in vitro and in vivo systems. OFS treatment inhibited α-glucosidase activity and intestinal glucose absorption assessed by Na⁺-dependent glucose uptake using brush border membrane vesicles. AMP-activated protein kinase (AMPK) is widely recognized as an important regulator of glucose transport in skeletal muscle, and p38 mitogen-activated protein kinase (MAPK) has been proposed to be a component of AMPK-mediated signaling. In the present study, OFS dose-dependently increased glucose uptake in L6 muscle cells. The AMPK and p38 MAPK phosphorylations were stimulated by OFS, and inhibitors of AMPK (compound C ) and p38 MAPK (SB203580) abolished the effects of OFS. Furthermore, OFS increased glucose transporter 4 (GLUT4) translocation to the plasma membrane. OFS administration (1 g/kg and 2 g/kg body weight) in db/db mice dose-dependently ameliorated hyperglycemia, hyperinsulinemia, and glucose tolerance. Insulin resistance assessed by homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were also dose-dependently improved with OFS treatment. OFS administration improved pancreatic function through increased β-cell mass in db/db mice. These findings suggest that OFS acts by inhibiting glucose absorption from the intestine and enhancing glucose uptake from insulin-sensitive muscle cells through the AMPK/p38 MAPK signaling pathway.

Hypoglycemic Effect of Opuntia ficus-indica var. saboten Is Due to Enhanced Peripheral Glucose Uptake through Activation of AMPK/p38 MAPK Pathway

PubMed Central

Leem, Kang-Hyun; Kim, Myung-Gyou; Hahm, Young-Tae; Kim, Hye Kyung

2016-01-01

Opuntia ficus-indica var. saboten (OFS) has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, detailed mechanisms underlying hypoglycemic effects remain unclear. In this study, the mechanism underlying the hypoglycemic activity of OFS was evaluated using in vitro and in vivo systems. OFS treatment inhibited α-glucosidase activity and intestinal glucose absorption assessed by Na+-dependent glucose uptake using brush border membrane vesicles. AMP-activated protein kinase (AMPK) is widely recognized as an important regulator of glucose transport in skeletal muscle, and p38 mitogen-activated protein kinase (MAPK) has been proposed to be a component of AMPK-mediated signaling. In the present study, OFS dose-dependently increased glucose uptake in L6 muscle cells. The AMPK and p38 MAPK phosphorylations were stimulated by OFS, and inhibitors of AMPK (compound C) and p38 MAPK (SB203580) abolished the effects of OFS. Furthermore, OFS increased glucose transporter 4 (GLUT4) translocation to the plasma membrane. OFS administration (1 g/kg and 2 g/kg body weight) in db/db mice dose-dependently ameliorated hyperglycemia, hyperinsulinemia, and glucose tolerance. Insulin resistance assessed by homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were also dose-dependently improved with OFS treatment. OFS administration improved pancreatic function through increased β-cell mass in db/db mice. These findings suggest that OFS acts by inhibiting glucose absorption from the intestine and enhancing glucose uptake from insulin-sensitive muscle cells through the AMPK/p38 MAPK signaling pathway. PMID:27941667

Contrary seasonal changes of rates of nutrient uptake, organ mass, and voluntary food intake in red deer (Cervus elaphus)

PubMed Central

Beiglböck, Christoph; Burmester, Marion; Guschlbauer, Maria; Lengauer, Astrid; Schröder, Bernd; Wilkens, Mirja; Breves, Gerhard

2015-01-01

Northern ungulates acclimatize to winter conditions with restricted food supply and unfavorable weather conditions by reducing energy expenditure and voluntary food intake. We investigated in a study on red deer whether rates of peptide and glucose transport in the small intestines are also reduced during winter as part of the thrifty phenotype of winter-acclimatized animals, or whether transport rates are increased during winter in order to exploit poor forage more efficiently. Our results support the latter hypothesis. We found in a feeding experiment that total energy intake was considerably lower during winter despite ad libitum feeding. Together with reduced food intake, mass of visceral organs was significantly lower and body fat reserves were used as metabolic fuel in addition to food. However, efficacy of nutrient absorption seemed to be increased simultaneously. Extraction of crude protein from forage was higher in winter animals, at any level of crude protein intake, as indicated by the lower concentration of crude protein in feces. In line with these in vivo results, Ussing chamber experiments revealed greater electrogenic responses to both peptides and glucose in the small intestines of winter-acclimatized animals, and peptide uptake into jejunal brush-border membrane vesicles was increased. We conclude that reduced appetite of red deer during winter avoids energy expenditure for unproductive search of scarcely available food and further renders the energetically costly maintenance of a large gut and visceral organs unnecessary. Nevertheless, extraction of nutrients from forage is more efficient in the winter to attenuate an inevitably negative energy balance. PMID:26017492

Morphology and histology of the alimentary canal of Lygus hesperus (Heteroptera: Cimicomoropha: Miridae)

USGS Publications Warehouse

Habibi, J.; Coudron, T.A.; Backus, E.A.; Brandt, S.L.; Wagner, R.M.; Wright, M.K.; Huesing, J.E.

2008-01-01

Microdissection and transverse semithin sections were used to perform a light microscopy survey of the gross morphology and cellular anatomy of the alimentary canal, respectively, of Lygus hesperus Knight, a key pest of cotton (Gossypium hirsutum L.), alfalfa (Medicago sativa L.), and other crops. The gross morphology of the alimentary canal showed a relatively unadorned tube compared with other hemipterans, with variably shaped compartments and one small diverticulum. However, the epithelial cell anatomy of the gut was relatively complex, with the midgut having the most diverse structure and cell types. The midgut was typical of the "Lygus-type gut" seen in the older literature, i.e., it consisted of three major regions, the first (descending), second (ascending), and third (descending) ventriculi, with different variants of three major epithelial cell types in each region. Our light microscopy (LM) study suggests that the three cell types are nondifferentiated regenerative cells (which sparsely occurred throughout the midgut but were abundant in the anterior region of the first ventriculus), endocrine cells, and columnar cells. Although the Lygus gut cells strongly resemble those cell types seen in other insects, their identification should be confirmed via transmission electron microscopy to be considered definitive. These cell types differed in the size and opacity of vesicles, geometry of cell surface in the gut lumen, and size, shape, and concentration of brush-border microvilli and location within the gut. Comparison of gut structure in L. hesperus with that of other hemipterans, especially in relation to hemipteran phylogeny and feeding strategies, is discussed.

Fibroblast growth factor-23 increases mouse PGE2 production in vivo and in vitro.

PubMed

Syal, Ashu; Schiavi, Susan; Chakravarty, Sumana; Dwarakanath, Vangipuram; Quigley, Raymond; Baum, Michel

2006-02-01

Fibroblast growth factor-23 (FGF-23) has been implicated in the renal phosphate wasting in X-linked hypophosphatemia, tumor-induced osteomalacia, and autosomal dominant hypophosphatemic rickets. Recently, we demonstrated that Hyp mice have greater urinary PGE2 levels compared with C57/B6 mice and that indomethacin administration in vivo and in vitro ameliorates the phosphate transport defect in Hyp mice. To determine further whether altered prostaglandin metabolism plays a role in the renal phosphate transport defect in Hyp mice, we incubated renal proximal tubules with arachidonic acid. We find that PGE2 production was higher in Hyp mice than in C57/B6 mice. Incubation of C57/B6 mouse renal proximal tubules with FGF-23R176Q, an active mutant form of FGR23, increased tubular PGE2 production, an effect that was inhibited by 50 microM PD-98059 and 10 microM SB-203580, inhibitors of the MAP kinase pathway. C57/B6 mice injected with FGF-23R176Q had a approximately 10-fold increase in PGE2 excretion 24 h after intraperitoneal injection of FGF-23R176Q compared with vehicle-treated controls. Finally, we show that PGE2 inhibited both phosphate and volume absorption in mouse proximal convoluted tubules perfused in vitro and reduced brush-border membrane vesicle NaPi-2a protein abundance from renal cortex incubated in vitro with PGE2. In conclusion, FGF-23 increases urinary and renal tubular PGE2 production via the MAP kinase pathway and PGE2 inhibits proximal tubule phosphate transport.

Fibroblast growth factor-23 increases mouse PGE2 production in vivo and in vitro

PubMed Central

Syal, Ashu; Schiavi, Susan; Chakravarty, Sumana; Dwarakanath, Vangipuram; Quigley, Raymond; Baum, Michel

2014-01-01

Fibroblast growth factor-23 (FGF-23) has been implicated in the renal phosphate wasting in X-linked hypophosphatemia, tumor-induced osteomalacia, and autosomal dominant hypophosphatemic rickets. Recently, we demonstrated that Hyp mice have greater urinary PGE2 levels compared with C57/B6 mice and that indomethacin administration in vivo and in vitro ameliorates the phosphate transport defect in Hyp mice. To determine further whether altered prostaglandin metabolism plays a role in the renal phosphate transport defect in Hyp mice, we incubated renal proximal tubules with arachidonic acid. We find that PGE2 production was higher in Hyp mice than in C57/B6 mice. Incubation of C57/B6 mouse renal proximal tubules with FGF-23R176Q, an active mutant form of FGR23, increased tubular PGE2 production, an effect that was inhibited by 50 μM PD-98059 and 10 μM SB-203580, inhibitors of the MAP kinase pathway. C57/B6 mice injected with FGF-23R176Q had a ~10-fold increase in PGE2 excretion 24 h after intraperitoneal injection of FGF-23R176Q compared with vehicle-treated controls. Finally, we show that PGE2 inhibited both phosphate and volume absorption in mouse proximal convoluted tubules perfused in vitro and reduced brush-border membrane vesicle NaPi-2a protein abundance from renal cortex incubated in vitro with PGE2. In conclusion, FGF-23 increases urinary and renal tubular PGE2 production via the MAP kinase pathway and PGE2 inhibits proximal tubule phosphate transport. PMID:16144964

The dual actions of morin (3,5,7,2',4'-pentahydroxyflavone) as a hypouricemic agent: uricosuric effect and xanthine oxidase inhibitory activity.

PubMed

Yu, Zhifeng; Fong, Wing Ping; Cheng, Christopher H K

2006-01-01

Hyperuricemia is associated with a number of pathological conditions such as gout. Lowering of elevated uric acid level in the blood could be achieved by xanthine oxidase inhibitors and inhibitors of renal urate reabsorption. Some natural compounds isolated from herbs used in traditional Chinese medicine have been previously demonstrated to possess xanthine oxidase inhibitory activities. In the present investigation, morin (3,5,7,2',4'-pentahydroxyflavone), which occurs in the twigs of Morus alba L. documented in traditional Chinese medicinal literature to treat conditions akin to gout, was demonstrated to exert potent inhibitory action on urate uptake in rat renal brush-border membrane vesicles, indicating that this compound acts on the kidney to inhibit urate reabsorption. Lineweaver-Burk transformation of the inhibition kinetics data demonstrated that the inhibition of urate uptake was of a competitive type, with a K(i) value of 17.4 microM. In addition, morin was also demonstrated to be an inhibitor of xanthine oxidase. Lineweaver-Burk analysis of the enzyme kinetics indicated that the mode of inhibition was of a mixed type, with K(i) and K(ies) values being 7.9 and 35.1 microM, respectively. Using an oxonate-induced hyperuricemic rat model, morin was indeed shown to exhibit an in vivo uricosuric action, which could explain, in part at least, the observed hypouricemic effect of morin in these rats. The potential application of this compound in the treatment of conditions associated with hyperuricemia was discussed.

Cell-specific effects of luminal acid, bicarbonate, cAMP, and carbachol on transporter trafficking in the intestine

PubMed Central

Jakab, Robert L.; Collaco, Anne M.

2012-01-01

Changes in intestinal luminal pH affect mucosal ion transport. The aim of this study was to compare how luminal pH and specific second messengers modulate the membrane traffic of four major ion transporters (CFTR, NHE3, NKCC1, and NBCe1) in rat small intestine. Ligated duodenal, jejunal, and ileal segments were infused with acidic or alkaline saline, 8-Br-cAMP, or the calcium agonist carbachol in vivo for 20 min. Compared with untreated intestine, lumen pH was reduced after cAMP or carbachol and increased following HCO3−-saline. Following HCl-saline, lumen pH was restored to control pH levels. All four secretory stimuli resulted in brush-border membrane (BBM) recruitment of CFTR in crypts and villi. In villus enterocytes, CFTR recruitment was coincident with internalization of BBM NHE3 and basolateral membrane recruitment of the bicarbonate transporter NBCe1. Both cAMP and carbachol recruited NKCC1 to the basolateral membrane of enterocytes, while luminal acid or HCO3− retained NKCC1 in intracellular vesicles. Luminal acid resulted in robust recruitment of CFTR and NBCe1 to their respective enterocyte membrane domains in the upper third of the villi; luminal HCO3− induced similar membrane changes lower in the villi. These findings indicate that each stimulus promotes a specific transporter trafficking response along the crypt-villus axis. This is the first demonstration that physiologically relevant secretory stimuli exert their actions in villus enterocytes by membrane recruitment of CFTR and NBCe1 in tandem with NHE3 internalization. PMID:22936272

Cell-specific effects of luminal acid, bicarbonate, cAMP, and carbachol on transporter trafficking in the intestine.

PubMed

Jakab, Robert L; Collaco, Anne M; Ameen, Nadia A

2012-10-15

Changes in intestinal luminal pH affect mucosal ion transport. The aim of this study was to compare how luminal pH and specific second messengers modulate the membrane traffic of four major ion transporters (CFTR, NHE3, NKCC1, and NBCe1) in rat small intestine. Ligated duodenal, jejunal, and ileal segments were infused with acidic or alkaline saline, 8-Br-cAMP, or the calcium agonist carbachol in vivo for 20 min. Compared with untreated intestine, lumen pH was reduced after cAMP or carbachol and increased following HCO(3)(-)-saline. Following HCl-saline, lumen pH was restored to control pH levels. All four secretory stimuli resulted in brush-border membrane (BBM) recruitment of CFTR in crypts and villi. In villus enterocytes, CFTR recruitment was coincident with internalization of BBM NHE3 and basolateral membrane recruitment of the bicarbonate transporter NBCe1. Both cAMP and carbachol recruited NKCC1 to the basolateral membrane of enterocytes, while luminal acid or HCO(3)(-) retained NKCC1 in intracellular vesicles. Luminal acid resulted in robust recruitment of CFTR and NBCe1 to their respective enterocyte membrane domains in the upper third of the villi; luminal HCO(3)(-) induced similar membrane changes lower in the villi. These findings indicate that each stimulus promotes a specific transporter trafficking response along the crypt-villus axis. This is the first demonstration that physiologically relevant secretory stimuli exert their actions in villus enterocytes by membrane recruitment of CFTR and NBCe1 in tandem with NHE3 internalization.

Differential Protection of Cry1Fa Toxin against Spodoptera frugiperda Larval Gut Proteases by Cadherin Orthologs Correlates with Increased Synergism

PubMed Central

Rahman, Khalidur; Abdullah, Mohd Amir F.; Ambati, Suresh; Taylor, Milton D.

2012-01-01

The Cry proteins produced by Bacillus thuringiensis (Bt) are the most widely used biopesticides effective against a range of crop pests and disease vectors. Like chemical pesticides, development of resistance is the primary threat to the long-term efficacy of Bt toxins. Recently discovered cadherin-based Bt Cry synergists showed the potential to augment resistance management by improving efficacy of Cry toxins. However, the mode of action of Bt Cry synergists is thus far unclear. Here we elucidate the mechanism of cadherin-based Cry toxin synergism utilizing two cadherin peptides, Spodoptera frugiperda Cad (SfCad) and Manduca sexta Cad (MsCad), which differentially enhance Cry1Fa toxicity to Spodoptera frugiperda neonates. We show that differential SfCad- and MsCad-mediated protection of Cry1Fa toxin in the Spodoptera frugiperda midgut correlates with differential Cry1Fa toxicity enhancement. Both peptides exhibited high affinity for Cry1Fa toxin and an increased rate of Cry1Fa-induced pore formation in S. frugiperda. However, only SfCad bound the S. frugiperda brush border membrane vesicle and more effectively prolonged the stability of Cry1Fa toxin in the gut, explaining higher Cry1Fa enhancement by this peptide. This study shows that cadherin fragments may enhance B. thuringiensis toxicity by at least two different mechanisms or a combination thereof: (i) protection of Cry toxin from protease degradation in the insect midgut and (ii) enhancement of pore-forming ability of Cry toxin. PMID:22081566

Molecular identification and functional characteristics of peptide transporters in the bonnethead shark (Sphyrna tiburo).

PubMed

Hart, Hannah R; Evans, Andrew N; Gelsleichter, James; Ahearn, Gregory A

2016-10-01

Elasmobranchs are considered to be top marine predators, and in general play important roles in the transfer of energy within marine ecosystems. Despite this, little is known regarding the physiological processes of digestion and nutrient absorption in these fishes. One topic that is particularly understudied is the process of nutrient uptake across the elasmobranch gastrointestinal tract. Given their carnivorous diet, the present study sought to expand knowledge on dietary nutrient uptake in elasmobranchs by focusing on the uptake of products of protein digestion. To accomplish this, a full-length cDNA encoding peptide transporter 1 (PepT1), a protein previously identified within the brush border membrane of vertebrates that is responsible for the translocation of peptides released during digestion by luminal and membrane-bound proteases, was isolated from the bonnethead shark (Sphyrna tiburo). A cDNA encoding the related peptide transporter PepT2 was also isolated from S. tiburo using the same methodology. The presence of PepT1 was then localized in multiple components of the bonnethead digestive tract (esophagus, stomach, duodenum, intestine, rectum, and pancreas) using immunohistochemistry. Vesicle studies were used to identify the apparent affinity of PepT1 and to quantify the rate of dipeptide uptake by its H(+)-dependent cotransporter properties. The results of this study provide insight into the properties of peptide uptake within the bonnethead gut, and can facilitate future work on physiological regulation of protein metabolism and absorption including how these processes may vary in elasmobranchs that exhibit different feeding strategies.

A Bioinformatics Approach for Integrated Transcriptomic and Proteomic Comparative Analyses of Model and Non-sequenced Anopheline Vectors of Human Malaria Parasites*

PubMed Central

Mohien, Ceereena Ubaida; Colquhoun, David R.; Mathias, Derrick K.; Gibbons, John G.; Armistead, Jennifer S.; Rodriguez, Maria C.; Rodriguez, Mario Henry; Edwards, Nathan J.; Hartler, Jürgen; Thallinger, Gerhard G.; Graham, David R.; Martinez-Barnetche, Jesus; Rokas, Antonis; Dinglasan, Rhoel R.

2013-01-01

Malaria morbidity and mortality caused by both Plasmodium falciparum and Plasmodium vivax extend well beyond the African continent, and although P. vivax causes between 80 and 300 million severe cases each year, vivax transmission remains poorly understood. Plasmodium parasites are transmitted by Anopheles mosquitoes, and the critical site of interaction between parasite and host is at the mosquito's luminal midgut brush border. Although the genome of the “model” African P. falciparum vector, Anopheles gambiae, has been sequenced, evolutionary divergence limits its utility as a reference across anophelines, especially non-sequenced P. vivax vectors such as Anopheles albimanus. Clearly, technologies and platforms that bridge this substantial scientific gap are required in order to provide public health scientists with key transcriptomic and proteomic information that could spur the development of novel interventions to combat this disease. To our knowledge, no approaches have been published that address this issue. To bolster our understanding of P. vivax–An. albimanus midgut interactions, we developed an integrated bioinformatic-hybrid RNA-Seq-LC-MS/MS approach involving An. albimanus transcriptome (15,764 contigs) and luminal midgut subproteome (9,445 proteins) assembly, which, when used with our custom Diptera protein database (685,078 sequences), facilitated a comparative proteomic analysis of the midgut brush borders of two important malaria vectors, An. gambiae and An. albimanus. PMID:23082028

A bioinformatics approach for integrated transcriptomic and proteomic comparative analyses of model and non-sequenced anopheline vectors of human malaria parasites.

PubMed

Ubaida Mohien, Ceereena; Colquhoun, David R; Mathias, Derrick K; Gibbons, John G; Armistead, Jennifer S; Rodriguez, Maria C; Rodriguez, Mario Henry; Edwards, Nathan J; Hartler, Jürgen; Thallinger, Gerhard G; Graham, David R; Martinez-Barnetche, Jesus; Rokas, Antonis; Dinglasan, Rhoel R

2013-01-01

Malaria morbidity and mortality caused by both Plasmodium falciparum and Plasmodium vivax extend well beyond the African continent, and although P. vivax causes between 80 and 300 million severe cases each year, vivax transmission remains poorly understood. Plasmodium parasites are transmitted by Anopheles mosquitoes, and the critical site of interaction between parasite and host is at the mosquito's luminal midgut brush border. Although the genome of the "model" African P. falciparum vector, Anopheles gambiae, has been sequenced, evolutionary divergence limits its utility as a reference across anophelines, especially non-sequenced P. vivax vectors such as Anopheles albimanus. Clearly, technologies and platforms that bridge this substantial scientific gap are required in order to provide public health scientists with key transcriptomic and proteomic information that could spur the development of novel interventions to combat this disease. To our knowledge, no approaches have been published that address this issue. To bolster our understanding of P. vivax-An. albimanus midgut interactions, we developed an integrated bioinformatic-hybrid RNA-Seq-LC-MS/MS approach involving An. albimanus transcriptome (15,764 contigs) and luminal midgut subproteome (9,445 proteins) assembly, which, when used with our custom Diptera protein database (685,078 sequences), facilitated a comparative proteomic analysis of the midgut brush borders of two important malaria vectors, An. gambiae and An. albimanus.

EPA blocks TNF-α-induced inhibition of sugar uptake in Caco-2 cells via GPR120 and AMPK.

PubMed

Castilla-Madrigal, Rosa; Barrenetxe, Jaione; Moreno-Aliaga, María J; Lostao, María Pilar

2018-03-01

The aim of the present work was to investigate in Caco-2 cells whether eicosapentaenoic acid (EPA), an omega-3 polyunsaturated fatty acid, could block the inhibitory effect of tumor necrosis factor-α (TNF-α) on sugar transport, and identify the intracellular signaling pathways involved. After pre-incubation of the Caco-2 cells with TNF-α and EPA for 1 hr, EPA prevented the inhibitory effect of the cytokine on α-methyl-d-glucose (αMG) uptake (15 min) and on SGLT1 expression at the brush border membrane, measured by Western blot. The ERK1/2 inhibitor PD98059 and the AMPK activator AICAR also prevented the inhibitory effect of TNF-α on both αMG uptake and SGLT1 expression. Interestingly, the AMPK inhibitor, Compound C, abolished the ability of EPA to prevent TNF-α-induced reduction of sugar uptake and transporter expression. The GPR120 antagonist, AH7614, also blocked the preventive effect of EPA on TNF-α-induced decrease of αMG uptake and AMPK phosphorylation. In summary, TNF-α inhibits αMG uptake by decreasing SGLT1 expression in the brush border membrane through the activation of ERK1/2 pathway. EPA prevents the inhibitory effect of TNF-α through the involvement of GPR120 and AMPK activation. © 2017 Wiley Periodicals, Inc.

Dimerization and actin-bundling properties of villin and its role in the assembly of epithelial cell brush borders.

PubMed

George, Sudeep P; Wang, Yaohong; Mathew, Sijo; Srinivasan, Kamalakkannan; Khurana, Seema

2007-09-07

Villin is a major actin-bundling protein in the brush border of epithelial cells. In this study we demonstrate for the first time that villin can bundle actin filaments using a single F-actin binding site, because it has the ability to self-associate. Using fluorescence resonance energy transfer, we demonstrate villin self-association in living cells in microvilli and in growth factor-stimulated cells in membrane ruffles and lamellipodia. Using sucrose density gradient, size-exclusion chromatography, and matrix-assisted laser desorption ionization time-of-flight, the majority of villin was identified as a monomer or dimer. Villin dimers were also identified in Caco-2 cells, which endogenously express villin and Madin-Darby canine kidney cells that ectopically express villin. Using truncation mutants of villin, site-directed mutagenesis, and fluorescence resonance energy transfer, an amino-terminal dimerization site was identified that regulated villin self-association in parallel conformation as well as actin bundling by villin. This detailed analysis describes for the first time microvillus assembly by villin, redefines the actin-bundling function of villin, and provides a molecular mechanism for actin bundling by villin, which could have wider implications for other actin cross-linking proteins that share a villin-like headpiece domain. Our study also provides a molecular basis to separate the morphologically distinct actin-severing and actin-bundling properties of villin.

Intraluminal polyethylene glycol stabilizes tight junctions and improves intestinal preservation in the rat.

PubMed

Oltean, M; Joshi, M; Björkman, E; Oltean, S; Casselbrant, A; Herlenius, G; Olausson, M

2012-08-01

Rapidly progressing mucosal breakdown limits the intestinal preservation time below 10 h. Recent studies indicate that intraluminal solutions containing polyethylene glycol (PEG) alleviate preservation injury of intestines stored in UW-Viaspan. We investigated whether a low-sodium PEG solution is beneficial for intestines stored in histidine-tryptophane-ketoglutarate (HTK) preservation solution. Rat intestines used as control tissue (group 1) were perfused with HTK, groups 2 and 3 received either a customized PEG-3350 (group 2) or an electrolyte solution (group 3) intraluminally before cold storage. Tissue injury, brush-border maltase activity, zonula occludens-1 (ZO-1) and claudin-3 expression in the tight junctions (TJ) were analyzed after 8, 14 and 20 h. We measured epithelial resistance and permeability (Ussing chamber) after 8 and 14 h. Group 2 had superior morphology while maltase activity was similar in all groups. TJ proteins rapidly decreased and decolocalized in groups 1 3; these negative events were delayed in group 2, where colocalization persisted for about 14 h. Intestines in group 2 had higher epithelial resistance and lower permeability than the other groups. These results suggest that a customized PEG solution intraluminally reduces the intestinal preservation injury by improving several major epithelial characteristics without negatively affecting the brush-border enzymes or promoting edema. © Copyright 2012 The American Society of Transplantation and the American Society of Transplant Surgeons.

Dbl3 drives Cdc42 signaling at the apical margin to regulate junction position and apical differentiation

PubMed Central

Zihni, Ceniz; Munro, Peter M.G.; Elbediwy, Ahmed; Keep, Nicholas H.; Terry, Stephen J.; Harris, John

2014-01-01

Epithelial cells develop morphologically characteristic apical domains that are bordered by tight junctions, the apical–lateral border. Cdc42 and its effector complex Par6–atypical protein kinase c (aPKC) regulate multiple steps during epithelial differentiation, but the mechanisms that mediate process-specific activation of Cdc42 to drive apical morphogenesis and activate the transition from junction formation to apical differentiation are poorly understood. Using a small interfering RNA screen, we identify Dbl3 as a guanine nucleotide exchange factor that is recruited by ezrin to the apical membrane, that is enriched at a marginal zone apical to tight junctions, and that drives spatially restricted Cdc42 activation, promoting apical differentiation. Dbl3 depletion did not affect junction formation but did affect epithelial morphogenesis and brush border formation. Conversely, expression of active Dbl3 drove process-specific activation of the Par6–aPKC pathway, stimulating the transition from junction formation to apical differentiation and domain expansion, as well as the positioning of tight junctions. Thus, Dbl3 drives Cdc42 signaling at the apical margin to regulate morphogenesis, apical–lateral border positioning, and apical differentiation. PMID:24379416

Regulated Production of Mineralization-competent Matrix Vesicles in Hypertrophic Chondrocytes

PubMed Central

Kirsch, Thorsten; Nah, Hyun-Duck; Shapiro, Irving M.; Pacifici, Maurizio

1997-01-01

Matrix vesicles have a critical role in the initiation of mineral deposition in skeletal tissues, but the ways in which they exert this key function remain poorly understood. This issue is made even more intriguing by the fact that matrix vesicles are also present in nonmineralizing tissues. Thus, we tested the novel hypothesis that matrix vesicles produced and released by mineralizing cells are structurally and functionally different from those released by nonmineralizing cells. To test this hypothesis, we made use of cultures of chick embryonic hypertrophic chondrocytes in which mineralization was triggered by treatment with vitamin C and phosphate. Ultrastructural analysis revealed that both control nonmineralizing and vitamin C/phosphatetreated mineralizing chondrocytes produced and released matrix vesicles that exhibited similar round shape, smooth contour, and average size. However, unlike control vesicles, those produced by mineralizing chondrocytes had very strong alkaline phosphatase activity and contained annexin V, a membrane-associated protein known to mediate Ca2+ influx into matrix vesicles. Strikingly, these vesicles also formed numerous apatite-like crystals upon incubation with synthetic cartilage lymph, while control vesicles failed to do so. Northern blot and immunohistochemical analyses showed that the production and release of annexin V-rich matrix vesicles by mineralizing chondrocytes were accompanied by a marked increase in annexin V expression and, interestingly, were followed by increased expression of type I collagen. Studies on embryonic cartilages demonstrated a similar sequence of phenotypic changes during the mineralization process in vivo. Thus, chondrocytes located in the hypertrophic zone of chick embryo tibial growth plate were characterized by strong annexin V expression, and those located at the chondro–osseous mineralizing border exhibited expression of both annexin V and type I collagen. These findings reveal that hypertrophic chondrocytes can qualitatively modulate their production of matrix vesicles and only when induced to initiate mineralization, will release mineralization-competent matrix vesicles rich in annexin V and alkaline phosphatase. The occurrence of type I collagen in concert with cartilage matrix calcification suggests that the protein may facilitate crystal growth after rupture of the matrix vesicle membrane; it may also offer a smooth transition from mineralized type II/type X collagen-rich cartilage matrix to type I collagen-rich bone matrix. PMID:9166414

Carbachol regulation of rabbit ileal brush border Na+–H+ exchanger 3 (NHE3) occurs through changes in NHE3 trafficking and complex formation and is Src dependent

PubMed Central

Li, Xuhang; Zhang, Huiping; Cheong, Alice; Yueping Chen, Sharon Leu; Elowsky, Christian G; Donowitz, Mark

2004-01-01

The epithelial brush border membrane (BBM) Na+–H+ exchanger 3 (NHE3) is the major transport protein responsible for ileal electroneutral Na+ absorption. We have previously shown that ileal BBM NHE3 activity is rapidly inhibited by carbachol, an agonist that mimics cholinergic activation in digestion. In this study, we investigated the mechanisms involved in this NHE3 inhibition. Carbachol decreased the amount of ileal Na+ absorptive cell BBM NHE3 within 10 min of exposure. Based on OptiPrep gradient centrifugation, carbachol increased the amount of NHE3 in early endosomes and decreased the amount of NHE3 in BBM, consistent with effects on NHE3 trafficking. The decrease in BBM NHE3 occurred in the detergent-soluble BBM fraction with no change in the amount of NHE3 in the BBM detergent-resistant membranes. The size of BBM NHE3 complexes increased in carbachol-exposed ileum, as studied with sucrose gradient centrifugation. The NHE3 complex size increased in the total BBM, but did not change in the detergent-soluble fraction. This suggests that carbachol treatment enhanced the association of proteins with NHE3 complexes specifically in the detergent-resistant fraction of ileal BBM. NHERF2, α-actinin-4 and protein kinase C were among those NHE3-associated proteins because they were more efficiently coimmunoprecipitated from total BBM after carbachol treatment. Moreover, Src was involved in the carbachol-mediated inhibition since: (1) c-Src was rapidly activated in the detergent-resistant membranes by carbachol; and (2) carbachol inhibition of ileal Na+ absorption was completely abolished by the Src family inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2). Moreover, the carbachol-induced increase in the size of NHE3-containing complexes was reversed by PP2. These data demonstrate that regulation of NHE3 activity by carbachol can be achieved at several interrelated levels: (1) the subcellular level, at which NHE3 is rapidly endocytosed from BBM to endocytic vesicles upon treatment with carbachol; (2) multiple BBM pools, in which carbachol selectively decreases the amount of NHE3 in the BBM detergent-soluble fraction but not the detergent-resistant membrane; and (3) the molecular level, at which NHE3 complex-associated proteins can be changed upon carbachol treatment, with carbachol leading to larger BBM NHE3 complexes and increased co-IP of NHERF2 with α-actinin-4 and activated PKC. The study further describes NHE3 presence simultaneously in multiple dynamic BBM pools in which NHE3 distribution and associated proteins are altered as part of carbachol-induced and Src-mediated rapid signal transduction, which decreases the amount of BBM NHE3 and thus inhibits NHE3 activity. PMID:14978207

Biologically Complex Planar Cell Plasma Membranes Supported on Polyelectrolyte Cushions Enhance Transmembrane Protein Mobility and Retain Native Orientation.

PubMed

Liu, Han-Yuan; Chen, Wei-Liang; Ober, Christopher K; Daniel, Susan

2018-01-23

Reconstituted supported lipid bilayers (SLB) are widely used as in vitro cell-surface models because they are compatible with a variety of surface-based analytical techniques. However, one of the challenges of using SLBs as a model of the cell surface is the limited complexity in membrane composition, including the incorporation of transmembrane proteins and lipid diversity that may impact the activity of those proteins. Additionally, it is challenging to preserve the transmembrane protein native orientation, function, and mobility in SLBs. Here, we leverage the interaction between cell plasma membrane vesicles and polyelectrolyte brushes to create planar bilayers from cell plasma membrane vesicles that have budded from the cell surface. This approach promotes the direct incorporation of membrane proteins and other species into the planar bilayer without using detergent or reconstitution and preserves membrane constituents. Furthermore, the structure of the polyelectrolyte brush serves as a cushion between the planar bilayer and rigid supporting surface, limiting the interaction of the cytosolic domains of membrane proteins with this surface. Single particle tracking was used to analyze the motion of GPI-linked yellow fluorescent proteins (GPI-YFP) and neon-green fused transmembrane P2X2 receptors (P2X2-neon) and shows that this platform retains over 75% mobility of multipass transmembrane proteins in its native membrane environment. An enzyme accessibility assay confirmed that the protein orientation is preserved and results in the extracellular domain facing toward the bulk phase and the cytosolic side facing the support. Because the platform presented here retains the complexity of the cell plasma membrane and preserves protein orientation and mobility, it is a better representative mimic of native cell surfaces, which may find many applications in biological assays aimed at understanding cell membrane phenomena.

Studies on the Electrical Potential Profile across Rabbit Ileum

PubMed Central

Rose, Richard C.; Schultz, Stanley G.

1971-01-01

When isolated strips of mucosal rabbit ileum are bathed by physiological electrolyte solution the electrical potential difference (PD) across the brush border (ψmc) averages 36 mv, cell interior negative. Rapid replacement of Na in the mucosal solution with less permeant cations, Tris or choline, results in an immediate hyperpolarization of ψmc. Conversely, replacement of choline in the mucosal solution with Na results in an abrupt depolarization of ψmc. These findings indicate that Na contributes to the conductance across the brush border. The presence of actively transported sugars or amino acids in the mucosal solution brings about a marked depolarization of ψmc and a smaller increase in the transmural PD (Δψms). It appears that the Na influx that is coupled to the influxes of amino acids and sugars is electrogenic and responsible for the depolarization of ψmc. Under control conditions Δψms can be attributed to the depolarization of ψmc together with the presence of a low resistance transepithelial shunt, possibly the lateral intercellular spaces. However, quantitatively similar effects of amino acids on ψmc are also seen in tissues poisoned with metabolic inhibitors or ouabain. Under these conditions Δψmc is much smaller than under control conditions. Thus, the depolarization of ψmc might not account for the entire Δψms, observed in nonpoisoned tissue. An additional electromotive force which is directly coupled to metabolic processes might contribute to the normal Δψms. PMID:5576764

Water pumps.

PubMed

Loo, Donald D F; Wright, Ernest M; Zeuthen, Thomas

2002-07-01

The transport of water across epithelia has remained an enigma ever since it was discovered over 100 years ago that water was transported across the isolated small intestine in the absence of osmotic and hydrostatic pressure gradients. While it is accepted that water transport is linked to solute transport, the actual mechanisms are not well understood. Current dogma holds that active ion transport sets up local osmotic gradients in the spaces between epithelial cells, the lateral intercellular spaces, and this in turn drives water transport by local osmosis. In the case of the small intestine, which in humans absorbs about 8 l of water a day, there is no direct evidence for either local osmosis or aquaporin gene expression in enterocytes. Intestinal water absorption is greatly enhanced by glucose, and this is the basis for oral rehydration therapy in patients with secretory diarrhoea. In our studies of the intestinal brush border Na+-glucose cotransporter we have obtained evidence that there is a direct link between the transport of Na+, glucose and water transport, i.e. there is cotransport of water along with Na+ and sugar, that will account for about 50 % of the total water transport across the human intestinal brush border membrane. In this short review we summarize the evidence for water cotransport and propose how this occurs during the enzymatic turnover of the transporter. This is a general property of cotransporters and so we expect that this may have wider implications in the transport of water and other small polar molecules across cell membranes in animals and plants.

Lipids in the proximal convoluted tubule of the cat kidney and the reabsorption of cholesterol.

PubMed

Bargmann, W; Krisch, B; Leonhardt, H

1977-02-14

Lipid deposits in the cat kidney are mainly located in the epithelium of the proximal tubuli contorti, particularly in the pars contorta. As the amount of fatty acids in the blood of renal arteries is higher than in renal veins, the lipid inclusions are likely to be formed in the proximal convoluted tubule. Whether fat occurring in the urine has been released from the nephron epithelium and the mode of this release remains obscure. The structural equivalent of lipid extrusion into the tubules has not been observed. Components of the tubular lipids include triglycerides, phosphoglycerides and cholesterol. The results of the digitonin-cholesterol reaction favour the assumption that cholesterol is eliminated in the glomeruli and pinocytotically reabsorbed by the brush border cells, this process possibly serving recycling of this compound. The dilated basal labyrinth and intercellular space contain perpendicularly oriented lipid accumulations that reach the basal lamina. The ultrastructure of the lipid storing cells of pars contorta reacting positively for phosphoglyceride and cholesterol is characterised mainly by bodies with marginal plates. As far as can be judged from their morphology, these bodies are interpreted as large peroxisomes. A special feature of the pars recta are dumbbell shaped bodies and elongated or cup-like mitochondria concentrically surrounding cytoplasmic areas, as well as a well-developed smooth ER. In what way the organelles of the brush border cells are involved in catabolic and anabolic processes as far as renal lipid metabolism is concerned remains to be answered.

Protein-Linked Glycan Degradation in Infants Fed Human Milk

PubMed Central

Dallas, David C.; Sela, David; Underwood, Mark A.; German, J. Bruce; Lebrilla, Carlito

2014-01-01

Many human milk proteins are glycosylated. Glycosylation is important in protecting bioactive proteins and peptide fragments from digestion. Protein-linked glycans have a variety of functions; however, there is a paucity of information on protein-linked glycan degradation in either the infant or the adult digestive system. Human digestive enzymes can break down dietary disaccharides and starches, but most of the digestive enzymes required for complex protein-linked glycan degradation are absent from both human digestive secretions and the external brush border membrane of the intestinal lining. Indeed, complex carbohydrates remain intact throughout their transit through the stomach and small intestine, and are undegraded by in vitro incubation with either adult pancreatic secretions or intact intestinal brush border membranes. Human gastrointestinal bacteria, however, produce a wide variety of glycosidases with regio- and anomeric specificities matching those of protein-linked glycan structures. These bacteria degrade a wide array of complex carbohydrates including various protein-linked glycans. That bacteria possess glycan degradation capabilities, whereas the human digestive system, perse, does not, suggests that most dietary protein-linked glycan breakdown will be of bacterial origin. In addition to providing a food source for specific bacteria in the colon, protein-linked glycans from human milk may act as decoys for pathogenic bacteria to prevent invasion and infection of the host. The composition of the intestinal microbiome may be particularly important in the most vulnerable humans-the elderly, the immunocompromised, and infants (particularly premature infants). PMID:24533224

Acrosome reaction in spermatozoa from the amphioxus Branchiostoma belcheri (Cephalochordata, Chordata).

PubMed

Morisawa, Sachiko; Mizuta, Takanobu; Kubokawa, Kaoru; Tanaka, Hiroyuki; Morisawa, Masaaki

2004-11-01

The formation of an acrosomal process at acrosomal exocytosis in spermatozoa of the amphioxus was described in the present report for the first time. A non-reacted acrosome was located in front of the nucleus, where a cup-shaped acrosomal vesicle covered a conical accumulation of subacrosomal material. When naturally spawned spermatozoa were treated with a calcium ionophore, ionomycin, the acrosomal vesicle opened at the apex and an acrosomal process was projected. The process exhibited a filamentous structure. The reaction followed the mode typically seen in marine invertebrates. These observations suggest that the features and function of the acrosome of amphioxus, whose position is on the border between invertebrates and vertebrates, reflect their ecological adaptation and phylogenic position.

Na+-dependent and Na+-independent betaine transport across the apical membrane of rat renal epithelium.

PubMed

Cano, Mercedes; Calonge, María L; Ilundáin, Anunciación A

2015-10-01

The low renal excretion of betaine indicates that the kidney efficiently reabsorbs the betaine filtered by the glomeruli but the mechanisms involved in such a process have been scarcely investigated. We have detected concentrative and non-concentrative betaine transport activity in brush-border membrane vesicles (BBMV) from rat renal cortex and medulla. The concentrative system is the Sodium/Imino-acid Transporter 1 (SIT1) because it is Na+- and Cl--dependent, electrogenic and is inhibited by an anti-SIT1 antibody. Its apparent affinity constant for betaine, Kt, is 1.1±0.5 mM and its maximal transport velocity, Vmax, 0.5±0.1 nmol betaine/mg protein/s. Inhibitors of the Na+/Cl-/betaine uptake are L-proline (75%) and cold betaine, L-carnitine and choline (40-60%). Neither creatine, TEA, taurine, β-alanine, GABA nor glycine significantly inhibited Na+/Cl-/betaine uptake. The non-concentrative betaine transport system is Na+- and H+-independent, electroneutral, with a Kt for betaine of 47±7 μM and a Vmax of 7.8±1 pmol betaine/mg protein/s. Its transport activity is nearly abolished by betaine, followed by L-carnitine (70-80%) and proline (40-50%), but a difference from the Na+/Cl-/betaine transport is that it is inhibited by TEA (approx. 50%) and unaffected by choline. The underlying carrier functions as an antiporter linking betaine entry into the BBMV with the efflux of either L-carnitine or betaine, an exchange unaffected by the anti-SIT1 antibody. As far as we know this is the first work reporting that betaine crosses the apical membrane of rat renal epithelium by SIT1 and by a Na+- and H+-independent transport system. Copyright © 2015 Elsevier B.V. All rights reserved.

Bitrophic and tritrophic effects of Bt Cry3A transgenic potato on beneficial, non-target, beetles.

PubMed

Ferry, Natalie; Mulligan, Evan A; Majerus, Michael E N; Gatehouse, Angharad M R

2007-12-01

Insect-resistant transgenic plants have been suggested to have unpredictable effects on the biodiversity of the agro-ecosystem, including potential effects on insect natural enemies, beneficial in control of crop pests. Whilst carnivorous as adults, many of these predators may also consume plant tissues, in particular plant pollen and nectar. Coleoptera are important in terms of agro-ecological research not only because of the large number of species in this order, but also because of their role as biological control agents. Thus any detrimental impact on this group of insects would be highly undesirable. The effects of potato expressing the coleopteran-specific Bacillus thuringiensis delta-endotoxin Cry3A (Bt Cry3A) on the ladybird beetle Harmonia axyridis and the carabid beetle Nebria brevicollis were investigated via the bitrophic interaction of the adult ladybird with potato flowers and the tritrophic interaction of the carabid consuming a non-target potato pest. Immunoassays confirmed accumulation of the transgene product in potato leaves and floral tissues (at levels of up to 0.01% (pollen) and 0.0285% (anthers) of total soluble protein). Despite H. axyridis and N. brevicollis belonging to the targeted insect order, no significant effects upon survival or overall body mass change of either beetle were observed. Furthermore, Bt Cry3A had no detrimental effects on reproductive fitness of either beetle species, either in terms of fecundity or subsequent egg viability. Behavioural analysis revealed no significant impact of Bt Cry3A on beetle activity or locomoter behaviour. Ligand blots indicate that this is due to either the absence of Bt-binding sites in brush border membrane vesicles (BBMV) isolated from Nebria brevicollis, or in the case of Harmonia axyridis, the binding did not functionally lead to behavioural or physical effects.

Insecticidal spectrum and mode of action of the Bacillus thuringiensis Vip3Ca insecticidal protein.

PubMed

Gomis-Cebolla, Joaquín; Ruiz de Escudero, Iñigo; Vera-Velasco, Natalia Mara; Hernández-Martínez, Patricia; Hernández-Rodríguez, Carmen Sara; Ceballos, Tomás; Palma, Leopoldo; Escriche, Baltasar; Caballero, Primitivo; Ferré, Juan

2017-01-01

The Vip3Ca protein, discovered in a screening of Spanish collections of Bacillus thuringiensis, was known to be toxic to Chrysodeixis chalcites, Mamestra brassicae and Trichoplusia ni. In the present study, its activity has been tested with additional insect species and we found that Cydia pomonella is moderately susceptible to this protein. Vip3Ca (of approximately 90kDa) was processed to an approximately 70kDa protein when incubated with midgut juice in all tested species. The kinetics of proteolysis correlated with the susceptibility of the insect species to Vip3Ca. The activation was faster to slower in the following order: M. brassicae (susceptible), Spodoptera littoralis (moderately susceptible), Agrotis ipsilon and Ostrinia nubilalis (slightly susceptible). Processing Vip3Ca by O. nubilalis or M. brassicae midgut juice did not significantly changed its toxicity to either insect species, indicating that the low susceptibility of O. nubilalis is not due to a problem in the midgut processing of the toxin. M. brassicae larvae fed with Vip3Ca showed binding of this toxin to the apical membrane of the midgut epithelial cells. Histopathological inspection showed sloughing of the epithelial cells with further disruption, which suggests that the mode of action of Vip3Ca is similar to that described for Vip3Aa. Biotin-labeled Vip3Ca and Vip3Aa bound specifically to M. brassicae brush border membrane vesicles and both toxins competed for binding sites. This result suggests that insects resistant to Vip3A may also be cross-resistant to Vip3C, which has implications for Insect Resistance Management (IRM). Copyright © 2016 Elsevier Inc. All rights reserved.

Regulation of renal NaPi-2 expression and tubular phosphate reabsorption by growth hormone in the juvenile rat.

PubMed

Woda, Craig B; Halaihel, Nabil; Wilson, Paul V; Haramati, Aviad; Levi, Moshe; Mulroney, Susan E

2004-07-01

Growth hormone (GH) is an important factor in the developmental adaptation to enhance P(i) reabsorption; however, the nephron sites and mechanisms by which GH regulates renal P(i) uptake remain unclear and are the focus of the present study. Micropuncture experiments were performed after acute thyroparathyroidectomy in the presence and absence of parathyroid hormone (PTH) in adult (14- to 17-wk old), juvenile (4-wk old), and GH-suppressed juvenile male rats. While the phosphaturic effect of PTH was blunted in the juvenile rat compared with the adult, suppression of GH in the juvenile restored fractional P(i) excretion to adult levels. In the presence or absence of PTH, GH suppression in the juvenile rat caused a significant increase in the fractional P(i) delivery to the late proximal convoluted (PCT) and early distal tubule, so that delivery was not different from that in adults. These data were confirmed by P(i) uptake studies into brush-border membrane (BBM) vesicles. Immunofluorescence studies indicate increased BBM type IIa NaP(i) cotransporter (NaPi-2) expression in the juvenile compared with adult rat, and GH suppression reduced NaPi-2 expression to levels observed in the adult. GH replacement in the [N-acetyl-Tyr(1)-d-Arg(2)]-GRF-(1-29)-NH(2)-treated juveniles restored high NaPi-2 expression and P(i) uptake. Together, these novel results demonstrate that the presence of GH in the juvenile animal is crucial for the early developmental upregulation of BBM NaPi-2 and, most importantly, describe the enhanced P(i) reabsorption along the PCT and proximal straight nephron segments in the juvenile rat.

Differential cystine and dibasic amino acid handling after loss of function of the amino acid transporter b0,+AT (Slc7a9) in mice.

PubMed

Di Giacopo, Andrea; Rubio-Aliaga, Isabel; Cantone, Alessandra; Artunc, Ferruh; Rexhepaj, Rexhep; Frey-Wagner, Isabelle; Font-Llitjós, Mariona; Gehring, Nicole; Stange, Gerti; Jaenecke, Isabel; Mohebbi, Nilufar; Closs, Ellen I; Palacín, Manuel; Nunes, Virginia; Daniel, Hannelore; Lang, Florian; Capasso, Giovambattista; Wagner, Carsten A

2013-12-15

Cystinuria is an autosomal recessive disease caused by mutations in SLC3A1 (rBAT) and SLC7A9 (b(0,+)AT). Gene targeting of the catalytic subunit (Slc7a9) in mice leads to excessive excretion of cystine, lysine, arginine, and ornithine. Here, we studied this non-type I cystinuria mouse model using gene expression analysis, Western blotting, clearance, and brush-border membrane vesicle (BBMV) uptake experiments to further characterize the renal and intestinal consequences of losing Slc7a9 function. The electrogenic and BBMV flux studies in the intestine suggested that arginine and ornithine are transported via other routes apart from system b(0,+). No remarkable gene expression changes were observed in other amino acid transporters and the peptide transporters in the intestine and kidney. Furthermore, the glomerular filtration rate (GFR) was reduced by 30% in knockout animals compared with wild-type animals. The fractional excretion of arginine was increased as expected (∼100%), but fractional excretions of lysine (∼35%), ornithine (∼16%), and cystine (∼11%) were less affected. Loss of function of b(0,+)AT reduced transport of cystine and arginine in renal BBMVs and completely abolished the exchanger activity of dibasic amino acids with neutral amino acids. In conclusion, loss of Slc7a9 function decreases the GFR and increases the excretion of several amino acids to a lesser extent than expected with no clear regulation at the mRNA and protein level of alternative transporters and no increased renal epithelial uptake. These observations indicate that transporters located in distal segments of the kidney and/or metabolic pathways may partially compensate for Slc7a9 loss of function.

Transgenic cotton coexpressing Vip3A and Cry1Ac has a broad insecticidal spectrum against lepidopteran pests.

PubMed

Chen, Wen-Bo; Lu, Guo-Qing; Cheng, Hong-Mei; Liu, Chen-Xi; Xiao, Yu-Tao; Xu, Chao; Shen, Zhi-Cheng; Wu, Kong-Ming

2017-10-01

Although farmers in China have grown transgenic Bt-Cry1Ac cotton to resist the major pest Helicoverpa armigera since 1997 with great success, many secondary lepidopteran pests that are tolerant to Cry1Ac are now reported to cause considerable economic damage. Vip3AcAa, a chimeric protein with the N-terminal part of Vip3Ac and the C-terminal part of Vip3Aa, has a broad insecticidal spectrum against lepidopteran pests and has no cross resistance to Cry1Ac. In the present study, we tested insecticidal activities of Vip3AcAa against Spodoptera litura, Spodoptera exigua, and Agrotis ipsilon, which are relatively tolerant to Cry1Ac proteins. The bioassay results showed that insecticidal activities of Vip3AcAa against these three pests are superior to Cry1Ac, and after an activation pretreatment, Vip3AcAa retained insecticidal activity against S. litura, S. exigua and A. ipsilon that was similar to the unprocessed protein. The putative receptor for this chimeric protein in the brush border membrane vesicle (BBMV) in the three pests was also identified using biotinylated Vip3AcAa toxin. To broaden Bt cotton activity against a wider spectrum of pests, we introduced the vip3AcAa and cry1Ac genes into cotton. Larval mortality rates for S. litura, A. ipsilon and S. exigua that had fed on this new cotton increased significantly compared with larvae fed on non-Bt cotton and Bt-Cry1Ac cotton in a laboratory experiment. These results suggested that the Vip3AcAa protein is an excellent option for a "pyramid" strategy for integrated pest management in China. Copyright © 2017 Elsevier Inc. All rights reserved.

Binding Site Concentration Explains the Differential Susceptibility of Chilo suppressalis and Sesamia inferens to Cry1A-Producing Rice

PubMed Central

Han, Chao; Liu, Zewen; Chen, Fajun; Hou, Maolin; Peng, Yufa

2014-01-01

Chilo suppressalis and Sesamia inferens are two important lepidopteran rice pests that occur concurrently during outbreaks in paddy fields in the main rice-growing areas of China. Previous and current field tests demonstrate that the transgenic rice line Huahui 1 (HH1) producing a Cry1Ab-Cry1Ac hybrid toxin from the bacterium Bacillus thuringiensis reduces egg and larval densities of C. suppressalis but not of S. inferens. This differential susceptibility to HH1 rice correlates with the reduced susceptibility to Cry1Ab and Cry1Ac toxins in S. inferens larvae compared to C. suppressalis larvae. The goal of this study was to identify the mechanism responsible for this differential susceptibility. In saturation binding assays, both Cry1Ab and Cry1Ac toxins bound with high affinity and in a saturable manner to midgut brush border membrane vesicles (BBMV) from C. suppressalis and S. inferens larvae. While binding affinities were similar, a dramatically lower concentration of Cry1A toxin binding sites was detected for S. inferens BBMV than for C. suppressalis BBMV. In contrast, no significant differences between species were detected for Cry1Ca toxin binding to BBMV. Ligand blotting detected BBMV proteins binding Cry1Ac or Cry1Ca toxins, some of them unique to C. suppressalis or S. inferens. These data support that reduced Cry1A binding site concentration is associated with a lower susceptibility to Cry1A toxins and HH1 rice in S. inferens larvae than in C. suppressalis larvae. Moreover, our data support Cry1Ca as a candidate for pyramiding efforts with Cry1A-producing rice to extend the activity range and durability of this technology against rice stem borers. PMID:24928872

Milan hypertensive rat as a model for studying cation transport abnormality in genetic hypertension

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferrari, P.; Barber, B.R.; Torielli, L.

1987-11-01

Environmental factors, genetic polymorphisms, and different experimental designs have been the main impediments to evaluating a genetic association between cell membrane cation transport abnormalities and human essential or genetic hypertension. We review the results obtained in the Milan hypertensive strain of rats (MHS) and in its appropriate control normotensive strain (MNS) to illustrate our approach to defining the role of cation transport abnormality in a type of genetic hypertension. Before the development of a difference in blood pressure between the two strains, the comparison of kidney and erythrocyte functions showed that MHS had an increased glomerular filtration rate and urinarymore » output, and lower plasma renin and urine osmolality. Kidney cross-transplantation between the strains showed that hypertension is transplanted with the kidney. Proximal tubular cell volume and sodium content were lower in MHS while sodium transport across the brush border membrane vesicles of MHS was faster. Erythrocytes in MHS were smaller and had lower sodium concentration, and Na+-K+ cotransport and passive permeability were faster. The differences in volume, sodium content, and Na+-K+ cotransport between erythrocytes of the two strains persisted after transplantation of bone marrow to irradiated F1 (MHS X MNS) hybrids. Moreover, in normal segregating F2 hybrid populations there was a positive correlation between blood pressure and Na+-K+ cotransport. These results suggest a genetic and functional link in MHS between cell membrane cation transport abnormalities and hypertension. Thus, erythrocyte cell membrane may be used for approaching the problem of defining the genetically determined molecular mechanism underlying the development of a type of essential hypertension. 35 references.« less

The efficacy of a novel insecticidal protein, Allium sativum leaf lectin (ASAL), against homopteran insects monitored in transgenic tobacco.

PubMed

Dutta, Indrajit; Saha, Prasenjit; Majumder, Pralay; Sarkar, Anindya; Chakraborti, Dipankar; Banerjee, Santanu; Das, Sampa

2005-11-01

The homopteran group of polyphagous sucking insect pests causes severe damage to many economically important plants including tobacco. Allium sativum leaf lectin (ASAL), a mannose-binding 25-kDa homodimeric protein, has recently been found to be antagonistic to various sucking insects in the homopteran group through artificial diet bioassay experiments. The present study describes, for the first time, the expression of the ASAL coding sequence under the control of the cauliflower mosaic virus (CaMV) 35S promoter in tobacco by Agrobacterium-mediated transformation technology. Molecular analyses demonstrated the integration of the chimeric ASAL gene in tobacco and its inheritance in the progeny plants. Western blot analysis followed by enzyme-linked immunosorbent assay (ELISA) determined the level of ASAL expression in different lines to be in the range of approximately 0.68%-2% of total soluble plant protein. An in planta bioassay conducted with Myzus persicae, peach potato aphid (a devastating pest of tobacco and many other important plants), revealed that the percentage of insect survival decreased significantly to 16%-20% in T0 plants and T1 progeny, whilst approximately 75% of insects survived on untransformed tobacco plants after 144 h of incubation. Ligand analyses of insect brush border membrane vesicle receptors and expressed ASAL in transgenic tobacco showed that the expressed ASAL binds to the aphid gut receptor in the same manner as native ASAL, pointing to the fact that ASAL maintains the biochemical characteristics even in the transgenic situation. These findings in a model plant open up the possibility of expressing the novel ASAL gene in a wide range of crop plants susceptible to various sap-sucking insects.

Inactivation by omeprazole of the carnitine transporter (OCTN2) reconstituted in liposomes.

PubMed

Pochini, Lorena; Scalise, Mariafrancesca; Indiveri, Cesare

2009-05-15

The effect of omeprazole on the carnitine (OCTN2) transporter reconstituted in liposomes has been studied. Omeprazole externally added to the proteoliposomes, inhibited the carnitine/carnitine antiport catalysed by the reconstituted transporter. The inhibition was partially reversed by DTE indicating that it was caused by the covalent reaction of omeprazole with Cys residue(s) of the transporter. Similar results were found with intact brush border vesicles. The residual inhibition of the transport in the presence of DTE, indicated the occurrence of an alternative inhibition mechanism of non-covalent nature. The IC(50) of the two inhibition modes derived from dose-response curves, were 5.7 microM and 20.4 microM, respectively. Kinetic studies of the inhibition showed that in the absence of DTE omeprazole behaved as non-competitive inhibitor. On the contrary, in the presence of DTE competitive inhibition was found. The K(i) of the transporter for the inhibitor was 5.2 microM or 14.6 microM in the absence or presence of DTE, i.e., under condition of covalent (non-competitive) or non-covalent (competitive) interaction of the inhibitor with the transporter. The presence of the substrate during the incubation of the omeprazole (in the absence of DTE) with the proteoliposomes facilitated the covalent reaction of the pharmacological compound with the transporter. Omeprazole did not inhibit when present in the internal proteoliposomal compartment, indicating that the inhibition was specifically due to interaction with external site(s) of the protein. The pharmacological compound was not transported by the reconstituted transporter. The possible in vivo implications of the interaction of omeprazole with the transporter are discussed.

Modulation of ileal bile acid transporter (ASBT) activity by depletion of plasma membrane cholesterol: association with lipid rafts

PubMed Central

Annaba, Fadi; Sarwar, Zaheer; Kumar, Pradeep; Saksena, Seema; Turner, Jerrold R.; Dudeja, Pradeep K.; Gill, Ravinder K.; Alrefai, Waddah A.

2016-01-01

Apical sodium-dependent bile acid transporter (ASBT) represents a highly efficient conservation mechanism of bile acids via mediation of their active transport across the luminal membrane of terminal ileum. To gain insight into the cellular regulation of ASBT, we investigated the association of ASBT with cholesterol and sphingolipid-enriched specialized plasma membrane microdomains known as lipid rafts and examined the role of membrane cholesterol in maintaining ASBT function. Human embryonic kidney (HEK)-293 cells stably transfected with human ASBT, human ileal brush-border membrane vesicles, and human intestinal epithelial Caco-2 cells were utilized for these studies. Floatation experiments on Optiprep density gradients demonstrated the association of ASBT protein with lipid rafts. Disruption of lipid rafts by depletion of membrane cholesterol with methyl-β-cyclodextrin (MβCD) significantly reduced the association of ASBT with lipid rafts, which was paralleled by a decrease in ASBT activity in Caco-2 and HEK-293 cells treated with MβCD. The inhibition in ASBT activity by MβCD was blocked in the cells treated with MβCD-cholesterol complexes. Kinetic analysis revealed that MβCD treatment decreased the Vmax of the transporter, which was not associated with alteration in the plasma membrane expression of ASBT. Our study illustrates that cholesterol content of lipid rafts is essential for the optimal activity of ASBT and support the association of ASBT with lipid rafts. These findings suggest a novel mechanism by which ASBT activity may be rapidly modulated by alterations in cholesterol content of plasma membrane and thus have important implications in processes related to maintenance of bile acid and cholesterol homeostasis. PMID:18063707

Different natriuretic responses in obese and lean rats in response to nitric oxide reduction.

PubMed

Ambrozewicz, Marta A; Khraibi, Ali A; Simsek-Duran, Fatma; DeBose, Sophia C; Baydoun, Hind A; Dobrian, Anca D

2011-08-01

Nitric oxide (NO) is an important regulator of renal sodium transport and participates in the control of natriuresis and diuresis. In obesity, the nitric oxide bioavailability was reportedly reduced, which may contribute to the maintenance of hypertension. The aim of this study was to determine the effect of NO depletion on renal sodium handling in a model of diet-induced obesity hypertension. Obese hypertensive (obesity-prone (OP)) and lean normotensive (obesity-resistant (OR)) Sprague-Dawley rats were treated with 1.2 mg/kg/day N(G)-nitro-L-arginine-methyl ester (L-NAME) for 4 weeks to inhibit NO synthesis. Acute pressure natriuresis and diuresis were measured in response to an increase in perfusion pressure. NHE3 and Na(+), K(+)-ATPase protein expression were measured by Western blot and NHE3 activity was determined as the rate of pH change in brush border membrane vesicles. NHE3 membrane localization was determined by confocal microscopy. L-NAME did not significantly attenuate the natriuretic and diuretic responses to increases in renal perfusion pressure (RPP) in OP rats while inducing a significant reduction in OR rats. Following chronic NO inhibition, NHE3 protein expression and activity and Na(+), K(+)-ATPase protein expression were significantly increased in the OR but not in the OP group. Immunofluorescence studies indicated that the increase in NHE3 activity could be, at least in part, due to NHE3 membrane trafficking. Obese hypertensive rats have a weaker natriuretic response in response to NO inhibition compared to lean rats and the mechanism involves different regulation of the apical sodium exchanger NHE3 expression, activity, and trafficking.

Iran-Iraq Border Quake Region Imaged by NASA Satellite

NASA Image and Video Library

2017-11-15

On Sunday, Nov. 12, 2017, a magnitude 7.3 earthquake struck along the Iran-Iraq border near Halabjah, Iraq. The earthquake was felt as far away as Kuwait, Qatar, Turkey, Lebanon and Israel. Extensive damage and numerous casualties were reported in the area near the epicenter (yellow star on image). The earthquake occurred along the boundary between the Arabian and Eurasian tectonic plates. This is an earthquake-prone area, and has experienced many deadly earthquakes in the past. In this perspective-view image, bright red areas are crops in fields, pale red on mountain ridges are shrubs and trees, dark gray areas are traces of earlier brush fires, and gray and tan colors are different rock types. The image was acquired Sept. 8, 2017, and the star marks the earthquake epicenter at 34.9 degrees north, 45.9 degrees east. https://photojournal.jpl.nasa.gov/catalog/PIA22112

Recombinant VSV G proteins reveal a novel raft-dependent endocytic pathway in resorbing osteoclasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mulari, Mika T.K.; Centre for Military Medicine, Research Department, Lahti; Nars, Martin

2008-05-01

Transcytotic membrane flow delivers degraded bone fragments from the ruffled border to the functional secretory domain, FSD, in bone resorbing osteoclasts. Here we show that there is also a FSD-to-ruffled border trafficking pathway that compensates for the membrane loss during the matrix uptake process and that rafts are essential for this ruffled border-targeted endosomal pathway. Replacing the cytoplasmic tail of the vesicular stomatitis virus G protein with that of CD4 resulted in partial insolubility in Triton X-100 and retargeting from the peripheral non-bone facing plasma membrane to the FSD. Recombinant G proteins were subsequently endosytosed and delivered from the FSDmore » to the peripheral fusion zone of the ruffled border, which were both rich in lipid rafts as suggested by viral protein transport analysis and visualizing the rafts with fluorescent recombinant cholera toxin. Cholesterol depletion by methyl-{beta}-cyclodextrin impaired the ruffled border-targeted vesicle trafficking pathway and inhibited bone resorption dose-dependently as quantified by measuring the CTX and TRACP 5b secreted to the culture medium and by measuring the resorbed area visualized with a bi-phasic labeling method using sulpho-NHS-biotin and WGA-lectin. Thus, rafts are vital for membrane recycling from the FSD to the late endosomal/lysosomal ruffled border and bone resorption.« less

[Current concepts of digestion and absorption of carbohydrates].

PubMed

Luz, S dos S; de Campos, P L; Ribeiro, S M; Tirapegui, J

1997-01-01

The aim of this paper is to review recent aspects of digestion and absorption of carbohydrates that are the main source of energy in human diets. Recent researches have found that starch is not largely hydrolysed and absorbed in the small bowel but one part of it is resistant to digestion. Several food factors may be responsible for digestion and absorption velocity and totality of carbohydrates. Therefore, carbohydrate classification must be based not only on molecular size to express the real carbohydrates utilization as an energy source by humans. In agreement with molecular size of carbohydrate, its classification can be: a) monosaccharides; b) disaccharides; c) oligosaccharides; d) polysaccharides. In agreement with carbohydrate digestibility or availability, its classification can be: a) digestible carbohydrates; b) undigestable carbohydrates (NSP). Carbohydrate digestibility can be altered by several factors like: Intrinsic factors: a) physical structure; b) molecular physical distribution; c) physical state of food; d) food antinutrients. Extrinsics factors: a) chewing; b) transit time of food; c) amount of starch present; d) diet antinutrients. Under influence of this factors, process of digestion happen by enzymatic activity a long the gastrointestinal tract. Salivary and pancreatic amylase; glycosidases of the duodenal enterocyte brush border (lactase, sacarase and maltase), whose activity happen by close interaction of digestive breakdown with transport. The summarized pathways of the absorptive process: 1. movement from the bulk phase of the lumenal or mucosal fluid to enterocyte surface; 2. movement across the brush border membrane through specific transporters: a) SGLT1; b) GLUT 5; c) passive diffusion. 3. movement across the basolateral membrane by the GLUT 2.

Effects of protease, phytase and a Bacillus sp. direct-fed microbial on nutrient and energy digestibility, ileal brush border digestive enzyme activity and cecal short-chain fatty acid concentration in broiler chickens.

PubMed

Murugesan, Ganapathi R; Romero, Luis F; Persia, Michael E

2014-01-01

Two experiments were conducted to determine the effects of protease and phytase (PP) and a Bacillus sp. direct-fed microbial (DFM) on dietary energy and nutrient utilization in broiler chickens. In the first experiment, Ross 308 broiler chicks were fed diets supplemented with PP and DFM in a 2×2 factorial arrangement. The 4 diets (control (CON), CON + PP, CON + DFM, and CON + PP + DFM) were fed from 15-21 days of age. In Experiment 1, significant interaction (P≤0.01) between PP and DFM on the apparent ileal digestibility coefficient for starch, crude protein, and amino acid indicated that both additives increased the digestibility. Both additives increased the nitrogen retention coefficient with a significant interaction (P≤0.01). Although no interaction was observed, significant main effects (P≤0.01) for nitrogen-corrected apparent ME (AMEn) for PP or DFM indicated an additive response. In a follow-up experiment, Ross 308 broiler chicks were fed the same experimental diets from 1-21 days of age. Activities of ileal brush border maltase, sucrase, and L-alanine aminopeptidase were increased (P≤0.01) by PP addition, while a trend (P = 0.07) for increased sucrase activity was observed in chickens fed DFM, in Experiment 2. The proportion of cecal butyrate was increased (P≤0.01) by DFM addition. Increased nutrient utilization and nitrogen retention appear to involve separate but complementary mechanisms for PP and DFM, however AMEn responses appear to have separate and additive mechanisms.

Transmissible Gastroenteritis in Feeder Pigs: Observations on the Jejunal Epithelium of Normal Feeder Pigs and Feeder Pigs Infected with TGE Virus

PubMed Central

Morin, M.; Morehouse, L. G.

1974-01-01

Light and electron microscopy findings in the jejunal mucosa of the normal feeder pig and feeder pigs infected with transmissible gastroenteritis (TGE) virus are reported. Villi in the mid jejunum of the normal feeder pig were elongated, finger shaped and covered with a layer of columnar absorptive cells with a well developed and regular brush border. Severe lesions of villous atrophy were present in all jejunal segments of feeder swine killed 96 hours post infection with TGE virus. Atrophic villi were covered by flat to cuboidal cells with a poorly developed brush border in some areas. In other segments, cells varied in appearance from sub-columnar to columnar type of near normal appearance. The ultrastructure of the jejunal absorptive cells in the normal feeder pig was found to be similar to that described for the jejunal cells of other adult mammals. There were no significant indications of high pinocytotic activity. The epithelial cells covering the atrophic villi of TGE infected pigs had a fine structure similar to that described for the crypt cells, ranging in appearance from very immature to moderately differentiated cells. Microvilli were very short, decreased markedly in number and irregular in arrangement. The terminal web was poorly developed. Strands of rough endoplasmic reticulum were markedly diminished and an increase in free ribosomes was noted. The significance of these observations in explaining pathogenesis of TGE in feeder pigs is discussed. ImagesFig. 1.Fig. 2.Fig. 3.Fig. 4.Fig. 5.Fig. 6.Fig. 7.Fig. 8. PMID:4277743

Impaired organic ion transport in proximal tubules of rats with Heymann nephritis.

PubMed

Park, E K; Hong, S K; Goldinger, J; Andres, G; Noble, B

1985-10-01

Organic ion transport across the basolateral membrane of proximal tubules was measured by means of the tissue slice technique in each of the four different stages of Heymann nephritis. Impairment of both organic anion and cation transport was detected early in Stage 2, and became more severe in Stage 3 of Heymann nephritis. The decreased transport function was associated with extensive damage to proximal tubule cells, including loss of brush border microvilli and basal infoldings. Despite these abnormalities of structure and function, oxygen consumption of proximal tubule cells remained essentially normal. Partial recovery of organic cation transport was noted late in Heymann nephritis (Stage 4). Recovery of the cation transport function was associated with a partial restoration of brush border microvilli and basal infoldings to proximal tubule cells. However, organic anion transport remained depressed throughout the entire course of disease. Impairment of organic ion transport in rats with Heymann nephritis appeared to result from damage to basolateral membrane transport elements rather than general deterioration of the metabolic machinery of proximal tubule cells. Decreased organic cation transport appeared to be the consequence of a reduction in the number of carrier sites, a phenomenon that could have resulted from decreased membrane surface area. However, the depression of organic anion transport was associated with decreased substrate affinity of the anion carrier, indicating that qualitative, rather than quantitative changes, were primarily responsible for that defect. Specific antibody-mediated damage to the anion transport elements in basolateral membranes of proximal tubules is postulated to occur in Heymann nephritis.

Inhibition of gentamicin binding to rat renal brush-border membrane by megalin ligands and basic peptides.

PubMed

Nagai, Junya; Saito, Masaki; Adachi, Yoshinori; Yumoto, Ryoko; Takano, Mikihisa

2006-05-01

Our previous studies showed that coadministration of cytochrome c and a 20-residue basic peptide, N-WASP181-200 (NISHTKEKKKGKAKKKRLTK, pI=10.87) inhibits renal accumulation of gentamicin. In this study, we examined effects of ligands of megalin, an endocytic receptor involved in renal uptake of gentamicin, and basic peptides including N-WASP180-200 and its mutant peptides on gentamicin binding to isolated rat renal brush-border membrane (BBM). Gentamicin binding to BBM was inhibited by megalin ligands, basic peptide fragments of cytochrome c, and N-WASP181-200 in a concentration-dependent manner. Klotz plot analysis showed that N-WASP181-200 inhibited the binding of gentamicin in a competitive manner. By substituting glycines for lysines in N-WASP181-200 at positions 9 and 15, the inhibitory effect on gentamicin binding to BBM was reduced, which may be related to a decrease in the alpha-helix content in the peptide. Gentamicin binding to BBM treated with trypsin, in which megalin completely disappeared, was significantly but not completely decreased compared with the native BBM. In addition, treatment of BBM with trypsin led to a decrease in the inhibitory effect of N-WASP181-200 on gentamicin binding. These observations support that megalin ligands and basic peptides including N-WASP181-200 decrease renal accumulation of gentamicin by inhibiting its binding to BBM of proximal tubule cells, partly interacting with megalin. In addition, the alpha-helix conformation may play an important role in the inhibitory effect of N-WASP181-200 on the binding of gentamicin to BBM.

Water pumps

PubMed Central

Loo, Donald D F; Wright, Ernest M; Zeuthen, Thomas

2002-01-01

The transport of water across epithelia has remained an enigma ever since it was discovered over 100 years ago that water was transported across the isolated small intestine in the absence of osmotic and hydrostatic pressure gradients. While it is accepted that water transport is linked to solute transport, the actual mechanisms are not well understood. Current dogma holds that active ion transport sets up local osmotic gradients in the spaces between epithelial cells, the lateral intercellular spaces, and this in turn drives water transport by local osmosis. In the case of the small intestine, which in humans absorbs about 8 l of water a day, there is no direct evidence for either local osmosis or aquaporin gene expression in enterocytes. Intestinal water absorption is greatly enhanced by glucose, and this is the basis for oral rehydration therapy in patients with secretory diarrhoea. In our studies of the intestinal brush border Na+-glucose cotransporter we have obtained evidence that there is a direct link between the transport of Na+, glucose and water transport, i.e. there is cotransport of water along with Na+ and sugar, that will account for about 50 % of the total water transport across the human intestinal brush border membrane. In this short review we summarize the evidence for water cotransport and propose how this occurs during the enzymatic turnover of the transporter. This is a general property of cotransporters and so we expect that this may have wider implications in the transport of water and other small polar molecules across cell membranes in animals and plants. PMID:12096049

Cleistanthus collinus induces type I distal renal tubular acidosis and type II respiratory failure in rats.

PubMed

Maneksh, Delinda; Sidharthan, Anita; Kettimuthu, Kavithapriya; Kanthakumar, Praghalathan; Lourthuraj, Amala A; Ramachandran, Anup; Subramani, Sathya

2010-06-01

A water decoction of the poisonous shrub Cleistanthus collinus is used for suicidal purposes. The mortality rate is 28%. The clinical profile includes distal renal tubular acidosis (DRTA) and respiratory failure. The mechanism of toxicity is unclear. To demonstrate features of C. collinus toxicity in a rat model and to identify its mechanism(s) of action. Rats were anesthetized and the carotid artery was cannulated. Electrocardiogram and respiratory movements were recorded. Either aqueous extract of C. collinus or control solution was administered intraperitoneally. Serial measurements of blood gases, electrolytes and urinary pH were made. Isolated brush border and basolateral membranes from rat kidney were incubated with C. collinus extract and reduction in ATPase activity was assessed. Venous blood samples from human volunteers and rats were incubated with an acetone extract of C. collinus and plasma potassium was estimated as an assay for sodium-potassium pump activity. The mortality was 100% in tests and 17% in controls. Terminal event in test animals was respiratory arrest. Controls had metabolic acidosis, respiratory compensation acidic urine and hyperkalemia. Test animals showed respiratory acidosis, alkaline urine and low blood potassium as compared to controls. C. collinus extract inhibited ATPase activity in rat kidney. Plasma K(+) did not increase in human blood incubated with C. collinus extract. Active principles of C. collinus inhibit proton pumps in the renal brush border, resulting in type I DRTA in rats. There is no inhibition of sodium-potassium pump activity. Test animals develop respiratory acidosis, and the immediate cause of death is respiratory arrest.

F4+ enterotoxigenic Escherichia coli (ETEC) adhesion mediated by the major fimbrial subunit FaeG.

PubMed

Xia, Pengpeng; Song, Yujie; Zou, Yajie; Yang, Ying; Zhu, Guoqiang

2015-09-01

The FaeG subunit is the major constituent of F4(+) fimbriae, associated with glycoprotein and/or glycolipid receptor recognition and majorly contributes to the pathogen attachment to the host cells. To investigate the key factor involved in the fimbrial binding of F4(+) Escherichia coli, both the recombinant E. coli SE5000 strains carrying the fae operon gene clusters that express the different types of fimbriae in vitro, named as rF4ab, rF4ac, and rF4ad, respectively, corresponding to the fimbrial types F4ab, F4ac, and F4ad, and the three isogenic in-frame faeG gene deletion mutants were constructed. The adhesion assays and adhesion inhibition assays showed that ΔfaeG mutants had a significant reduction in the binding to porcine brush border as well as the intestinal epithelial cell lines, while the complemented strain ΔfaeG/pfaeG restored the adhesion function. The recombinant bacterial strains rF4ab, rF4ac, and rF4ad have the same binding property as wild-type F4(+) E. coli strains do and improvement in terms of binding to porcine brush border and the intestinal epithelial cells, and the adherence was blocked by the monoclonal antibody anti-F4 fimbriae. These data demonstrate that the fimbrial binding of F4(+) E. coli is directly mediated by the major FaeG subunit. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Early Biochemical Effects of an Organic Mercury Fungicide on Infants: ``Dose Makes the Poison''

NASA Astrophysics Data System (ADS)

Gotelli, Carlos A.; Astolfi, Emilio; Cox, Christopher; Cernichiari, Elsa; Clarkson, Thomas W.

1985-02-01

Phenylmercury absorbed through the skin from contaminated diapers affected urinary excretion in infants in Buenos Aires. The effects were reversible and quantitatively related to the concentration of urinary mercury. Excretion of γ -glutamyl transpeptidase, an enzyme in the brush borders of renal tubular cells, increased in a dose-dependent manner when mercury excretion exceeded a ``threshold'' value. Urine volume also increased but at a higher threshold with respect to mercury. The results support the threshold concept of the systemic toxicity of metals. γ -Glutamyl transpeptidase is a useful and sensitive marker for preclinical effects of toxic metals.

TU-AB-303-06: Does Online Adaptive Radiation Therapy Mean Zero Margin for Intermediate-Risk Prostate Cancer? An Intra-Fractional Seminal Vesicles Motion Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, Y; Li, T; Lee, W

Purpose: To provide benchmark for seminal vesicles (SVs) margin selection to account for intra-fractional motion; and to investigate the effectiveness of two motion surrogates in predicting intra-fractional SV underdosage. Methods: 9 prostate SBRT patients were studied; each has five pairs of pre-treatment and post-treatment cone-beam CTs (CBCTs). Each pair of CBCTs was registered based on fiducial markers in the prostate. To provide “ground truth” for coverage evaluation, all pre-treatment SVs were expanded with isotropic margin of 1,2,3,5 and 8mm, and their overlap with post-treatment SVs were used to quantify intra-fractional coverage. Two commonly used motion surrogates, the center-of-mass (COM) andmore » the border of contour (the most distal points in SI/AP/LR directions) were evaluated using Receiver-Operating Characteristic (ROC) analyses for predicting SV underdosage due to intra-fractional motion. Action threshold of determining underdosage for each surrogate was calculated by selecting the optimal balancing between sensitivity and specificity. For comparison, margin for each surrogate was also calculated based on traditional margin recipe. Results: 90% post-treatment SV coverage can be achieved in 47%, 82%, 91%, 98% and 98% fractions for 1,2,3,5 and 8mm margins. 3mm margin ensured the 90% intra-fractional SV coverage in 90% fractions when prostate was aligned. The ROC analysis indicated the AUC for COM and border were 0.88 and 0.72. The underdosage threshold was 2.9mm for COM and 4.1mm for border. The Van Herk’s margin recipe recommended 0.5, 0 and 1.8mm margin in LR, AP and SI direction based on COM and for border, the corresponding margin was 2.1, 4.5 and 3mm. Conclusion: 3mm isotropic margin is the minimum required to mitigate the intra-fractional SV motion when prostate is aligned. ROC analysis reveals that both COM and border are acceptable predictors for SV underdosage with 2.9mm and 4.1mm action threshold. Traditional margin calculation is less reliable for this application. This work is partially supported a master research grant from Varian Medical Systems.« less

Restoring effect of selenium on the molecular content, structure and fluidity of diabetic rat kidney brush border cell membrane.

PubMed

Gurbanov, Rafig; Bilgin, Mehmet; Severcan, Feride

2016-04-01

Diabetic kidney disease (DKD) is a dominant factor standing for kidney impairments during diabetes. In this study, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used to disclose the diabetes-induced structural changes in the kidney and evaluate the effects of selenium on diabetes. The increase in the area of the olefinic band indicated increased amount of lipid peroxidation end products in diabetic kidney brush border cell membrane. Moreover, saturated lipid content of this cell membrane considerably diminished. DKD was found to disrupt lipid order and cause a decrease in membrane dynamics. However, the administration of selenium at low and medium doses was shown to improve these conditions by changing the lipid contents toward control values, restoring the ordered structure of the lipids and membrane dynamics. Curve-fitting and artificial neural network (ANN) analyses of secondary structures of proteins demonstrated a relative increase in α-helix and reduction in the β-sheet during diabetes in comparison to the control group, which were ameliorated following selenium treatment at low and medium doses. These findings were further confirmed by applying hierarchical cluster analysis (HCA) and principal component analysis (PCA). A clear separation of the experimental groups was obtained with high heterogeneity in the lipid and protein regions. These chemometric analyses showed that the low and medium doses of selenium-treated diabetic groups are successfully segregated from the diabetic group and clustered closer to the control. The study suggests that medium and, more predominantly, low-dose selenium treatment can be efficient in eliminating diabetes-induced structural alterations. Copyright © 2016 Elsevier B.V. All rights reserved

The effect of big endothelin-1 in the proximal tubule of the rat kidney

PubMed Central

Beara-Lasić, Lada; Knotek, Mladen; Čejvan, Kenan; Jakšić, Ozren; Lasić, Zoran; Skorić, Boško; Brkljačić, Vera; Banfić, Hrvoje

1997-01-01

An obligatory step in the biosynthesis of endothelin-1 (ET-1) is the conversion of its inactive precursor, big ET-1, into the mature form by the action of specific, phosphoramidon-sensitive, endothelin converting enzyme(s) (ECE). Disparate effects of big ET-1 and ET-1 on renal tubule function suggest that big ET-1 might directly influence renal tubule function. Therefore, the role of the enzymatic conversion of big ET-1 into ET-1 in eliciting the functional response (generation of 1,2-diacylglycerol) to big ET-1 was studied in the rat proximal tubules.In renal cortical slices incubated with big ET-1, pretreatment with phosphoramidon (an ECE inhibitor) reduced tissue immunoreactive ET-1 to a level similar to that of cortical tissue not exposed to big ET-1. This confirms the presence and effectiveness of ECE inhibition by phosphoramidon.In freshly isolated proximal tubule cells, big ET-1 stimulated the generation of 1,2-diacylglycerol (DAG) in a time- and dose-dependent manner. Neither phosphoramidon nor chymostatin, a chymase inhibitor, influenced the generation of DAG evoked by big ET-1.Big ET-1-dependent synthesis of DAG was found in the brush-border membrane. It was unaffected by BQ123, an ETA receptor antagonist, but was blocked by bosentan, an ETA,B-nonselective endothelin receptor antagonist.These results suggest that the proximal tubule is a site for the direct effect of big ET-1 in the rat kidney. The effect of big ET-1 is confined to the brush-border membrane of the proximal tubule, which may be the site of big ET-1-sensitive receptors. PMID:9051300

Vigabatrin transport across the human intestinal epithelial (Caco-2) brush-border membrane is via the H+-coupled amino-acid transporter hPAT1

PubMed Central

Abbot, Emily L; Grenade, Danielle S; Kennedy, David J; Gatfield, Kelly M; Thwaites, David T

2005-01-01

The aim of this investigation was to determine if the human proton-coupled amino-acid transporter 1 (hPAT1 or SLC36A1) is responsible for the intestinal uptake of the orally-administered antiepileptic agent 4-amino-5-hexanoic acid (vigabatrin). The Caco-2 cell line was used as a model of the human small intestinal epithelium. Competition experiments demonstrate that [3H]GABA uptake across the apical membrane was inhibited by vigabatrin and the GABA analogues trans-4-aminocrotonic acid (TACA) and guvacine, whereas 1-(aminomethyl)cyclohexaneacetic acid (gabapentin) had no affect. Experiments with 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-loaded Caco-2 cells demonstrate that apical exposure to vigabatrin and TACA induce comparable levels of intracellular acidification (due to H+/amino-acid symport) to that generated by GABA, suggesting that they are substrates for a H+-coupled absorptive transporter such as hPAT1. In hPAT1 and mPAT1-expressing Xenopus laevis oocytes [3H]GABA uptake was inhibited by vigabatrin, TACA and guvacine, whereas gabapentin failed to inhibit [3H]GABA uptake. In Na+-free conditions, vigabatrin and TACA evoked similar current responses (due to H+/amino-acid symport) in hPAT1-expressing oocytes under voltage-clamp conditions to that induced by GABA (whereas no current was observed in water-injected oocytes) consistent with the ability of these GABA analogues to inhibit [3H]GABA uptake. This study demonstrates that hPAT1 is the carrier responsible for the uptake of vigabatrin across the brush-border membrane of the small intestine and emphasises the therapeutic potential of hPAT1 as a delivery route for orally administered, clinically significant GABA-related compounds. PMID:16331283

Effects of Protease, Phytase and a Bacillus sp. Direct-Fed Microbial on Nutrient and Energy Digestibility, Ileal Brush Border Digestive Enzyme Activity and Cecal Short-Chain Fatty Acid Concentration in Broiler Chickens

PubMed Central

Murugesan, Ganapathi R.; Romero, Luis F.; Persia, Michael E.

2014-01-01

Two experiments were conducted to determine the effects of protease and phytase (PP) and a Bacillus sp. direct-fed microbial (DFM) on dietary energy and nutrient utilization in broiler chickens. In the first experiment, Ross 308 broiler chicks were fed diets supplemented with PP and DFM in a 2×2 factorial arrangement. The 4 diets (control (CON), CON + PP, CON + DFM, and CON + PP + DFM) were fed from 15–21 days of age. In Experiment 1, significant interaction (P≤0.01) between PP and DFM on the apparent ileal digestibility coefficient for starch, crude protein, and amino acid indicated that both additives increased the digestibility. Both additives increased the nitrogen retention coefficient with a significant interaction (P≤0.01). Although no interaction was observed, significant main effects (P≤0.01) for nitrogen-corrected apparent ME (AMEn) for PP or DFM indicated an additive response. In a follow-up experiment, Ross 308 broiler chicks were fed the same experimental diets from 1–21 days of age. Activities of ileal brush border maltase, sucrase, and L-alanine aminopeptidase were increased (P≤0.01) by PP addition, while a trend (P = 0.07) for increased sucrase activity was observed in chickens fed DFM, in Experiment 2. The proportion of cecal butyrate was increased (P≤0.01) by DFM addition. Increased nutrient utilization and nitrogen retention appear to involve separate but complementary mechanisms for PP and DFM, however AMEn responses appear to have separate and additive mechanisms. PMID:25013936

Activation of intestinal brush border guanylate cyclase by aromatic disulphide compounds.

PubMed Central

elDeib, M M; Parker, C D; White, A A

1991-01-01

Guanylate cyclase in pig intestinal brush border membranes was stimulated by certain aromatic disulphides. The most effective were 6-thioguanine disulphide [(TGS)2], 6-mercaptopurine disulphide, 6,6'-dithiodinicotinic acid, 5,5'-dithiobis-(2-nitrobenzoic acid) and 5-carboxy-2-thiouracil disulphide. (TGS)2 stimulated activity 15-fold when present at 0.1 mM. The optimum concentration for each disulphide was different, and higher concentrations were inhibitory. There was no activation by alkyl disulphides or by N-ethylmaleimide. Activation by 50 microM-(TGS)2 was partially reversed by later addition of 0.1 mM-dithiothreitol, whereas activation by the Escherichia coli heat-stable enterotoxin STa was relatively unaffected. Pretreatment of the membranes with (TGS)2 produced a concentration-dependent inhibition of STa-stimulated activity, while stimulating basal activity, until the activities were equal at 50 microM. Activity was [Mg2+]-dependent, the optimal [Mg2+] progressively increasing as the enzyme was stimulated by (TGS)2, STa and Lubrol PX respectively. However, (TGS)2 pretreatment prevented the shift to higher [Mg2+]optima induced by STa or Lubrol alone. Substitution of Mn2+ for Mg2+ in the reaction elevated basal activity and eliminated by activation (TGS)2. (TGS)2 only inhibited Mn2(+)-dependent activity (both basal and stimulated). The affinity of 125I-STa for its receptor was slightly increased by (TGS)2. We propose that (TGS)2 undergoes thiol-disulphide exchange with at least three different protein thiols of decreasing reactivity. The first is associated with Mg2(+)-dependent activation, the second is associated with a tonic inhibition of activity and the third is associated with the catalytic activity, although probably not at the active site. PMID:1673335

Food grade titanium dioxide disrupts intestinal brush border microvilli in vitro independent of sedimentation.

PubMed

Faust, James J; Doudrick, Kyle; Yang, Yu; Westerhoff, Paul; Capco, David G

2014-06-01

Bulk- and nano-scale titanium dioxide (TiO2) has found use in human food products for controlling color, texture, and moisture. Once ingested, and because of their small size, nano-scale TiO2 can interact with a number of epithelia that line the human gastrointestinal tract. One such epithelium responsible for nutrient absorption is the small intestine, whose constituent cells contain microvilli to increase the total surface area of the gut. Using a combination of scanning and transmission electron microscopy it was found that food grade TiO2 (E171 food additive coded) included ∼25% of the TiO2 as nanoparticles (NPs; <100 nm), and disrupted the normal organization of the microvilli as a consequence of TiO2 sedimentation. It was found that TiO2 isolated from the candy coating of chewing gum and a commercially available TiO2 food grade additive samples were of the anatase crystal structure. Exposure to food grade TiO2 additives, containing nanoparticles, at the lowest concentration tested within this experimental paradigm to date at 350 ng/mL (i.e., 100 ng/cm(2) cell surface area) resulted in disruption of the brush border. Through the use of two independent techniques to remove the effects of gravity, and subsequent TiO2 sedimentation, it was found that disruption of the microvilli was independent of sedimentation. These data indicate that food grade TiO2 exposure resulted in the loss of microvilli from the Caco-2BBe1 cell system due to a biological response, and not simply a physical artifact of in vitro exposure.

Structural and functional development of small intestine in intrauterine growth retarded porcine offspring born to gilts fed diets with differing protein ratios throughout pregnancy.

PubMed

Mickiewicz, M; Zabielski, R; Grenier, B; Le Normand, L; Savary, G; Holst, J J; Oswald, I P; Metges, C C; Guilloteau, P

2012-06-01

Protein level in the maternal diet plays a crucial role in fetal programming during pregnancy. Low or high protein level increases the risk of intrauterine growth retardation (IUGR). The aim of this study was to investigate the structural and functional development of the small intestine in piglets from sows fed a control (C, 12.1% protein), a high protein (HP, 30% protein), or a low protein (LP, 6.5% protein) diet during pregnancy. Newborns were classified as IUGR (birth weight ≤1.18 kg) and non-IUGR (birth weight >1.18 kg). The piglets were euthanized on postnatal day (PD)1, PD28 and PD188. The LP diet in non-IUGR neonates resulted in decreased body weight on PD1. The LP and HP diets resulted in both decreased body weight and delayed catch-up growth in the IUGR piglets. The HP and LP-diets increased the length of villi on PD1 in non-IUGRs but not in IUGRs. At birth, the expressions of Ki67 and active caspase 3 in mid-jejunum epithelium of HP and LP non-IUGR neonates were significantly lower as compared to C non-IUGRs whilst in IUGRs the respective expressions were as high as in C non-IUGRs. The postnatal dynamics of brush border enzyme activities and vacuolated enterocytes disappearance showed significant drop in enterocyte maturation in IUGR as compared to non-IUGR neonates. In conclusion, both HP and LP diets led to retarded development of non-IUGR piglets. In IUGR piglets both HP and LP diets resulted in delayed catch-up growth, without adaptive changes in brush border digestive enzymes.

Studies on the uptake of fatty acids by brush border membranes of the rabbit intestine.

PubMed

Proulx, P; Aubry, H; Brglez, I; Williamson, D G

1985-04-01

Initial studies revealed that the uptake of palmitic acid and oleic acid into brush border membranes was similar when these were isolated from either whole small intestine, jejunum, or ileum. The uptake of these fatty acids was somewhat lower with membranes obtained from duodenum. Subsequent studies, all with membranes obtained from whole intestine, indicated an increase in binding with chain length of fatty acid of up to 16 carbons. Unsaturation decreased this uptake somewhat. Taurocholate and 1-palmitoyl lysolecithin had a moderate stimulatory effect on the binding of oleic acid and palmitic acid at concentrations of 10 and 0.5 mM, respectively, and inhibited at higher concentrations. Addition of 1.4 mM egg lecithin to the fatty acid - bile salt micelles, such that the lecithin - bile salt ratio was 0.2, decreased the uptake of fatty acids generally, but did not significantly affect the pattern of binding by membrane fractions isolated from different segments nor did it change the pattern of labelling when fatty acid chain length and unsaturation were varied. At lower concentrations, egg lecithin had little effect on the uptake of oleic acid, whereas dipalmitoyl phosphatidylcholine stimulated binding of both palmitic acid and oleic acid over the entire range of concentrations tested. Preincubation of the membranes with this saturated phospholipid stimulated the uptake of oleic acid, and addition of this choline lipid to the oleic acid - bile salt containing micelles did not substantially enhance fatty acid uptake in lipid-treated membranes. The binding of fatty acid was very rapid either in the presence or the absence of Ca2+, such that even in zero-time controls essentially equilibrium bindings were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Two-phase vesicles: a study on evolutionary and stationary models.

PubMed

Sahebifard, MohammadMahdi; Shahidi, Alireza; Ziaei-Rad, Saeed

2017-05-01

In the current article, the dynamic evolution of two-phase vesicles is presented as an extension to a previous stationary model and based on an equilibrium of local forces. In the simplified model, ignoring the effects of membrane inertia, a dynamic equilibrium between the membrane bending potential and local fluid friction is considered in each phase. The equilibrium equations at the domain borders are completed by extended introduction of membrane section reactions. We show that in some cases, the results of stationary and evolutionary models are in agreement with each other and also with experimental observations, while in others the two models differ markedly. The value of our approach is that we can account for unresponsive points of uncertainty using our equations with the local velocity of the lipid membranes and calculating the intermediate states (shapes) in the consequent evolutionary, or response, path.

Vesicular glutamate transporters VGLUT1 and VGLUT2 define two subsets of unipolar brush cells in organotypic cultures of mouse vestibulocerebellum.

PubMed

Nunzi, M G; Russo, M; Mugnaini, E

2003-01-01

Different isoforms of a vesicular glutamate transporter (VGLUT) mediate glutamate uptake into synaptic vesicles of excitatory neurons. There is agreement that the VGLUTs are differentially expressed in brain, and that two isoforms, VGLUT1 and VGLUT2, are localized to excitatory axon terminals in the cerebellar cortex. While granule cells express solely VGLUT1, there is no report about the VGLUT(s) of the unipolar brush cell (UBC), the second type of glutamatergic interneuron residing in the cerebellar granular layer. In the mouse, UBCs are particularly numerous in the uvula (lobule IX) and nodulus (lobule X). These folia contain two distinct subsets of UBCs: one kind expresses the calcium-binding protein calretinin (CR), and the other kind expresses the metabotropic glutamate receptor (mGluR) 1alpha. UBCs give rise to an extensive system of intrinsic mossy fibers (MF), whose terminals innervate granule cells and other UBCs, altogether similar to those formed by the extrinsic MFs. The presence of both extrinsic and intrinsic MFs in the vestibulocerebellum makes it difficult to determine which type of VGLUT is contained in MFs formed by the UBC axons. Hence, the nodulus was isolated from sagittal cerebellar slices from postnatal day 10 mice, and cultured for 15-20 days in vitro. Double immunofluorescence and confocal microscopy showed that mossy terminals of CR-positive (CR(+)) UBCs were immunoreactive for VGLUT1 and VGLUT2, while mossy terminals of mGluR1alpha-positive (mGluR1alpha(+)) UBCs were provided with VGLUT1 only. Moreover, CR(+) dendritic brushes were contacted by mossy terminals provided with both transporters, while mGluR1alpha(+) dendritic brushes were contacted by mossy terminals immunopositive for VGLUT1 and immunonegative for VGLUT2. These data indicate that the two UBC subsets use different modalities of vesicular glutamate storage and form separate networks. We consider it possible that expressions of CR with VGLUT1/VGLUT2 and mGluR1alpha(+) with VGLUT1 in the two subsets of vestibulocerebellar UBCs are determined by specific vestibular inputs, carried by groups of primary and/or secondary vestibular afferents.

Design and field results of a walk-through EDS

NASA Astrophysics Data System (ADS)

Wendel, Gregory J.; Bromberg, Edward E.; Durfee, Memorie K.; Curby, William A.

1997-01-01

A walk-through portal sampling module which incorporates active sampling has been developed. The module uses opposing wands which actively brush the subjects exterior clothing to disturb explosive traces. These traces are entrained in an air stream and transported to a High Speed GC- chemiluminescence explosives detection system. This combination provides automatic screening of passengers at rates of 10 per minute. The system exhibits sensitivity and selectivity which equals or betters that available from commercially available manual equipment. The systems has been developed for deployment at border crossings, airports and other security screening points. Detailed results of laboratory tests and airport field trials are reviewed.

Gadolinium and didymium (praseodymium/neodymium) cations as capture agents in lightmicroscopical histochemistry of acid and alkaline phosphatase.

PubMed

Halbhuber, K J; Zimmermann, N

1987-01-01

In previous papers, cerium and lanthanum based methods for light-microscopical detection of acid and alkaline phosphatase activity were proposed. In this paper, the usefulness of other lanthanide cations such as gadolinium and praseodymium/neodymium cations as capture agents in phosphatase histochemistry is tested. It is evident that phosphate ions were sufficiently trapped by these cations. According to the lead and silver multistep procedures earlier described it is possible to visualize alkaline phosphatase activity in the brush borders of the intestine or kidney as well as acid phosphatase activity in the lysosomes. These methods can be recommended.

D-sorbose inhibits disaccharidase activity and demonstrates suppressive action on postprandial blood levels of glucose and insulin in the rat.

PubMed

Oku, Tsuneyuki; Murata-Takenoshita, Yoko; Yamazaki, Yuko; Shimura, Fumio; Nakamura, Sadako

2014-11-01

In an attempt to develop D-sorbose as a new sweetener that could help in preventing lifestyle-related diseases, we investigated the inhibitory effect of D-sorbose on disaccharidase activity, using the brush border membrane vesicles of rat small intestines. The inhibitory effect was compared with that of L-sorbose and other rare sugars, and the small intestinal disaccharidases in rats was compared with that of humans as well. In humans and the small intestines of rats, d-sorbose strongly inhibited sucrase activity and weakly inhibited maltase activity. Inhibition by D-sorbose of sucrase activity was similar to that of L-arabinose, and the K(i) of D-sorbose was 7.5 mM. Inhibition by D-sorbose was very strong in comparison with that of L-sorbose (K(i), 60.8 mM), whereas inhibition of d-tagatose was between that of D-sorbose and L-sorbose. The inhibitory mode of D-sorbose for sucrose and maltase was uncompetitive, and that of L-sorbose was competitive. To determine a suppressive effect on postprandial blood levels of glucose and insulin via inhibition of sucrase activity, sucrose solution with or without D-sorbose was administered to rats. Increments in the blood levels of glucose and insulin were suppressed significantly after administration of sucrose solution with D-sorbose to rats, in comparison to administration of sucrose solution without D-sorbose. In contrast, the suppressive effect of L-sorbose on postprandial blood levels of glucose and insulin was very weak. These results suggest that D-sorbose may have an inhibitory effect on disaccharidase activity and could be used as a sweetener to suppress the postprandial elevation of blood levels of glucose and insulin. The use of D-sorbose as a sweetener may contribute to the prevention of lifestyle-related diseases, such as type 2 diabetes mellitus. Copyright © 2014 Elsevier Inc. All rights reserved.

Bacillus thuringiensis Cry1Ia10 and Vip3Aa protein interactions and their toxicity in Spodoptera spp. (Lepidoptera).

PubMed

Bergamasco, V B; Mendes, D R P; Fernandes, O A; Desidério, J A; Lemos, M V F

2013-02-01

The polyphagous pests belonging to the genus Spodoptera are considered to be among the most important causes of damage and are widely distributed throughout the Americas'. Due to the extensive use of genetically modified plants containing Bacillus thuringiensis genes that code for insecticidal proteins, resistant insects may arise. To prevent the development of resistance, pyramided plants, which express multiple insecticidal proteins that act through distinct mode of actions, can be used. This study analyzed the mechanisms of action for the proteins Cry1Ia10 and Vip3Aa on neonatal Spodoptera frugiperda, Spodoptera albula, Spodoptera eridania and Spodoptera cosmioides larvae. The interactions of these toxins with receptors on the intestinal epithelial membrane were also analyzed by binding biotinylated toxins to brush border membrane vesicles (BBMVs) from the intestines of these insects. A putative receptor of approximately 65 kDa was found by ligand blotting in all of these species. In vitro competition assays using biotinylated proteins have indicated that Vip3Aa and Cry1Ia10 do not compete for the same receptor for S. frugiperda, S. albula and S. cosmioides and that Vip3Aa was more efficient than Cry1Ia10 when tested individually, by bioassays. A synergistic effect of the toxins in S. frugiperda, S. albula and S. cosmioides was observed when they were combined. However, in S. eridania, Cry1Ia10 and Vip3Aa might compete for the same receptor and through bioassays Cry1Ia10 was more efficient than Vip3Aa and showed an antagonistic effect when the proteins were combined. These results suggest that using these genes to develop pyramided plants may not prove effective in preventing the development of resistance in S. eridiana. Copyright © 2012 Elsevier Inc. All rights reserved.

Extrusion decreases the negative effects of kidney bean on enzyme and transport activities of the rat small intestine.

PubMed

Marzo, F; Milagro, F I; Urdaneta, E; Barrenetxe, J; Ibañez, F C

2011-10-01

The objective of the present study was to evaluate the influence of raw and extruded kidney bean (Phaseolus vulgaris L. var. Pinto) consumption on the gut physiology of young growing rats. The intestinal enzyme activity (sucrase, maltase, Na(+) /K(+) ATPase, aminopeptidase N, dipeptidylpeptidase IV, alkaline phosphatase) and the uptake of sugar (d-galactose) and amino acids (l-leucine) were measured in brush border membrane vesicles. Five groups of growing male Wistar rats were fed ad libitum for 15 days on five different 10% protein diets: one containing casein as the main source of protein (Control, C), and four containing raw (RKB1, RKB6) or extruded kidney bean (EKB1, EKB6) at 1% and 6% of total protein content respectively. Extrusion treatment significantly reduced the content of bioactive factors (phytates, tannins) and abolished lectins, trypsin, chymotrypsin, and α-amylase inhibitory activities. Rats fed raw beans (especially RKB6) showed lower growth rate and food intake as compared to those fed extruded legumes, probably due to the high levels of lectins and other anti-nutritive factors in the raw beans. Gut enzymatic activities and uptake of d-galactose and l-leucine were lower in RKB6 and RKB1-fed animals, although they significantly improved in the groups fed extruded beans. Enzymatic activity and uptake in EKB1 were similar to those of casein-fed rats, whereas the uptake and growth rate of EKB6 were different to the control. This is attributable to the higher non-thermolabile biofactor content in the EKB6 diet, especially phytates and tannins, than in EKB1. This article shows the dose-dependent toxicological effects of bioactive factors contained in kidney beans on gut function. The extrusion process reduced their adverse impact on gut physiology and growth rate. © 2010 Blackwell Verlag GmbH.

Field-Evolved Mode 1 Resistance of the Fall Armyworm to Transgenic Cry1Fa-Expressing Corn Associated with Reduced Cry1Fa Toxin Binding and Midgut Alkaline Phosphatase Expression

PubMed Central

Jakka, Siva R. K.; Gong, Liang; Hasler, James; Banerjee, Rahul; Sheets, Joel J.; Narva, Kenneth; Blanco, Carlos A.

2015-01-01

Insecticidal protein genes from the bacterium Bacillus thuringiensis (Bt) are expressed by transgenic Bt crops (Bt crops) for effective and environmentally safe pest control. The development of resistance to these insecticidal proteins is considered the most serious threat to the sustainability of Bt crops. Resistance in fall armyworm (Spodoptera frugiperda) populations from Puerto Rico to transgenic corn producing the Cry1Fa insecticidal protein resulted, for the first time in the United States, in practical resistance, and Bt corn was withdrawn from the local market. In this study, we used a field-collected Cry1Fa corn-resistant strain (456) of S. frugiperda to identify the mechanism responsible for field-evolved resistance. Binding assays detected reduced Cry1Fa, Cry1Ab, and Cry1Ac but not Cry1Ca toxin binding to midgut brush border membrane vesicles (BBMV) from the larvae of strain 456 compared to that from the larvae of a susceptible (Ben) strain. This binding phenotype is descriptive of the mode 1 type of resistance to Bt toxins. A comparison of the transcript levels for putative Cry1 toxin receptor genes identified a significant downregulation (>90%) of a membrane-bound alkaline phosphatase (ALP), which translated to reduced ALP protein levels and a 75% reduction in ALP activity in BBMV from 456 compared to that of Ben larvae. We cloned and heterologously expressed this ALP from susceptible S. frugiperda larvae and demonstrated that it specifically binds with Cry1Fa toxin. This study provides a thorough mechanistic description of field-evolved resistance to a transgenic Bt crop and supports an association between resistance and reduced Cry1Fa toxin binding and levels of a putative Cry1Fa toxin receptor, ALP, in the midguts of S. frugiperda larvae. PMID:26637593

Evidence of Field-Evolved Resistance of Spodoptera frugiperda to Bt Corn Expressing Cry1F in Brazil That Is Still Sensitive to Modified Bt Toxins

PubMed Central

Monnerat, Rose; Martins, Erica; Macedo, Cristina; Queiroz, Paulo; Praça, Lilian; Soares, Carlos Marcelo; Moreira, Helio; Grisi, Isabella; Silva, Joseane; Soberon, Mario; Bravo, Alejandra

2015-01-01

Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda. PMID:25830928

Evidence of field-evolved resistance of Spodoptera frugiperda to Bt corn expressing Cry1F in Brazil that is still sensitive to modified Bt toxins.

PubMed

Monnerat, Rose; Martins, Erica; Macedo, Cristina; Queiroz, Paulo; Praça, Lilian; Soares, Carlos Marcelo; Moreira, Helio; Grisi, Isabella; Silva, Joseane; Soberon, Mario; Bravo, Alejandra

2015-01-01

Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda.

Binding site concentration explains the differential susceptibility of Chilo suppressalis and Sesamia inferens to Cry1A-producing rice.

PubMed

Han, Lanzhi; Han, Chao; Liu, Zewen; Chen, Fajun; Jurat-Fuentes, Juan Luis; Hou, Maolin; Peng, Yufa

2014-08-01

Chilo suppressalis and Sesamia inferens are two important lepidopteran rice pests that occur concurrently during outbreaks in paddy fields in the main rice-growing areas of China. Previous and current field tests demonstrate that the transgenic rice line Huahui 1 (HH1) producing a Cry1Ab-Cry1Ac hybrid toxin from the bacterium Bacillus thuringiensis reduces egg and larval densities of C. suppressalis but not of S. inferens. This differential susceptibility to HH1 rice correlates with the reduced susceptibility to Cry1Ab and Cry1Ac toxins in S. inferens larvae compared to C. suppressalis larvae. The goal of this study was to identify the mechanism responsible for this differential susceptibility. In saturation binding assays, both Cry1Ab and Cry1Ac toxins bound with high affinity and in a saturable manner to midgut brush border membrane vesicles (BBMV) from C. suppressalis and S. inferens larvae. While binding affinities were similar, a dramatically lower concentration of Cry1A toxin binding sites was detected for S. inferens BBMV than for C. suppressalis BBMV. In contrast, no significant differences between species were detected for Cry1Ca toxin binding to BBMV. Ligand blotting detected BBMV proteins binding Cry1Ac or Cry1Ca toxins, some of them unique to C. suppressalis or S. inferens. These data support that reduced Cry1A binding site concentration is associated with a lower susceptibility to Cry1A toxins and HH1 rice in S. inferens larvae than in C. suppressalis larvae. Moreover, our data support Cry1Ca as a candidate for pyramiding efforts with Cry1A-producing rice to extend the activity range and durability of this technology against rice stem borers. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Effects of dietary glucose and sodium chloride on intestinal glucose absorption of common carp (Cyprinus carpio L.).

PubMed

Qin, Chaobin; Yang, Liping; Zheng, Wenjia; Yan, Xiao; Lu, Ronghua; Xie, Dizhi; Nie, Guoxing

2018-01-08

The co-transport of sodium and glucose is the first step for intestinal glucose absorption. Dietary glucose and sodium chloride (NaCl) may facilitate this physiological process in common carp (Cyprinus carpio L.). To test this hypothesis, we first investigated the feeding rhythm of intestinal glucose absorption. Carps were fed to satiety once a day (09:00 a.m.) for 1 month. Intestinal samples were collected at 01:00, 05:00, 09:00, 13:00, 17:00 and 21:00. Result showed that food intake greatly enhanced sodium/glucose cotransporter 1 (SGLT1) and glucose transporter type 2 (GLUT2) expressions, and improved glucose absorption, with highest levels at 09:00 a.m.. Then we designed iso-nitrogenous and iso-energetic diets with graded levels of glucose (10%, 20%, 30%, 40% and 50%) and NaCl (0%, 1%, 3% and 5%), and submitted to feeding trial for 10 weeks. The expressions of SGLT1 and GLUT2, brush border membrane vesicles (BBMVs) glucose transport and intestinal villus height were determined after the feeding trial. Increasing levels of dietary glucose and NaCl up-regulated mRNA and protein levels of SGLT1 and GLUT2, enhanced BBMVs glucose transport in the proximal, mid and distal intestine. As for histological adaptive response, however, high-glucose diet prolonged while high-NaCl diet shrank intestinal villus height. Furthermore, we also found that higher mRNA levels of SGLT1 and GLUT2, higher glucose transport capacity of BBMVs, and higher intestinal villus were detected in the proximal and mid intestine, compared to the distal part. Taken together, our study indicated that intestinal glucose absorption in carp was primarily occurred in the proximal and mid intestine, and increasing levels of dietary glucose and NaCl enhanced intestinal glucose absorption in carp. Copyright © 2017 Elsevier Inc. All rights reserved.

A study of the early detection of insect infestations and density/distribution of host plants. [Rio Grande

NASA Technical Reports Server (NTRS)

Hart, W. G. (Principal Investigator); Ingle, S. J.; Davis, M. R.

1975-01-01

The author has identified the following significant results. With comparative observations of film types and seasonal influences on reflectance characteristics, many crop varieties can be identified. This study shows that citrus, sugar cane, brush, some winter vegetables, and grain crops could be identified. Vegetative patterns in border areas can be detected. This information can be useful in detecting avenues of entry of pest species and areas of stress that require vigilance in stopping the spread of destructive species. Influence of some environmental factors on crops that may be confused with pest injury, or related factors, can be detected and identified with Skylab data (S-190B).

Structural Studies of the Intestinal α-Glucosidases, Maltase-glucoamylase and Sucrase-isomaltase.

PubMed

Rose, David R; Chaudet, Marcia M; Jones, Kyra

2018-06-01

Maltase-glucoamylase and sucrase-isomaltase are enzymes in the brush-border membrane of the small intestinal lumen responsible for the breakdown of postamylase starch polysaccharides to release monomeric glucose. As such, they are critical players in healthy nutrition and their malfunction can lead to severe disorders. This review covers investigations of the structures and functions of these enzymes. Each consists of 2 enzyme domains of the glycoside hydrolase family GH31 classification, yet with somewhat differing enzymatic properties. Crystallographic structures of 3 of the domains have been published. Insights into substrate binding and specificity will be discussed, along with future lines of inquiry related to the enzymes' roles in disease and potential avenues for therapeutics.

Pancreatic α-Amylase Controls Glucose Assimilation by Duodenal Retrieval through N-Glycan-specific Binding, Endocytosis, and Degradation*

PubMed Central

Date, Kimie; Satoh, Ayano; Iida, Kaoruko; Ogawa, Haruko

2015-01-01

α-Amylase, a major pancreatic protein and starch hydrolase, is essential for energy acquisition. Mammalian pancreatic α-amylase binds specifically to glycoprotein N-glycans in the brush-border membrane to activate starch digestion, whereas it significantly inhibits glucose uptake by Na+/glucose cotransporter 1 (SGLT1) at high concentrations (Asanuma-Date, K., Hirano, Y., Le, N., Sano, K., Kawasaki, N., Hashii, N., Hiruta, Y., Nakayama, K., Umemura, M., Ishikawa, K., Sakagami, H., and Ogawa, H. (2012) Functional regulation of sugar assimilation by N-glycan-specific interaction of pancreatic α-amylase with glycoproteins of duodenal brush border membrane. J. Biol. Chem. 287, 23104–23118). However, how the inhibition is stopped was unknown. Here, we show a new mechanism for the regulation of intestinal glucose absorption. Immunohistochemistry revealed that α-amylase in the duodena of non-fasted, but not fasted, pigs was internalized from the pancreatic fluid and immunostained. We demonstrated that after N-glycan binding, pancreatic α-amylase underwent internalization into lysosomes in a process that was inhibited by α-mannoside. The internalized α-amylase was degraded, showing low enzymatic activity and molecular weight at the basolateral membrane. In a human intestinal Caco-2 cell line, Alexa Fluor 488-labeled pancreatic α-amylase bound to the cytomembrane was transported to lysosomes through the endocytic pathway and then disappeared, suggesting degradation. Our findings indicate that N-glycan recognition by α-amylase protects enterocytes against a sudden increase in glucose concentration and restores glucose uptake by gradual internalization, which homeostatically controls the postprandial blood glucose level. The internalization of α-amylase may also enhance the supply of amino acids required for the high turnover of small intestine epithelial cells. This study provides novel and significant insights into the control of blood sugar during the absorption stage in the intestine. PMID:26023238

Molecular transport machinery involved in orchestrating luminal acid-induced duodenal bicarbonate secretion in vivo

PubMed Central

Singh, Anurag Kumar; Liu, Yongjian; Riederer, Brigitte; Engelhardt, Regina; Thakur, Basant Kumar; Soleimani, Manoocher; Seidler, Ursula

2013-01-01

The duodenal villus brush border membrane expresses several ion transporters and/or channels, including the solute carrier 26 anion transporters Slc26a3 (DRA) and Slc26a6 (PAT-1), the Na+/H+ exchanger isoform 3 (NHE3), as well as the anion channels cystic fibrosis transmembrane conductance regulator (CFTR) and Slc26a9. Using genetically engineered mouse models lacking Scl26a3, Slc26a6, Slc26a9 or Slc9a3 (NHE3), the study was carried out to assess the role of these transporters in mediating the protective duodenal bicarbonate secretory response (DBS-R) to luminal acid; and to compare it to their role in DBS-R elicited by the adenylyl cyclase agonist forskolin. While basal DBS was reduced in the absence of any of the three Slc26 isoforms, the DBS-R to forskolin was not altered. In contrast, the DBS-R to a 5 min exposure to luminal acid (pH 2.5) was strongly reduced in the absence of Slc26a3 or Slc26a9, but not Slc26a6. CFTR inhibitor [CFTR(Inh)-172] reduced the first phase of the acid-induced DBS-R, while NHE3 inhibition (or knockout) abolished the sustained phase of the DBS-R. Luminal acid exposure resulted in the activation of multiple intracellular signalling pathways, including SPAK, AKT and p38 phosphorylation. It induced a biphasic trafficking of NHE3, first rapidly into the brush border membrane, followed by endocytosis in the later stage. We conclude that the long-lasting DBS-R to luminal acid exposure activates multiple duodenocyte signalling pathways and involves changes in trafficking and/or activity of CFTR, Slc26 isoforms Slc26a3 and Slc26a9, and NHE3. PMID:24018950

Colon luminal content and epithelial cell morphology are markedly modified in rats fed with a high-protein diet.

PubMed

Andriamihaja, Mireille; Davila, Anne-Marie; Eklou-Lawson, Mamy; Petit, Nathalie; Delpal, Serge; Allek, Fadhila; Blais, Anne; Delteil, Corine; Tomé, Daniel; Blachier, François

2010-11-01

Hyperproteic diets are used in human nutrition to obtain body weight reduction. Although increased protein ingestion results in an increased transfer of proteins from the small to the large intestine, there is little information on the consequences of the use of such diets on the composition of large intestine content and on epithelial cell morphology and metabolism. Rats were fed for 15 days with either a normoproteic (NP, 14% protein) or a hyperproteic isocaloric diet (HP, 53% protein), and absorptive colonocytes were observed by electron microscopy or isolated for enzyme activity studies. The colonic luminal content was recovered for biochemical analysis. Absorbing colonocytes were characterized by a 1.7-fold reduction in the height of the brush-border membranes (P = 0.0001) after HP diet consumption when compared with NP. This coincided in the whole colon content of HP animals with a 1.8-fold higher mass content (P = 0.0020), a 2.2-fold higher water content (P = 0.0240), a 5.2-fold higher protease activity (P = 0.0104), a 5.5-fold higher ammonia content (P = 0.0008), and a more than twofold higher propionate, valerate, isobutyrate, and isovalerate content (P < 0.05). The basal oxygen consumption of colonocytes was similar in the NP and HP groups, but ammonia was found to provoke a dose-dependent decrease of oxygen consumption in the isolated absorbing colonocytes. The activity of glutamine synthetase (which condenses ammonia and glutamate) was found to be much higher in colonocytes than in small intestine enterocytes and was 1.6-fold higher (P = 0.0304) in colonocytes isolated from HP animals than NP. Glutaminase activity remained unchanged. Thus hyperproteic diet ingestion causes marked changes both in the luminal environment of colonocytes and in the characteristics of these cells, demonstrating that hyperproteic diet interferes with colonocyte metabolism and morphology. Possible causal relationships between energy metabolism, reduced height of colonocyte brush-border membranes, and reduced water absorption are discussed.

Ezetimibe Promotes Brush Border Membrane-to-Lumen Cholesterol Efflux in the Small Intestine

PubMed Central

Nakano, Takanari; Inoue, Ikuo; Takenaka, Yasuhiro; Ono, Hiraku; Katayama, Shigehiro; Awata, Takuya; Murakoshi, Takayuki

2016-01-01

Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1), an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE) assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM)-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to modulate the flux to dispose of endogenous cholesterol efficiently for therapeutic purposes. PMID:27023132

Ezetimibe Promotes Brush Border Membrane-to-Lumen Cholesterol Efflux in the Small Intestine.

PubMed

Nakano, Takanari; Inoue, Ikuo; Takenaka, Yasuhiro; Ono, Hiraku; Katayama, Shigehiro; Awata, Takuya; Murakoshi, Takayuki

2016-01-01

Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1), an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE) assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM)-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to modulate the flux to dispose of endogenous cholesterol efficiently for therapeutic purposes.

[Genetic hypophosphatemia: recent advances in physiopathogenic concept].

PubMed

Beraud, G; Perimenis, P; Velayoudom, Fr-L; Wemeau, J-L; Vantyghem, M-Chr

2005-04-01

Renal proximal tubular reabsorption of phosphate and intestinal absorption both regulate phosphate homeostasis. Brush-border membrane Npt2a cotransporter is the key element in proximal tubular P (i) reabsorption. Inactivating mutations of Npt2a cause bone demineralisation and urolithiasis. An excess of a phosphaturic factor, called "Phosphatonin", could modulate phosphate reabsorption by inhibition on Npt2a. Inactivating mutation of PHEX, an endopeptidase-membrane coding gene, is responsible for X-linked Hypophosphatemia (XLH), because of an impaired degradation of phosphatonine by PHEX product. Autosomic Dominant Hypophosphatemic Rickets (ADHR) is explained by a mutation preventing FGF23 (one of the best identified phosphatonines) from cleavage. According recent data, FGF23, MEPE (Matrix Extracellular Phosphoglycoprotein) et FRP4 (frizzled related protein-4) are 3 putative "phosphatonines".

Vaccination of sheep against haemonchosis with H11, a gut membrane-derived protective antigen from the adult parasite: prevention of the periparturient rise and colostral transfer of protective immunity.

PubMed

Andrews, S J; Hole, N J; Munn, E A; Rolph, T P

1995-07-01

Pregnant ewes were immunised with a fraction highly enriched in the membrane glycoprotein antigen H11, isolated from the intestinal brush border of adult Haemonchus contortus. Immunity induced by immunisation was able to abolish almost completely (98-99%) the worm egg output from pregnant ewes challenged with ca. 10,000 infective larvae of H. contortus during the last trimester. Furthermore, lambs born and reared on vaccinated ewes had substantial antibody levels to H11 derived from maternal transfer. This antibody conferred moderate protection against a bolus challenge of ca. 3000 infective larvae of H. contortus in 5-week-old lambs.

Metabolic stability of some tachykinin analogues to cell-surface peptidases: roles for endopeptidase-24.11 and aminopeptidase N.

PubMed

Medeiros, M D; Turner, A J

1995-01-01

The metabolism of several tachykinin antagonists by membrane peptidases has been examined. [beta Ala8]NKA(4-10) was not stabilized against degradation by endopeptidase-24.11 and this was the major activity in renal brush border membranes hydrolyzing this peptide. The antagonist MEN 10263 was much more resistant to hydrolysis by endopeptidase-24.11, although hydrolysis of the C-terminal Leu-Phe bond was detectable. Three other tachykinin receptor antagonists (MEN 10208, MEN 10207, and MEN 10376), by virtue of D-Trp substitutions, were rendered resistant to endopeptidase-24.11 but were still susceptible to aminopeptidase action. These studies provide further insight into design features necessary to produce metabolically stable peptide analogues.

Temperature dependence of structure, bending rigidity, and bilayer interactions of dioleoylphosphatidylcholine bilayers.

PubMed

Pan, Jianjun; Tristram-Nagle, Stephanie; Kucerka, Norbert; Nagle, John F

2008-01-01

X-ray diffuse scattering was measured from oriented stacks and unilamellar vesicles of dioleoylphosphatidylcholine lipid bilayers to obtain the temperature dependence of the structure and of the material properties. The area/molecule, A, was 75.5 A(2) at 45 degrees C, 72.4 A(2) at 30 degrees C, and 69.1 A(2) at 15 degrees C, which gives the area expansivity alpha(A) = 0.0029/deg at 30 degrees C, and we show that this value is in excellent agreement with the polymer brush theory. The bilayer becomes thinner with increasing temperature; the contractivity of the hydrocarbon portion was alpha(Dc) = 0.0019/deg; the difference between alpha(A) and alpha(Dc) is consistent with the previously measured volume expansivity alpha(Vc) = 0.0010/deg. The bending modulus K(C) decreased as exp(455/T) with increasing T (K). Our area compressibility modulus K(A) decreased with increasing temperature by 5%, the same as the surface tension of dodecane/water, in agreement again with the polymer brush theory. Regarding interactions between bilayers, the compression modulus B as a function of interbilayer water spacing D'(W) was found to be nearly independent of temperature. The repulsive fluctuation pressure calculated from B and K(C) increased with temperature, and the Hamaker parameter for the van der Waals interaction was nearly independent of temperature; this explains why the fully hydrated water spacing, D'(W), that we obtain from our structural results increases with temperature.

Three-Dimensional Polypeptide Architectures Through Tandem Catalysis and Click Chemistry

NASA Astrophysics Data System (ADS)

Rhodes, Allison Jane

Rapid renal clearance, liver accumulation, proteolytic degradation and non-specificity are challenges small molecule drugs, peptides, proteins and nucleic acid therapeutics encounter en route to their intended destination within the body. Nanocarriers (i.e. dendritric polymers, vesicles, and micelles) of approximately 100 nm in diameter, shuttle small molecule drugs to their desired location through passive (EPR effect) and active (ligand-mediated) targeting, maximizing therapeutic efficiency. Polypeptide-based polymers are water-soluble, biocompatible, non-toxic and are therefore excellent candidates for nanocarriers. Dendritic polymers, including dendrimers, cylindrical brushes, and star polymers, are the newest class of nanomedicine drug delivery vehicles. The synthesis and characterization of dendritic polymers is challenging, with tedious and costly procedures. Dendritic polymers possess peripheral pendent functional groups that can potentially be used in ligand-mediated drug delivery vehicles and bioimaging applications. More specifically, cylindrical brushes are dendritic polymers where a single linear polymer (primary chain) has polymer chains (secondary chains) grafted to it. Recently, research groups have shown that cylindrical brush polymers are capable of nanoparticle and supramolecular structure self-assembly. The facile preparation of high-density brush copolypeptides by the "grafting from" approach will be discussed. This approach utilizes a novel, tandem catalytic methodology where alloc-alpha-aminoamide groups are installed within the side-chains of the alpha-amino-N-carboxyanhydride (NCA) monomer serving as masked initiators. These groups are inert during cobalt initiated NCA polymerization, and give alloc-alpha-aminoamide substituted polypeptide main-chains. The alloc-alpha-aminoamide groups are activated in situ using nickel to generate initiators for growth of side-chain brush segments. This method proves to be efficient, yielding well-defined, high-density brushes for applications in drug delivery and imaging. Here, we also report a method for the synthesis of soluble, well-defined, azido functionalized polypeptides in a straightforward, 3-step synthesis. Homo and diblock azidopolypeptides were prepared with controlled segment lengths via living polymerization using Co(PMe3)4 initiator. Through copper azide alkyne click chemistry (CuAAC) in organic solvent, azidopolypeptides were regioselectively and quantitatively modified with carboxylic acid (pH-responsive), amino acid and sugar functional groups. Finally, the advances towards well-defined hyperbranched polypeptides through alpha-amino-acid-N-thiocarboxyanhydrides (NTAs) will be discussed. Within the past 10 years, controlled NCA (alpha-amino acid-N-carboxyanhydride) ring-opening polymerization (ROP) has emerged, expanding the application of copolypeptide polymers in various drug delivery and tissue engineering motifs. Modification of NCA monomers to the corresponding alpha-amino-acid-N-thiocarboxyanhydride (NTA) will diversify ROP reactions, leading to more complex polypeptides (such as hyperbranched polymers), in addition to the possibility of performing these polymerizations under ambient conditions, which would greatly expand their potential utility. The project focuses on the preparation of hyperbranched polypeptides with well-defined architectures and controlled branching density in a one-pot reaction. This will be accomplished by taking advantage of the different selectivities of Co(PMe3)4 and depeNi(COD) polymerization initiators, and by exploiting the reactivity difference between NCA and the more stable NTA monomers.

Intestinal alkaline phosphatase prevents metabolic syndrome in mice.

PubMed

Kaliannan, Kanakaraju; Hamarneh, Sulaiman R; Economopoulos, Konstantinos P; Nasrin Alam, Sayeda; Moaven, Omeed; Patel, Palak; Malo, Nondita S; Ray, Madhury; Abtahi, Seyed M; Muhammad, Nur; Raychowdhury, Atri; Teshager, Abeba; Mohamed, Mussa M Rafat; Moss, Angela K; Ahmed, Rizwan; Hakimian, Shahrad; Narisawa, Sonoko; Millán, José Luis; Hohmann, Elizabeth; Warren, H Shaw; Bhan, Atul K; Malo, Madhu S; Hodin, Richard A

2013-04-23

Metabolic syndrome comprises a cluster of related disorders that includes obesity, glucose intolerance, insulin resistance, dyslipidemia, and fatty liver. Recently, gut-derived chronic endotoxemia has been identified as a primary mediator for triggering the low-grade inflammation responsible for the development of metabolic syndrome. In the present study we examined the role of the small intestinal brush-border enzyme, intestinal alkaline phosphatase (IAP), in preventing a high-fat-diet-induced metabolic syndrome in mice. We found that both endogenous and orally supplemented IAP inhibits absorption of endotoxin (lipopolysaccharides) that occurs with dietary fat, and oral IAP supplementation prevents as well as reverses metabolic syndrome. Furthermore, IAP supplementation improves the lipid profile in mice fed a standard, low-fat chow diet. These results point to a potentially unique therapy against metabolic syndrome in at-risk humans.

Explicit Solvent Simulations of Friction between Brush Layers of Charged and Neutral Bottle-Brush Macromolecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carrillo, Jan-Michael; Brown, W Michael; Dobrynin, Andrey

2012-01-01

We study friction between charged and neutral brush layers of bottle-brush macromolecules using molecular dynamics simulations. In our simulations the solvent molecules were treated explicitly. The deformation of the bottle-brush macromolecules under the shear were studied as a function of the substrate separation and shear stress. For charged bottle-brush layers we study effect of the added salt on the brush lubricating properties to elucidate factors responsible for energy dissipation in charged and neutral brush systems. Our simulations have shown that for both charged and neutral brush systems the main deformation mode of the bottle-brush macromolecule is associated with the backbonemore » deformation. This deformation mode manifests itself in the backbone deformation ratio, , and shear viscosity, , to be universal functions of the Weissenberg number W. The value of the friction coefficient, , and viscosity, , are larger for the charged bottle-brush coatings in comparison with those for neutral brushes at the same separation distance, D, between substrates. The additional energy dissipation generated by brush sliding in charged bottle-brush systems is due to electrostatic coupling between bottle-brush and counterion motion. This coupling weakens as salt concentration, cs, increases resulting in values of the viscosity, , and friction coefficient, , approaching corresponding values obtained for neutral brush systems.« less

Effect of Frequency of Brushing Teeth on Plaque and Calculus Accumulation, and Gingivitis in Dogs.

PubMed

Harvey, Colin; Serfilippi, Laurie; Barnvos, Donald

2015-01-01

The efficacy of brushing the teeth of beagle dogs in a randomized, controlled, blinded study design using a clearly-defined brushing technique was evaluated for 4 brushing frequencies: brushing daily, brushing every other day, brushing weekly and brushing every other week, compared with no brushing in a control group of dogs. All dogs were fed a standard dry kibble diet during the study. Standard plaque, calculus, and gingivitis indices were used to score the teeth. A 'clean tooth' model was used. No gingival or non-gingival lacerations or other signs of injury to oral tissues were found at the end of the 28 day trial period. Brushing more frequently had greater effectiveness in retarding accumulation of plaque and calculus, and reducing the severity of pre-existing gingivitis. Brushing daily or every other day produced statistically significant improved results compared with brushing weekly or every other week. Based on the results of this study, daily brushing is recommended.

Band-like arrangement of taste-like sensory cells at the gastric groove: evidence for paracrine communication.

PubMed

Eberle, Julia Anna-Maria; Richter, Patric; Widmayer, Patricia; Chubanov, Vladimir; Gudermann, Thomas; Breer, Heinz

2013-01-01

The discovery of taste-related elements within the gastrointestinal tract has led to a growing interest in the mechanisms and physiological significance of chemosensory monitoring of chymus composition. Previous work suggests that brush cells located in the "gastric groove," which parallels the "limiting ridge," a structure in rodents that divides the fundus from the corpus, are candidate sensory cells. A novel sectioning technique revealed that these cells are arranged in a palisade-like manner forming a band which borders the whole length of the corpus epithelium. Using transgenic PLCβ2 promoter-GFP mice and specific antibodies, we have demonstrated that most of these cells express gustducin, PLCβ2, and TRPM5; typical signaling proteins of gustatory sensory "type II" cells. These molecular features strongly suggest that the cells may be capable of sensing nutrient or non-nutrient constituents of the ingested food. Since there is no evidence that brush cells are endocrine cells, attempts were made to explore how such putative chemosensory cells might transmit the information to "effector" cells. It was found that most of the cells express the neuronal nitric oxide synthase (NOS) suggesting some paracrine interaction with adjacent cells. Moreover, they also express choline acetyltransferase (ChAT) as well as the vesicular protein SNAP25, indicating the potential for cholinergic transmission, possibly with subjacent enteric nerve fibers.

Band-like arrangement of taste-like sensory cells at the gastric groove: evidence for paracrine communication

PubMed Central

Eberle, Julia Anna-Maria; Richter, Patric; Widmayer, Patricia; Chubanov, Vladimir; Gudermann, Thomas; Breer, Heinz

2013-01-01

The discovery of taste-related elements within the gastrointestinal tract has led to a growing interest in the mechanisms and physiological significance of chemosensory monitoring of chymus composition. Previous work suggests that brush cells located in the “gastric groove,” which parallels the “limiting ridge,” a structure in rodents that divides the fundus from the corpus, are candidate sensory cells. A novel sectioning technique revealed that these cells are arranged in a palisade-like manner forming a band which borders the whole length of the corpus epithelium. Using transgenic PLCβ2 promoter-GFP mice and specific antibodies, we have demonstrated that most of these cells express gustducin, PLCβ2, and TRPM5; typical signaling proteins of gustatory sensory “type II” cells. These molecular features strongly suggest that the cells may be capable of sensing nutrient or non-nutrient constituents of the ingested food. Since there is no evidence that brush cells are endocrine cells, attempts were made to explore how such putative chemosensory cells might transmit the information to “effector” cells. It was found that most of the cells express the neuronal nitric oxide synthase (NOS) suggesting some paracrine interaction with adjacent cells. Moreover, they also express choline acetyltransferase (ChAT) as well as the vesicular protein SNAP25, indicating the potential for cholinergic transmission, possibly with subjacent enteric nerve fibers. PMID:23565094

Spermatogenesis in Animals as Revealed by Electron Microscopy

PubMed Central

Yasuzumi, G.; Tanaka, Hiroaki

1958-01-01

This paper reports an electron microscope study of typical and atypical spermatogenesis in the pond snail, Cipangopaludina malteata. In the typical spermatid the nucleus undergoes profound changes as development proceeds, affecting both its form and internal fine structure. A large number of roughly parallel, dense filaments, arranged along the long axis of the nucleus, fuse with each other to form in the end the homogeneous helical body characteristic of the head of the adult spermatozoa. The nebenkern is apparently mitochondrial in nature and, in its early development, is similar to that of insects except that it appears as a double structure from the beginning. As differentiation proceeds, the mitochondria lose their membranes, and the residual, now denuded cristae, reorganize to give a parallel radial arrangement. In the last stages of development, the nebenkern derivations become applied to the sheath of the middle piece in a compact helical fashion. In the development of the atypical spermatozoa, the nucleus fails to differentiate and simply shrinks in volume until only a remnant, devoid of DNA, is left. The cytoplasm shows numerous vesicles containing small Feulgen-positive bodies, 80 to 130 mµ in diameter. These vesicles plus contents increase in number as spermatogenesis proceeds. The "head" structure of the atypical spermatozoa consists of a bundle (7 to 17) of tail flagella, each with a centriole at its anterior end. The end-piece of the atypical form appears brush-like and is made up of the free ends of the several flagella. PMID:13587559

Venom and Dufour's glands of the emerald cockroach wasp Ampulex compressa (Insecta, Hymenoptera, Sphecidae): structural and biochemical aspects.

PubMed

Gnatzy, Werner; Michels, Jan; Volknandt, Walter; Goller, Stephan; Schulz, Stefan

2015-09-01

The digger wasp species Ampulex compressa produces its venom in two branched gland tubules. They terminate in a short common duct, which is bifurcated at its proximal end. One leg is linked with the venom reservoir, the other one extends to the ductus venatus. Each venom gland tubule possesses, over its entire length, a cuticle-lined central duct. Around this duct densely packed class 3 gland units each composed of a secretory cell and a canal cell are arranged. The position of their nuclei was demonstrated by DAPI staining. The brush border of the secretory cells surrounds the coiled end-apparatus. Venom is stored in a bladder like reservoir, which is surrounded by a thin reticulated layer of muscle fibres. The reservoir as a whole is lined with class 3 gland units. The tubiform Dufour's gland has a length of about 350 μm (∅ 125 μm) only and is surrounded by a network of pronounced striated muscle fibres. The glandular epithelium is mono-layered belonging to the class 1 type of insect epidermal glands. The gland cells are characterized by conspicuous lipid vesicles. Secretion of material via the gland cuticle into the gland lumen is apparent. Analysis of the polypeptide composition demonstrated that the free gland tubules and the venom reservoir contain numerous proteins ranging from 3.4 to 200 kDa. The polypeptide composition of the Dufour's gland is completely different and contains no lectin-binding glycoproteins, whereas a dominant component of the venom droplets is a glycoprotein of about 80 kDa. Comparison of the venom reservoir contents with the polypeptide pattern of venom droplets revealed that all of the major proteinaceous constituents are secreted. The secreted venom contains exclusively proteins present in the soluble contents of the venom gland. The most abundant compound class in the Dufour's gland consisted of n-alkanes followed by monomethyl-branched alkanes and alkadienes. Heptacosane was the most abundant n-alkane. Furthermore, a single volatile compound, 2-methylpentan-3-one, was identified in various concentrations in the lipid extract of the Dufour's gland. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cry64Ba and Cry64Ca, Two ETX/MTX2-Type Bacillus thuringiensis Insecticidal Proteins Active against Hemipteran Pests.

PubMed

Liu, Yonglei; Wang, Yinglong; Shu, Changlong; Lin, Kejian; Song, Fuping; Bravo, Alejandra; Soberón, Mario; Zhang, Jie

2018-02-01

Genetically modified crops that express insecticidal Bacillus thuringiensis (Bt) proteins have become a primary approach for control of lepidopteran (moth) and coleopteran (beetle) pests that feed by chewing the plants. However, the sap-sucking insects (Hemiptera) are not particularly susceptible to Bt toxins. In this study, we describe two Cry toxins (Cry64Ba and Cry64Ca) from Bt strain 1012 that showed toxicity against two important hemipteran rice pests, Laodelphax striatellus and Sogatella furcifera Both of these proteins contain an ETX/MTX2 domain and share common sequence features with the β-pore-forming toxins. Coexpression of cry64Ba and cry64Ca genes in the acrystalliferous Bt strain HD73 - resulted in high insecticidal activity against both hemipteran pests. No toxicity was observed on other pests such as Ostrinia furnacalis , Plutella xylostella , or Colaphellus bowringi Also, no hemolytic activity or toxicity against cancer cells was detected. Binding assays showed specific binding of the Cry64Ba/Cry64Ca toxin complex to brush border membrane vesicles isolated from L. striatellus Cry64Ba and Cry64Ca are Bt Cry toxins highly effective against hemipteran pests and could provide a novel strategy for the environmentally friendly biological control of rice planthoppers in transgenic plants. IMPORTANCE In Asia, rice is an important staple food, whose production is threatened by rice planthoppers. To date, no effective Bacillus thuringiensis (Bt) protein has been shown to have activity against rice planthoppers. We cloned two Bt toxin genes from Bt strain 1012 that showed toxicity against small brown planthoppers ( Laodelphax striatellus ) and white-backed planthoppers ( Sogatella furcifera ). To our knowledge, the proteins encoded by the cry64Ba and cry64Ca genes are the most efficient insecticidal Bt Cry proteins with activity against hemipteran insects reported so far. Cry64Ba and Cry64Ca showed no toxicity against some lepidopteran or coleopteran pests. These two proteins should be able to be used for integrated hemipteran pest management. Copyright © 2018 American Society for Microbiology.

Shared Midgut Binding Sites for Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac and Cry1Fa Proteins from Bacillus thuringiensis in Two Important Corn Pests, Ostrinia nubilalis and Spodoptera frugiperda

PubMed Central

Hernández-Rodríguez, Carmen Sara; Hernández-Martínez, Patricia; Van Rie, Jeroen; Escriche, Baltasar; Ferré, Juan

2013-01-01

First generation of insect-protected transgenic corn (Bt-corn) was based on the expression of Cry1Ab or Cry1Fa proteins. Currently, the trend is the combination of two or more genes expressing proteins that bind to different targets. In addition to broadening the spectrum of action, this strategy helps to delay the evolution of resistance in exposed insect populations. One of such examples is the combination of Cry1A.105 with Cry1Fa and Cry2Ab to control O. nubilalis and S. frugiperda. Cry1A.105 is a chimeric protein with domains I and II and the C-terminal half of the protein from Cry1Ac, and domain III almost identical to Cry1Fa. The aim of the present study was to determine whether the chimeric Cry1A.105 has shared binding sites either with Cry1A proteins, with Cry1Fa, or with both, in O. nubilalis and in S. frugiperda. Brush-border membrane vesicles (BBMV) from last instar larval midguts were used in competition binding assays with 125I-labeled Cry1A.105, Cry1Ab, and Cry1Fa, and unlabeled Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac, Cry1Fa, Cry2Ab and Cry2Ae. The results showed that Cry1A.105, Cry1Ab, Cry1Ac and Cry1Fa competed with high affinity for the same binding sites in both insect species. However, Cry2Ab and Cry2Ae did not compete for the binding sites of Cry1 proteins. Therefore, according to our results, the development of cross-resistance among Cry1Ab/Ac, Cry1A.105, and Cry1Fa proteins is possible in these two insect species if the alteration of shared binding sites occurs. Conversely, cross-resistance between these proteins and Cry2A proteins is very unlikely in such case. PMID:23861865

Influence of substrate structure on turnover of the organic cation/H+ exchanger of the renal luminal membrane.

PubMed

Wright, S H; Wunz, T M

1998-08-01

We examined the influence of organic cation (OC) structure on the rate of turnover of the OC/H+ exchanger in rabbit renal brush-border membrane vesicles (BBMV). The rate of efflux of [14C]tetraethylammonium ([14C]TEA) from BBMV, measured in the presence of an inwardly directed chemical gradient for test agent, provided an indirect measure of activity of the OC/H+(OC) exchanger. The trans-stimulation of [14C]TEA efflux from BBMV was a saturable function of increasing extravesicular concentration of both unlabeled TEA and tetramethylammonium (TMA), with an apparent Michaelis constant (Kt) for the interaction of these compounds with the OC/H+(OC) exchanger of 25 microM and 1 mM, respectively. The effect on [14C]TEA efflux of saturating extravesicular concentrations of a series of n-tetraalkylammonium compounds was examined. Whereas the short-chain compounds TMA and TEA markedly stimulated [14C]TEA efflux (by 830% and 690%, respectively), the long-chain compounds tetrapropylammonium and tetrabutylammonium were less effective, increasing efflux by only 40% and 120%, respectively. When the exchanger was saturated with tetrapentylammonium, mediated efflux of [14C]TEA was reduced. Increasing alkyl chain length was also correlated with an increase in the inhibitory effect (as measured by the apparent inhibition constant, Ki, or the IC50 value) that these compounds had against transport of [14C]TEA by the OC/H+(OC) exchanger; i.e., there was a correlation between decreasing IC50 and decreasing turnover of the OC/H+(OC) exchanger. This same correlation was observed for a broader set of test agents of diverse molecular structure, including a series of n-tetraalkylammonium and -phosphonium compounds and the OCs, choline, N1-methyl nicotinamide, 1-methyl-4-phenylpyridinium, and amiloride. Because high affinity of substrates for the OC/H+(OC) exchanger is correlated with increasing substrate hydrophobicity, we conclude that the interaction of hydrophobic OCs with the renal OC/H+(OC) exchanger results in the formation of a substrate-exchanger complex that has a comparatively low rate of turnover.

Control of brushing variables for the in vitro assessment of toothpaste abrasivity using a novel laboratory model.

PubMed

Parry, Jason; Harrington, Edward; Rees, Gareth D; McNab, Rod; Smith, Anthony J

2008-02-01

Design and construct a tooth-brushing simulator incorporating control of brushing variables including brushing force, speed and temperature, thereby facilitating greater understanding of their importance in toothpaste abrasion testing methodologies. A thermostable orbital shaker was selected as a base unit and 16- and 24-specimen brushing rigs were constructed to fit inside, consisting of: a square bath partitioned horizontally to provide brushing channels, specimen holders for 25 mm diameter mounted specimens to fit the brushing channels and individually weighted brushing arms, able to support four toothbrush holders suspended over the brushing channels. Brush head holders consisted of individually weighted blocks of Delrin, or PTFE onto which toothbrush heads were fixed. Investigating effects of key design criteria involved measuring abrasion depths of polished human enamel and dentine. The brushing simulator demonstrated good reproducibility of abrasion on enamel and dentine across consecutive brushing procedures. Varying brushing parameters had a significant impact on wear results: increased brushing force demonstrated a trend towards increased wear, with increased reproducibility for greater abrasion levels, highlighting the importance of achieving sufficient wear to optimise accuracy; increasing brushing temperature demonstrated increased enamel abrasion for silica and calcium carbonate systems, which may be related to slurry viscosities and particle suspension; varying brushing speed showed a small effect on abrasion of enamel at lower brushing speed, which may indicate the importance of maintenance of the abrasive in suspension. Adjusting key brushing variables significantly affected wear behaviour. The brushing simulator design provides a valuable model system for in vitro assessment of toothpaste abrasivity and the influence of variables in a controlled manner. Control of these variables will allow more reproducible study of in vitro tooth wear processes.

Adaptations to the air breathing in the posterior intestine of the catfish (Corydoras aeneus, Callichthyidae). A histological and ultrastructural study.

PubMed

Podkowa, Dagmara; Goniakowska-Witalińska, Lucyna

2002-01-01

A light and transmission electron microscopic study of the intestine of catfish C. aeneus shows that the anterior part of the intestine is a site of digestion and absorption and its structure is typical of that of other teleostean fishes. However, in this species the thin-walled posterior intestine is adapted to air breathing. In this region mucosa is smooth and lined with respiratory epithelium with capillary network. Several types of cells are observed in the epithelium: flattened respiratory epithelial cells with short microvili, goblet cells, scarce epithelial cells with numerous longer microvilli, and two types of endocrine cells (EC). The solitary brush cells with several long and thick microvilli described here are the first observation of such cells in the gastrointestinal tract of fishes. Bodies of respiratory epithelial cells lie between capillaries. Their cytoplasm, apart from typical organelles contains dense and lamellar bodies, which are a site of accumulation of surfactant. In regions where capillaries are covered by thin cytoplasmic sheets of respiratory epithelial cells, a thin (0.24-3.00 microm) air-blood barrier is formed, thus enabling gas exchange. Epithelial cells with longer microvilli do not participate in the formation of the air-blood barrier and are probably responsible for absorbtion. EC of the closed type are dispersed within the epithelium. Their cytoplasm contains characteristic round or oval dense core vesicles 69 to 230 nm in diameter. The role of EC and brush cells in the regulation of processes related to absorbtion, and to respiration, is disscused.

An amphioxus winged helix/forkhead gene, AmphiFoxD: insights into vertebrate neural crest evolution

NASA Technical Reports Server (NTRS)

Yu, Jr-Kai; Holland, Nicholas D.; Holland, Linda Z.

2002-01-01

During amphioxus development, the neural plate is bordered by cells expressing many genes with homologs involved in vertebrate neural crest induction. However, these amphioxus cells evidently lack additional genetic programs for the cell delaminations, migrations, and differentiations characterizing definitive vertebrate neural crest. We characterize an amphioxus winged helix/forkhead gene (AmphiFoxD) closely related to vertebrate FoxD genes. Phylogenetic analysis indicates that the AmphiFoxD is basal to vertebrate FoxD1, FoxD2, FoxD3, FoxD4, and FoxD5. One of these vertebrate genes (FoxD3) consistently marks neural crest during development. Early in amphioxus development, AmphiFoxD is expressed medially in the anterior neural plate as well as in axial (notochordal) and paraxial mesoderm; later, the gene is expressed in the somites, notochord, cerebral vesicle (diencephalon), and hindgut endoderm. However, there is never any expression in cells bordering the neural plate. We speculate that an AmphiFoxD homolog in the common ancestor of amphioxus and vertebrates was involved in histogenic processes in the mesoderm (evagination and delamination of the somites and notochord); then, in the early vertebrates, descendant paralogs of this gene began functioning in the presumptive neural crest bordering the neural plate to help make possible the delaminations and cell migrations that characterize definitive vertebrate neural crest. Copyright 2002 Wiley-Liss, Inc.

Intra-Amniotic Administration (Gallus gallus) of Cicer arietinum and Lens culinaris Prebiotics Extracts and Duck Egg White Peptides Affects Calcium Status and Intestinal Functionality

PubMed Central

Hou, Tao; Glahn, Raymond P.; Tako, Elad

2017-01-01

Calcium (Ca) is one of the most abundant inorganic elements in the human body and has many important physiological roles. Prebiotics and bioactive peptides are two important substances used to promote calcium uptake. However, the difference in mechanisms of the calcium uptake from these two supplements is not clear. By using the Gallus gallus model and the intra-amniotic administration procedure, the aim of this study was to investigate whether Ca status, intestinal functionality, and health-promoting bacterial populations were affected by prebiotics extracted from chickpea and lentil, and duck egg white peptides (DPs). Eleven groups (non-injected; 18 MΩ H2O; 4 mmol/L CaCl2; 50 mg/mL chickpea + 4 mmol/L CaCl2; 50 mg/mL lentil + 4 mmol/L CaCl2; 40 mg/mL DPs + 4 mmol/L CaCl2; 5 mg/mL Val-Ser-Glu-Glu (VSEE) + 4 mmol/L CaCl2; 50 mg/mL chickpea; 50 mg/mL lentil; 40 mg/mL DPs; 5 mg/mL VSEE) were utilized. Upon hatch, blood, cecum, small intestine, liver and bone were collected for assessment of serum bone alkaline phosphate level (BALP), the relative abundance of intestinal microflora, expression of Ca-related genes, brush border membrane (BBM) functional genes, and liver and bone mineral levels, respectively. The BALP level increased in the presence of lentil, DPs and VSEE (p < 0.05). The relative abundance of probiotics increased significantly (p < 0.05) by VSEE + Ca and chickpea. The expression of CalbindinD9k (Ca transporter) increased (p < 0.05) in Ca, chickpea + Ca and lentil + Ca groups. In addition, the brush border membrane functionality genes expressions increased (p < 0.05) by the chickpea or lentil extracts. Prebiotics and DPs beneficially affected the intestinal microflora and duodenal villus surface area. This research expands the understanding of the prebiotics’ properties of chickpea and lentil extracts, and peptides’ effects on calcium metabolism and gut health. PMID:28754012

Intra-Amniotic Administration (Gallus gallus) of Cicer arietinum and Lens culinaris Prebiotics Extracts and Duck Egg White Peptides Affects Calcium Status and Intestinal Functionality.

PubMed

Hou, Tao; Kolba, Nikolai; Glahn, Raymond P; Tako, Elad

2017-07-21

Calcium (Ca) is one of the most abundant inorganic elements in the human body and has many important physiological roles. Prebiotics and bioactive peptides are two important substances used to promote calcium uptake. However, the difference in mechanisms of the calcium uptake from these two supplements is not clear. By using the Gallus gallus model and the intra-amniotic administration procedure, the aim of this study was to investigate whether Ca status, intestinal functionality, and health-promoting bacterial populations were affected by prebiotics extracted from chickpea and lentil, and duck egg white peptides (DPs). Eleven groups (non-injected; 18 MΩ H₂O; 4 mmol/L CaCl₂; 50 mg/mL chickpea + 4 mmol/L CaCl₂; 50 mg/mL lentil + 4 mmol/L CaCl₂; 40 mg/mL DPs + 4 mmol/L CaCl₂; 5 mg/mL Val-Ser-Glu-Glu (VSEE) + 4 mmol/L CaCl₂; 50 mg/mL chickpea; 50 mg/mL lentil; 40 mg/mL DPs; 5 mg/mL VSEE) were utilized. Upon hatch, blood, cecum, small intestine, liver and bone were collected for assessment of serum bone alkaline phosphate level (BALP), the relative abundance of intestinal microflora, expression of Ca-related genes, brush border membrane (BBM) functional genes, and liver and bone mineral levels, respectively. The BALP level increased in the presence of lentil, DPs and VSEE ( p < 0.05). The relative abundance of probiotics increased significantly ( p < 0.05) by VSEE + Ca and chickpea. The expression of CalbindinD9k (Ca transporter) increased ( p < 0.05) in Ca, chickpea + Ca and lentil + Ca groups. In addition, the brush border membrane functionality genes expressions increased ( p < 0.05) by the chickpea or lentil extracts. Prebiotics and DPs beneficially affected the intestinal microflora and duodenal villus surface area. This research expands the understanding of the prebiotics' properties of chickpea and lentil extracts, and peptides' effects on calcium metabolism and gut health.

Uptake mechanism of valproic acid in human placental choriocarcinoma cell line (BeWo).

PubMed

Ushigome, F; Takanaga, H; Matsuo, H; Tsukimori, K; Nakano, H; Ohtani, H; Sawada, Y

2001-04-13

Valproic acid is an anticonvulsant widely used for the treatment of epilepsy. However, valproic acid is known to show fetal toxicity, including teratogenicity. In the present study, to elucidate the mechanisms of valproic acid transport across the blood-placental barrier, we carried out transcellular transport and uptake experiments with human placental choriocarcinoma epithelial cells (BeWo cells) in culture. The permeability coefficient of [3H]valproic acid in BeWo cells for the apical-to-basolateral flux was greater than that for the opposite flux, suggesting a higher unidirectional transport in the fetal direction. The uptake of [3H]valproic acid from the apical side was temperature-dependent and enhanced under acidic pH. In the presence of 50 microM carbonyl cyanide p-trifluoromethoxylhydrazone, the uptake of [3H]valproic acid was significantly reduced. A metabolic inhibitor, 10 mM sodium azide, also significantly reduced the uptake of [3H]valproic acid. Therefore, valproic acid is actively transported in a pH-dependent manner on the brush-border membrane of BeWo cells. Kinetic analysis of valproic acid uptake revealed the involvement of a non-saturable component and a saturable component. The Michaelis constant for the saturable transport (K(t)) was smaller under acidic pH, suggesting a proton-linked active transport mechanism for valproic acid in BeWo cells. In the inhibitory experiments, some short-chain fatty acids, such as acetic acid, lactic acid, propanoic acid and butyric acid, and medium-chain fatty acids, such as hexanoic acid and octanoic acid, inhibited the uptake of [3H]valproic acid. The uptake of [3H]valproic acid was also significantly decreased in the presence of 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, salicylic acid and furosemide, which are well-known inhibitors of the anion exchange system. Moreover, p-aminohippuric acid significantly reduced the uptake of [3H]valproic acid. These results suggest that an active transport mechanism for valproic acid exists on the brush-border membrane of placental trophoblast cells and operates in a proton-linked manner.

Differentiation of F4 receptor profiles in pigs based on their mucin 4 polymorphism, responsiveness to oral F4 immunization and in vitro binding of F4 to villi.

PubMed

Nguyen, V U; Goetstouwers, T; Coddens, A; Van Poucke, M; Peelman, L; Deforce, D; Melkebeek, V; Cox, E

2013-03-15

F4(+) enterotoxigenic Escherichia coli (F4(+) ETEC) are an important cause of diarrhoea and mortality in piglets. F4(+) ETEC use their F4 fimbriae to adhere to specific receptors (F4Rs) on small intestinal brush borders, resulting in colonization of the small intestine. To prevent pigs from post-weaning diarrhoea, pigs should be vaccinated during the suckling period. Previously, we demonstrated that F4acR(+), but not F4acR(-) piglets could be orally immunized with purified F4 fimbriae resulting in a protective immunity against F4(+) ETEC infections, indicating that this immune response was F4R dependent. Recently, aminopeptidase N has been identified as a glycoprotein receptor important for this oral immune response. However, in some oral immunization experiments, a few F4acR(+) piglets did not show an antibody response upon oral immunization, suggesting additional receptors. Therefore, the binding profile of F4 to brush border membrane (glyco)proteins was determined for pigs differing in F4-specific antibody response upon oral immunization, in in vitro adhesion of F4(+)E. coli to small intestinal villi, and in Muc4 genotype. Six groups of pigs could be identified. Only two groups positive in all three assays showed two high molecular weight (MW) glycoprotein bands (>250kDa) suggesting that these high MW bands are linked to the MUC4 susceptible genotype. The fact that these bands were absent in the MUC4 resistant group which showed a positive immune response against F4 and was positive in the adhesion test confirm that at least one or perhaps more other F4Rs exist. Interestingly, two pigs that were positive in the villous adhesion assay did not show an immune response against F4 fimbriae. This suggests that a third receptor category might exist which allows the bacteria to adhere but does not allow effective immunization with soluble F4 fimbriae. Future research will be necessary to confirm or reveal the identity of these receptors. Copyright © 2012 Elsevier B.V. All rights reserved.

RhoB controls endothelial barrier recovery by inhibiting Rac1 trafficking to the cell border

PubMed Central

Marcos-Ramiro, Beatriz; García-Weber, Diego; Barroso, Susana; Feito, Jorge; Ortega, María C.; Cernuda-Morollón, Eva; Reglero-Real, Natalia; Fernández-Martín, Laura; Durán, Maria C.; Alonso, Miguel A.; Correas, Isabel; Cox, Susan; Ridley, Anne J.

2016-01-01

Endothelial barrier dysfunction underlies chronic inflammatory diseases. In searching for new proteins essential to the human endothelial inflammatory response, we have found that the endosomal GTPase RhoB is up-regulated in response to inflammatory cytokines and expressed in the endothelium of some chronically inflamed tissues. We show that although RhoB and the related RhoA and RhoC play additive and redundant roles in various aspects of endothelial barrier function, RhoB specifically inhibits barrier restoration after acute cell contraction by preventing plasma membrane extension. During barrier restoration, RhoB trafficking is induced between vesicles containing RhoB nanoclusters and plasma membrane protrusions. The Rho GTPase Rac1 controls membrane spreading and stabilizes endothelial barriers. We show that RhoB colocalizes with Rac1 in endosomes and inhibits Rac1 activity and trafficking to the cell border during barrier recovery. Inhibition of endosomal trafficking impairs barrier reformation, whereas induction of Rac1 translocation to the plasma membrane accelerates it. Therefore, RhoB-specific regulation of Rac1 trafficking controls endothelial barrier integrity during inflammation. PMID:27138256

Brush head composition, wear profile, and cleaning efficacy: an assessment of three electric brush heads using in vitro methods.

PubMed

Kaiser, Eva; Meyners, Michael; Markgraf, Dirk; Stoerkel, Ulrich; von Koppenfels, Roxana; Adam, Ralf; Soukup, Martin; Wehrbein, Heinrich; Erbe, Christina

2014-01-01

The objective of this research was to evaluate a current store brand (SB) brush head for composition/physical characteristics, Wear Index (WI), and cleaning efficacy versus the previous SB brush head refill design (SB control) and the Oral-B Precision Clean brush head (positive control, PC). This research consisted of three parts: 1) Analytical analysis using Fourier Transform Infrared (FT-IR) spectrometry to evaluate the chemical composition of the current SB brush head bristles relative to the SB control. In addition, physical parameters such as bristle count and diameter were determined. 2) Wear Index (WI) investigation to determine the Wear Index scores of in vitro-aged brush heads at four weeks (one month) and 13 weeks (three months) by a trained investigator. To "age" the brush heads, a robot system was used as a new alternative in vitro method to simulate aging by consumer use. 3) Robot testing to determine the cleaning performance of in vitro-aged brush heads, comparing one month-aged current SB brush heads with the SB control (one and three months-aged) and the PC brush heads (three months-aged) in a standardized fashion. 1) FT-IR analysis revealed that the chemical composition of the current and control SB refill brush heads is identical. In terms of physical parameters, the current SB brush head has 12% more bristles and a slightly oval brush head compared to the round brush head of the SB control. 2) Wear Index analysis showed there was no difference in the one month-aged current SB brush head versus the one month-aged SB control (1.67 vs. 1.50, p = 0.65) or versus the three months-aged PC brush head (1.67 vs. 1.50, p = 0.65). The one month-aged current SB brush head demonstrated statistically significantly less wear than the three months-aged SB control (1.67 vs. 2.67, p = 0.01). 3) Analysis of cleaning efficacy shows that the one month-aged current SB brush head had improved cleaning performance over the one month-aged SB control brush head (p < 0.05), despite no statistically significant difference in wear. Both the one month-aged current and control SB brush heads showed statistically significantly lower cleaning performance compared to the three months-aged PC brush heads (p < 0.01). While the current SB brush head showed improved cleaning over the SB control, it demonstrated significantly lower durability and cleaning in comparison to the PC brush head. Dental professionals should be aware of these differences, both in durability and in cleaning performance, when recommending brush heads to their patients.

Virtual reality using guided imagery to create Kanji or Hiragana by computer graphics: I

NASA Astrophysics Data System (ADS)

Ishigame, Masaaki; Miura, Nozomu; Hosaka, Akiko

1997-04-01

We have been studying a kind of word-processor that is able to create Japanese characters, Kanji or Hiragana strings in the cursive style, using an electronic writing brush model. Int his paper, we describe in detail the operation characteristics of the electronic writing brush which we have proposed. We defined a touch shape pattern of the electronic writing brush as a form which is projected as a circle and a cone. The brush goes on certain points of the skeleton of the character figure which is given as skeleton data. The thickness of the line is determined by a diametric variable brush pressure. Our progressive action model can rotate the direction of the writing brush tip corresponding to the difference angle between the direction of brush tip and the direction of the brush movement, and also the softness of the writing brush to express the writing brush method called the side writing brush. The front side and back side of the writing brush can be expressed in a calligraphic drawing. With our technique we can draw characters in actual stroke order on a virtual computer plane as if they are written by an actual writing brush.

Tooth brushing habits in uninstructed adults--frequency, technique, duration and force.

PubMed

Ganss, C; Schlueter, N; Preiss, S; Klimek, J

2009-06-01

Professional recommendations for individual oral hygiene mostly include tooth brushing at least twice daily for 2-3 min with gentle force using the Bass technique or modifications of it. This study evaluated whether habitual tooth brushing actually meets these standards. Uninstructed adults (n = 103; mean age 31 +/- 6 years; 61 female, 42 male) with habitual manual tooth brushing were given a self-administered questionnaire about the frequency of brushing and a computer system recorded their brushing technique, duration and force. The majority (79.6%) of participants brushed twice daily. The mean brushing duration was 96.6 +/- 36.0 s, the mean brushing force was 2.3 +/- 0.7 N (max. 4.1 N), and no significant differences were found for quadrants. Most subjects (73.8%) brushed with circling, 8.7% with horizontal/scrubbing, 13.6% with horizontal/circling and 3.9% with vertical/sweeping movements. Modified Bass technique was not observed. When appropriate brushing habits were defined as brushing at least twice daily for 120 s with a brushing force of less than 3 N and with circling or vertical sweeping movements, only 25.2% of the participants fulfilled all criteria, emphasising the ongoing need for oral hygiene education.

Distribution of the cystine/glutamate antiporter system xc- in the brain, kidney, and duodenum.

PubMed

Burdo, Joseph; Dargusch, Richard; Schubert, David

2006-05-01

System x(c)(-), one of the main transporters responsible for central nervous system cystine transport, is comprised of two subunits, xCT and 4F2hc. The transport of cystine into cells is rate limiting for glutathione synthesis, the major antioxidant and redox cofactor in the brain. Alterations in glutathione status are prevalent in numerous neurodegenerative diseases, emphasizing the importance of proper cystine homeostasis. However, the distribution of xCT and 4F2hc within the brain and other areas has not been described. Using specific antibodies, both xCT and 4F2hc were localized predominantly to neurons in the mouse and human brain, but some glial cells were labeled as well. Border areas between the brain proper and periphery including the vascular endothelial cells, ependymal cells, choroid plexus, and leptomeninges were also highly positive for the system x(c)(-) components. xCT and 4F2hc are also present at the brush border membranes in the kidney and duodenum. These results indicate that system x(c)(-) is likely to play a role in cellular health throughout many areas of the brain as well as other organs by maintaining intracellular cystine levels, thereby resulting in low levels of oxidative stress.

Increasing operational life of brush-contact device in the turbine generator due to using lubricating molybdenum disulphide brushes

NASA Astrophysics Data System (ADS)

Izotov, A. I.; Fominykh, A. A.; Nikulin, S. V.; Prokoshev, D. K.; Legoti, A. B.; Timina, N. V.

2018-01-01

A way of reducing irregular current distribution in multi-brush systems of sliding current transfer with its wear reduction due to installing lubricating molybdenum disulphide brushes on slip rings to ensure a greasing nano-sized cover on the slip ring surface is proposed. The authors give the results of industrial tests estimated on the performance effectiveness of lubricating brushes on slip rings of the TBB-320-2UZ-type turbine generator. The results showed that the lubricating brushes reduce a) the wear of 6110 OM+M and EG2AF+M brushes by 1.2 and 2.1 times respectively, b) current distribution irregularity in parallel operating brushes due to stabilizing the contact arc, and c) the temperature of the electrical brush-contact device due to the friction reduction in brushes.

Ordered quasi-two-dimensional structure of nanoparticles in semiflexible ring polymer brushes under compression

NASA Astrophysics Data System (ADS)

Hua, Yunfeng; Deng, Zhenyu; Jiang, Yangwei; Zhang, Linxi

2017-06-01

Molecular dynamics simulations of a coarse-grained bead-spring model of ring polymer brushes under compression are presented. Flexible polymer brushes are always disordered during compression, whereas semiflexible polymer brushes tend to be ordered under sufficiently strong compression. Further, the polymer monomer density of the semiflexible polymer brush is very high near the brush surface, inducing a peak value of the free energy near the surface. Therefore, when nanoparticles are compressed in semiflexible ring polymer brushes, they tend to exhibit a closely packed single-layer structure between the brush surface and the impenetrable wall, and a quasi-two-dimensional ordered structure near the brush surface is formed under strong compression. These findings provide a new approach to designing responsive applications.

An Eight-Week Clinical Evaluation of an Oscillating-Rotating Power Toothbrush with a Brush Head Utilizing Angled Bristles Compared with a Sonic Toothbrush in the Reduction of Gingivitis and Plaque.

PubMed

Ccahuana-Vasquez, Renzo A; Conde, Erinn; Grender, Julie M; Cunningham, Pamela; Qaqish, Jimmy; Goyal, C Ram

2015-01-01

To evaluate and compare the efficacy of an oscillating-rotating (O-R) power toothbrush with a brush head utilizing angled bristles to a marketed sonic toothbrush in the reduction of plaque and gingivitis over an eight-week period. This study used a randomized, examiner-blind, single-center, two-treatment, parallel group, eight-week design. Subjects with mild-to-moderate plaque and gingivitis were evaluated for baseline whole mouth, gingival margin, and approximal plaque, gingivitis, and gingival bleeding. Clinical assessments were performed using the Modified Gingival Index, Gingival Bleeding Index, and the Rustogi Modified Navy Plaque Index. Subjects received either the O-R brush (Oral-B Professional Care 1000 [D16u] with Oral-B CrossAction brush head [EB50]) or the sonic brush (Sonicare DiamondClean with the standard DiamondClean brush head). Subjects brushed twice daily for two minutes per brushing with the assigned brush and a standard fluoride dentifrice for eight weeks before returning for plaque and gingivitis evaluations using the same methods. Prior to baseline and Week 8 measurements, participants abstained from oral hygiene for 12 hours. One hundred and forty-eight subjects completed the study; 75 in the O-R group and 73 in the sonic group. Both brushes demonstrated statistically significant reductions in plaque and gingivitis over the eight-week study period (p < 0.00 1). The O-R brush was statistically significantly more effective in reducing plaque and gingivitis than the sonic brush. Whole mouth, gingival margin, and approximal plaque reductions were 27.7%, 46.8%, and 29.3% greater, respectively, compared with the sonic brush, while the reductions in gingivitis, gingival bleeding, and number of bleeding sites were 34.6%, 36.4%, and 36.1% greater, respectively, for the O-R brush than for the sonic brush (p < 0.001 for all six measures). No adverse events were observed for either brush. The plaque and gingivitis reductions for the O-R power brush incorporating the angled-bristled brush head were significantly greater than for the sonic power brush.

Structure of Weakly Charged Polyelectrolyte Brushes: Monomer Density Profiles

NASA Astrophysics Data System (ADS)

Borisov, O. V.; Zhulina, E. B.

1997-03-01

The internal structure (the monomer density profiles) of weakly charged polyelectrolyte brushes of different morphologies has been analyzed on the basis of the self-consistent-field approach. In contrast to previous studies based on the local electroneutrality approximation valid for sufficiently strongly charged or densely grafted (“osmotic") brushes we consider the opposite limit of sparse brushes which are unable to retain the counterions inside the brush. We have shown that an exact analytical solution of the SCF-equations is available in the case of a planar brush. In contrast to Gaussian monomer density profile known for “osmotic" polyelectrolyte brushes we have found that weakly charged brushes are characterized by constant monomer density. At the same time free ends of grafted polyions are distributed throughout the brush. Thus, the structural cross-over between polyelectrolyte “mushrooms" and dense brush regimes is established.

NPC1L1 and Cholesterol Transport

PubMed Central

Betters, Jenna L.; Yu, Liqing

2010-01-01

The polytopic transmembrane protein, Niemann-Pick C1-Like 1 (NPC1L1), is enriched in the apical membrane of small intestine absorptive enterocytes where it mediates extracellular sterol transport across the brush border membrane. It is essential for intestinal sterol absorption and is the molecular target of ezetimibe, a potent cholesterol absorption inhibitor that lowers blood cholesterol in humans. NPC1L1 is also highly expressed in human liver. The hepatic function of NPC1L1 may be to limit excessive biliary cholesterol loss. NPC1L1-dependent sterol uptake seems to be a clathrin-mediated endocytic process and is regulated by cellular cholesterol content. Recently, NPC1L1 inhibition has been shown to have beneficial effects on components of the metabolic syndrome, such as obesity, insulin resistance, fatty liver, in addition to atherosclerosis. PMID:20307540

Effects of desensitizing toothpastes on the permeability of dentin after different brushing times: An in vitro study.

PubMed

Yang, Meng; Lin, Hong; Jiang, Ruodan; Zheng, Gang

2016-12-01

To investigate the effects of three commercially available desensitizing toothpastes on dentin permeability, and compare the efficacy of each product for reducing dentin permeability in the short term according to the frequency and duration of usage. 100 dentin discs with no caries were prepared from freshly extracted human third molar teeth. The dentin discs were brushed with three desensitizing toothpastes or with a non-desensitizing toothpaste and distilled water, which served as control. The 100 dentin slices were randomly divided into two groups (n= 50): one group underwent continuous brushing (brushed for 3 minutes continuously), and the other group underwent discontinuous brushing (brushed three times, each time for 1 minute). Then, the two groups were divided into five subgroups (n = 10) for the five brushing applications. Dentin permeability was measured with a hydraulic permeability system before and after brushing. All desensitizing toothpastes reduced dentin permeability significantly after treatment. Sensodyne Repair and Protect (calcium sodium phosphosilicate) and discontinuous brushing reduced dentin permeability significantly compared with continuous brushing. Dentin permeability values showed no significant difference between the three toothpastes after 3 minutes of continuous brushing. When comparing the three toothpastes under discontinuous brushing conditions after 3 minutes, Sensodyne Repair and Protect (calcium sodium phosphosilicate) reduced dentin permeability significantly. Sensodyne Repair and Protect (calcium sodium phosphosilicate) and discontinuous brushing reduced dentin permeability significantly compared with continuous brushing. Moreover, brushing with Sensodyne Repair and Protect (calcium sodium phosphosilicate) resulted in the lowest dentin permeability compared with those of the other two toothpastes. These results indicated that Sensodyne Repair and Protect may relieve dentin hypersensitivity.

Interproximal plaque mass and fluoride retention after brushing and flossing--a comparative study of powered toothbrushing, manual toothbrushing and flossing.

PubMed

Sjögren, Karin; Lundberg, Ann-Britt; Birkhed, Dowen; Dudgeon, Douglas J; Johnson, Matthew R

2004-01-01

To determine differences in interproximal plaque mass and fluoride retention with different modes of toothbrushing and flossing. Forty-seven subjects in good health used four treatments in a four-period, randomized, crossover design: 1) manual brushing only; 2) manual brushing and daily flossing; 3) electric brushing using a rotational oscillation toothbrush; and 4) electric brushing using a sonic toothbrush. Subjects used a standard sodium fluoride dentifrice during the eight-day experimental periods and a fluoride-free dentifrice during the seven-day washout periods between treatments. Interproximal plaque samples were taken on Day 1 and on Day 8, weighed, and analyzed for fluoride content. The amount of interproximal plaque was lowest with sonic brushing, which left 43-65% less plaque than all other treatments. Manual brushing and flossing yielded less plaque than manual brushing alone and rotational oscillation brushing. Differences were statistically significant (p < 0.05) for treatment; there was no time effect on plaque mass. For fluoride retention, at Day 1 sonic brushing gave at least 54% more fluoride in the interproximal plaque than all other treatments, which was significant. All treatments demonstrated a significant increase in fluoride concentration with time except manual brushing and flossing, which showed a significant decrease. At Day 8, the fluoride concentration was significantly higher for sonic brushing than for manual brushing or rotational oscillation brushing by over 40%, and all treatments exhibited significantly greater fluoride than the manual brushing and flossing combination. The mode of toothbrushing may impact the amount of plaque retained interproximally and its fluoride concentration.

Application of tooth brushing behavior to active rest.

PubMed

Sadachi, Hidetoshi; Murakami, Yoshinori; Tonomura, Manabu; Yada, Yukihiro; Simoyama, Ichiro

2010-01-01

We evaluated the usefulness of tooth brushing with toothpaste as active rest using the flicker value as a physiological parameter and a subjective questionnaire as a psychological parameter. Seventeen healthy, right-handed subjects (12 males and 5 females) aged 22.5 +/- 1.5 yr (mean +/- standard deviation) were randomly divided into tooth brushing with toothpaste (N=9) and non-tooth brushing groups (N=8). The subjects performed a serial calculation task for 20 min using personal computers. Subsequently, the tooth brushing group brushed their teeth, and the flicker value and mood were compared before and after the tooth brushing. The flicker value significantly increased in the tooth brushing group compared with the non-tooth brushing group (p<0.05). Concerning the mood, in the tooth brushing group, the incidence of a "feeling of being refreshed" significantly increased (p<0.05), that of "concentration power" or a "feeling of clear-headedness" tended to increase (p<0.1), and that of "lassitude" or "sleepiness" significantly decreased (p<0.01). Somatosensory stimulation and intraoral tactile stimulation during tooth brushing activated cerebral activity, producing refreshing effects. These results suggest the applicability of tooth brushing to active rest.

Social ranking effects on tooth-brushing behaviour.

PubMed

Maltby, John; Paterson, Kevin; Day, Liz; Jones, Ceri; Kinnear, Hayley; Buchanan, Heather

2016-05-01

A tooth-brushing social rank hypothesis is tested suggesting tooth-brushing duration is influenced when individuals position their behaviour in a rank when comparing their behaviour with other individuals. Study 1 used a correlation design, Study 2 used a semi-experimental design, and Study 3 used a randomized intervention design to examine the tooth-brushing social rank hypothesis in terms of self-reported attitudes, cognitions, and behaviour towards tooth-brushing duration. Study 1 surveyed participants to examine whether the perceived health benefits of tooth-brushing duration could be predicted from the ranking of each person's tooth-brushing duration. Study 2 tested whether manipulating the rank position of the tooth-brushing duration influenced participant-perceived health benefits of tooth-brushing duration. Study 3 used a longitudinal intervention method to examine whether messages relating to the rank positions of tooth-brushing durations causally influenced the self-report tooth-brushing duration. Study 1 demonstrates that perceptions of the health benefits from tooth-brushing duration are predicted by the perceptions of how that behaviour ranks in comparison to other people's behaviour. Study 2 demonstrates that the perceptions of the health benefits of tooth-brushing duration can be manipulated experimentally by changing the ranked position of a person's tooth-brushing duration. Study 3 experimentally demonstrates the possibility of increasing the length of time for which individuals clean their teeth by focusing on how they rank among their peers in terms of tooth-brushing duration. The effectiveness of interventions using social-ranking methods relative to those that emphasize comparisons made against group averages or normative guidelines are discussed. What is already known on this subject? Individual make judgements based on social rank information. Social rank information has been shown to influence positive health behaviours such as exercise. What does this study add? The health benefits of tooth-brushing are predicted by how tooth-brushing duration ranks within a distribution. Focussing on how teeth-cleaning duration ranks among others produces longer teeth-cleaning durations. © 2015 The British Psychological Society.

[Effect of a tooth-brushing education program on oral health of preschool children].

PubMed

Kang, Bok-Hee; Park, Sun-Nam; Sohng, Kyeong-Yae; Moon, Jung-Soon

2008-12-01

To examine the effect of tooth-brushing education on the oral health of preschoolers. A quasi-experimental design with a non-equivalent control group was used. Two kindergartens were selected and 39 preschoolers from one kindergarten were assigned to the experimental group with tooth-brushing education and 39 from the other kindergarten to the control group. The tooth-brushing education program included 1 session on oral health education, individual tooth-brushing instruction for 1 week and supervised tooth-brushing after lunch for 4 weeks. Oral health behavior including use of tooth paste, tooth-brushing time and method of tooth-brushing, plague, streptococcus mutans, lactobacillus and dental caries were measured before and after the education. Fisher's exact test, t-test and paired t-test with the Window SAS 9.1 program were used to analyze the data. A significant increase in the use of tooth paste, tooth-brushing time and the practice of correct tooth-brushing and a decrease in plague and development of dental caries were observed in the experimental group. This tooth-brushing education was partially effective in improving oral health of preschoolers.

Polyelectrolyte brushes on dielectric surfaces

NASA Astrophysics Data System (ADS)

Antila, Hanne; Luijten, Erik

When chains of charged polymers are grafted to a solid surface, a polyelectrolyte (PE) brush results. These types of PE assemblies have a wide range of applications ranging from fuel cells and switchable electrodes to drug delivery. Many of these applications stem from the ability of PE brushes to respond to external stimuli: the brush properties can be tuned, for example, by varying electric field, PE grafting density, pH, salt concentration or salt valency. Accordingly, deciphering the brush behavior under different conditions has been a subject of considerable experimental, theoretical, and computational research efforts. However, the effect of the dielectric properties of the substrate on the PE brush has received much less attention. We use coarse-grained molecular dynamics simulations to show how varying the dielectric mismatch between the solvent and the substrate can significantly affect the brush. We demonstrate how tuning this mismatch can either diminish or enhance the effects of other control parameters, such as pH, on the brush properties. Furthermore, we investigate how dielectric properties of the substrate affect the brush, and the ion distribution and mobility within the brush, when the brush is exposed to an electric field.

Computer simulations of the mechanical response of brushes on the surface of cancerous epithelial cells

NASA Astrophysics Data System (ADS)

Goicochea, A. Gama; Guardado, S. J. Alas

2015-08-01

We report a model for atomic force microscopy by means of computer simulations of molecular brushes on surfaces of biological interest such as normal and cancerous cervical epithelial cells. Our model predicts that the force needed to produce a given indentation on brushes that can move on the surface of the cell (called “liquid” brushes) is the same as that required for brushes whose ends are fixed on the cell’s surface (called “solid” brushes), as long as the tip of the microscope covers the entire area of the brush. Additionally, we find that cancerous cells are softer than normal ones, in agreement with various experiments. Moreover, soft brushes are found to display larger resistance to compression than stiff ones. This phenomenon is the consequence of the larger equilibrium length of the soft brushes and the cooperative association of solvent molecules trapped within the brushes, which leads to an increase in the osmotic pressure. Our results show that a careful characterization of the brushes on epithelial cells is indispensable when determining the mechanical response of cancerous cells.

DNA decontamination of fingerprint brushes.

PubMed

Szkuta, Bianca; Oorschot, Roland A H van; Ballantyne, Kaye N

2017-08-01

Genetic profiling of DNA collected from fingerprints that have been exposed to various enhancement techniques is routine in many forensic laboratories. As a result of direct contact with fingermark residues during treatment, there is concern around the DNA contamination risk of dusting fingermarks with fingerprint brushes. Previous studies have demonstrated the potential for cross-contamination between evidentiary items through various mechanisms, highlighting the risk of using the same fingerprint brush to powder multiple surfaces within and between crime-scenes. Experiments were performed to assess the contamination risk of reused fingerprint brushes through the transfer of dried saliva and skin deposits from and to glass surfaces with new unused squirrel hair and fiberglass brushes. Additional new unused brushes and brushes previously used in casework were also tested for their ability to contaminate samples. In addition, the ability to eradicate DNA from used squirrel hair and fiberglass fingerprint brushes was assessed using a 1% sodium hypochlorite solution and a 5% solution of a commercially available alternative, Virkon. DNA profiling results from surfaces contacted by treated and untreated brushes were compared to determine the effectiveness of the devised cleaning protocol. Brush durability was also assessed over multiple wash/rinse/dry cycles with both agents. Varying amounts of DNA-containing material were collected and transferred by squirrel hair and fiberglass brushes, with detectability on the secondary surface dependent on the biological nature of the material being transferred. The impact of DNA contamination from dirty fingerprint brushes was most apparent in simulations involving the transfer of dried saliva and brushes previously used in casework, while minimal transfer of touch DNA was observed. Alarmingly, large quantities of DNA were found to reside on new unused squirrel hair brushes, while no DNA was detected on new unused fiberglass brushes or brushes sold as DNA-free. Squirrel hair brushes were easily and effectively cleaned with both hypochlorite and Virkon, with no evidence of DNA transfer between exhibits by treated brushes. Brushes were still deemed useable after multiple cleaning cycles with either agent. In contrast, fiberglass bristles became tangled and matted when wet and could not be cleaned effectively using either method. It is recommended they are disposed of following use. Each laboratory should consider their current circumstances before adapting a cleaning method. The implementation of a program to monitor the effectiveness of the cleaning regime is also advised. Copyright © 2017 Elsevier B.V. All rights reserved.

Directed deposition of inorganic oxide networks on patterned polymer templates

NASA Astrophysics Data System (ADS)

Ford, Thomas James Robert

Inspired by nature, we have successfully directed the deposition of inorganic oxide materials on polymer templates via a combination of top-down and bottom-up fabrication methods. We have functionally mimicked the hierarchical silica exoskeletons of diatoms, where specialized proteins chaperone the condensation of silicic acid into nanoscale silica networks confined by microscopic vesicle walls. We replaced the proteins with functionally analogous polyamines and vesicles with lithographically defined polymer templates. We grafted the polyamines either to the surface or throughout the template by changing the template chemistry and altering our grafting strategy. Exposure to an inorganic oxide precursor solution led to electrostatic aggregation at the polyamine chains, catalyzing hydrolysis and condensation to form long-range inorganic oxide nanoparticle networks. Grafted to epoxy surfaces, swelling effects and the hyperbranched brush morphology lead to the formation of nanofruit features that generated thin, conformal inorganic coatings. When the polyamines were grafted throughout hydrogel templates, we obtained composite networks that yielded faithful inorganic replicas of the original patterns. By varying the polyamine chain length and combustion parameters, we controlled the nanoparticle size, morphology, and crystalline phase. The polyamine morphology affected the resulting inorganic network in both fabrication schemes and we could control the depostion over multiple length scales. Because our methods were compatible with a variety of lithographic methods, we were able to generate inorganic replicas of 1D, 2D, and 3D polymer structures. These may be used for a wide range of applications, including sensing, catalysis, photonic, phononic, photovoltaic, and others that require well-defined inorganic structures.

Development of a Brush Seals Program Leading to Ceramic Brush Seals

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Flower, Ralph; Howe, Harold

1994-01-01

Some events of a U.S. Army/NASA Lewis Research Center brush seals program are reviewed, and the development of ceramic brush seals is described. Some preliminary room-temperature flow data are given, and the results of testing metallic brushes in cryogenic nitrogen are discussed.

Efficient Energy Conversion by Grafting Nanochannels with End-charged Stimuli-responsive Polyelectrolyte Brush

NASA Astrophysics Data System (ADS)

Chen, Guang; Das, Siddhartha

2017-11-01

Polyelectrolyte (PE) brushes have aroused increasing attention in applications in energy conversion and chemical sensing due to the environmentally-responsive and designable nature. PE brushes are charged polymer chains densely grafted on solid-liquid interfaces. By designing copolymeric systems, one can localize the ionizable sites at the brush tip in order to get end-charged PE brushes. Such brushes demonstrate anomalous shrinking/swelling behaviors with tunable environmental parameters such as pH and salt concentration. In this study, we probe the conformation and electrostatics of such PE brush systems with various size, grafting density and charge distribution, and exploit the electrochemomechanical energy conversion capabilities of nanochannels grafted with such PE brush systems. Our results indicate that the presence of the end-charged PE brush layer can massively enhance the streaming potential mediated energy conversion efficiency, and the improvement is more significant in strongly ionic solution.

Inhibitory effect of hydrophilic polymer brushes on surface-induced platelet activation and adhesion.

PubMed

Zou, Yuquan; Lai, Benjamin F L; Kizhakkedathu, Jayachandran N; Brooks, Donald E

2010-12-08

Poly(N,N-dimethylacrylamide) (PDMA) brushes are successfully grown from unplasticized poly(vinyl chloride) (uPVC) by well-controlled surface-initiated atom transfer radical polymerization (SI-ATRP). Molecular weights of the grafted PDMA brushes vary from ≈ 35,000 to 2,170000 Da, while the graft density ranges from 0.08 to 1.13 chains · nm(-2). The polydispersity of the grafted PDMA brushes is controlled within 1.20 to 1.80. Platelet activation (expression of CD62) and adhesion studies reveal that the graft densities of the PDMA brushes play an important role in controlling interfacial properties. PDMA brushes with graft densities between 0.35 and 0.50 chains · nm(-2) induce a significantly reduced platelet activation compared to unmodified uPVC. Moreover, the surface adhesion of platelets on uPVC is significantly reduced by the densely grafted PDMA brushes. PDMA brushes that have high molecular weights lead to a relatively lower platelet activation compared to low-molecular-weight brushes. However, the graft density of the brush is more important than molecular weight in controlling platelet interactions with PVC. PDMA brushes do not produce any significant platelet consumption in platelet rich plasma. Up to a seven-fold decrease in the number of platelets adhered on high graft density brushes is observed compared to the bare PVC surface. Unlike the bare PVC, platelets do not form pseudopodes or change morphology on PDMA brush-coated surfaces. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Salt Concentration on the pH Responses of Strong and Weak Polyelectrolyte Brushes.

PubMed

Zhang, Jian; Kou, Ran; Liu, Guangming

2017-07-11

Strong polyelectrolyte brushes (SPB) and weak polyelectrolyte brushes (WPB) have different origins with response to pH, which makes their pH-responsive properties sensitive to salt concentration in different ways. Herein, we have employed poly[2-(methacryloyloxy)ethyl trimethylammonium chloride] (PMETAC) and poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) brushes as model systems for SPB and WPB, respectively, to investigate the effect of salt concentration on the pH responses of SPB and WPB using several surface-sensitive techniques. The pH-responsive properties of the PMETAC brushes are governed by the reorganization of the interchain hydrogen bonds between the grafted chains, whereas the pH response of the PDMAEMA brushes is controlled by the charge of the grafted chains. The response of the properties of the PMETAC brushes including hydration, conformation, and surface wettability becomes weaker with increasing salt concentration induced by the competitive adsorption of counterions to the brushes between OH - and Cl - . The weakening of the pH response of the PMETAC brushes is more remarkable at the relatively high pH values. The pH response of the PDMAEMA brushes also exhibits a salt-concentration dependence. As the salt concentration increases, the weakening of the pH response of the PDMAEMA brushes is attributed to the decrease in osmotic pressure within the brushes at relatively low pH values.

Ordering nanoparticles with polymer brushes

NASA Astrophysics Data System (ADS)

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

2017-12-01

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a single layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. An interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.

α-synuclein expression in the mouse cerebellum is restricted to VGluT1 excitatory terminals and is enriched in unipolar brush cells

PubMed Central

Lee, Sun Kyong; Sillitoe, Roy V.; Silva, Coralie; Martina, Marco; Sekerkova, Gabriella

2015-01-01

α-synuclein has a crucial role in synaptic vesicle release and synaptic membrane recycling. Although its general expression pattern has been described in the cerebellum, the precise cerebellar structures where α-synuclein is localized are poorly understood. To address this question, we used α-synuclein immunohistochemistry in adult mice cerebellar sections. We found that α-synuclein labels glutamatergic but not glycinergic and GABAergic synaptic terminals in the molecular and granule cell layers. α-synuclein was preferentially expressed in parallel and mossy fiber synaptic terminals that also express vesicular glutamate transporter 1 (VGluT1) while it was not detected in VGluT2-positive climbing fibers. α-synuclein was particularly enriched in lobules IX and X, a region known to contain high density of unipolar brush cells (UBCs). To elucidate whether the α-synuclein-positive mossy fibers belong to UBCs, we double labeled cerebellar sections with antibodies to α-synuclein and UBCs type specific markers(calretinin for type I and metabotropic glutamate receptor 1α (mGluR1α) for type II UBCs), and took advantage of organotypic cerebellar cultures (in which all mossy fibers are UBC axons) and moonwalker mice (in which almost all UBCs are ablated) and found that both type I and type II UBCs express α-synuclein. In moonwalker mutant cerebella, the α-synuclein/VGluT1 immunolabeling showed dramatic decrease in the vestibulocerebellum that correlated with the absence of UBC. α-synuclein appears to be an excellent marker for intrinsic mossy fibers of the VGluT1 subset in conjunction with UBCs of both subtypes. PMID:25917213

α-Synuclein expression in the mouse cerebellum is restricted to VGluT1 excitatory terminals and is enriched in unipolar brush cells.

PubMed

Lee, Sun Kyong; Sillitoe, Roy V; Silva, Coralie; Martina, Marco; Sekerkova, Gabriella

2015-10-01

α-Synuclein has a crucial role in synaptic vesicle release and synaptic membrane recycling. Although its general expression pattern has been described in the cerebellum, the precise cerebellar structures where α-synuclein is localized are poorly understood. To address this question, we used α-synuclein immunohistochemistry in adult mice cerebellar sections. We found that α-synuclein labels glutamatergic but not glycinergic and GABAergic synaptic terminals in the molecular and granule cell layers. α-Synuclein was preferentially expressed in parallel and mossy fiber synaptic terminals that also express vesicular glutamate transporter 1 (VGluT1), while it was not detected in VGluT2-positive climbing fibers. α-Synuclein was particularly enriched in lobules IX and X, a region known to contain a high density of unipolar brush cells (UBCs). To elucidate whether the α-synuclein-positive mossy fibers belong to UBCs, we double-labeled cerebellar sections with antibodies to α-synuclein and UBC-type-specific markers (calretinin for type I and metabotropic glutamate receptor 1α (mGluR1α) for type II UBCs) and took advantage of organotypic cerebellar cultures (in which all mossy fibers are UBC axons) and moonwalker mice (in which almost all UBCs are ablated) and found that both type I and type II UBCs express α-synuclein. In moonwalker mutant cerebella, the α-synuclein/VGluT1 immunolabeling showed a dramatic decrease in the vestibulocerebellum that correlated with the absence of UBC. α-Synuclein appears to be an excellent marker for intrinsic mossy fibers of the VGluT1 subset in conjunction with UBCs of both subtypes.

Ureteral retrograde brush biopsy

MedlinePlus

Biopsy - brush - urinary tract; Retrograde ureteral brush biopsy cytology; Cytology - ureteral retrograde brush biopsy ... should not be performed in people with a: Urinary tract infection Blockage at or below the biopsy site ...

Protocol for measurement of enamel loss from brushing with an anti-erosive toothpaste after an acidic episode.

PubMed

Dehghan, Mojdeh; Vieira Ozorio, Jose Estevam; Chanin, Simon; Tantbirojn, Daranee; Versluis, Antheunis; Garcia-Godoy, Franklin

2017-01-01

Tooth erosion from an acidic insult may be exacerbated by toothbrushing. The purposes of this study were to develop an in vitro methodology to measure enamel loss after brushing immediately following an acidic episode and to investigate the effect of brushing with an anti-erosive toothpaste. The null hypotheses tested were that tooth erosion after brushing with the toothpaste would not be different from brushing with water and that a 1-hour delay before brushing would not reduce tooth erosion. Forty bovine enamel slabs were embedded, polished, and subjected to baseline profilometry. Specimens were bathed in hydrochloric acid for 10 minutes to simulate stomach acid exposure before post-acid profilometry. Toothbrushing was then simulated with a cross-brushing machine and followed by postbrushing profilometry. Group 1 was brushed with water; group 2 was brushed with a 50:50 toothpaste-water slurry; and groups 3 and 4 were immersed in artificial saliva for 1 hour before brushing with water or the toothpaste slurry, respectively. The depth of enamel loss was analyzed and compared using 1-way analysis of variance and post hoc testing (α = 0.05). Greater enamel loss was measured in groups brushed with toothpaste than in groups brushed with water. One-hour immersion in artificial saliva significantly reduced enamel loss when teeth were brushed with water (group 3; P < 0.05) but not with toothpaste (group 4). This study established a protocol for measuring enamel loss resulting from erosion followed by toothbrush abrasion. The results confirmed the abrasive action of toothpaste on acid-softened enamel.

Comparison of Three types of Tooth Brushes on Plaque and Gingival Indices: A Randomized Clinical Trial.

PubMed

Moeintaghavi, Amir; Sargolzaie, Naser; Rostampour, Mehrnoosh; Sarvari, Sara; Kargozar, Sanaz; Gharaei, Shideh

2017-01-01

To compare clinical results of three types of manual tooth brushes on plaque removal efficacy and gingivitis. This study is a single blind randomized trial with crossover design which involved 30 periodontaly healthy individuals. Professional plaque removal and oral hygiene instruction were performed for all the participants in the first step of our study followed by asking them to avoid brushing for 2 days. Thereafter plaque and gingivitis scores were measured using plaque and gingival indices (PI and GI). Then subjects were instructed to use Pulsar tooth brush for a two-week period and then, GI and PI indices were assessed again. After passing one-week period for wash out, subjects didn't brush for 2 days and indices were recorded again. The same procedure was done for CrossAction, and Butler 411 tooth brushes respectively and at the end of the study these variables were analyzed using SPSS software ver.16. Repeated measurement ANOVA test was used to compare the scores between different brushes. Finding of this study reveals that using all three types of tooth brushes resulted in significant plaque and gingivitis reduction compared to baseline levels. Pulsar tooth brush was significantly more effective in diminishing PI and GI than Butler tooth brush (p=0.044 and 0.031 respectively). According to our findings all 3 types of tooth brushes are effective in reduction of plaque and gingivitis and this reduction is significantly greater for Pulsar tooth brush compared to Butler and CrossAction tooth brushes.

Self-Renewing Microns-Thick Biopolymer Brush Made of Hyaluronan under Active Synthesis

NASA Astrophysics Data System (ADS)

Wei, W.; Washburn, J.; Weigel, P.; Curtis, J. E.

Hyaluronan (HA) is a large anionic polysaccharide distributed throughout many vertebrate tissues. We introduce a technology to produce dynamic HA polymer brush interfaces. The strategy relies on the enzyme hyaluronan synthase (HA synthase), which synthesizes and extrudes HA polymers up to 20 microns in length. We show that interfaces decorated by HA synthase-rich membrane fragments robustly produce polymer brushes of predictable heights and concentration profiles. The brush thickness can be tuned by the duration of growth or the enzyme density in the membranes. The system is self-renewing in that old polymers desorb and new polymers are produced. The brush can also be replenished after enzymatic removal multiple times. The large extent of the polymer interface allows for characterization of the brush architecture and for studying dynamic processes inside the brush using optical microscopy. At low ionic strengths (1 mM), we measure one of the largest polymer brushes yet reported, an average of 7.8 microns thick. For applications that require a stable brush interface, we have covalently reinforced the HA to the surfaces, and demonstrated that the brush is stable for at least two months. This self-renewing, dynamic biopolymer brush has great potential as a new biomaterial for implants, antifouling, tissue engineering and drug delivery.

Surface friction of hydrogels with well-defined polyelectrolyte brushes.

PubMed

Ohsedo, Yutaka; Takashina, Rikiya; Gong, Jian Ping; Osada, Yoshihito

2004-08-03

Hydrogels of poly(2-hydroxyethyl methacrylate) (PHEMA) with well-defined polyelectrolyte brushes of poly(sodium 4-styrenesulfonate) (PNaSS) of various molecular weights were synthesized, keeping the distance between the polymer brushes constant at ca. 20 nm. The effect of polyelectrolyte brush length on the sliding friction against a glass plate, an electrorepulsive solid substrate, was investigated in water in a velocity range of 7.5 x 10(-5) to 7.5 x 10(-2) m/s. It is found that the presence of polymer brush can dramatically reduce the friction when the polymer brushes are short. With an increase in the length of the polymer brush, this drag reduction effect only works at a low sliding velocity, and the gel with long polymer brushes even shows a higher friction than that of a normal network gel at a high sliding velocity. The strong polymer length and sliding velocity dependence indicate a dynamic mechanism of the polymer brush effect.

Anthrax Cases Associated with Animal-Hair Shaving Brushes.

PubMed

Szablewski, Christine M; Hendricks, Kate; Bower, William A; Shadomy, Sean V; Hupert, Nathaniel

2017-05-01

During the First World War, anthrax cases in the United States and England increased greatly and seemed to be associated with use of new shaving brushes. Further investigation revealed that the source material and origin of shaving brushes had changed during the war. Cheap brushes of imported horsehair were being made to look like the preferred badger-hair brushes. Unfortunately, some of these brushes were not effectively disinfected and brought with them a nasty stowaway: Bacillus anthracis. A review of outbreak summaries, surveillance data, and case reports indicated that these cases originated from the use of ineffectively disinfected animal-hair shaving brushes. This historical information is relevant to current public health practice because renewed interest in vintage and animal-hair shaving brushes has been seen in popular culture. This information should help healthcare providers and public health officials answer questions on this topic.

Quantitative evaluation of toothbrush and arm-joint motion during tooth brushing.

PubMed

Inada, Emi; Saitoh, Issei; Yu, Yong; Tomiyama, Daisuke; Murakami, Daisuke; Takemoto, Yoshihiko; Morizono, Ken; Iwasaki, Tomonori; Iwase, Yoko; Yamasaki, Youichi

2015-07-01

It is very difficult for dental professionals to objectively assess tooth brushing skill of patients, because an obvious index to assess the brushing motion of patients has not been established. The purpose of this study was to quantitatively evaluate toothbrush and arm-joint motion during tooth brushing. Tooth brushing motion, performed by dental hygienists for 15 s, was captured using a motion-capture system that continuously calculates the three-dimensional coordinates of object's motion relative to the floor. The dental hygienists performed the tooth brushing on the buccal and palatal sides of their right and left upper molars. The frequencies and power spectra of toothbrush motion and joint angles of the shoulder, elbow, and wrist were calculated and analyzed statistically. The frequency of toothbrush motion was higher on the left side (both buccal and palatal areas) than on the right side. There were no significant differences among joint angle frequencies within each brushing area. The inter- and intra-individual variations of the power spectrum of the elbow flexion angle when brushing were smaller than for any of the other angles. This study quantitatively confirmed that dental hygienists have individual distinctive rhythms during tooth brushing. All arm joints moved synchronously during brushing, and tooth brushing motion was controlled by coordinated movement of the joints. The elbow generated an individual's frequency through a stabilizing movement. The shoulder and wrist control the hand motion, and the elbow generates the cyclic rhythm during tooth brushing.

Analysis of tooth brushing cycles.

PubMed

Tosaka, Yuki; Nakakura-Ohshima, Kuniko; Murakami, Nozomi; Ishii, Rikako; Saitoh, Issei; Iwase, Yoko; Yoshihara, Akihiro; Ohuchi, Akitsugu; Hayasaki, Haruaki

2014-11-01

The aim of this study was to demonstrate the effectiveness of an analysis of tooth brushing cycles using a system that measures tooth brushing motion and brushing force with an accelerometer and strain tension gage attached to a toothbrush. Mechanical plaque removal with a manual toothbrush remains the primary method of maintaining good oral hygiene for the majority of the population. Because toothbrush motion has not been fully understood, it should be clarified by analysis of tooth brushing cycles. Twenty healthy female dental hygienists participated in this study. Their tooth brushing motions were measured and analyzed using an American Dental Association-approved manual toothbrush to which a three-dimensional (3-D) accelerometer and strain tension gage were attached. 3-D motion and brushing force on the labial surface of the mandibular right central incisor and the lingual surface of the mandibular left first molar were measured, analyzed, and compared. Multilevel linear model analysis was applied to estimate variables and compare motion and forces related to the two tooth surfaces. The analysis of tooth brushing cycles was feasible, and significant differences were detected for durations and 3-D ranges of toothbrush motion as well as brushing force between the two tooth surfaces. The analysis used in this study demonstrated an ability to detect characteristics of tooth brushing motion, showing tooth brushing motion to change depending on the brushed location. These results also suggest that more detailed instructions might be required according to patient's oral condition.

Saccharomyces boulardii in childhood.

PubMed

Vandenplas, Yvan; Brunser, Oscar; Szajewska, Hania

2009-03-01

Probiotics are live microorganisms which confer a health benefit on the host. Saccharomyces boulardii, a yeast, has been found to be an effective probiotic in double-blind placebo-controlled randomized clinical studies. We reviewed the established mechanisms of actions and clinical efficacy in children of S. boulardii. The mechanisms of action of S. boulardii depend mainly on the inhibition of some bacterial toxins, anti-inflammatory effects, and on stimulating effects on the intestinal mucosa such as trophic effects on the brush border enzymes and immunostimulatory effects. At present, in pediatric populations, there is evidence that S. boulardii is beneficial for the treatment of acute gastroenteritis and the prevention of antibiotic-associated diarrhea. More data are needed in other indications such as traveller's diarrhea, Helicobacter pylori eradication, and inflammatory bowel disease. S. boulardii is a yeast strain that has been extensively studied in vitro and in vivo. Recent data have opened the door for new therapeutic indications.

Intestinal Alkaline Phosphatase Detoxifies Lipopolysaccharide and Prevents Inflammation in Response to the Gut Microbiota

PubMed Central

Bates, Jennifer M.; Akerlund, Janie; Mittge, Erika; Guillemin, Karen

2009-01-01

SUMMARY Vertebrates harbor abundant lipopolysaccharide (LPS) or endotoxin in their gut microbiota. Here we demonstrate that the brush border enzyme intestinal alkaline phosphatase (Iap), which dephosphorylates LPS, is induced during establishment of the microbiota and plays a crucial role in promoting mucosal tolerance to gut bacteria in zebrafish. We demonstrate that Iap deficient animals are hypersensitive to LPS toxicity through a mechanism mediated by Myd88 and Tumor Necrosis Factor Receptor (Tnfr). We further show that the endogenous microbiota establish the normal homeostatic level of neutrophils in the intestine through a process involving Myd88 and Tnfr. Iap deficient animals exhibit excessive intestinal neutrophil influx, similar to wild type animals exposed to LPS. When reared germ-free, however, the intestines of Iap deficient animals are devoid of neutrophils, demonstrating that Iap functions to prevent inflammatory responses to resident gut bacteria. PMID:18078689

Human epidermis is a novel site of phospholipase B expression.

PubMed

Maury, Eric; Prévost, Marie Claude; Nauze, Michel; Redoulès, Daniel; Tarroux, Roger; Charvéron, Marie; Salles, Jean Pierre; Perret, Bertrand; Chap, Hugues; Gassama-Diagne, Ama

2002-07-12

Phospholipase B (PLB) is an enzyme that displays both phospholipase A(2) and lysophospholipase activities. Analysis of human epidermis homogenates indicated the presence of a 97 kDa PLB protein, as well as a phospholipase A(2) activity, both being enriched in the soluble fraction. Immunolabelling and in situ hybridization experiments showed that this enzyme is expressed in the different layers of epidermis with an accumulation at the dermo-epidermis junction. RT-PCR data indicated that PLB is specifically expressed in natural and reconstructed epidermis. By 3'-RACE-PCR and screening of human genome databases, we obtained a 3600 bp cDNA coding for human PLB highly homologous to already described intestinal brush border PLBs. These data led us to conclude that the soluble PLB corresponds to a proteolytic cleavage of the membrane anchored protein. Altogether, our results provide the first characterization of human PLB which should play an important role in epidermal barrier function.

Brush seals for cryogenic applications

NASA Astrophysics Data System (ADS)

Proctor, Margaret P.

1994-07-01

This viewgraph presentation presents test results of brush seals for cryogenic applications. Leakage for a single brush seal was two to three times less than for a 12-tooth labyrinth seal. The maximum temperature rise for a single brush seal was less than 50 R and occurred at 25 psid across the seal and 35,000 rpm. A static blowout test demonstrated sealing capability up to 550 psid. The seal limit was not obtained. The power loss for a single brush at 35,000 rpm and 175 psid was 2.45 hp. Two brushes far apart leak less than two brushes tight packed. Rotor wear was approximately 0.00075 mils and bristle wear was 1-3 mils after 4-1/2 hours.

A Laterally-Mobile Mixed Polymer/Polyelectrolyte Brush Undergoes a Macroscopic Phase Separation

NASA Astrophysics Data System (ADS)

Lee, Hoyoung; Park, Hae-Woong; Tsouris, Vasilios; Choi, Je; Mustafa, Rafid; Lim, Yunho; Meron, Mati; Lin, Binhua; Won, You-Yeon

2013-03-01

We studied mixed PEO and PDMAEMA brushes. The question we attempted to answer was: When the chain grafting points are laterally mobile, how will this lateral mobility influence the structure and phase behavior of the mixed brush? Two different model mixed PEO/PDMAEMA brush systems were prepared: a mobile mixed brush by spreading a mixture of two diblock copolymers, PEO-PnBA and PDMAEMA-PnBA, onto the air-water interface, and an inseparable mixed brush using a PEO-PnBA-PDMAEMA triblock copolymer having respective brush molecular weights matched to those of the diblock copolymers. These two systems were investigated by surface pressure-area isotherm, X-ray reflectivity and AFM imaging measurements. The results suggest that the mobile mixed brush undergoes a lateral macroscopic phase separation at high chain grafting densities, whereas the inseparable system is only microscopically phase separated under comparable brush density conditions. We also conducted an SCF analysis of the phase behavior of the mixed brush system. This analysis further supported the experimental findings. The macroscopic phase separation observed in the mobile system is in contrast to the microphase separation behavior commonly observed in two-dimensional laterally-mobile small molecule mixtures.

Ordering nanoparticles with polymer brushes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a singlemore » layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. As a result, an interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.« less

Ordering nanoparticles with polymer brushes

DOE PAGES

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

2017-12-08

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a singlemore » layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. As a result, an interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.« less

The effect of tooth brushing and flossing sequence on interdental plaque reduction and fluoride retention: A randomized controlled clinical trial.

PubMed

Mazhari, Fatemeh; Boskabady, Marzie; Moeintaghavi, Amir; Habibi, Atieh

2018-05-09

Mechanical plaque control methods such as brushing and flossing are highly recommended to remove dental plaque. The aim of this study is to evaluate the efficacy of the sequence of brushing and flossing on reducing interdental plaque and increasing fluoride retention in that area. This randomized controlled crossover trial was conducted on 25 dental students. After prophylaxis, they were asked to discontinue all forms of oral hygiene for 48 hours. The study was performed in two phases with two-week washout intervals. In one phase, they first brushed, then flossed (sequence 1: brush-floss group). In the other phase they initially used dental floss then brushed (sequence 2: floss-brush group). At each phase, dental plaque (using the Rustogi Modified Navy Plaque Index) and fluoride concentrations (using a fluoride ion specific electrode) were measured before and after flossing and brushing, and the dental plaque reduction and fluoride increase were compared between the two groups using the mixed model test. A significance level of 5% was selected. In the floss-brush group interdental and whole plaque was reduced significantly more than the brush-floss group (p = 0.001, p = 0.009 respectively). However, marginal plaque did not show any statistically significant difference between the two groups (p = 0.2). Fluoride concentrations in interdental plaque were significantly higher in the floss-brush group than the other group (p = 0.027). The results showed that flossing followed by brushing is preferred to brushing then flossing in order to reduce interdental plaque and increase fluoride concentration in interdental plaque. This article is protected by copyright. All rights reserved. © 2018 American Academy of Periodontology.

Study on brush of moving electrode type electrostatic precipitator (MEEP)

NASA Astrophysics Data System (ADS)

Zhao, Haibao; He, Yuzhong; Yao, Yuping

2018-02-01

MEEP was an efficient particle removal technology for coal plant and sintering machine. As the stability of brush in MEEP was relatively poor, the experiments was designed for the brush which was made by 0Cr18Ni9 stainless steel wire to find the failure mode and cause. Combining the results of the experiments, the failure models of brushes were different under different conditions and the brushes were suitable for being used in the condition of small diameter particles. And the life span of brushes can be more than 6 years.

Turbine-Driven Pipe-Cleaning Brush

NASA Technical Reports Server (NTRS)

Werlink, Rudy J.; Rowell, David E.

1994-01-01

Simple pipe-cleaning device includes small turbine wheel axially connected, by standoff, to circular brush. Turbine wheel turns on hub bearing attached to end of upstream cable. Turbine-and-brush assembly inserted in pipe with cable trailing upstream and brush facing downstream. Water or cleaning solution pumped through pipe. Cable held at upstream end, so it holds turbine and brush in pipe at location to be cleaned. Flow in pipe turns turbine, which turns wheel, producing desired cleaning action. In addition to brushing action, device provides even mixing of cleaning solution in pipe.

Short communication: use of a mechanical brush by Holstein dairy cattle around parturition.

PubMed

Newby, Nathalie C; Duffield, Todd F; Pearl, David L; Leslie, Ken E; LeBlanc, Stephen J; von Keyserlingk, Marina A G

2013-04-01

Grooming is a normal behavior that may contribute to relief of stress. The purpose of this study was to investigate the effect of access to a mechanical brush on auto-grooming behavior in parturient cows. The hypothesis was that cows would increase the total time spent scratching using the brush if they had access to a brush around the time of calving, whereas auto-grooming would be lower for the brush group compared with the no-brush group. The use of a mechanical brush was analyzed both in a group-housed pen (72 to 48 h before calving) and in an individual maternity pen (6h before to 6h after calving) in 16 multiparous Holstein cows. In the maternity pen, cows were randomly assigned to have access to the brush or not. The provision of a mechanical brush in the individual maternity pen did not change the amount of time spent auto-grooming but cows did use the brush before calving and after the calf was removed. Despite being housed in pens containing a brush, cows failed to use it when the calf was present. However, cows with access to a brush spent more time licking their calves in the first hour postcalving (β=8.7 min; 95% confidence interval: 1.5, 15.8) than cows that did not have access to a brush. Regardless of treatment, cows increased the time spent auto-grooming and scratching following separation of their newborn calf (β=1.4 min; 95% confidence interval: 0.46, 2.3 and β=0.07 min; 95% confidence interval: 0.02, 0.12, respectively). Further research is warranted to investigate possible benefits of mechanical brush devices at the time of calving, particularly for cows that experience difficult calving and require manual or mechanical assistance. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Structure of Polyelectrolyte Brushes in the Presence of Multivalent Counterions

DOE PAGES

Yu, Jing; Mao, Jun; Yuan, Guangcui; ...

2016-07-20

Polyelectrolyte brushes are of great importance to a wide range of fields, ranging from colloidal stabilization to responsive and tunable materials to lubrication. Here, we synthesized high-density polystyrenesulfonate (PSS) brushes using surface initiated atom transfer radical polymerization and performed neutron reflectivity (NR) and surface force measurements using a surface forces apparatus (SFA) to investigate the effect of monovalent Na +, divalent Ca 2+, Mg 2+, and Ba 2+, and trivalent Y 3+ counterions on the structure of the PSS brushes. NR and SFA results demonstrate that in monovalent salt solution the behavior of the PSS brushes agrees with scaling theorymore » well, exhibiting two distinct regimes: the osmotic and salted brush regimes. Introducing trivalent Y 3+ cations causes an abrupt shrinkage of the PSS brush due to the uptake of Y 3+ counterions. The uptake of Y 3+ counterions and shrinkage of the brush are reversible upon increasing the concentration of monovalent salt. Divalent cations, Mg 2+, Ca 2+, and Ba 2+, while all significantly affecting the structure of PSS brushes, show strong ion specific effects that are related to the specific interactions between the divalent cations and the sulfonate groups. Our results demonstrate that the presence of multivalent counterions, even at relatively low concentrations, can strongly affect the structure of polyelectrolyte brushes. Finally, the results also highlight the importance of ion specificity to the structure of polyelectrolyte brushes in solution.« less

Evaluation of the tooth brushing skills in children aged 6-12 years.

PubMed

Pujar, P; Subbareddy, V V

2013-08-01

To evaluate the tooth brushing skills in children aged between 6 and 12 years and its relation with age, type of grip used, duration of brushing and gender. A total of 105 children aged between 6 and 12 years were divided into seven groups and their plaque scores, type of grip used and duration of brushing were assessed. The most preferred grip was the distal oblique (58.1 %). Oblique, distal oblique and power grips were more efficient (plaque reduction up to 70 %). Plaque removal efficacy improved with age (57 % in 6-year-olds and 82 % in 12-year-old children). Plaque reduction was greater when the duration of brushing was longer (82 % plaque reduction when the brushing time was >2.5 min). Overall, the mean duration of tooth brushing in children aged 6-12 years was 1.71 min (103 s). Tooth brushing skills improved with age and the duration of tooth brushing made a significant difference to the oral hygiene status of the child. The type of grip used and gender did not influence tooth brushing ability in this group of children. Tooth brushing skills were low in children younger than 10 years of age. Hence, parental supervision is considered necessary and recommended until 10 years of age.

Lateral Structure Formation in Polyelectrolyte Brushes Induced by Multivalent Ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brettmann, Blair; Pincus, Philip; Tirrell, Matthew

2017-01-13

We provide a theoretical model for the collapse of polyelectrolyte brushes in the presence of multivalent ions, focusing on the formation of lateral inhomogeneties in the collapsed state. Polyelectrolyte brushes are important in a variety of applications, including stabilizing colloidal particles and lubricating surfaces. Many uses rely on the extension of the densely grafted polymer chains from the surface in the extended brush morphology. In the presence Extended Brush of multivalent ions, brushes are significantly shorter than in monovalent ionic solutions, which greatly affects their properties. We base our theoretical analysis on an analogous collapse of polyelectrolyte brushes in amore » poor solvent, providing an energy balance representation for pinned micelles and cylindrical bundles. The equilibrium brush heights predicted for these structures are of a similar magnitude to those measured experimentally. The formation of lateral structures can open new avenues for stimuli-responsive applications that rely on nanoscale pattern formation on surfaces.« less

Synthesis and Biomedical Applications of Poly((meth)acrylic acid) Brushes.

PubMed

Qu, Zhenyuan; Xu, Hong; Gu, Hongchen

2015-07-15

Poly((meth)acrylic acid) (P(M)AA) brushes possess a number of distinctive properties that are particularly attractive for biomedical applications. This minireview summarizes recent advances in the synthesis and biomedical applications of P(M)AA brushes and brushes containing P(M)AA segments. First, we review different surface-initiated polymerization (SIP) methods, with a focus on recent progress in the surface-initiated controlled/living radical polymerization (SI-CLRP) techniques used to generate P(M)AA brushes with a tailored structure. Next, we discuss biomolecule immobilization methods for P(M)AA brushes, including physical adsorption, covalent binding, and affinity interactions. Finally, typical biomedical applications of P(M)AA brushes are reviewed, and their performance is discussed based on their unique properties. We conclude that P(M)AA brushes are promising biomaterials, and more potential biomedical applications are expected to emerge with the further development of synthetic techniques and increased understanding of their interactions with biological systems.

Antifouling Properties of Fluoropolymer Brushes toward Organic Polymers: The Influence of Composition, Thickness, Brush Architecture, and Annealing.

PubMed

Wang, Zhanhua; Zuilhof, Han

2016-07-05

Fluoropolymer brushes are widely used to prevent nonspecific adsorption of commercial polymeric or biological materials due to their strongly hydrophobic character. Herein, a series of fluoropolymer brushes with different compositions, thicknesses and molecular architectures was prepared via surface-initiated atom transfer radical polymerization (ATRP). Subsequently, the antifouling properties of these fluoropolymer brushes against organic polymers were studied in detail using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements and polystyrene as a representative fouling polymer. Among all of the molecular architectures studied, homopolymerized methacrylate-based fluoropolymer brushes (PMAF17) show the best antifouling properties. Annealing the fluoropolymer brushes improves the antifouling property dramatically due to the reregulated surface composition. These fluoropolymer brushes can be combined with, e.g., micro- and nanostructuring and other advanced materials properties to yield even better long-term antifouling behavior under harsh environments.

Brush Seals for Improved Steam Turbine Performance

NASA Technical Reports Server (NTRS)

Turnquist, Norman; Chupp, Ray; Baily, Fred; Burnett, Mark; Rivas, Flor; Bowsher, Aaron; Crudgington, Peter

2006-01-01

GE Energy has retrofitted brush seals into more than 19 operating steam turbines. Brush seals offer superior leakage control compared to labyrinth seals, owing to their compliant nature and ability to maintain very tight clearances to the rotating shaft. Seal designs have been established for steam turbines ranging in size from 12 MW to over 1200 MW, including fossil, nuclear, combined-cycle and industrial applications. Steam turbines present unique design challenges that must be addressed to ensure that the potential performance benefits of brush seals are realized. Brush seals can have important effects on the overall turbine system that must be taken into account to assure reliable operation. Subscale rig tests are instrumental to understanding seal behavior under simulated steam-turbine operating conditions, prior to installing brush seals in the field. This presentation discusses the technical challenges of designing brush seals for steam turbines; subscale testing; performance benefits of brush seals; overall system effects; and field applications.

Bursting bubbles and bilayers.

PubMed

Wrenn, Steven P; Dicker, Stephen M; Small, Eleanor F; Dan, Nily R; Mleczko, Michał; Schmitz, Georg; Lewin, Peter A

2012-01-01

This paper discusses various interactions between ultrasound, phospholipid monolayer-coated gas bubbles, phospholipid bilayer vesicles, and cells. The paper begins with a review of microbubble physics models, developed to describe microbubble dynamic behavior in the presence of ultrasound, and follows this with a discussion of how such models can be used to predict inertial cavitation profiles. Predicted sensitivities of inertial cavitation to changes in the values of membrane properties, including surface tension, surface dilatational viscosity, and area expansion modulus, indicate that area expansion modulus exerts the greatest relative influence on inertial cavitation. Accordingly, the theoretical dependence of area expansion modulus on chemical composition-- in particular, poly (ethylene glyclol) (PEG)--is reviewed, and predictions of inertial cavitation for different PEG molecular weights and compositions are compared with experiment. Noteworthy is the predicted dependence, or lack thereof, of inertial cavitation on PEG molecular weight and mole fraction. Specifically, inertial cavitation is predicted to be independent of PEG molecular weight and mole fraction in the so-called mushroom regime. In the "brush" regime, however, inertial cavitation is predicted to increase with PEG mole fraction but to decrease (to the inverse 3/5 power) with PEG molecular weight. While excellent agreement between experiment and theory can be achieved, it is shown that the calculated inertial cavitation profiles depend strongly on the criterion used to predict inertial cavitation. This is followed by a discussion of nesting microbubbles inside the aqueous core of microcapsules and how this significantly increases the inertial cavitation threshold. Nesting thus offers a means for avoiding unwanted inertial cavitation and cell death during imaging and other applications such as sonoporation. A review of putative sonoporation mechanisms is then presented, including those involving microbubbles to deliver cargo into a cell, and those--not necessarily involving microubbles--to release cargo from a phospholipid vesicle (or reverse sonoporation). It is shown that the rate of (reverse) sonoporation from liposomes correlates with phospholipid bilayer phase behavior, liquid-disordered phases giving appreciably faster release than liquid-ordered phases. Moreover, liquid-disordered phases exhibit evidence of two release mechanisms, which are described well mathematically by enhanced diffusion (possibly via dilation of membrane phospholipids) and irreversible membrane disruption, whereas liquid-ordered phases are described by a single mechanism, which has yet to be positively identified. The ability to tune release kinetics with bilayer composition makes reverse sonoporation of phospholipid vesicles a promising methodology for controlled drug delivery. Moreover, nesting of microbubbles inside vesicles constitutes a truly "theranostic" vehicle, one that can be used for both long-lasting, safe imaging and for controlled drug delivery.

Effects of short-term immersion and brushing with different denture cleansers on the roughness, hardness, and color of two types of acrylic resin.

PubMed

Panariello, Beatriz Helena Dias; Izumida, Fernanda Emiko; Moffa, Eduardo Buozi; Pavarina, Ana Claudia; Jorge, Janaina Habib; Giampaolo, Eunice Teresinha

2015-06-01

To investigate the cumulative effects of brushing (B) or immersion (I), using different cleansing agents, on the surface roughness, hardness and color stability of a heat-polymerized denture resin, Lucitone 550 (L), and a hard chairside reline resin, Tokuyama Rebase Fast II (T). A total of 316 specimens (10 x 2 mm) were fabricated. The specimens (n = 9) were divided into brushing or immersion groups according to the following agents: dentifrice/distilled water (D), 1% sodium hypochlorite (NaOCl), Corega Tabs (Pb), 1% chlorhexidine gluconate (Chx), and 0.2% peracetic acid (Ac). Brushing and immersion were tested independently. Assays were performed after 1, 3, 21, 45 and 90 brushing cycles or immersion of 10 seconds each. Data were evaluated statistically by repeated measures ANOVA. Tukey's honestly significant difference (HSD) post-hoc test was used to determine differences between means (α = 0.05). For L there was no statistically significant difference in roughness, except a significant decrease in roughness by brushing with D. T showed a significant effect on the roughness after 90 immersions with Ac. Hardness values decreased for L when specimens were immersed or brushed in NaOCl and Pb. The hardness of T decreased with increases in the repetitions (immersion or brushing), regardless of the cleaning method. Values of color stability for L resin showed significant color change after brushing with and immersion in Ac and Pb. Brushing with D exhibited a higher incidence of color change. For T there were no significant differences between cleaning agents and repetitions in immersion. A color change was noted after three brushings with the Ac, Chx, and D. Brushing with dentifrice decreased roughness of L. Immersion in or brushing with NaOCl and Pb decreased the hardness of L. For T, hardness decreased with increases in immersions or brushing. Color changes after the immersion in or brushing with cleaning agents were clinically acceptable according to National Bureau of Standards parameters for both resins.

Brush seal numerical simulation: Concepts and advances

NASA Technical Reports Server (NTRS)

Braun, M. J.; Kudriavtsev, V. V.

1994-01-01

The development of the brush seal is considered to be most promising among the advanced type seals that are presently in use in the high speed turbomachinery. The brush is usually mounted on the stationary portions of the engine and has direct contact with the rotating element, in the process of limiting the 'unwanted' leakage flows between stages, or various engine cavities. This type of sealing technology is providing high (in comparison with conventional seals) pressure drops due mainly to the high packing density (around 100 bristles/sq mm), and brush compliance with the rotor motions. In the design of modern aerospace turbomachinery leakage flows between the stages must be minimal, thus contributing to the higher efficiency of the engine. Use of the brush seal instead of the labyrinth seal reduces the leakage flow by one order of magnitude. Brush seals also have been found to enhance dynamic performance, cost less, and are lighter than labyrinth seals. Even though industrial brush seals have been successfully developed through extensive experimentation, there is no comprehensive numerical methodology for the design or prediction of their performance. The existing analytical/numerical approaches are based on bulk flow models and do not allow the investigation of the effects of brush morphology (bristle arrangement), or brushes arrangement (number of brushes, spacing between them), on the pressure drops and flow leakage. An increase in the brush seal efficiency is clearly a complex problem that is closely related to the brush geometry and arrangement, and can be solved most likely only by means of a numerically distributed model.

Voltage-induced swelling and deswelling of weak polybase brushes.

PubMed

Weir, Michael P; Heriot, Sasha Y; Martin, Simon J; Parnell, Andrew J; Holt, Stephen A; Webster, John R P; Jones, Richard A L

2011-09-06

We have investigated a novel method of remotely switching the conformation of a weak polybase brush using an applied voltage. Surface-grafted polyelectrolyte brushes exhibit rich responsive behavior and show great promise as "smart surfaces", but existing switching methods involve physically or chemically changing the solution in contact with the brush. In this study, high grafting density poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes were grown from silicon surfaces using atom transfer radical polymerization. Optical ellipsometry and neutron reflectivity were used to measure changes in the profiles of the brushes in response to DC voltages applied between the brush substrate and a parallel electrode some distance away in the surrounding liquid (water or D(2)O). Positive voltages were shown to cause swelling, while negative voltages in some cases caused deswelling. Neutron reflectometry experiments were carried out on the INTER reflectometer (ISIS, Rutherford Appleton Laboratory, UK) allowing time-resolved measurements of polymer brush structure. The PDMAEMA brushes were shown to have a polymer volume fraction profile described by a Gaussian-terminated parabola both in the equilibrium and in the partially swollen states. At very high positive voltages (in this study, positive bias means positive voltage to the brush-bearing substrate), the brush chains were shown to be stretched to an extent comparable to their contour length, before being physically removed from the interface. Voltage-induced swelling was shown to exhibit a wider range of brush swelling states in comparison to pH switching, with the additional advantages that the stimulus is remotely controlled and may be fully automated. © 2011 American Chemical Society

Brushing force of manual and sonic toothbrushes affects dental hard tissue abrasion.

PubMed

Wiegand, Annette; Burkhard, John Patrik Matthias; Eggmann, Florin; Attin, Thomas

2013-04-01

This study aimed to determine the brushing forces applied during in vivo toothbrushing with manual and sonic toothbrushes and to analyse the effect of these brushing forces on abrasion of sound and eroded enamel and dentin in vitro. Brushing forces of a manual and two sonic toothbrushes (low and high frequency mode) were measured in 27 adults before and after instruction of the respective brushing technique and statistically analysed by repeated measures analysis of variance (ANOVA). In the in vitro experiment, sound and eroded enamel and dentin specimens (each subgroup n = 12) were brushed in an automatic brushing machine with the respective brushing forces using a fluoridated toothpaste slurry. Abrasion was determined by profilometry and statistically analysed by one-way ANOVA. Average brushing force of the manual toothbrush (1.6 ± 0.3 N) was significantly higher than for the sonic toothbrushes (0.9 ± 0.2 N), which were not significantly different from each other. Brushing force prior and after instruction of the brushing technique was not significantly different. The manual toothbrush caused highest abrasion of sound and eroded dentin, but lowest on sound enamel. No significant differences were detected on eroded enamel. Brushing forces of manual and sonic toothbrushes are different and affect their abrasive capacity. Patients with severe tooth wear and exposed and/or eroded dentin surfaces should use sonic toothbrushes to reduce abrasion, while patients without tooth wear or with erosive lesions confining only to enamel do not benefit from sonic toothbrushes with regard to abrasion.

A switchable polymer layer: Chain folding in end-charged polymer brushes

NASA Astrophysics Data System (ADS)

Heine, David; Wu, David T.

2001-03-01

We use a self-consistent field approximation to model the configurations of end-charged homopolymer and block copolymer brushes in response to an external electric field due to charges on the grafting surface. By varying the charge density on the grafting surface, we can cause the chains either to extend outward, greatly increasing the brush height, or to loop back to the grafting surface. We show that such a copolymer brush can present one block at the exposed surface in the extended state and present the other block in the retracted state. This occurs for both a solvated brush and a dry brush. We also compare these results to those of a modified Alexander-de Gennes model for the end-charged homopolymer brush.

Macroscopic lateral heterogeneity observed in a laterally mobile immiscible mixed polyelectrolyte-neutral polymer brush

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Hoyoung; Tsouris, Vasilios; Lim, Yunho

We studied mixed poly(ethylene oxide) (PEO) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes. The question we attempted to answer was: when the chain grafting points are laterally mobile, how will this lateral mobility influence the structure and phase behavior of the mixed brush? Three different model mixed PEO/PDMAEMA brush systems were prepared: (1) a laterally mobile mixed brush by spreading onto the air–water interface a mixture of poly(ethylene oxide)–poly(n-butyl acrylate) (PEO–PnBA) and poly(2-(dimethylamino)ethyl methacrylate)–poly(n-butyl acrylate) (PDMAEMA–PnBA) diblock copolymers (the specific diblock copolymers used will be denoted as PEO 113–PnBA 100 and PDMAEMA 118–PnBA 100, where the subscripts refer to the number-average degreesmore » of polymerization of the individual blocks), (2) a mobility-restricted (inseparable) version of the above mixed brush prepared using a PEO–PnBA–PDMAEMA triblock copolymer (denoted as PEO 113–PnBA 89–PDMAEMA 120) having respective brush molecular weights matched with those of the diblock copolymers, and (3) a different laterally mobile mixed PEO and PDMAEMA brush prepared from a PEO 113–PnBA 100 and PDMAEMA 200–PnBA 103 diblock copolymer combination, which represents a further more height-mismatched mixed brush situation than described in (1). These three mixed brush systems were investigated by surface pressure–area isotherm and X-ray (XR) reflectivity measurements. These experimental data were analyzed within the theoretical framework of a continuum self-consistent field (SCF) polymer brush model. The combined experimental and theoretical results suggest that the mobile mixed brush derived using the PEO 113–PnBA 100 and PDMAEMA 118–PnBA 100 combination (i.e., mixed brush System #1) undergoes a lateral macroscopic phase separation at high chain grafting densities, whereas the more height-mismatched system (System #3) is only microscopically phase separated under comparable brush density conditions even though the lateral mobility of the grafted chains is unrestricted. The macroscopic phase separation observed in the laterally mobile mixed brush system is in contrast with the microphase separation behavior commonly observed in two-dimensional laterally mobile charged small molecule mixtures. Further study is needed to determine the detailed morphologies of the macro- and microphase-separated mixed PEO/PDMAEMA brushes.« less

A new species of Temnocephala (Platyhelminthes) with an unusual pharynx, including an amendment of the diagnosis of the genus.

PubMed

De leÓn, Rodrigo Ponce; Volonterio, Odile

2018-02-08

Three species of Temnocephala have been reported on Aegla from Uruguay: Temnocephala axenos, Temnocephala mertoni and Temnocephala talicei. As part of a systematic review of the Uruguayan species of Temnocephala, a fourth species was found on Aegla platensis and Aegla uruguayana. This species, new for the genus, has the following diagnostic characters: Large temnocephalan; slightly curved penial stylet (225 µm in length) with a symmetrical introvert (27 long by 18 µm in diameter) that has at least 44 spine-like projections, each bearing 7 rows of internal spines; a seminal vesicle that opens sub-polarly into the contractile vesicle; a muscular vagina with a strong asymmetrical sphincter; preequatorial nephridiopores close to the internal borders of the elongate-oval excretory syncytia; a large pharynx with anterior and posterior sphincters of about the same diameter and a narrow pharyngeal lumen with nearly uniform width. To contemplate the characters of the pharynx, an amendment of the genus Temnocephala is given. The new species resembles Temnocephala cyanoglandula, which also has a very long, slightly curved penial stylet, but differs from it by having a shorter penial stylet, a lower number of rows of spines in the introvert, a larger, different type of pharynx, a smaller contractile vesicle and a larger sucker. The new species is carnivorous and feeds on whole preys, which are mainly annelids (Stratiodrilus) and other species of Temnocephala. The new species was found to be hyperparasitised by plerocercoid and nematode larvae, but hyperparasites were not found in the other sympatric species of Temnocephala. Based on the findings presented here, it is clear that detailed histological descriptions of the pharynx should be contemplated as part of the normal work in taxonomy of temnocephalans.

The effect of toothbrush bristle stiffness on nanohybrid surface roughness

NASA Astrophysics Data System (ADS)

Zairani, O.; Irawan, B.; Damiyanti, M.

2017-08-01

The surface of a restoration can be affected by toothpaste containing abrasive agents and the stiffness of toothbrush bristles. Objective: To identify the effect of toothbrush bristle stiffness on nanohybrid surface roughness. Methods: Sixteen nanohybrid specimens were separated into two groups. The first group was brushed using soft-bristle toothbrushes, and the second group was brushed using medium-bristle toothbrushes. Media such as aqua bides was used for brushing in both groups. Brushing was done 3 times for 5 minutes. Surface roughness was measured initially and at 5, 10, and 15 minutes using a surface roughness tester. Results: The results, tested with One-Way ANOVA and Independent Samples t Test, demonstrated that after brushing for 15 minutes, the soft-bristle toothbrush group showed a significantly different value (p < 0.05) of nanohybrid surface roughness. The group using medium-bristle toothbrushes showed the value of nano hybrid surface roughness significant difference after brushing for 10 minutes. Conclusion: Roughness occurs more rapidly when brushing with medium-bristle tooth brushes than when brushing with soft-bristle toothbrushes.

Early response of ponderosa pine to spacing and brush: observations on a 12-year-old plantation

Treesearch

William W. Oliver

1979-01-01

Ponderosa pine (Pinus ponderosa Laws.) was planted at five different spacings, from 6 by 6 to 18 by 18 feet, on a productive site in northern California. Spacing and brush effects on tree growth were evaluated both on plots where brush was allowed to develop and on plots kept free of brush. Competition between trees in brush-free plots began during...

Nonlinearity in the rotational dynamics of Haidinger's brushes

NASA Astrophysics Data System (ADS)

Rothmayer, Mark; Dultz, Wolfgang; Frins, Erna; Zhan, Qiwen; Tierney, Dennis; Schmitzer, Heidrun

2007-10-01

Haidinger's brushes are an entoptic effect of the human visual system that enables us to detect polarized light. However, individual perceptions of Haidinger's brushes can vary significantly. We find that the birefringence of the cornea influences the rotational motion and the contrast of Haidinger's brushes and may offer an explanation for individual differences. We have devised an experimental setup to simulate various phase shifts of the cornea and found a switching effect in the rotational dynamics of Haidinger's brushes. In addition, age related macular degeneration reduces the polarization effect of the macula and thus also leads to changes in the brush pattern.

Behavioral Determinants of Brushing Young Children's Teeth: Implications for Anticipatory Guidance

PubMed Central

Huebner, Colleen E.; Riedy, Christine A.

2010-01-01

Purpose The purposes of this study were to identify parents' motivation, support, and barriers to twice daily tooth-brushing of infants and preschool-age children and to discover new approaches to encourage this important health behavior. Methods Qualitative interviews were conducted with 44 rural parents about tooth-brushing habits and experiences. Results Forty of 44 parents reported that they had begun to brush their child's teeth; 24 (55%) reported brushing twice a day or more. Parents who brushed twice a day, vs less often, were more likely to describe specific skills to overcome barriers; they expressed high self-efficacy and held high self-standards for brushing. Parents who brushed their children's teeth less than twice daily were more likely to: hold false beliefs about the benefits of twice daily tooth-brushing; report little normative pressure or social support for the behavior; have lower self-standards; describe more external constraints; and offer fewer ideas to overcome barriers. Conclusions The findings support an integrative framework in which barriers and support for parents' twice daily brushing of their young children's teeth are multiple and vary among individuals. Knowledge of behavioral determinants specific to individual parents could strengthen anticipatory guidance and recommendations about at-home oral hygiene of young children. PMID:20298653

Analysis of carbon fiber brush loading in anodes on startup and performance of microbial fuel cells

NASA Astrophysics Data System (ADS)

Hutchinson, Adam J.; Tokash, Justin C.; Logan, Bruce E.

Flat carbon anodes placed near a cathode in a microbial fuel cell (MFC) are adversely affected by oxygen crossover, but graphite fiber brush anodes placed near the cathode produce high power densities. The impact of the brush size and electrode spacing was examined by varying the distance of the brush end from the cathode and solution conductivity in multiple MFCs. The startup time was increased from 8 ± 1 days with full brushes (all buffer concentrations) to 13 days (50 mM), 14 days (25 mM) and 21 days (8 mM) when 75% of the brush anode was removed. When MFCs were all first acclimated with a full brush, up to 65% of the brush material could be removed without appreciably altering maximum power. Electrochemical impedance spectroscopy (EIS) showed that the main source of internal resistance (IR) was diffusion resistance, which together with solution resistance reached 100 Ω. The IR using EIS compared well with that obtained using the polarization data slope method, indicating no major components of IR were missed. These results show that using full brush anodes avoids adverse effects of oxygen crossover during startup, although brushes are much larger than needed to sustain high power.

Potential effects of tooth-brushing on human dentin wear following exposure to acidic soft drinks.

PubMed

Choi, S; Park, K-H; Cheong, Y; Moon, S W; Park, Y-G; Park, H-K

2012-08-01

This study used scanning electron microscopy and atomic force microscopy to examine the short-term potential effects of brushing time and the start-time of tooth-brushing after demineralization on primary dentin wear in vitro. Thirty-six noncarious primary central incisors were assigned to 12 experimental groups. Exposure to cola drinks was used to initiate the demineralization process. Three brushing times (5, 15 and 30 s) and four start-times of brushing (0, 30, 60 and 120 min) after an erosive attack were used for the abrasion process. Tooth-brushing the softened dentin surface led to increases in the open tubular fraction and microstructural changes on the dentin surface. Brushing immediately after exposure to cola resulted in the greatest irreversible dentin loss, whereas brushing 60 or 120 min after pretreatment resulted in the least irreversible dentin loss. However, brushing time had no effect on the irreversible loss of dentin wear. Based on these experimental results, tooth-brushing should be performed at least 60 min after consuming a cola drink to achieve the desired tooth cleaning and avoid the introduction of surface lesions on dentin. © 2012 The Authors Journal of Microscopy © 2012 Wadsworth Center, New York State Department of Health.

Polyelectrolyte brushes: a novel stable lubrication system in aqueous conditions.

PubMed

Kobayashi, Motoyasu; Terada, Masami; Takahara, Atsushi

2012-01-01

Surface-initiated controlled radical copolymerizations of 2-dimethylaminoethyl methacrylate (DMAEMA), 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), 2-(methacryloyloxy)ethyltrimethylammonium chloride) (MTAC), and 3-sulfopropyl methacrylate potassium salt (SPMK) were carried out on a silicon wafer and glass ball to prepare polyelectrolyte brushes with excellent water wettability. The frictional coefficient of the polymer brushes was recorded on a ball-on-plate type tribometer by linear reciprocating motion of the brush specimen at a selected velocity of 1.5 x 10(-3) m s-1 under a normal load of 0.49 N applied to the stationary glass ball (d = 10 mm) at 298 K. The poly(DMAEMA-co-MPC) brush partially cross-linked by bis(2-iodoethoxy)ethane maintained a relatively low friction coefficient around 0.13 under humid air (RH > 75%) even after 200 friction cycles. The poly(SPMK) brush revealed an extremely low friction coefficient around 0.01 even after 450 friction cycles. We supposed that the abrasion of the brush was prevented owing to the good affinity of the poly(SPMK) brush for water forming a water lubrication layer, and electrostatic repulsive interactions among the brushes bearing sulfonic acid groups. Furthermore, the poly(SPMK-co-MTAC) brush with a chemically cross-linked structure showed a stable low friction coefficient in water even after 1400 friction cycles under a normal load of 139 MPa, indicating that the cross-linking structure improved the wear resistance of the brush layer.

Schoolchildren's tooth brushing characteristics and oral hygiene habits assessed with video-recorded sessions at school and a questionnaire.

PubMed

Martignon, Stefania; González, María Clara; Tellez, Marisol; Guzmán, Adriana; Quintero, Ingrid K; Sáenz, Viviana; Martínez, Miguel; Mora, Angelica; Espinosa, Luis Fernando; Castiblanco, Gina A

2012-01-01

Tooth brushing habits become established during the first years of childhood and last throughout lifetime. To assess tooth-brushing characteristics, the procedure was videotaped at school and a questionnaire on oral hygiene knowledge, attitudes and practices was completed. A total 146 5- to 8-year-old low-SES schoolchildren from Bogotá participated. The median total tooth brushing time was 115 sec (75% Q3-178 sec; 25% Q1-83 sec). The median time the toothbrush was in the child's mouth was 89 sec (75% Q3-145 sec; 25% Q1-65 sec). Most children brushed their maxillary (97%), mandibular (95%), anterior (96%) and posterior (81%) teeth. The surfaces most often brushed were the buccal-anterior-maxillary (96%) and mandibular (94%) surfaces. The amount of toothpaste dispensed was 2/3 of toothbrush head in 51% of children. Most children spat (93%), used the mirror (78%), and rinsed their mouth (72%). The majority (97%) was confident that the toothbrushing session was effective. The questionnaire revealed the following: none of the children brush their teeth at school; only 34% is supervised by an adult during the tooth brushing procedure, and only 30% brush twice a day. The study shows overall positive findings of tooth brushing while being observed, in terms of time and use of toothpaste. These results, together with the poor oral-health status and toothbrushing habits reported at home, highly recommend incorporating daily-supervised school-based tooth brushing sessions with fluoride toothpaste.

Frequency of daily tooth brushing: predictors of change in 9- to 11-year old US children.

PubMed

Polk, D E; Geng, M; Levy, S; Koerber, A; Flay, B R

2014-09-01

To investigate whether an increase in daily tooth brushing frequency in children was predicted by either a) having a strong intention to brush twice a day or b) their parents receiving information about their new caries experience. Secondary data analyses were conducted on two waves of data from the Aban Aya Youth Project and the Iowa Fluoride Study. The Aban Aya study included 576 10- and 11-year olds from Chicago, Illinois. The Iowa Fluoride Study included a convenience sample of 709 babies born in Iowa. The present study includes those children at age 9. In both studies, reported daily tooth brushing frequency was assessed twice six months apart. In the Aban Aya data, compared with children with a weak intention at wave 1 to brush twice a day, children with a strong intention to brush twice a day were more likely to increase their brushing frequency by wave 2, OR 7.0, 95%CI 1.5,32.9. In the Iowa Fluoride Study, compared with children who did not have new caries at wave 1, children who had new caries experience were less likely to increase their brushing frequency by wave 2, OR 0.4, 95%CI 0.2,0.9. Strengthening intention to brush twice a day might increase children's brushing frequency. However, simply providing parents with information about new caries probably will not. Future studies should assess tooth brushing frequency, habit strength, intention, and situational cues at closely-spaced waves.

The effect of brushing with toothpaste containing nano calcium carbonate upon nanofill composite resin surface roughness

NASA Astrophysics Data System (ADS)

Ramadhani, A. M.; Herda, E.; Triaminingsih, S.

2017-08-01

This study aims to determine the effect of brushing with toothpaste containing nanocalcium carbonate on the roughness of nanofill composite resin surface. Brushing was conducted with 3 types of materials for 3 consecutive brushing periods of 10 minutes each. Surface roughness was measured using a surface-roughness tester and the results were analyzed using the repeated ANOVA and the one-way ANOVA test. The surface morphology was observed using SEM after 3 months’ worth of brushing with the 3 materials. It was found that the nanofill composite resin surface-roughness value increased significantly (p<0.005) after brushing with toothpaste containing nano calcium carbonate for 3 months, but the value was not as high as that obtained when brushing with other types of toothpaste.

The effect of dentifrice quantity and toothbrushing behaviour on oral delivery and retention of fluoride in vivo.

PubMed

Creeth, Jonathan; Zero, Domenick; Mau, Melissa; Bosma, Mary Lynn; Butler, Andrew

2013-12-01

While toothpaste F(-) concentration and rinsing regimen have well-characterised impacts on fluoride's effectiveness, other aspects of brushing regimen have much less well-established effects, in particular, dentifrice quantity and brushing duration. An in vivo study (n = 42) of oral fluoride delivery (i.e. oral disposition post-brushing), and retention (i.e. concentration of F(-) in saliva post-brushing, a known efficacy predictor), was performed to compare effects observed with those of dentifrice F(-) concentration and rinsing regimen. Subjects brushed with a NaF-silica dentifrice (Aquafresh Advanced, 1,150 ppm F(-) ) or a control dentifrice (250 ppm F(-) , same base), for 45, 60, 120 or 180 seconds with 0.5 or 1.5 g dentifrice, and rinsed with 15 ml water once or three times in a cross-over design. The F(-) concentration was measured in post-brushing expectorate, rinse and toothbrush washing samples, and in saliva between 5-120 minutes after brushing. Using 1.5 g versus 0.5 g dentifrice increased F(-) in all samples: oral retention of F(-) was almost doubled by this increase. Increasing duration of brushing had more complex effects. The amount of F(-) in the expectorate increased but decreased in both rinse and toothbrush washing samples. Oral F(-) retention increased, but only in the period 30-120 minutes after brushing. Over the ranges investigated, the order of importance on oral F(-) retention was: dentifrice F(-) concentration > quantity > rinsing regimen > brushing duration. Hence, increasing dentifrice quantity and, to a lesser extent, the duration of brushing, can elevate oral fluoride post-brushing. Evidence is accumulating that the importance of these variables to fluoride efficacy may have been underestimated. © 2013 FDI World Dental Federation.

Impact of brushing force on abrasion of acid-softened and sound enamel.

PubMed

Wiegand, A; Köwing, L; Attin, T

2007-11-01

The study aimed to analyse the effects of different brushing loads on abrasion of acid-softened and sound enamel surfaces. Sound and acid-softened surfaces of each 10 human enamel samples were submitted to brushing abrasion in an automatic brushing machine at 1.5 N (A), 2.5 N (B), 3.5 N (C) or 4.5 N (D) brushing load. Prior to abrasion, demineralisation of half of each enamel surface was performed by storage in hydrochloric acid (pH 2.0) for 60s. Brushing was carried out (1000 strokes) using a manual toothbrush and toothpaste slurry in a ratio of 1:3. Enamel loss was measured after 10, 20, 50, 100, 150, 200, 250, 300, 350 and 1000 brushing strokes (BS). Pre- and post-brushing values of Knoop indentation length (5 indentations each sample) were measured and mean enamel loss was calculated from the change in indentation depth. Within- and between-group comparisons were performed by ANOVA and t-test followed by Bonferroni-correction. Enamel loss of acid-softened surfaces was significantly influenced by the brushing load applied and was mostly significantly higher in group D (10-1000 BS: 225-462 nm) compared to A (10-1000 BS: 164-384), B (10-1000 BS: 175-370 nm) and C (10-1000 BS: 191-396 nm). Abrasion of acid-softened enamel was fourfold higher compared to sound surfaces. Sound enamel was significantly influenced by the brushing force at 20-200 brushing strokes only, but revealed no significant differences between groups A-D. Brushing load influences abrasion of briefly eroded enamel, but might be of minor importance for abrasion of sound enamel surfaces.

Effect of tooth brushing on gloss retention and surface roughness of five bulk-fill resin composites.

PubMed

O'Neill, Catherine; Kreplak, Laurent; Rueggeberg, Frederick A; Labrie, Daniel; Shimokawa, Carlos Alberto Kenji; Price, Richard Bengt

2018-01-01

To determine the effects of tooth brushing on five bulk-fill resin based composites (RBCs). Ten samples of Filtek Supreme Enamel (control), Filtek One Bulk Fill, Tetric EvoCeram Bulk Fill, SonicFill 2, SDR flow+, and Admira Fusion X-tra were light cured for 20 seconds using the Valo Grand curing light. After 24 hours storage in air at 37°C, specimens were brushed in a random order using Colgate OpticWhite dentifrice and a soft toothbrush. Surface gloss was measured prior to brushing, after 5,000, 10,000 and 15,000 back and forth brushing cycles. Surface roughness was measured after 15,000 brushing cycles using atomic force microscopy (AFM) and selected scanning electron microscope (SEM) images were taken. The data was examined using ANOVA and pair-wise comparisons using Scheffe's post-hoc multiple comparison tests (α = 0.05). Surface gloss decreased and the surface roughness increased after brushing. Two-way ANOVA showed that both the RBC and the number of brushing cycles had a significant negative effect on the gloss. One-way ANOVA showed that the RBC had a significant effect on the roughness after 15,000 brushing cycles. For both gloss and roughness, brushing had the least effect on the nano-filled control and nano-filled bulk-fill RBC, and the greatest negative effect on Admira Fusion X-tra. The SEM images provided visual agreement. There was an excellent linear correlation (R 2  = 0.98) between the logarithm of the gloss and roughness. After brushing, the bulk-fill RBCs were all rougher than the control nano-filled RBC. The nano-filled bulk-fill RBC was the least affected by brushing. Bulk-fill RBCs lose their gloss faster and become rougher than the nanofilled conventional RBC, Filtek Supreme Ultra. The nanofilled bulk-fill RBC was the least affected by tooth brushing. © 2017 Wiley Periodicals, Inc.

A randomized clinical trial evaluating gingivitis and plaque reduction of an oscillating-rotating power brush with a new brush head with angled bristles versus a marketed sonic brush with self-adjusting technology.

PubMed

Klukowska, Malgorzata; Grender, Julie M; Conde, Erinn; Ccahuana-Vasquez, Renzo Alberto; Ram Goyal, C

2014-08-01

To compare the efficacy of an oscillating-rotating power toothbrush with a novel brush head incorporating angled CrissCross bristles (Oral-B Pro 7000 SmartSeries and Oral-B CrossAction brush head) versus a marketed sonic toothbrush (Colgate ProClinical A1500 with the Triple Clean brush head) in the reduction of gingivitis and plaque over a 6-week period. This was a single center, randomized, open label, examiner-blind, 2-treatment, parallel group study. Study participants who met the entrance criteria were enrolled in the study and randomly assigned to one of the two toothbrush groups. Study participants brushed with their assigned toothbrush and a marketed fluoride dentifrice for 2 minutes twice daily at home for 6 weeks. Gingivitis and plaque were evaluated at baseline and Week 6. Gingivitis was assessed using the Modified Gingival Index (MGI) and Gingival Bleeding Index (GBI) and plaque was assessed using the Rustogi Modified Navy Plaque Index (RMNPI). Data was analyzed using the ANCOVA with baseline as the covariate. In total, 130 study participants were randomized to treatment resulting in 64 study participants per group completing the study. Both brushes produced statistically significant (P < 0.001) reductions in gingivitis and plaque measures relative to baseline. The oscillating-rotating,brush with the novel brush head demonstrated statistically significantly (P < 0.05) greater reductions in all gingivitis measures, as well as whole mouth and interproximal plaque measures, compared to the sonic toothbrush. The benefit for the oscillating- rotating brush over the sonic brush was 21.3% for gingivitis, 35.7% for gingival bleeding, 34.7% for number of bleeding sites, 17.4% for whole mouth plaque, and 21.2% for interproximal plaque. There were no adverse events reported or observed for either brush.

Toothbrush abrasivity in a long-term simulation on human dentin depends on brushing mode and bristle arrangement.

PubMed

Bizhang, Mozhgan; Schmidt, Ilka; Chun, Yong-Hee Patricia; Arnold, Wolfgang H; Zimmer, Stefan

2017-01-01

The aim of this study was to evaluate the susceptibility of dentin to brushing abrasion using four different toothbrushes (rotating-oscillating, sonic and two types of manual toothbrushes) with the same brushing forces. Dentin samples (n = 72) were selected from 72 impacted third molars. Half of the surface of dentin samples was covered with an adhesive tape, creating a protected and a freely exposed area in the same specimen. Brushing was performed with either a: sonic (Sonicare PowerUp, Philips GmbH, Hamburg, Germany), b: oscillating-rotating (Oral B Vitality Precisions Clean, Procter & Gamble, Schwalbach am Taunus, Germany) or two different manual toothbrushes c: flat trim brush head toothbrush (Dr. Best: Original, Glaxo-Smith-Kline, Bühl, Germany) and d: rippled-shaped brush head toothbrush (Blend-a-Dent, Complete V-Interdental, Blend-a-med, Schwalbach, Germany) in a custom made automatic brushing machine. The brushing force was set to 2 N and a whitening toothpaste (RDA = 150) was used. The simulation period was performed over a calculated period to mimic a brushing behavior of two times a day brushing for eight years and six months. Dentin loss was quantitatively determined by profilometry and statistically analyzed by Wilcoxon and Mann-Whitney-U Test (p < 0.05). The mean (standard deviation) surface loss was 21.03 (±1.26) μm for the sonic toothbrush, 15.71 (±0.85) μm for the oscillating-rotating toothbrush, 6.13 (±1.24) μm for the manual toothbrush with flat trim brush head and 2.50 (±0.43) μm for the manual toothbrush with rippled-shaped brush head. Differences between all groups were statistically significant at p<0.05. Using the same brushing force and a highly abrasive toothpaste, manual toothbrushes are significantly less abrasive compared to power toothbrushes for an 8.5-year simulation.

[Clinical relevance of tooth brushing in relation to dental caries].

PubMed

Pita-Fernández, Salvador; Pombo-Sánchez, Antonio; Suárez-Quintanilla, Juan; Novio-Mallón, Silvia; Rivas-Mundiña, Berta; Pértega-Díaz, Sonia

2010-07-01

To determine the impact and clinical relevance of tooth brushing on oral health. Prevalence study. Fontiñas Health Centre. (Santiago de Compostela, Spain). Prevalence study (n=281 children aged 5-14 years. Odontological examination according to WHO methodology, to determine the frequency of tooth brushing, frequency of sweet consumption and their impact on the prevalence of caries. Logistic regression and estimation of the relative prevalence difference (RPD) and the Number Needed to Treat in order to prevent one additional bad outcome (NNT). The children who never brush their teeth have a 40% (95% CI: 24.3%-57.8%) of early caries, while those who brush their teeth several times a day have 15.3% (95% CI: 9.4%-23.7%). An association between not brushing the teeth and caries in primary teeth (OR=2.3; 95% CI:1.05-5.3) was observed after adjusting for age, sweet consumption and visits to the dentist. The same occurred with final teeth (OR=3.9; 95% CI:1.4-10.3). The RPD was 62%(95% CI: 30%-79%), meaning that prevalence of caries is 62% lower in children who brush their teeth several times a day as compared to those who never brush their teeth. The NNT is 4 (95% CI: 2.4-14), so for every 4 children who brush their teeth several times a day, there is one less case of caries, compared to those who never brush their teeth. There is a dose-response relationship between prevalence of caries and brushing frequency. The same effect was observed with definitive caries: RPD=55% (95% CI:16%-76%), NNT=5 (95% CI:2.8-53.3). Tooth brushing is related to oral health, with a major clinical impact. The positive effect of tooth brushing was superior to that of a correct diet. 2009 Elsevier España, S.L. All rights reserved.

Toothbrush abrasivity in a long-term simulation on human dentin depends on brushing mode and bristle arrangement

PubMed Central

2017-01-01

Objective The aim of this study was to evaluate the susceptibility of dentin to brushing abrasion using four different toothbrushes (rotating-oscillating, sonic and two types of manual toothbrushes) with the same brushing forces. Methods Dentin samples (n = 72) were selected from 72 impacted third molars. Half of the surface of dentin samples was covered with an adhesive tape, creating a protected and a freely exposed area in the same specimen. Brushing was performed with either a: sonic (Sonicare PowerUp, Philips GmbH, Hamburg, Germany), b: oscillating-rotating (Oral B Vitality Precisions Clean, Procter & Gamble, Schwalbach am Taunus, Germany) or two different manual toothbrushes c: flat trim brush head toothbrush (Dr. Best: Original, Glaxo-Smith-Kline, Bühl, Germany) and d: rippled-shaped brush head toothbrush (Blend-a-Dent, Complete V-Interdental, Blend-a-med, Schwalbach, Germany) in a custom made automatic brushing machine. The brushing force was set to 2 N and a whitening toothpaste (RDA = 150) was used. The simulation period was performed over a calculated period to mimic a brushing behavior of two times a day brushing for eight years and six months. Dentin loss was quantitatively determined by profilometry and statistically analyzed by Wilcoxon and Mann-Whitney-U Test (p < 0.05). Results The mean (standard deviation) surface loss was 21.03 (±1.26) μm for the sonic toothbrush, 15.71 (±0.85) μm for the oscillating-rotating toothbrush, 6.13 (±1.24) μm for the manual toothbrush with flat trim brush head and 2.50 (±0.43) μm for the manual toothbrush with rippled-shaped brush head. Differences between all groups were statistically significant at p<0.05. Conclusion Using the same brushing force and a highly abrasive toothpaste, manual toothbrushes are significantly less abrasive compared to power toothbrushes for an 8.5—year simulation. PMID:28222156

``Smart'' Surfaces of Polymer Brushes

NASA Astrophysics Data System (ADS)

Wang, Qiang; Meng, Dong

2009-03-01

``Smart'' surfaces, also known as stimuli-responsive surfaces, can change their properties (e.g., wettability, adhesion, friction, elasticity, and biocompatibility) in response to external stimuli (e.g., temperature, pressure, light, solvent selectivity, ionic strength, type of salt, pH, applied electric field, etc.). In this work, we use numerical self-consistent field calculations to study in detail the structure and stimuli- responses of various polymer brushes, including (1) the thermo- response of PNIPAM brushes in water, (2) solvent-response of uncharged diblock copolymer brushes, and (3) the stimuli- response of charged two-component polymer brushes (including both the binary A/B brushes and diblock copolymer A-B brushes) to ionic strength, pH, and applied electric field. Among the many design parameters (e.g., chain lengths, grafting densities, A-B incompatibility, degree of ionization of charged polymers, etc.) we identify those that strongly affect the surface switchability. Such knowledge is useful to the experimental design of these smart polymer brushes for their applications.

Comparing solvophobic and multivalent induced collapse in polyelectrolyte brushes

DOE PAGES

Jackson, Nicholas E.; Brettmann, Blair K.; Vishwanath, Venkatram; ...

2017-02-03

Here, coarse-grained molecular dynamics enhanced by free-energy sampling methods is used to examine the roles of solvophobicity and multivalent salts on polyelectrolyte brush collapse. Specifically, we demonstrate that while ostensibly similar, solvophobic collapsed brushes and multivalent-ion collapsed brushes exhibit distinct mechanistic and structural features. Notably, multivalent-induced heterogeneous brush collapse is observed under good solvent polymer backbone conditions, demonstrating that the mechanism of multivalent collapse is not contingent upon a solvophobic backbone. Umbrella sampling of the potential of mean-force (PMF) between two individual brush strands confirms this analysis, revealing starkly different PMFs under solvophobic and multivalent conditions, suggesting the role ofmore » multivalent “bridging” as the discriminating feature in trivalent collapse. Structurally, multivalent ions show a propensity for nucleating order within collapsed brushes, whereas poor-solvent collapsed brushes are more disordered; this difference is traced to the existence of a metastable PMF minimum for poor solvent conditions, and a global PMF minimum for trivalent systems, under experimentally relevant conditions.« less

Comparing solvophobic and multivalent induced collapse in polyelectrolyte brushes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Nicholas E.; Brettmann, Blair K.; Vishwanath, Venkatram

Here, coarse-grained molecular dynamics enhanced by free-energy sampling methods is used to examine the roles of solvophobicity and multivalent salts on polyelectrolyte brush collapse. Specifically, we demonstrate that while ostensibly similar, solvophobic collapsed brushes and multivalent-ion collapsed brushes exhibit distinct mechanistic and structural features. Notably, multivalent-induced heterogeneous brush collapse is observed under good solvent polymer backbone conditions, demonstrating that the mechanism of multivalent collapse is not contingent upon a solvophobic backbone. Umbrella sampling of the potential of mean-force (PMF) between two individual brush strands confirms this analysis, revealing starkly different PMFs under solvophobic and multivalent conditions, suggesting the role ofmore » multivalent “bridging” as the discriminating feature in trivalent collapse. Structurally, multivalent ions show a propensity for nucleating order within collapsed brushes, whereas poor-solvent collapsed brushes are more disordered; this difference is traced to the existence of a metastable PMF minimum for poor solvent conditions, and a global PMF minimum for trivalent systems, under experimentally relevant conditions.« less

Repetitive switching for an electromagnetic rail gun

NASA Astrophysics Data System (ADS)

Gruden, J. M.

1983-12-01

Previous testing on a repetitive opening switch for inductive energy storage has proved the feasibility of the rotary switch concept. The concept consists of a rotating copper disk (rotor) with a pie-shaped insulator section and brushes which slide along each of the rotor surfaces. While on top of the copper surface, the brushes and rotor conduct current allowing the energy storage inductor to charge. When the brushes slide onto the insulator section, the current cannot pass through the rotor and is diverted into the load. This study investigates two new brush designs and a rotor modification designed to improve the current commutating capabilities of the switch. One brush design (fringe fiber) employs carbon fibers on the leading and trailing edge of the brush to increase the resistive commutating action as the switch opens and closes. The other brush design uses fingers to conduct current to the rotor surface, effectively increasing the number of brush contact points. The rotor modification was the placement of tungsten inserts at the copper-insulator interfaces.

Brush border enzyme-cleavable linkers: Evaluation for reducing renal uptake of radiolabeled prostate-specific membrane antigen inhibitors.

PubMed

Vaidyanathan, Ganesan; Kang, Choong Mo; McDougald, Darryl; Minn, Il; Brummet, Mary; Pomper, Martin G; Zalutsky, Michael R

2018-05-05

Radiolabeled, low-molecular-weight prostate-specific membrane antigen (PSMA) inhibitors based on the Glu-ureido pharmacophore show promise for the detection and treatment of castration-resistant prostate cancer; however, high renal retention of activity, related in part to overexpression of PSMA in kidneys can be problematic. The goal of the current study was to investigate the use of brush border enzyme-cleavable linkers as a strategy for reducing kidney activity levels from radiolabeled PSMA inhibitors. PSMA-769 (6), a derivative of the prototypical PSMA inhibitor (((S)‑1‑carboxy‑5‑(4‑iodobenzamido)pentyl)carbamoyl)glutamate (12) modified to contain a Gly-Tyr linker, and its protected tin precursor (11) were synthesized starting from the basic pharmacophore molecule Lys-urea-Glu. An analogue of 6 containing d‑tyrosine in lieu of l‑tyrosine (PSMA-769-d-tyrosine) and the corresponding tin precursor (d-11) also were synthesized. Both radioiodinated and 211 At-labeled 6 were synthesized by radiohalogenation of 11 and deprotection in situ. Similarly, radioiodinated d-6 was synthesized from d-11. Paired label biodistribution of [ 125 I]12 and [ 131 I]6 was performed in normal mice and in SCID mice bearing both PC3 PIP (PSMA+) and PC3 flu (PSMA-) subcutaneous prostate carcinoma xenografts. The biodistribution of [ 131 I]6 and [ 211 At]6 was also evaluated in this tumor model. Biodistribution of the two radioiodinated diastereomers of 6 was evaluated in normal mice and urine samples were analyzed for the presence of 4‑iodohippuric acid. Compounds [ 131 I]6 and [ 211 At]6 were synthesized from 11 in overall radiochemical yields of 32.5 ± 0.1% (n = 4) and 22% (n = 1), respectively; radiochemical purity was >95%. In normal mice, renal uptake of [ 131 I]6 was 1.4-, 2.8- and 161-fold lower than that seen for co-injected [ 125 I]12 at 1 h, 4 h and 21 h, respectively. In tumor-bearing mice, kidney uptake of [ 131 I]6 was similar to that for [ 125 I]12 (P > 0.05) at 1 h and 4 h but was 6- to 7-fold lower at 21 h; however, [ 131 I]6 uptake in PC3 PIP tumors was also lower than that seen for [ 125 I]12 at 21 h (12.6 ± 3.4%ID/g vs. 36.8 ± 12.4%ID/g). Uptake of [ 211 At]PSMA-769 in PC3 PIP tumors was slightly higher than that seen for [ 131 I]PSMA-769 at 4 h (9.6 ± 1.6%ID/g versus 7.8 ± 1.6%ID/g; P = 0.002); its uptake in a number of normal tissues also was higher. In normal mice, kidney uptake of [ 125 I]PSMA-769 at 4 h was about 73% of that seen for [ 131 I]PSMA-769-d-tyrosine. Activity in the urine of mice receiving [ 125 I]PSMA-769 contained mainly 4‑[ 125 I]iodohippuric acid while unmetabolized intact molecule was present in the case of [ 125 I]PSMA-769-d-tyrosine. Use of this brush border enzyme-cleavable linker reduced kidney uptake and resulted in improved tumor:kidney uptake ratios. Although further structural improvements are needed, this linker approach might be useful as a component in strategies for reducing renal uptake of radiolabeled PSMA inhibitors. Copyright © 2018 Elsevier Inc. All rights reserved.

AFM-based force spectroscopy on polystyrene brushes: effect of brush thickness on protein adsorption.

PubMed

Hentschel, Carsten; Wagner, Hendrik; Smiatek, Jens; Heuer, Andreas; Fuchs, Harald; Zhang, Xi; Studer, Armido; Chi, Lifeng

2013-02-12

Herein we present a study on nonspecific binding of proteins at highly dense packed hydrophobic polystyrene brushes. In this context, an atomic force microscopy tip was functionalized with concanavalin A to perform single-molecule force spectroscopy measurements on polystyrene brushes with thicknesses of 10 and 60 nm, respectively. Polystyrene brushes with thickness of 10 nm show an almost two times stronger protein adsorption than brushes with a thickness of 60 nm: 72 pN for the thinner and 38 pN for the thicker layer, which is in qualitative agreement with protein adsorption studies conducted macroscopically by fluorescence microscopy.

Design optimization of a brush turbine with a cleaner/water based solution

NASA Technical Reports Server (NTRS)

Kim, Rhyn H.

1995-01-01

Recently, a turbine-brush was analyzed based on the energy conservation and the force momentum equation with an empirical relationship of the drag coefficient. An equation was derived to predict the rotational speed of the turbine-brush in terms of the blade angle, number of blades, rest of geometries of the turbine-brush and the incoming velocity. Using the observed flow conditions, drag coefficients were determined. Based on the experimental values as boundary conditions, the turbine-brush flows were numerically simulated to understand first the nature of the flows, and to extend the observed drag coefficient to a flow without holding the turbine-brush.

Synthesis and characterization of poly(3-sulfopropylmethacrylate) brushes for potential antibacterial applications.

PubMed

Ramstedt, Madeleine; Cheng, Nan; Azzaroni, Omar; Mossialos, Dimitris; Mathieu, Hans Jörg; Huck, Wilhelm T S

2007-03-13

This article describes the aqueous atom transfer radical polymerization synthesis of poly(3-sulfopropylmethacrylate) brushes onto gold and Si/SiO2 surfaces in a controlled manner. The effect of Cu(I)/Cu(II) ratio was examined, and a quartz crystal microbalance was used to study the kinetics of the brush synthesis. The synthesized brushes displayed a thickness from a few nanometers to several hundred nanometers and were characterized using atomic force microscopy, ellipsometry, Fourier transform infrared spectroscopy (FTIR), contact angle measurements, and X-ray photoelectron spectroscopy (XPS). The as-synthesized sulfonate brushes had very good ion-exchange properties for the ions tested in this study, i.e., Na+, K+, Cu2+, and Ag+. FTIR and XPS show that the metal ions are coordinating to sulfonate moieties inside the brushes. The brushes were easily loaded with silver ions, and the effect of silver ion concentration on silver loading of the brush was examined. The silver-loaded brushes were shown to be antibacterial toward both gram negative and gram positive bacteria. The silver leaching was studied through leaching experiments into water, NaNO3, and NaCl (physiological medium). The results from these leaching experiments are compared and discussed in the article.

Distribution of Chains in Polymer Brushes Produced by a “Grafting From” Mechanism

DOE PAGES

Martinez, Andre P.; Carrillo, Jan-Michael Y.; Dobrynin, Andrey V.; ...

2016-01-11

The molecular weight and polydispersity of the chains in a polymer brush are critical parameters determining the brush properties. However, the characterization of polymer brushes is hindered by the vanishingly small mass of polymer present in brush layers. In this study, in order to obtain sufficient quantities of polymer for analysis, polymer brushes were grown from high surface area fibrous nylon membranes by ATRP. We synthesized the brushes with varying surface initiator densities, polymerization times, and amounts of sacrificial initiator, then cleaved from the substrate, and analyzed by GPC and NMR. Characterization showed that the surface-grown polymer chains were moremore » polydisperse and had lower average molecular weight compared to solution-grown polymers synthesized concurrently. Furthermore, the molecular weight distribution of the polymer brushes was observed to be bimodal, with a low molecular weight population of chains representing a significant mass fraction of the polymer chains at high surface initiator densities. Moreover, the origin of this low MW polymer fraction is proposed to be the termination of growing chains by recombination during the early stages of polymerization, a mechanism confirmed by molecular dynamics simulations of brush polymerization.« less

Comparison of Saudi child versus parent-report of child tooth-brushing practices.

PubMed

Salama, F; Abobakr, I; Al-Khodair, N; Al-Wakeel, M

2016-01-01

This cross-sectional study compared Saudi children's tooth-brushing practices as reported by children and parents and then matched the agreement of reports. A sample of 100 Saudi parents and their children of ages 8-12 years participated in this cross-sectional investigation. A self-administered structured questionnaire regarding the current tooth-brushing practice and habits at home was filled by the child. The same questionnaire was filled independently by parents. Mothers were more likely to teach children about tooth-brushing and fathers were minimally helping children during tooth-brushing. Mothers were the first to teach the children and approximately 33% of the children started brushing their teeth by age 5. Children and parents reported that children clean their teeth using a tooth-brush (73.74% and 76.77%), miswak (5.05% and 5.05%), or both (21.21% and 18.18%), respectively. There was some agreement between reported tooth-brushing practice of children and their parents. It is important to question both the child and parent regarding oral hygiene practice and compare their answers to get more broad knowledge about their practices. Approximately, one-third of the children started brushing their teeth by age 5, which differs from recommended oral hygiene practices.

In Vitro Assessment of the Abrasion Resistance of Two Types of Artificial Teeth Submitted to Brushing.

PubMed

Policastro, Vivian Barnabé; Giro, Gabriela; Leite, Andressa Rosa Perin; Mendoza-Marin, Danny Omar; Paleari, André Gustavo; Compagnoni, Marco Antonio; Pero, Ana Carolina

2016-08-01

To assess the effect of brushing with different solutions on the abrasion resistance of two types of acrylic resin teeth. Maxillary premolars from two types of acrylic teeth (Biotone and Biotone IPN) were divided into six groups (n = 12), according to the solution used during brushing: distilled water (control), coconut soap, or dentifrice. A mechanical brushing machine was used to simulate approximately 1 year of brushing (11,000 strokes). The weight loss (WL) of teeth was obtained from the difference between the initial (IW) and final weight (FW) of each specimen, and the mean of percentage of weight loss (PWL) was calculated for each group. Data were analyzed using the Kruskal-Wallis test, followed by Bonferroni's post-test comparison (α = 0.05). A statistically significant difference was found for the factor solution (p < 0.001). Brushing using dentifrice caused the highest values of weight loss (-0.50%), in comparison with the groups brushed with coconut soap (0.00%) or distilled water (0.00%). For both types of artificial teeth, brushing with dentifrice produced higher abrasion than brushing with coconut soap or water. © 2016 by the American College of Prosthodontists.

The efficacy of oral brush biopsy with computer-assisted analysis in identifying precancerous and cancerous lesions

PubMed Central

2011-01-01

Background Cancer of the oral cavity is the sixth most common malignancy reported worldwide and one with the highest mortality rate among all malignancies. There is a paucity of reliable diagnostic methods to detect early malignancies. This study was performed to evaluate the sensitivity and specificity of brush biopsy in identifying oral premalignant and malignant lesions. Methods Oral brush and scalpel biopsies were performed on 85 consecutive patients presenting with an oral lesion deemed to be minimally suspicious by clinical examination and the results were compared. Results Of 79 patients with adequate brush biopsy samples with matching scalpel biopsies, 27 revealed histopathologic evidence of dysplasia or carcinoma, 26 of which were independently identified with the oral brush biopsy (sensitivity: 96.3% - 95% CI, 87%-100%). 52 oral lesions did not reveal any histopathologic evidence of dysplasia or carcinoma and of these, brush biopsy reported 47 as "negative" and 5 as "atypical"(specificity of "positive" brush biopsy result is 100%- 95% CI, 93%-100%; specificity for "atypical" brush biopsy result is 90.4%- 95% CI, 82%-97%. The positive predictive value of an abnormal oral brush biopsy was 84% and the negative predictive value was 98%. Conclusion Our study demonstrated that the oral brush biopsy is an accurate test in identifying oral premalignant and malignant lesions, even if minimally suspicious. PMID:21864339

Effects of carbon brush anode size and loading on microbial fuel cell performance in batch and continuous mode

NASA Astrophysics Data System (ADS)

Lanas, Vanessa; Ahn, Yongtae; Logan, Bruce E.

2014-02-01

Larger scale microbial fuel cells (MFCs) require compact architectures to efficiently treat wastewater. We examined how anode-brush diameter, number of anodes, and electrode spacing affected the performance of the MFCs operated in fed-batch and continuous flow mode. All anodes were initially tested with the brush core set at the same distance from the cathode. In fed-batch mode, the configuration with three larger brushes (25 mm diameter) produced 80% more power (1240 mW m-2) than reactors with eight smaller brushes (8 mm) (690 mW m-2). The higher power production by the larger brushes was due to more negative and stable anode potentials than the smaller brushes. The same general result was obtained in continuous flow operation, although power densities were reduced. However, by moving the center of the smaller brushes closer to the cathode (from 16.5 to 8 mm), power substantially increased from 690 to 1030 mW m-2 in fed batch mode. In continuous flow mode, power increased from 280 to 1020 mW m-2, resulting in more power production from the smaller brushes than the larger brushes (540 mW m-2). These results show that multi-electrode MFCs can be optimized by selecting smaller anodes, placed as close as possible to the cathode.

Clinical validation of robot simulation of toothbrushing - comparative plaque removal efficacy

PubMed Central

2014-01-01

Background Clinical validation of laboratory toothbrushing tests has important advantages. It was, therefore, the aim to demonstrate correlation of tooth cleaning efficiency of a new robot brushing simulation technique with clinical plaque removal. Methods Clinical programme: 27 subjects received dental cleaning prior to 3-day-plaque-regrowth-interval. Plaque was stained, photographically documented and scored using planimetrical index. Subjects brushed teeth 33–47 with three techniques (horizontal, rotating, vertical), each for 20s buccally and for 20s orally in 3 consecutive intervals. The force was calibrated, the brushing technique was video supported. Two different brushes were randomly assigned to the subject. Robot programme: Clinical brushing programmes were transfered to a 6-axis-robot. Artificial teeth 33–47 were covered with plaque-simulating substrate. All brushing techniques were repeated 7 times, results were scored according to clinical planimetry. All data underwent statistical analysis by t-test, U-test and multivariate analysis. Results The individual clinical cleaning patterns are well reproduced by the robot programmes. Differences in plaque removal are statistically significant for the two brushes, reproduced in clinical and robot data. Multivariate analysis confirms the higher cleaning efficiency for anterior teeth and for the buccal sites. Conclusions The robot tooth brushing simulation programme showed good correlation with clinically standardized tooth brushing. This new robot brushing simulation programme can be used for rapid, reproducible laboratory testing of tooth cleaning. PMID:24996973

Use of a disclosed plaque visualization technique improved the self-performed, tooth brushing ability of primary schoolchildren.

PubMed

Chounchaisithi, Napa; Santiwong, Busayarat; Sutthavong, Sirikarn; Asvanit, Pompun

2014-02-01

Disclosing agents have a long history of use as an aid in children's tooth brushing instruction. However, their benefit when used to improve self-performed tooth brushing ability without any tooth brushing instruction has not been investigated. To evaluate the effect of disclosed plaque visualization on improving the self-performed, tooth brushing ability of primary school children. A cluster-randomized, crossover study was conducted in Nakhon Nayok province, Thailand. A total of 122 second-grade schoolchildren, aged 8-10 years old, from 12 schools were randomly divided into 2 groups. The first group was assigned to brush with disclosed plaque visualization, while the other group brushed without disclosed plaque visualization. One month later the groups switched procedures. Tooth brushing ability was evaluated by the subjects' reduction in patient hygiene performance (PHP) scores. The data were analyzed using repeated-measures analysis of variance, with significance set at p<0.05. Disclosed plaque visualization had a significant effect on improving the children's self-performed, tooth brushing ability in all areas of the mouth (p<0.001), particularly for anterior teeth, mandibular teeth, buccal surfaces, and areas adjacent to the gingival margin (p<0.001). Disclosed plaque visualization is a viable technique to improve children's self-performed tooth brushing ability, and could be used in school-based oral health promotion programs.

Clinical validation of robot simulation of toothbrushing--comparative plaque removal efficacy.

PubMed

Lang, Tomas; Staufer, Sebastian; Jennes, Barbara; Gaengler, Peter

2014-07-04

Clinical validation of laboratory toothbrushing tests has important advantages. It was, therefore, the aim to demonstrate correlation of tooth cleaning efficiency of a new robot brushing simulation technique with clinical plaque removal. Clinical programme: 27 subjects received dental cleaning prior to 3-day-plaque-regrowth-interval. Plaque was stained, photographically documented and scored using planimetrical index. Subjects brushed teeth 33-47 with three techniques (horizontal, rotating, vertical), each for 20s buccally and for 20s orally in 3 consecutive intervals. The force was calibrated, the brushing technique was video supported. Two different brushes were randomly assigned to the subject. Robot programme: Clinical brushing programmes were transfered to a 6-axis-robot. Artificial teeth 33-47 were covered with plaque-simulating substrate. All brushing techniques were repeated 7 times, results were scored according to clinical planimetry. All data underwent statistical analysis by t-test, U-test and multivariate analysis. The individual clinical cleaning patterns are well reproduced by the robot programmes. Differences in plaque removal are statistically significant for the two brushes, reproduced in clinical and robot data. Multivariate analysis confirms the higher cleaning efficiency for anterior teeth and for the buccal sites. The robot tooth brushing simulation programme showed good correlation with clinically standardized tooth brushing.This new robot brushing simulation programme can be used for rapid, reproducible laboratory testing of tooth cleaning.

Polymer Brushes Containing Sulfonated Sugar Repeat Units: Synthesis, Characterization and In Vitro Testing of Blood Coagulation Activation

PubMed Central

Ayres, N.; Holt, D. J.; Jones, C.F.; Corum, L. E.; Grainger, D. W.

2009-01-01

A new polymer brush chemistry containing sulfonated carbohydrate repeat units has been synthesized from silicon substrates using ATRP methods and characterized both in bulk and using surface analysis. The polymer brush was designed to act as a mimic for the naturally occurring sulfonated glycosaminoglycan, heparin, commonly used for modifying blood-contacting surfaces both in vitro and in vivo. Surface analysis showed conversion of brush saccharide precursor chemistry to the desired sulfonated polymer product. The sulfonated polymer brush surface was further analyzed using three conventional in vitro tests for blood compatibility -- plasma recalcification times, complement activation, and thrombin generation. The sulfonated polymer brush films on silicon oxide wafers exhibited better assay performance in these blood component assays than the unsulfonated sugar functionalized polymer brush in all tests performed. PMID:19859552

The fine structure of the stomach mucosa of the Llama (Llama guanacoe). II. The fundic region of the hind stomach.

PubMed

Luciano, L; Reale, E; von Engelhardt, W

1980-01-01

The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron desity of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals.

Methylation analysis of CMTM3 and DUSP1 gene promoters in high-quality brush hair in the Yangtze River delta white goat.

PubMed

Qiang, Wang; Guo, Haiyan; Li, Yongjun; Shi, Jianfei; Yin, Xiuyuan; Qu, Jingwen

2018-08-20

The Yangtze River delta white goat is the only goat breed that produces high-quality brush hair, which is specifically used in top-grade writing brushes. Previous studies have indicated that the CMTM3 and DUSP1 genes are involved in the growth and cycle of high-quality brush hair, and these genes are thought to be involved in the formation of high-quality brush hair traits. In this study, we investigated the relationship between methylation of CMTM3 and DUSP1 and such traits. The results indicated that the relative expression levels of the CMTM3 and DUSP1 genes were higher in non-high-quality brush hair than in high-quality brush hair. Furthermore, the CpG sites of the DUSP1 gene were not methylated, and the methylation level of CMTM3 was negatively correlated with the gene expression level. We believe that the DUSP1 gene regulates the formation of high-quality brush hair by non-methylated, and that methylation of the CMTM3 gene results in a decrease in its expression, causing an increase in the activity of the androgen receptor and the level of androgen. This high androgen level promotes the growth of high-quality brush hair. These study results provide a theoretical basis for further elucidating the molecular mechanism of the formation of high-quality brush hair characteristics, and provide scientific reference for the molecular breeding of high-quality brush hair. Copyright © 2018 Elsevier B.V. All rights reserved.

Attitudes and behavioural factors relating to toothbrushing and the use of fluoride toothpaste among caries-active Swedish adolescents - a questionnaire study.

PubMed

Nordström, Anna; Birkhed, Dowen

2017-10-01

The aim of this study was to identify attitudes and behaviour relating to fluoride toothpaste and toothbrushing habits among caries-active Swedish adolescents. This cross-sectional study is based on an earlier clinical, two-year toothpaste intervention study. At the last appointment, 206 adolescents (of 211) answered a questionnaire comprising nine semi-closed questions. The majority (93%) brushed their teeth every day, while 7% did so only occasionally. Most participants (77%) brushed twice a day, while 12% brushed just once a day. About half of those brushing just once a day forgot to brush in the evening. Similarly, more than half of the adolescents (53%) used 1 cm of toothpaste or less on their toothbrush. Moreover, 49% brushed for less than 2 min, 41% brushed for 2 min and 10% for more than 2 min. The majority (73%) rinsed with water after toothbrushing. A difference between boys and girls was also observed; 87% of the girls brushed twice a day, whereas only 67% of the boys did so and boys more frequently forgot in the evening. Attitudes and behaviour relating to fluoride toothpaste and toothbrushing habits among caries-active Swedish adolescents are still inadequate after two years of toothpaste intervention. There are several areas where improvements can be made, such as frequency of brushing, brushing time, amount of toothpaste and post-brushing procedures. The majority (81%) included 'fresh breath' as a reason for performing oral hygiene and this aspect can be used by dental staff in health promotion.

Effectiveness of Plaque Control with Novel Pediatric Oral Hygiene Need Station (Modified Oral Irrigation Device) as Compared with Manual Brushing and Flossing: Randomized Controlled Pilot Trial.

PubMed

Murthy, Prashanth Sadashiva; Shaik, Naseemoon; Deshmukh, Seema; Girish, M S

2018-01-01

Establishing good hygiene habits are valuable for present and future oral health. Below 6 years, tooth brushing should be performed by parents, as increasing dexterity and cognition may permit supervised brushing until the child is capable of independent brushing. The aim of the present study was to evaluate the effectiveness of modified oral irrigation device in children in terms of plaque control and to compare the effectiveness of plaque control with manual brushing with the modified oral irrigation device in children. A randomized clinical trial was performed on 12 subjects who were allocated to the two study groups. After obtaining the consent, the control group was instructed tooth brushing with regular pediatric commercially available toothbrush and the intervention group with modified oral irrigation device. Plaque scores in both groups were assessed pre- and post-brushing using modified navy plaque index. The data were subjected to Descriptive statistics and Paired t -test using SPSS version 22. Intragroup comparison of mean difference of plaque score in control group and intervention group pre- and post-brushing was statistically significant. Intergroup comparison of manual brushing group with modified oral irrigation group shows P < 0.05 was statistically significant. Within the limitation of the present study, it has been found novel pediatric oral hygiene need Station is more effective than manual brushing since it combined the effect of brushing, flossing (water floss), and rinsing in children simultaneously and at the same time did not demand any special motor skill.

Computer Simulations of Bottle Brushes: From Melts to Soft Networks

DOE PAGES

Cao, Zhen; Carrillo, Jan-Michael Y.; Sheiko, Sergei S.; ...

2015-07-13

We use a combination of Molecular dynamics simulations and analytical calculations, and study dens bottle-brush systems in a melt and network State. Analysis of our simulation results shows that bottle-brush macromolecules in melt behave as ideal chains with effective Kuhn length b K. Simulations show that the bottle-brush-induced bending rigidity is due to an entropy decrease caused by redistribution of the side chains upon backbone bending. The Kuhn length of the bottle:brushes increases with increasing the side-chain degree of polymerization n sc as b K proportional to n sc 0.46. Moreover, this model of bottle brush macromolecules is extended tomore » describe mechanical properties of bottle brush networks in linear and nonlinear deformation regimes. In the linear deformation regime, the network shear modulus scales with the degree of polymerization of the side chains as G 0 proportional to (n sc + 1) -1 as long as the ratio of the Kuhn length, b K, to the size of the fully extended bottle-brush backbone between cross-links, R-max, is smaller than unity, b K/R max << 1. Bottle-brush networks With b K/R max proportional to 1 demonstrate behavior similar to that of networks Of semiflexible chains with G 0 proportional to n sc -0.5. Finally, in the nonlinear network deformation regime, the deformation-dependent shear modulus is a universal function of the first strain invariant I 1 and bottle-brush backbone deformation ratio beta describing stretching ability of the bottle-brush backbone between cross-links.« less

Fluoroscopic percutaneous brush cytology, forceps biopsy and both in tandem for diagnosis of malignant biliary obstruction.

PubMed

Boos, Johannes; Yoo, Raphael J; Steinkeler, Jennifer; Ayata, Gamze; Ahmed, Muneeb; Sarwar, Ammar; Weinstein, Jeffrey; Faintuch, Salomao; Brook, Olga R

2018-02-01

To evaluate percutaneous brush cytology, forceps biopsy and a tandem procedure consisting of both, in the diagnosis of malignant biliary obstruction. A retrospective review of consecutive patients who underwent biliary brush cytology and/or forceps biopsy between 01/2010 and 09/2014 was performed. The cytology and pathology results were compared to the composite outcome (including radiological, pathological and clinical data). Cost for tandem procedure compared to brush cytology and forceps biopsy alone was calculated. A total of 232 interventions in 129 patients (70.8 ± 11.0 years) were included. Composite outcome showed malignancy in 94/129 (72.9%) patients. Sensitivity for brush cytology, forceps biopsy and tandem procedure was 40.6% (95% CI 32.6-48.7%), 42.7% (32.4-53.0%) and 55.8% (44.7-66.9%) with 100% specificity, respectively. There were 9/43 (20.9%) additional cancers diagnosed when forceps biopsy was performed in addition to brush cytology, while there were 13/43 (30.2%) more cancers diagnosed when brush cytology was performed in addition to forceps biopsy. Additional costs per additionally diagnosed malignancy if tandem approach is to be utilised in all cases was $704.96. Using brush cytology and forceps biopsy in tandem improves sensitivity compared to brush cytology and forceps biopsy alone in the diagnosis of malignant biliary obstruction. • Tandem procedure improves sensitivity compared to brush cytology and forceps biopsy. • Brush cytology may help to overcome "crush artefacts" from forceps biopsy. • The cost per diagnosed malignancy may warrant tandem procedure in all patients.

Experience of racism and tooth brushing among pregnant Aboriginal Australians: exploring psychosocial mediators.

PubMed

Ben, J; Jamieson, L M; Priest, N; Parker, E J; Roberts-Thomson, K F; Lawrence, H P; Broughton, J; Paradies, Y

2014-09-01

Despite burgeoning evidence regarding the pathways by which experiences of racism influence health outcomes, little attention has been paid to the relationship between racism and oral health-related behaviours in particular. We hypothesised that self-reported racism was associated with tooth brushing, and that this association was mediated by perceived stress and sense of control and moderated by social support. Data from 365 pregnant Aboriginal Australian women were used to evaluate tooth brushing behaviour, sociodemographic factors, psychosocial factors, general health, risk behaviours and racism exposure. Bivariate associations were explored and hierarchical logistic regression models estimated odds ratios (OR) and 95% confidence intervals (CI) for tooth brushing. Perceived stress and sense of control were examined as mediators of the association between self-reported racism and tooth brushing using binary mediation with bootstrapping. High levels of self-reported racism persisted as a risk indicator for tooth brushing (OR 0.51, 95%CI 0.27,0.98) after controlling for significant covariates. Perceived stress mediated the relationship between self-reported racism and tooth brushing: the direct effect of racism on tooth brushing was attenuated, and the indirect effect on tooth brushing was significant (beta coefficient -0.09; bias-corrected 95%CI -0.166,-0.028; 48.1% of effect mediated). Sense of control was insignificant as a mediator of the relationship between racism and tooth brushing. High levels of self-reported racism were associated with non-optimal tooth brushing behaviours, and perceived stress mediated this association among this sample of pregnant Aboriginal women.. Limitations and implications are discussed.

Frequency of daily tooth brushing: predictors of change in 9- to 11-year old US children

PubMed Central

Polk, D.E.; Geng, M.; Levy, S.; Koerber, A.; Flay, B.R.

2014-01-01

Objective To investigate whether an increase in daily tooth brushing frequency in children was predicted by either a) having a strong intention to brush twice a day or b) their parents receiving information about their new caries experience. Basic Research Design Secondary data analyses were conducted on two waves of data from the Aban Aya Youth Project and the Iowa Fluoride Study. Participants The Aban Aya study included 576 10- and 11-year olds from Chicago, Illinois. The Iowa Fluoride Study included a convenience sample of 709 babies born in Iowa. The present study includes those children at age 9. Main Outcome Measures In both studies, reported daily tooth brushing frequency was assessed twice six months apart. Results In the Aban Aya data, compared with children with a weak intention at wave 1 to brush twice a day, children with a strong intention to brush twice a day were more likely to increase their brushing frequency by wave 2, OR 7.0, 95%CI 1.5,32.9. In the Iowa Fluoride Study, compared with children who did not have new caries at wave 1, children who had new caries experience were less likely to increase their brushing frequency by wave 2, OR 0.4, 95%CI 0.2,0.9. Conclusions Strengthening intention to brush twice a day might increase children’s brushing frequency. However, simply providing parents with information about new caries probably will not. Future studies should assess tooth brushing frequency, habit strength, intention, and situational cues at closely-spaced waves. PMID:25300146

Enteroendocrine-derived glucagon-like peptide-2 controls intestinal amino acid transport.

PubMed

Lee, Jennifer; Koehler, Jacqueline; Yusta, Bernardo; Bahrami, Jasmine; Matthews, Dianne; Rafii, Mahroukh; Pencharz, Paul B; Drucker, Daniel J

2017-03-01

Glucagon-like peptide-2 (GLP-2) is co-secreted with GLP-1 from gut endocrine cells, and both peptides act as growth factors to expand the surface area of the mucosal epithelium. Notably, GLP-2 also enhances glucose and lipid transport in enterocytes; however, its actions on control of amino acid (AA) transport remain unclear. Here we examined the mechanisms linking gain and loss of GLP-2 receptor (GLP-2R) signaling to control of intestinal amino acid absorption in mice. Absorption, transport, and clearance of essential AAs, specifically lysine, were measured in vivo by Liquid Chromatography triple quadrupole Mass Spectrometry (LC-MS/MS) and ex vivo with Ussing chambers using intestinal preparations from Glp2 r +/+ and Glp2r - / - mice. Immunoblotting determined jejunal levels of protein components of signaling pathways (PI3K-AKT, and mTORC1-pS6-p4E-BP1) following administration of GLP-2, protein gavage, and rapamycin to fasted Glp2 r +/+ and Glp2r - / - mice. Expression of AA transporters from full thickness jejunum and 4F2hc from brush border membrane vesicles (BBMVs) was measured by real-time PCR and immunoblotting, respectively. Acute administration of GLP-2 increased basal AA absorption in vivo and augmented basal lysine transport ex vivo . GLP-2-stimulated lysine transport was attenuated by co-incubation with wortmannin, rapamycin, or tetrodotoxin ex vivo . Phosphorylation of mTORC1 effector proteins S6 and 4E-BP1 was significantly increased in wild-type mice in response to GLP-2 alone, or when co-administered with protein gavage, and abolished following oral gavage of rapamycin. In contrast, activation of GLP-1R signaling did not enhance S6 phosphorylation. Disruption of GLP-2 action in Glp2r -/- mice reduced lysine transport ex vivo and attenuated the phosphorylation of S6 and 4E-BP1 in response to oral protein. Moreover, the expression of cationic AA transporter slc7a9 in response to refeeding, and the abundance of 4F2hc in BBMVs following protein gavage, was significantly attenuated in Glp2r -/- mice. These findings reveal an important role for GLP-2R signaling in the physiological and pharmacological control of enteral amino acid sensing and assimilation, defining an enteroendocrine cell-enterocyte axis for optimal energy absorption.

Holotrichia oblita Midgut Proteins That Bind to Bacillus thuringiensis Cry8-Like Toxin and Assembly of the H. oblita Midgut Tissue Transcriptome

PubMed Central

Jiang, Jian; Huang, Ying; Shu, Changlong; Soberón, Mario; Bravo, Alejandra; Liu, Chunqing; Song, Fuping; Lai, Jinsheng

2017-01-01

ABSTRACT The Bacillus thuringiensis strain HBF-18 (CGMCC 2070), containing two cry genes (cry8-like and cry8Ga), is toxic to Holotrichia oblita larvae. Both Cry8-like and Cry8Ga proteins are active against this insect pest, and Cry8-like is more toxic. To analyze the characteristics of the binding of Cry8-like and Cry8Ga proteins to brush border membrane vesicles (BBMVs) in H. oblita larvae, binding assays were conducted with a fluorescent DyLight488-labeled Cry8-like toxin. The results of saturation binding assays demonstrated that Cry8-like bound specifically to binding sites on BBMVs from H. oblita, and heterologous competition assays revealed that Cry8Ga shared binding sites with Cry8-like. Furthermore, Cry8-like-binding proteins in the midgut from H. oblita larvae were identified by pulldown assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, the H. oblita midgut transcriptome was assembled by high-throughput RNA sequencing and used for identification of Cry8-like-binding proteins. Eight Cry8-like-binding proteins were obtained from pulldown assays conducted with BBMVs. The LC-MS/MS data for these proteins were successfully matched with the H. oblita transcriptome, and BLASTX results identified five proteins as serine protease, transferrin-like, uncharacterized protein LOC658236 of Tribolium castaneum, ATPase catalytic subunit, and actin. These identified Cry8-like-binding proteins were different from those confirmed previously as receptors for Cry1A proteins in lepidopteran insect species, such as aminopeptidase, alkaline phosphatase, and cadherin. IMPORTANCE Holotrichia oblita is one of the main soil-dwelling pests in China. The larvae damage the roots of crops, resulting in significant yield reductions and economic losses. H. oblita is difficult to control, principally due to its soil-dwelling habits. In recent years, some Cry8 toxins from Bacillus thuringiensis were shown to be active against this pest. Study of the mechanism of action of these Cry8 toxins is needed for their effective use in the control of H. oblita and for their future utilization in transgenic plants. Our work provides important basic data and promotes understanding of the insecticidal mechanism of Cry8 proteins against H. oblita larvae. PMID:28389549

Mast cell regulation of Na-glutamine co-transporters B0AT1 in villus and SN2 in crypt cells during chronic intestinal inflammation.

PubMed

Singh, Soudamani; Arthur, Subha; Talukder, Jamilur; Palaniappan, Balasubramanian; Coon, Steven; Sundaram, Uma

2015-04-15

In the chronically inflamed rabbit small intestine, brush border membrane (BBM) Na-glutamine co-transport is inhibited in villus cells (mediated by B0AT1), while it is stimulated in crypt cells (mediated by SN2/SNAT5). How mast cells, known to be enhanced in the chronically inflamed intestine, may regulate B0AT1 in villus and SN2/SNAT5 in crypt cell is unknown. Thus, the aim of the present study is to determine the regulation of B0AT1 and SN2/SNAT5 by mast cells during chronic enteritis. Chronic intestinal inflammation was induced in male rabbits with intra-gastric inoculation of Eimeria magna oocytes. Rabbits with chronic inflammation were treated with ketotifen (10 mg/day) or saline (Placebo) for 2 days. Villus and crypts cells were isolated from the rabbit intestine using the Ca++ chelation technique. Na/K-ATPase activity was measured as Pi from cellular homogenate. BBM vesicles (BBMV) were prepared from villus and crypt cells and uptake studies were performed using rapid filtration technique with (3)H-Glutamine. Western blot analyses were done using B0AT1 and SN2 specific antibodies. In villus cells, Na-glutamine co-transport inhibition observed during inflammation was completely reversed by ketotifen, a mast cell stabilizer. In contrast, in crypt cells, Na-glutamine co-transport stimulation was reversed to normal levels by ketotifen. Kinetic studies demonstrated that ketotifen reversed the inhibition of B0AT1 in villus cells by restoring co-transporter numbers in the BBM, whereas the stimulation of SN2/SNAT5 in crypts cells was reversed secondary to restoration of affinity of the co-transporter. Western blot analysis showed that ketotifen restored immune-reactive levels of B0AT1 in villus cells, while SN2/SNAT5 levels from crypts cell remained unchanged. In the present study we demonstrate that mast cells likely function as a common upstream immune pathway regulator of the Na-dependent glutamine co-transporters, B0AT1 in villus cells and SN2 in crypts cells that are uniquely altered in the chronically inflamed small intestine.

Characterization of Small DC Brushed and Brushless Motors

DTIC Science & Technology

2013-03-01

8 Figure 6. Torque vs. RPM for a SS7 -1.7-1 brushed motor...9 Figure 7. Efficiency vs. motor power output for SS7 -1.7-1 brushed motor...10 Figure 8. Efficiency vs. RPM for SS7 -1.7-1 brushed motor. ........................................................10 Figure 9

75 FR 21347 - Natural Bristle Paint Brushes From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-23

... Brushes From China AGENCY: United States International Trade Commission. ACTION: Scheduling of a full five-year review concerning the antidumping duty order on natural bristle paint brushes from China. SUMMARY... antidumping duty order on natural bristle paint brushes from China would be likely to lead to continuation or...

46 CFR 108.187 - Ventilation for brush type electric motors in classified spaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for brush type electric motors in classified... Ventilation for brush type electric motors in classified spaces. Ventilation for brush type electric motors in... Electrical Equipment in Hazardous Locations”, except audible and visual alarms may be used if shutting down...

77 FR 77037 - Procurement List; Additions

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-31

...-Compatible, 2'' x 8'' NSN: 7920-00-NIB-0545--Scrub Brush, Wire, Knuckle Guard, Long Handle, Ergonomic, 6'' x 1 1/8'', w/built-in scraper NSN: 7920-00-NIB-0547--Scrub Brush, Wire, Stainless, Ergonomic, 5'' NSN: 7920-00-NIB-0558--Scrub Brush, Wire, Black Tempered, Ergonomic, 5'' NSN: 7920-00-NIB-0563--Wire Brush...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez, Andre P.; Carrillo, Jan-Michael Y.; Dobrynin, Andrey V.

The molecular weight and polydispersity of the chains in a polymer brush are critical parameters determining the brush properties. However, the characterization of polymer brushes is hindered by the vanishingly small mass of polymer present in brush layers. In this study, in order to obtain sufficient quantities of polymer for analysis, polymer brushes were grown from high surface area fibrous nylon membranes by ATRP. We synthesized the brushes with varying surface initiator densities, polymerization times, and amounts of sacrificial initiator, then cleaved from the substrate, and analyzed by GPC and NMR. Characterization showed that the surface-grown polymer chains were moremore » polydisperse and had lower average molecular weight compared to solution-grown polymers synthesized concurrently. Furthermore, the molecular weight distribution of the polymer brushes was observed to be bimodal, with a low molecular weight population of chains representing a significant mass fraction of the polymer chains at high surface initiator densities. Moreover, the origin of this low MW polymer fraction is proposed to be the termination of growing chains by recombination during the early stages of polymerization, a mechanism confirmed by molecular dynamics simulations of brush polymerization.« less

Facilitators and barriers to twice daily tooth brushing among children with special health care needs

PubMed Central

Campanaro, Maria; Huebner, Colleen E.; Davis, Beth Ellen

2015-01-01

Purpose The oral hygiene routines of preschool-age children with special health care needs (CSHCN) were examined to identify caregiver behaviors and beliefs associated with twice daily tooth brushing. Methods Ninety caregivers of CSHCN, ages 23 to 62 months, were interviewed to determine supports or barriers to tooth brushing. Results Ninety-eight percent of caregivers had begun brushing their child’s teeth and half reported brushing twice daily. Caregivers’ brushing skills and the availability of child-friendly supplies were associated with twice daily versus less frequent brushing (p = .02). Conclusions This study adds insight into the challenges of establishing daily oral health care for children who must rely on others for their care. The facilitators and barriers to tooth brushing by caregivers of CSHCN are similar to those noted previously among parents of typically developing children. Efforts to improve all caregivers’ oral hygiene skills are needed. For caregivers of CSHCN, oral health teaching opportunities may exist among professionals who provide ongoing medical care, special services and therapies. PMID:24252060

Facilitators and barriers to twice daily tooth brushing among children with special health care needs.

PubMed

Campanaro, Maria; Huebner, Colleen E; Davis, Beth Ellen

2014-01-01

The oral hygiene routines of preschool-age children with special health care needs (CSHCN) were examined to identify caregiver behaviors and beliefs associated with twice daily tooth brushing. Ninety caregivers of CSHCN, ages 23 to 62 months, were interviewed to determine supports or barriers to tooth brushing. Ninety-eight percent of caregivers had begun brushing their child's teeth and half reported brushing twice daily. Caregivers' brushing skills and the availability of child-friendly supplies were associated with twice daily versus less frequent brushing (p = .02). This study adds insight into the challenges of establishing daily oral health care for children who must rely on others for their care. The facilitators and barriers to tooth brushing by caregivers of CSHCN are similar to those noted previously among parents of typically developing children. Efforts to improve all caregivers' oral hygiene skills are needed. For caregivers of CSHCN, oral health teaching opportunities may exist among professionals who provide ongoing medical care, special services and therapies. © 2014 Special Care Dentistry Association and Wiley Periodicals, Inc.

Effectiveness of Plaque Control with Novel Pediatric Oral Hygiene Need Station (Modified Oral Irrigation Device) as Compared with Manual Brushing and Flossing: Randomized Controlled Pilot Trial

PubMed Central

Murthy, Prashanth Sadashiva; Shaik, Naseemoon; Deshmukh, Seema; Girish, M. S.

2018-01-01

Background: Establishing good hygiene habits are valuable for present and future oral health. Below 6 years, tooth brushing should be performed by parents, as increasing dexterity and cognition may permit supervised brushing until the child is capable of independent brushing. Aim and Objectives: The aim of the present study was to evaluate the effectiveness of modified oral irrigation device in children in terms of plaque control and to compare the effectiveness of plaque control with manual brushing with the modified oral irrigation device in children. Materials and Methods: A randomized clinical trial was performed on 12 subjects who were allocated to the two study groups. After obtaining the consent, the control group was instructed tooth brushing with regular pediatric commercially available toothbrush and the intervention group with modified oral irrigation device. Plaque scores in both groups were assessed pre- and post-brushing using modified navy plaque index. Results: The data were subjected to Descriptive statistics and Paired t-test using SPSS version 22. Intragroup comparison of mean difference of plaque score in control group and intervention group pre- and post-brushing was statistically significant. Intergroup comparison of manual brushing group with modified oral irrigation group shows P < 0.05 was statistically significant. Conclusion: Within the limitation of the present study, it has been found novel pediatric oral hygiene need Station is more effective than manual brushing since it combined the effect of brushing, flossing (water floss), and rinsing in children simultaneously and at the same time did not demand any special motor skill. PMID:29875555

Oral hygiene practices and risk of oral leukoplakia.

PubMed

Macigo, F G; Gathece, L W; Guthua, S W; Njeru, E K; Wagaiyu, E G; Mulli, T K

2006-04-01

To determine the influence of oral hygiene habits and practices on the risk of developing oral leukoplakia. Case control study. Githongo sublocation in Meru District. Eighty five cases and 141 controls identified in a house-to-house screening. The relative risk (RR) of oral leukoplakia increased gradually across the various brushing frequencies from the reference RR of 1.0 in those who brushed three times a day, to 7.6 in the "don't brush" group. The trend of increase was statistically significant (X2 for Trend : p = 0.001). The use of chewing stick as compared to conventional tooth brush had no significant influence on RR of oral leukoplakia. Non-users of toothpastes had a significantly higher risk of oral leukoplakia than users (RR = 1.8; 95% confidence levels (CI) = 1.4-2.5). Among tobacco smokers, the RR increased from 4.6 in those who brushed to 7.3 in those who did not brush. Among non-smokers, the RR of oral leukoplakia in those who did not brush (1.8) compared to those who brushed was also statistically significant (95% CL = 1.6-3.8). Failure to brush teeth and none use of toothpastes are significantly associated with the development of oral leukoplakia, while the choice of brushing tools between conventional toothbrush and chewing stick is not. In addition, failure to brush teeth appeared to potentiate the effect of smoking tobacco in the development of oral leukoplakia. Oral health education, instruction and motivation for the improvement of oral hygiene habits and practices; and therefore oral hygiene status, should be among the strategies used in oral leukoplakia preventive and control programmes.

Interdental cleaning and gingival injury potential of interdental toothbrushes.

PubMed

Vogel, Marc; Sener, Beatrice; Roos, M; Attin, Thomas; Schmidlin, Patrick R

2014-01-01

The effective cleaning of interdental spaces using toothbrushes is a challenge. The aim of the present in vitro study was to evaluate on the one hand the interdental cleaning efficiency and on the other hand the gingival injury potential of an electric single-headed sonic toothbrush (Water-pik) and two single-tufted manual toothbrushes (Curaprox 1009; Lactona Interdental Brush). Brushes were evaluated using a brushing device. Test dental casts (maxillary sextants) consisting of black teeth coated with white paint were brushed using standardized horizontal movements. Thereafter, black (i.e. cleaned) areas were measured planimetrically. The soft tissue injury potential was evaluated using front segments of porcine mandibles. In the same brushing device, test brushes were moved over the gingiva. Before and after each treatment, the porcine mucosa was stained with a plaque disclosing agent to visualize injured areas, which could then be measured planimetrically as well. These evaluations were each made after 15, 30, 60, and 120 seconds of brushing. The statistical analysis was performed using non-parametric Mann-Whitney tests, and the level of significance was set at 5%. The best cleaning performance of 46% across all interdental spaces assessed was found with the electric sonic toothbrush (Waterpik), while the performances of the manual brushes from Lactona and Curaprox were 14.8% and 5%, respectively. At each point of evaluation, the gingiva was injured most markedly by the powered sonic toothbrush (Waterpik), followed by the manual Curaprox brush. The smallest damage of the porcine gingiva was produced by the manual Lactona brush. When comparing the manual toothbrushes, the Lactona product revealed a better cleaning performance combined with a smaller injury potential than the Curaprox brush. Thus, the prophylactic goal to achieve high degrees of cleaning while producing minimal damage is important and should have priority when evaluating and selecting toothbrushes.

Efficacy of 3 toothbrush treatments on plaque removal in orthodontic patients assessed with digital plaque imaging: a randomized controlled trial.

PubMed

Erbe, Christina; Klukowska, Malgorzata; Tsaknaki, Iris; Timm, Hans; Grender, Julie; Wehrbein, Heinrich

2013-06-01

Good oral hygiene is a challenge for orthodontic patients because food readily becomes trapped around the brackets and under the archwires, and appliances are an obstruction to mechanical brushing. The purpose of this study was to compare plaque removal efficacy of 3 toothbrush treatments in orthodontic subjects. This was a replicate-use, single-brushing, 3-treatment, examiner-blind, randomized, 6-period crossover study with washout periods of approximately 24 hours between visits. Forty-six adolescent and young adult patients with fixed orthodontics from a university clinic in Germany were randomized, based on computer-generated randomization, to 1 of 3 treatments: (1) oscillating-rotating electric toothbrush with a specially designed orthodontic brush head (Oral-B Triumph, OD17; Procter & Gamble, Cincinnati, Ohio); (2) the same electric toothbrush handle with a regular brush head (EB25; Procter & Gamble); and (3) a regular manual toothbrush (American Dental Association, Chicago, Ill). The primary outcome was the plaque score change from baseline, which we determined using digital plaque image analysis. Forty-five subjects completed the study. The differences in mean plaque removal (95% confidence interval) between the electric toothbrush with an orthodontic brush head (6% [4.4%-7.6%]) or a regular brush head (3.8% [2.2%-5.3%]) and the manual toothbrush were significant (P <0.001). Plaque removal with the electric toothbrush with the orthodontic brush head was superior (2.2%; P = 0.007) to the regular brush head. No adverse events were seen. The electric toothbrush, with either brush head, demonstrated significantly greater plaque removal over the manual brush. The orthodontic brush head was superior to the regular head. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Development and testing of a theory-based behavioural change intervention: a pilot investigation in a nursery school in a deprived area of Scotland.

PubMed

Gilinsky, A; Swanson, V; Merrett, M; Power, K; Marley, L

2012-03-01

Investigate the effect of a theory-based intervention on oral-health knowledge, attitudes and behaviours of early years staff (EYS), parents and nursery children. Qualitative research with staff and parents from eight nurseries through interviews/focus groups. An intervention was developed and piloted using pre-posttest design. Nurseries in deprived communities in Dundee, Scotland. 111 children aged 3-5 years attending nursery, including 79 parents and 8 nursery staff. Staff session targeted outcome expectancies, subjective norms and self-efficacy for tooth-brushing in nursery using information provision, modelling and goal-setting, followed by a three-week intervention. Parent-child dyads received a leaflet with instructions for goal-setting, planning and monitoring home brushing. Tooth-brushing self-monitoring materials (e.g. two-minute timer, diaries) were used and certificates provided in the nursery as rewards. EYS knowledge, attitudes and behaviours were assessed before and after the intervention using self-report questionnaires. Parents completed interviews assessing beliefs about tooth-brushing and their children's tooth-brushing behaviour at baseline and post-intervention follow-up. Significant improvements in staff knowledge, but not attitudes, self-efficacy, or nursery tooth-brushing were reported. Parent-child dyads completing the intervention were not more likely to report their child carried out twice-daily tooth-brushing at home. The intervention did not improve parents' intentions to brush their child's teeth twice a day or beliefs about the ease of twice-daily tooth-brushing. Only past behaviour significantly predicted posttest brushing. Parents who found brushing easier at baseline were more likely to complete the intervention. Recommendations are made regarding implementing psychological theory and methods into oral-health interventions.

Polymer brush coatings for DNA: fundamental polymer physics and nanofabrication applications

NASA Astrophysics Data System (ADS)

de Vries, Renko

Recombinant DNA technology allows for the production of precisely defined self-assembling protein-based polymers. So far, the major applications for such protein-based polymers have been self-assembling hydrogels and micellar structures with biomedical application. Inspired by minimal models for the self-ssembly of rod-shaped viruses such as the tobacco mosaic virus, I have developed protein-polymers that co-assemble with DNA into rod-shaped virus-like particles, and protein-polymers that provide brush coatings around single DNA molecules. In this presentation I will focus on the latter, showing that on the one hand brush coated DNA is a rich model system for exploring the physics of bottle-brush polymers, while on the other hand brush coatings of DNA can also play an important practical role in nanofabrication. A key problem in the physics of bottle-brush polymers that I will address is the scale-dependence of bottle-brush elasticity. For long-wavelength thermal deformations probed by AFM imaging I will demonstrate that there is significant stiffening due to the brush coating, while for short wavelength thermal deformations probed by force spectroscopy, we find that stiffening due to the brush coating disappears completely. DNA brush coatings can also play an important practical role in nanofabrication by acting as a compatibilizer between chemically different building blocks. I will explore the example of DNA origami in combination with gold nanoparticles: while Mg2+ ions and high concentrations of monovalent salts are crucial for the stability of DNA origami, such solution conditions are typically incompatible with the colloidal stability of gold nanoparticles.I will show how DNA brush coatings can dramatically enhance the yield of formation of isolated DNA-gold nanoparticle composite nanostructures.

Tooth brushing among 11- to 15-year-olds in Denmark: combined effect of social class and migration status.

PubMed

Bast, L S; Nordahl, H; Christensen, L B; Holstein, B E

2015-03-01

Regular tooth brushing in adolescence predicts stable tooth brushing habits later in life. Differences in tooth brushing habits by ethnic background and socioeconomic position have been suggested. We investigated migration status and social class in relation to infrequent tooth brushing both separately and combined. The study population was 11-15 year-olds chosen from a clustered random sample of schools. Univariate and multivariate logistic regression analyses estimated the separate and combined effects of migration status and social class on less than twice daily tooth brushing. 10,607 respondents: a response rate of 88.3%. Boys of lower social class had higher odds ratio (OR) of infrequent tooth brushing than girls: 1.98 (95% confidence interval 1.62-2.41) vs 1.80 (1.53-2.24). Immigrants and descendants had higher odds compared to adolescents of Danish origin: immigrant boys OR 1.39 (1.05-1.89), girls OR 1.92 (1.47-2.50); descendant boys OR 2.53 (1.97-3.27), girls OR 2.56 (2.02-3.35). Analyses of the combined effect of social class and migration status showed that the social gradient in tooth brushing habits observed among ethnic Danes cannot be found among groups of immigrants and descendants. The study shows that both non-Danish origin and low social class increases the risk of infrequent tooth brushing among school-aged children. The study calls for in depth analyses of the processes which influence young people's tooth brushing habits. Further, there is a need to strengthen the promotion of appropriate tooth brushing habits of minority and low social class youths.

Tooth-brushing behaviour in 6-12 year olds.

PubMed

Sandström, Anna; Cressey, Janet; Stecksén-Blicks, Christina

2011-01-01

A common clinical finding is that many schoolchildren display a nonacceptable oral hygiene. To evaluate the tooth-brushing behaviour in children aged 6-12 years. The study used a cross-sectional descriptive design. Children aged 6, 8, 10, and 12 years in an elementary school in a middle class area in Umeå, a city in northern Sweden, were invited and 82 (82%) consented. Visible plaque on buccal surfaces of incisors and canines was recorded from photographs of the participant's teeth before and after brushing using the scores of the Green and Vermillion Oral Hygiene Index. Brushing technique was recorded with a video camera. A questionnaire was used to collect data about oral hygiene habits at home. The ratio between the sum of plaque scores after and before brushing was statistically significantly higher in the 6-year-old group compared with the 10-year olds, (P < 0.05). There was a negative correlation between time spent for brushing and the ratio between the sum of plaque scores after and before brushing (r = -0.31, P < 0.01). The lowest correlation was displayed in the youngest age group (r = 0.07, P > 0.05). Six-year olds spent statistically significantly less time for brushing than older children (P < 0.05). Plaque removal from buccal surfaces from brushing was poor and averaged 19% for 6-year olds and 30% for older children. The results of brushing for children aged 8-12 years could benefit from increasing tooth-brushing time. Children could be given an increasing responsibility from 7 to 8 year of age but parental help is motivated up to 10 years of age. © 2010 The Authors. International Journal of Paediatric Dentistry © 2010 BSPD, IAPD and Blackwell Publishing Ltd.

A comparative evaluation of the in vitro penetration performance of the improved Crest complete toothbrush versus the Current Crest complete toothbrush, the Colgate Precision toothbrush and the Oral-B P40 toothbrush.

PubMed

Volpenhein, D W; Handel, S E; Hughes, T J; Wild, J

1996-01-01

Removal of plaque and debris from interproximal surfaces during toothbrushing has generally been difficult to achieve, in large part because traditional flat-bristled toothbrushes do not offer good interproximal penetration. As a result, a number of varying bristle designs have been developed, with the rippled-design brush shown to be particularly effective at removing interproximal plaque. Recently, an existing brush, the original Crest Complete, was modified to offer a more deeply rippled version. This study evaluated the interproximal penetration of four bristle designs: rippled pattern (original Crest Complete), deeper rippled pattern (improved Crest Complete), multi-level (Colgate Precision), and flat-tufted (Oral-B P40). The study used a previously reported in vitro model for determining interproximal penetration of manual toothbrushes (J Clin Dent 5:27-33, 1994). In order to effectively mimic the in-use characteristics of toothbrushing, this model is based on analysis of videotaped consumer brushing habits, tooth morphology, and in vivo plaque tenacity characteristics and uses the three most predominantly used brushing techniques (circular, up-and-down, and back-and-forth, with the brush held at both 45 and 90 degrees to the tooth surface). In addition, the model's brush stroke length, brush force, and brush speed are likewise based on analysis of consumer brushing patterns. The results of the study indicate that the new Crest Complete with deeper rippled bristles provided significantly superior (p < or = 0.05) interproximal penetration than the Colgate Precision and Oral-B brushes overall and for three of the four brush strokes tested. In addition, the new Crest Complete was found to provide significantly superior interproximal penetration to the original Crest Complete overall and in circular and up-and-down strokes, and the original Crest Complete provided superior overall interproximal penetration to the Colgate and Oral-B brushes.

A hybrid floating brush seal (HFBS) for improved sealing and wear performance in turbomachinery applications

NASA Astrophysics Data System (ADS)

Lattime, Scott Byran

A conceptually new type of seal has been developed for gas turbine applications which dramatically reduces wear and leakage associated with current labyrinth and brush seal technologies. The Hybrid Floating Brush Seal (HFBS) combines brush seal and film riding face seal technologies to create a hybrid seal that allows both axial and radial excursions of the sealed shaft, while simultaneously eliminating interface surface speeds (friction and heat) between the rotor and the brush material that characterize standard brush seal technology. A simple test rig was designed to evaluate feasibility of the HFBS under relatively low pressures and rotational speeds (50psig, 5krpm). A second test stand was created to study the effects of centrifugal force on bristle deflection. A third test facility was constructed for prototype development and extensive room temperature testing at moderate pressures and fairly high rotational speeds (100psig, 40krpm). This test rig also allowed the evaluation of the HFBS during axial movement of a rotating shaft. An analytical model to predict the effects of centrifugal force on the bristles of a rotating brush seal was developed. Room temperature analysis of the HFBS proved successful for relatively high operating rotational velocities at moderate pressures with very acceptable leakage rates for gas turbine engines. Brush seals were able to track rotor speeds up to 24krpm while maintaining sealing integrity. The HFBS's ability to function under axial shaft displacement and synchronous dynamic radial loading was also proven successful. Hydrodynamic performance of the face seal was proven to provide adequate stiffness and load carrying capacity to keep the brush seal from contacting the face seal at pressure drops across the brush of up to 100psi. Leakage performance over standard brush seal and labyrinth technology was quite dramatic. The HFBS showed its sealing advantage using much higher radial interference between the rotor and the bristle bore over standard brush seal designs. Experimental results of the HFBS showed leakage reductions of 6 to 7 times that of a standard brush seal at the same operating pressure ratios and rotational speed and an order of magnitude less than numerical predictions of a standard labyrinth seal. (Abstract shortened by UMI.)

Comparison between observed children's tooth brushing habits and those reported by mothers.

PubMed

Martins, Carolina C; Oliveira, Maria J; Pordeus, Isabela A; Paiva, Saul M

2011-09-03

Information bias can occur in epidemiological studies and compromise scientific outcomes, especially when evaluating information given by a patient regarding their own health. The oral habits of children reported by their mothers are commonly used to evaluate tooth brushing practices and to estimate fluoride intake by children. The aim of the present study was to compare observed tooth-brushing habits of young children using fluoridated toothpaste with those reported by mothers. A sample of 201 mothers and their children (aged 24-48 months) from Montes Claros, Brazil, took part in a cross-sectional study. At day-care centres, the mothers answered a self-administered questionnaire on their child's tooth-brushing habits. The structured questionnaire had six items with two to three possible answers. An appointment was then made with each mother/child pair at day-care centres. The participants were asked to demonstrate the tooth-brushing practice as usually performed at home. A trained examiner observed and documented the procedure. Observed tooth brushing and that reported by mothers were compared for overall agreement using Cohen's Kappa coefficient and the McNemar test. Cohen's Kappa values comparing mothers' reports and tooth brushing observed by the examiner ranged from poor-to-good (0.00-0.75). There were statistically significant differences between observed tooth brushing habits and those reported by mothers (p < 0.001). When observed by the examiner, the frequencies of dentifrice dispersed on all bristles (35.9%), children who brushed their teeth alone (33.8%) and those who did not rinse their mouths during brushing (42.0%) were higher than those reported by the mothers (12.1%, 18.9% and 6.5%, respectively; p < 0.001). In general, there was low agreement between observed tooth brushing and mothers' reports. Moreover, the different methods of estimation resulted in differences in the frequencies of tooth brushing habits, indicative of reporting bias. Data regarding children's tooth-brushing habits as reported by mothers should be considered with caution in epidemiological surveys on fluoridated dentifrice use and the risk of dental fluorosis.

Comparison between observed children's tooth brushing habits and those reported by mothers

PubMed Central

2011-01-01

Background Information bias can occur in epidemiological studies and compromise scientific outcomes, especially when evaluating information given by a patient regarding their own health. The oral habits of children reported by their mothers are commonly used to evaluate tooth brushing practices and to estimate fluoride intake by children. The aim of the present study was to compare observed tooth-brushing habits of young children using fluoridated toothpaste with those reported by mothers. Methods A sample of 201 mothers and their children (aged 24-48 months) from Montes Claros, Brazil, took part in a cross-sectional study. At day-care centres, the mothers answered a self-administered questionnaire on their child's tooth-brushing habits. The structured questionnaire had six items with two to three possible answers. An appointment was then made with each mother/child pair at day-care centres. The participants were asked to demonstrate the tooth-brushing practice as usually performed at home. A trained examiner observed and documented the procedure. Observed tooth brushing and that reported by mothers were compared for overall agreement using Cohen's Kappa coefficient and the McNemar test. Results Cohen's Kappa values comparing mothers' reports and tooth brushing observed by the examiner ranged from poor-to-good (0.00-0.75). There were statistically significant differences between observed tooth brushing habits and those reported by mothers (p < 0.001). When observed by the examiner, the frequencies of dentifrice dispersed on all bristles (35.9%), children who brushed their teeth alone (33.8%) and those who did not rinse their mouths during brushing (42.0%) were higher than those reported by the mothers (12.1%, 18.9% and 6.5%, respectively; p < 0.001). Conclusions In general, there was low agreement between observed tooth brushing and mothers' reports. Moreover, the different methods of estimation resulted in differences in the frequencies of tooth brushing habits, indicative of reporting bias. Data regarding children's tooth-brushing habits as reported by mothers should be considered with caution in epidemiological surveys on fluoridated dentifrice use and the risk of dental fluorosis. PMID:21888664

46 CFR 108.187 - Ventilation for brush type electric motors in classified spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation for brush type electric motors in classified... Ventilation for brush type electric motors in classified spaces. Ventilation for brush type electric motors in classified locations must meet N.F.P.A. 496-1974 “Standard for Purged and Pressurized Enclosures for...

Turbine with radial acting seal

DOEpatents

Eng, Darryl S; Ebert, Todd A

2016-11-22

A floating brush seal in a rim cavity of a turbine in a gas turbine engine, where the floating brush seal includes a seal holder in which the floating brush seal floats, and a expandable seal that fits within two radial extending seal slots that maintains a seal with radial displacement of the floating brush seal and the seal holder.

Brush seals for turbine engine fuel conservation

NASA Astrophysics Data System (ADS)

Sousa, Mike

1994-07-01

The program objective is to demonstrate brush seals for replacing labyrinth seals in turboprop engines. The approach taken was to design and procure brush seals with assistance from Sealol, modify and instrument an existing T407 low pressure turbine test rig, replace inner balance piston and outer balance piston labyrinth seals with brush seals, conduct cyclic tests to evaluate seal leakage at operating pressures and temperatures, and evaluate effect of seal pack width and rotor eccentricity. Results are presented in viewgraph format and show that brush seals offer performance advantages over labyrinth seals.

Nanopatterned polymer brushes: conformation, fabrication and applications.

PubMed

Yu, Qian; Ista, Linnea K; Gu, Renpeng; Zauscher, Stefan; López, Gabriel P

2016-01-14

Surfaces with end-grafted, nanopatterned polymer brushes that exhibit well-defined feature dimensions and controlled chemical and physical properties provide versatile platforms not only for investigation of nanoscale phenomena at biointerfaces, but also for the development of advanced devices relevant to biotechnology and electronics applications. In this review, we first give a brief introduction of scaling behavior of nanopatterned polymer brushes and then summarize recent progress in fabrication and application of nanopatterned polymer brushes. Specifically, we highlight applications of nanopatterned stimuli-responsive polymer brushes in the areas of biomedicine and biotechnology.

Nanopatterned polymer brushes: conformation, fabrication and applications

NASA Astrophysics Data System (ADS)

Yu, Qian; Ista, Linnea K.; Gu, Renpeng; Zauscher, Stefan; López, Gabriel P.

2015-12-01

Surfaces with end-grafted, nanopatterned polymer brushes that exhibit well-defined feature dimensions and controlled chemical and physical properties provide versatile platforms not only for investigation of nanoscale phenomena at biointerfaces, but also for the development of advanced devices relevant to biotechnology and electronics applications. In this review, we first give a brief introduction of scaling behavior of nanopatterned polymer brushes and then summarize recent progress in fabrication and application of nanopatterned polymer brushes. Specifically, we highlight applications of nanopatterned stimuli-responsive polymer brushes in the areas of biomedicine and biotechnology.

Method for making a high current fiber brush collector

NASA Astrophysics Data System (ADS)

Scuro, S. J.

1986-05-01

An axial-type homopolar motor having high density, high current fiber brush collectors affording efficient, low contact resistance and low operating temperatures is discussed. The collectors include a ring of concentric row of brushes in equally spaced beveled holes soldered in place using a fixture for heating the ring to just below the solder melting point at a soldering iron for the local application of additional heat at each brush. Prior to soldering, an oxide film is formed on the surfaces of the brushes and ring, and the bevels are burnished to form a wetting surface. Flux applied with the solder at each bevel removes to an effective soldering depth the oxide film on the brushes and the holes.

Frequency of tooth brushing and associated factors in Mexican schoolchildren six to nine years of age.

PubMed

Casanova-Rosado, J F; Vallejos-Sánchez, A A; Minaya-Sánchez, M; Medina-Solís, C E; De La Rosa-Santillana, R; Márquez-Corona, M de L; Maupomé, G

2013-01-01

To determine the prevalence of daily tooth brushing and evaluate some variables associated. A cross-sectional study was carried out in 320 schoolchildren six to nine years old in Campeche, Mexico. Information on sociodemographic and socio-economic variables, oral hygiene practices and attitudes were collected through a questionnaire. The frequency of tooth brushing was categorized as "0" = fewer than seven times/week, "1" = at least once a day. In the analysis, nonparametric tests were used. Mean age was 6.99 +/- 1.00 years, 52.5% were boys. The prevalence of daily tooth brushing was 81.6%. In bivariate analysis, the prevalence of tooth brushing was higher (p < 0.05) among the children of mothers with higher schooling (9.80 years vs 8.47 years, p < 0.05), and in younger children (84.6% in 6-7-year olds vs 71.2% in 8-9-year olds, p < 0.05). A slight, non-significant association (p < 0.10) was noted between the current frequency of tooth brushing and an earlier age when the child first started brushing with toothpaste. There were no statistically significant differences (p > 0.05) in the frequency of tooth brushing by gender or by the mother's attitude toward the oral health of her child. The prevalence of daily tooth brushing was high compared to other studies. Mother's maximum level of schooling (as an indicator of socio-economic position) was associated with higher frequency of tooth brushing. Maternal characteristics are associated with the oral health behaviour of their children.

Parental Attitudes and Tooth Brushing Habits in Preschool Children in Mangalore, Karnataka: A Cross-sectional Study.

PubMed

Pullishery, Fawaz; Shenoy Panchmal, Ganesh; Shenoy, Rekha

2013-09-01

Adoption of consistent behavioral habits in childhood takes place at home, with the parents especially the mother, being the primary model for behavior. Tooth brushing habits which is learnt during early years of life, is deeply ingrained in the child's mind and it is expected that this leads to an adaptation of good oral hygiene in their later life. To assess the tooth brushing habits of preschool children and to determine the role and amount of supervision given to them by parents. A pretested self-designed questionnaire was used to collect information from parents of 130 preschool children in Anganwadi and Kindergarten in Mangalore. Statistical analysis was done and Chi-square test was used. Tooth brushing habits in these children was started at a mean age of 22.4 months (SD 8.4).62% of the preschool children used toothbrush and toothpaste for cleaning teeth and brushing habits were mainly (84%) introduced by mothers. Seventy-one percent of the children were cooperative when they were introduced to tooth brushing. Preschool children of Mangalore were introduced to tooth brushing at a mean age of 22.4 months. Mothers played a vital role in introducing and teaching the child how to brush. In children less than 10 months of age tooth brushing was not started at all. How to cite this article: Pullishery F, Panchmal GS, Shenoy R. Parental Attitudes and Tooth Brushing Habits in Preschool Children in Mangalore, Karnataka: A Cross-sectional Study. Int J Clin Pediatr Dent 2013;6(3):156-160.

Parental Attitudes and Tooth Brushing Habits in Preschool Children in Mangalore, Karnataka: A Cross-sectional Study

PubMed Central

Shenoy Panchmal, Ganesh; Shenoy, Rekha

2013-01-01

ABSTRACT Background: Adoption of consistent behavioral habits in childhood takes place at home, with the parents especially the mother, being the primary model for behavior. Tooth brushing habits which is learnt during early years of life, is deeply ingrained in the child's mind and it is expected that this leads to an adaptation of good oral hygiene in their later life. Objectives: To assess the tooth brushing habits of preschool children and to determine the role and amount of supervision given to them by parents. Study design: A pretested self-designed questionnaire was used to collect information from parents of 130 preschool children in Anganwadi and Kindergarten in Mangalore. Statistical analysis was done and Chi-square test was used. Results: Tooth brushing habits in these children was started at a mean age of 22.4 months (SD 8.4).62% of the preschool children used toothbrush and toothpaste for cleaning teeth and brushing habits were mainly (84%) introduced by mothers. Seventy-one percent of the children were cooperative when they were introduced to tooth brushing. Conclusion: Preschool children of Mangalore were introduced to tooth brushing at a mean age of 22.4 months. Mothers played a vital role in introducing and teaching the child how to brush. In children less than 10 months of age tooth brushing was not started at all. How to cite this article: Pullishery F, Panchmal GS, Shenoy R. Parental Attitudes and Tooth Brushing Habits in Preschool Children in Mangalore, Karnataka: A Cross-sectional Study. Int J Clin Pediatr Dent 2013;6(3):156-160. PMID:25206214

Tribological properties of hydrophilic polymer brushes under wet conditions.

PubMed

Kobayashi, Motoyasu; Takahara, Atsushi

2010-08-01

This article demonstrates a water-lubrication system using high-density hydrophilic polymer brushes consisting of 2,3-dehydroxypropyl methacrylate (DHMA), vinyl alcohol, oligo(ethylene glycol)methyl ether methacrylate, 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTAC), 3-sulfopropyl methacrylate potassium salt (SPMK), and 2-methacryloyloxyethyl phosphorylcholine (MPC) prepared by surface-initiated controlled radical polymerization. Macroscopic frictional properties of brush surfaces were characterized by sliding a glass ball probe in water using a ball-on-plate type tribotester under the load of 0.1-0.49 N at the sliding velocity of 10(-5)-10(-1) m s(-1) at 298 K. A poly(DHMA) brush showed a relatively larger friction coefficient in water, whereas the polyelectrolyte brushes, such as poly(SPMK) and poly(MPC), revealed significantly low friction coefficients below 0.02 in water and in humid air conditions. A drastic reduction in the friction coefficient of polyelectrolyte brushes in aqueous solution was observed at around 10(-3)-10(-2) m s(-1) owing to the hydrodynamic lubrication effect, however, an increase in salt concentration in the aqueous solution led to the increase in the friction coefficients of poly(MTAC) and poly(SPMK) brushes. The poly(SPMK) brush showed a stable and low friction coefficient in water even after sliding over 450 friction cycles, indicating a good wear resistance of the brush film. Copyright 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

Assessment of parental tooth-brushing following instruction with single-headed and triple-headed toothbrushes.

PubMed

Telishevesky, Yoel S; Levin, Liran; Ashkenazi, Malka

2012-01-01

The purpose of this study was to evaluate the effect of toothbrush design on the ability of parents to effectively brush their children's teeth. Parents of children (mean age=5.1±0.75 years old) from 4 kindergarten schools were randomly assigned to receive instruction in brushing their children's teeth using a manual single-headed toothbrush (2 schools) or a triple-headed toothbrush (2 schools). The parents' ability to brush their children's teeth was evaluated according to a novel toothbrush performing skill index (Ashkenazi Index), based on 2 criteria: (1) placement of the toothbrush on each tooth segment to be brushed ("reach"); and (2) completion of enough strokes on each segment ("stay"). One month after instruction, tooth-brushing ability was re-evaluated and plaque index of the children's teeth was assessed. One month after instruction, parents using the triple-headed toothbrush received significantly higher scores on the tooth-brushing performance index (~86%), than did those in the single-headed group (~61%; P=.001). The plaque index was significantly higher in the single-headed group (0.97±0.38) vs the triple-headed group (0.72±0.29; P<.01). The tooth-brushing performance index correlated negatively with the plaque index (P<.01). A triple-headed toothbrush promotes more consistent tooth-brushing by parents than does a single-headed toothbrush.

Chemical control of brush in ponderosa pine forests of central Oregon.

Treesearch

Walter G. Dahms

1961-01-01

The many acres of forest land that are occupied by brush in central Oregon represent a large-scale waste of timber-growing capacity and a major economic loss to the area. Although large brushfields devoid of tree growth present the most spectacular examples of loss, less obvious but equally important brush problems are common in established timber stands. Brush...

Spirit Has Flower Power

NASA Technical Reports Server (NTRS)

2004-01-01

The Mars Exploration Rover Spirit took this image with its hazard-avoidance camera on sol 86 (March 31, 2004), after the rover's rock abrasion tool had brushed for three minutes on each of six locations on the rock named 'Mazatzal' to create a flower-shaped mosaic.

The goal for this operation was to create a brushed area big enough for the miniature thermal emission spectrometer to capture within one of its pixels, which are 11 centimeters (4.3 inches) in diameter at the distance between the rock and the instrument. Because the rock abrasion tool creates individual brushed areas only about 5 centimeters (2 inches) in diameter, the team designed this six-location series of tool placements in order to brush 92 percent to 95 percent of the spectrometer's pixel size.

This operation was only the second time the rock abrasion tool has created a brushing mosaic. The first time was a three-spot brushing on the rock called 'Humphrey.' The brush was originally designed to be used as an aide during full grinding operations, however it has been very effective in brushing the top layer off of dusty martian rocks to allow scientists a multi-depth look into the rocks on Mars.

Regression modeling and prediction of road sweeping brush load characteristics from finite element analysis and experimental results.

PubMed

Wang, Chong; Sun, Qun; Wahab, Magd Abdel; Zhang, Xingyu; Xu, Limin

2015-09-01

Rotary cup brushes mounted on each side of a road sweeper undertake heavy debris removal tasks but the characteristics have not been well known until recently. A Finite Element (FE) model that can analyze brush deformation and predict brush characteristics have been developed to investigate the sweeping efficiency and to assist the controller design. However, the FE model requires large amount of CPU time to simulate each brush design and operating scenario, which may affect its applications in a real-time system. This study develops a mathematical regression model to summarize the FE modeled results. The complex brush load characteristic curves were statistically analyzed to quantify the effects of cross-section, length, mounting angle, displacement and rotational speed etc. The data were then fitted by a multiple variable regression model using the maximum likelihood method. The fitted results showed good agreement with the FE analysis results and experimental results, suggesting that the mathematical regression model may be directly used in a real-time system to predict characteristics of different brushes under varying operating conditions. The methodology may also be used in the design and optimization of rotary brush tools. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of multivalent counterions to the structure of highly dense polystyrene sulfonate brushes

DOE PAGES

Yu, Jing; Mao, Jun; Yuan, Guangcui; ...

2016-02-23

Surface tethered polyelectrolyte brushes are scientifically interesting and technologically relevant to many applications, ranging from colloidal stabilization to responsive and tunable materials to lubrication. Many applications operate in environments containing multi-valent ions, media in which our scientific understanding is not yet well-developed. In this paper, we synthesized high-density polystyrene sulfonate (PSS) brushes via surface initiated atom-transfer radical polymerization, and performed neutron reflectivity (NR) measurements to investigate and compare the effects of mono-valent Rb + and tri-valent Y 3+ counterions to the structure of the densely tethered PSS brushes. Our NR results show that in mono-valent RbNO 3 solution, the densemore » PSS brush retained its full thickness up to a salt concentration of 1 M, whereas it immediately collapsed upon adding 1.67 mM of tri-valent Y 3+. Increasing the concentration of Y 3+ beyond this level did not lead to any significant further structure change of the PSS brush. Finally, our findings demonstrate that the presence of multi-valent counterions can significantly alter the structure of polyelectrolyte brushes, in a manner different from mono-valent ions, which has implications for the functionality of the brushes.« less

Design optimization of a brush turbine with a cleaner/water based solution

NASA Technical Reports Server (NTRS)

Kim, Rhyn H.

1994-01-01

Recently, a fluid turbine which has a brush attached to it has been designed and tested with water as fluid. The purpose of the turbine-brush is to clean up fouling in a tube. The Montreal Protocol prohibits the use of CFC products from refrigeration industry or from industry in general as a cleanser in 1996. Alternatives for the cleansers, devices or a combination of alternative devices with a cleanser should be found. One of the methods is to develop a device which cleans fouling with a cleaning medium. In this paper, we describe a turbine connected with a brush. However, the turbine with the brush should be simple and easy to install. This device is a combined small liquid turbine with a brush. The turbine is activated by the liquid flowing through the tube. Then the turbine turns the brush cleaning fouling along the tube. Based on the energy conservation and the Bernoulli equation along with an empirical relationship of drag force obtained from an experimental apparatus, a relationship of the rotational speed, the number of blades, and geometric variables of the turbine-brush was obtained. The predicted rotational speeds were compared with the experimental observations. Further work was recommended for improvements.

Stimuli Responsive Morphological Changes of Pnipa Polymer Brushes Synthesized on Silicon Substrate

NASA Astrophysics Data System (ADS)

Huda, Muhammad Nurul; Kabir, A. N. M. Hamidul

2013-08-01

High-density polymer brushes were grown from the silicon surface by atom transfer radical polymerization of Poly(N-isopropylacrylamide) (PNIPA) at different polymerization conditions. PNIPA brushes were prepared using Copper (I) Chloride/tris(2-(dimetylamino)ethyl)amine (Me6TREN) as a catalytic system in DMSO at 20°C. Free polymer formed during the brush formation was characterized by gel permeation chromatography. The grafting densities up to 0.52 chains/nm2 were obtained. The layer thickness of polymer brush increases with the increase of conversion of the monomer conversion as well as polymerization time. Atomic force microscopy and air bubble contact angle under pH solution were employed to study the surface morphology, reversible conformational changes of and stimulus-response behavior. PNIPA brushes exhibited a different nanomorphology after treatment with different pH solution. It also revealed a unique reversible wetting behavior with pH. The reversible properties of the PNIPA brushes can be used to regulate the adsorption of the sulfonated PS nanoparticles.

Grafting density effects, optoelectrical properties and nano-patterning of poly(para-phenylene) brushes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jihua; Alonzo, Jose; Yu, Xiang

2013-09-24

Well-defined conjugated polymers in confined geometries are challenging to synthesize and characterize, yet they are potentially useful in a broad range of organic optoelectronic devices such as transistors, light emitting diodes, solar cells, sensors, and nanocircuits. We report a systematic study of optoelectrical properties, grafting density effects, and nanopatterning of a model, end-tethered conjugated polymer system. Specifically, poly(para-phenylene) (PPP) brushes of various grafting density are created in situ by aromatizing well-defined, end-tethered poly(1,3-cyclohexadiene) (PCHD) “precursor brushes”. Furthermore, this novel precursor brush approach provides a convenient way to make and systematically control the grafting density of high molecular weight conjugated polymermore » brushes that would otherwise be insoluble. Finally, this allows us to examine how grafting density impacts the effective conjugation length of the conjugated PPP brushes and to adapt the fabrication method to develop spatially patterned conjugated brush systems, which is important for practical applications of conjugated polymer brushes.« less

The effect of brushing with nano calcium carbonate and calcium carbonate toothpaste on the surface roughness of nano-ionomer

NASA Astrophysics Data System (ADS)

Anisja, D. H.; Indrani, D. J.; Herda, E.

2017-08-01

Nanotechnology developments in dentistry have resulted in the development of nano-ionomer, a new restorative material. The surface roughness of restorative materials can increase bacteria adhesion and lead to poor oral hygiene. Abrasive agents in toothpaste can alter tooth and restorative material surfaces. The aim of this study is to identify the effect of brushing with nano calcium carbonate, and calcium carbonate toothpaste on surface roughness of nano-ionomer. Eighteen nano-ionomer specimens were brushed with Aquabidest (doubledistilled water), nano calcium carbonate and calcium carbonate toothpaste. Brushing lasted 30 minutes, and the roughness value (Ra) was measured after each 10 minute segment using a surface roughness tester. The data was analyzed using repeated ANOVA and one-way ANOVA test. The value of nano-ionomer surface roughness increased significantly (p<0.05) after 20 minutes of brushing with the nano calcium carbonate toothpaste. Brushing with calcium carbonate toothpaste leaves nano-ionomer surfaces more rugged than brushing with nano calcium carbonate toothpaste.

Drilling Deeper into tooth brushing skills: Is proactive interference an under-recognized factor in oral hygiene behavior change?

PubMed

Thavarajah, Rooban; Kumar, Madan; Mohandoss, Anusa Arunachalam; Vernon, Lance T

2015-09-01

Proper tooth brushing is a seemingly simple motor activity that can promote oral health. Applying health theories, such as the Information-Motivation-Behavioral Skills (IMB) model, Motivational Interviewing (MI) and Integrated Health Coaching (IHC), may help optimize tooth brushing technique in those with suboptimal skills. Some motor activities, including tooth brushing, may over time become rote and unconscious actions, such that an existing habit can inhibit new learning, i.e., exert proactive interference on learning the new skill. Proactive interference may impede the acquisition of new tooth brushing skills; thus, in this report, we: (1) Review how the habit of tooth brushing is formed; (2) Postulate how proactive interference could impede the establishment of proper tooth brushing retraining; (3) Discuss the merits of this hypothesis; and (4) Provide guidance for future work in this topic within the context of an approach to behavior change that integrates IMB, MI and IHC methodology.

Drilling Deeper into tooth brushing skills: Is proactive interference an under-recognized factor in oral hygiene behavior change?

PubMed Central

Thavarajah, Rooban; Kumar, Madan; Mohandoss, Anusa Arunachalam

2015-01-01

Proper tooth brushing is a seemingly simple motor activity that can promote oral health. Applying health theories, such as the Information-Motivation-Behavioral Skills (IMB) model, Motivational Interviewing (MI) and Integrated Health Coaching (IHC), may help optimize tooth brushing technique in those with suboptimal skills. Some motor activities, including tooth brushing, may over time become rote and unconscious actions, such that an existing habit can inhibit new learning, i.e., exert proactive interference on learning the new skill. Proactive interference may impede the acquisition of new tooth brushing skills; thus, in this report, we: (1) Review how the habit of tooth brushing is formed; (2) Postulate how proactive interference could impede the establishment of proper tooth brushing retraining; (3) Discuss the merits of this hypothesis; and (4) Provide guidance for future work in this topic within the context of an approach to behavior change that integrates IMB, MI and IHC methodology. PMID:26457238

The Art and Science of Polymer Brushes: Recent Developments in Patterning and Characterization Approaches.

PubMed

Panzarasa, Guido

2017-06-28

Polymer brushes are dense arrays of macromolecular chains tethered by one end at a surface. They are at the cutting edge of polymer nanotechnology since the dawn of controlled surface-initiated polymerization techniques unlocked new prospects for the synthesis of polymer brushes with tailorable properties. More recently, thanks to the growing interest in the use of brushes for the generation of functional surfaces, the need for advanced patterning and characterization approaches rapidly increased. Meeting these needs requires the contribution of experts from different disciplines: polymer chemistry, surface science, electrochemistry and particle physics. The focus of this review is to highlight recent developments in the field of polymer brushes, specifically the application of photocatalytic lithography as a versatile patterning strategy, the study of grafted-from polymer brushes by electrochemical methods and, most importantly, the introduction of positron annihilation spectroscopy as a powerful technique for the investigation of the structure of polymer brushes and of their composites with nanoparticles.

Friction, wear, and noise of slip ring and brush contacts for synchronous satellite use.

NASA Technical Reports Server (NTRS)

Lewis, N. E.; Cole, S. R.; Glossbrenner, E. W.; Vest, C. E.

1973-01-01

A program is being conducted for testing of slip rings for synchronous orbit application. Instrumentation systems necessary for monitoring electrical noise, friction, and brush wear at atmospheric pressure and at less than 50 nanotorr have been developed. A multiplex scheme necessary for the simultaneous recording of brush displacement, friction, and electrical noise has also been developed. Composite brushes consisting of silver-molybdenum disulfide-graphite and silver-niobium diselenide-graphite have been employed on rings of coin silver and rhodium plate. Brush property measurements made included measurement of density, electrical resistivity, shear strength, and microstructure.

[Daily living activities and oral condition among care facility residents with severe intellectual disabilities. Comparative analyses between residents receiving tooth-brushing assistance and those not receiving tooth-brushing assistance].

PubMed

Chiwata, Kaoru; Takeda, Fumi

2007-06-01

To clarify 1) differences in daily living activities and oral condition among care facility residents with severe intellectual disabilities and 2) chronological changes in daily living activities and oral condition for residents receiving tooth-brushing assistance and those never receiving tooth-brushing assistance. Subjects were 44 residents at a care facility for individuals with severe intellectual disabilities, who underwent dental screening in July 1994 and October 2003. At each time point, daily living activities, behavior during oral health guidance, behavior during dental health screening and oral condition were compared between residents receiving tooth-brushing assistance (assistance group) and those not receiving tooth-brushing assistance (independent group). Furthermore, chronological changes were analyzed for residents requiring assistance at both screenings, those requiring assistance only at the second screening, and those not requiring assistance at either screening. 1) In the assistance group, 100% and 36.4% of residents were unable to brush their teeth independently in 1994 and 2003, respectively. Significant differences between the assistance and independent groups were observed in all items of behavior during dental health screening in 1994, but not in 2003. No significant intergroup differences in oral condition were observed in 1994, but differences were seen in 2003; when compared to the assistance group, the number of lost teeth was significantly higher in the independent group, while the number of remaining teeth was lower. 2) Regarding changes over the nine-year period, a significantly greater proportion of residents not requiring assistance at either screening and those requiring assistance only at the second screening finally required assistance in bathing. As for oral condition, no significant changes in healthy teeth were observed in residents requiring assistance at both screening time points, while significant increases in dental caries and filled teeth and a significant decrease in the number of healthy teeth were observed in residents requiring assistance only at the second screening and those not requiring assistance at either screening. Over the nine-year period, the subjects of tooth-brushing assistance changed, and assistance was given to those able to brush their teeth independently in addition to those unable to brush their teeth independently. The number of healthy teeth did not change in residents receiving tooth-brushing assistance during this period, but in residents never receiving tooth-brushing assistance, decrease was noted. Therefore, even for individuals able to brush their teeth independently, some form of tooth-brushing assistance is needed to sufficiently prevent oral diseases.

Effects of whitening dentifrice on yttria-stabilized tetragonal zirconia polycrystal surfaces after simulating brushing.

PubMed

Pinelli, Lígia Antunes Pereira; Gimenes Olbera, Amanda Caroline; Candido, Lucas Miguel; Miotto, Larissa Natiele; Antonio, Selma Gutierrez; Fais, Laiza Maria Grassi

2017-01-01

The changes that occur after brushing yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) are unknown. These changes may favor the retention of microorganisms and chemisorption of water, impairing its longevity. The purpose of this in vitro study was to evaluate the effects of a whitening dentifrice on Y-TZP surfaces after simulating 10 years of brushing. Seventy-two bar-shaped specimens (20×4×1.2 mm) were divided into 4 groups: storage in distilled water (SW, control), brushing with distilled water (BW), brushing with dentifrice (BD), and brushing with whitening dentifrice (BWD). Brushing was conducted using a linear brushing machine (878400 cycles, 0.98 N, soft toothbrush). The mean roughness (Ra) was analyzed with a profilometer and the superficial topography with scanning electron microscopy (SEM) at baseline and after treatment. Crystalline phases were characterized using x-ray diffraction. Baseline and posttreatment Ra were analyzed using the 1-way ANOVA and Tukey HSD multiple comparison test; the paired t test was used for intragroup comparison (all α=.05). The Ra (μm) means (before/after treatment) were SW 0.28/0.28; BW 0.32/0.31; BD 0.28/0.36; BWD 0.30/0.20. No statistically significant difference was found for Ra at baseline (P=.108) than for posttreatment results (P<.001); the BD group had higher Ra values when compared with baseline (P=.019); the BWD group had the lowest values (P<.001). The BD surfaces showed pronounced scratches and detachment of the surface, while BWD showed smoother surfaces; similar crystallographic results among groups were observed. Brushing Y-TZP with conventional dentifrice increased roughness, while brushing with whitening dentifrice reduced roughness. Neither dentifrice changed the crystallographic phases after brushing. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Gingival abrasion and recession in manual and oscillating-rotating power brush users.

PubMed

Rosema, N A M; Adam, R; Grender, J M; Van der Sluijs, E; Supranoto, S C; Van der Weijden, G A

2014-11-01

To assess gingival recession (GR) in manual and power toothbrush users and evaluate the relationship between GR and gingival abrasion scores (GA). This was an observational (cross-sectional), single-centre, examiner-blind study involving a single-brushing exercise, with 181 young adult participants: 90 manual brush users and 91 oscillating-rotating power brush users. Participants were assessed for GR and GA as primary response variables. Secondary response variables were the level of gingival inflammation, plaque score reduction and brushing duration. Pearson correlation was used to describe the relationship between number of recession sites and number of abrasions. Prebrushing (baseline) and post-brushing GA and plaque scores were assessed and differences analysed using paired tests. Two-sample t-test was used to analyse group differences; ancova was used for analyses of post-brushing changes with baseline as covariate. Overall, 97.8% of the study population had at least one site of ≥1 mm of gingival recession. For the manual group, this percentage was 98.9%, and for the power group, this percentage was 96.7% (P = 0.621). Post-brushing, the power group showed a significantly smaller GA increase than the manual group (P = 0.004); however, there was no significant correlation between number of recession sites and number of abrasions for either group (P ≥ 0.327). Little gingival recession was observed in either toothbrush user group; the observed GR levels were comparable. Lower post-brushing gingival abrasion levels were seen in the power group. There was no correlation between gingival abrasion as a result of brushing and the observed gingival recession following use of either toothbrush. © 2014 The Authors International Journal of Dental Hygiene Published by John Wiley & Sons Ltd.

Synergy of brushing mode and antibacterial use on in vivo biofilm formation.

PubMed

Jongsma, Marije A; van de Lagemaat, Marieke; Busscher, Henk J; Geertsema-Doornbusch, Gesinda I; Atema-Smit, Jelly; van der Mei, Henny C; Ren, Yijin

2015-12-01

Orthodontic, multi-strand retention-wires are used as a generalized model for oral retention sites to investigate whether biofilm left-behind after powered toothbrushing in-vivo enabled better penetration of antibacterials as compared with manual brushing. 2-cm multi-strand, stainless-steel retention-wires were placed in brackets bonded bilaterally in the upper arches of 10-volunteers. Volunteers used NaF-sodium-lauryl-sulphate-containing toothpaste and antibacterial, triclosan-containing toothpaste supplemented or not with an essential-oils containing mouthrinse. Opposite sides of the dentition including the retention-wires, were brushed manually or with a powered toothbrush. Health-care-regimens were maintained for 1-week, after which wires were removed and oral biofilm was collected. When powered toothbrushing was applied, slightly less bacteria were collected than after manual brushing, regardless whether an antibacterial-regimen was used or not. Powered-toothbrushing combined with antibacterial-regimens yielded lower biofilm viability than manual brushing, indicating better antibacterial penetration into biofilm left-behind after powered brushing. Major shifts in biofilm composition, with a decrease in prevalence of both cariogenic species and periodontopathogens, were induced after powered brushing using an antibacterial-regimen. Oral biofilm left-behind after powered brushing in-vivo enabled better penetration of antibacterials than after manual brushing. Mechanical removal of oral biofilm is important for prevention of dental pathologies, but biofilm is always left-behind, such as in fissures, buccal pits, interproximal areas and gingival margins and around orthodontic appliances. Use of antibacterial toothpastes or mouthrinses can contribute to removal or killing of biofilm bacteria, but biofilm structure hampers antibacterial penetration. A synergy between brushing mode and antibacterial-regimen applied exists with clinically demonstrable effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

Compression induced phase transition of nematic brush: A mean-field theory study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Jiuzhou; Zhang, Xinghua, E-mail: zhangxh@bjtu.edu.cn; Yan, Dadong, E-mail: yandd@bnu.edu.cn

2015-11-28

Responsive behavior of polymer brush to the external compression is one of the most important characters for its application. For the flexible polymer brush, in the case of low grafting density, which is widely studied by the Gaussian chain model based theory, the compression leads to a uniform deformation of the chain. However, in the case of high grafting density, the brush becomes anisotropic and the nematic phase will be formed. The normal compression tends to destroy the nematic order, which leads to a complex responsive behaviors. Under weak compression, chains in the nematic brush are buckled, and the bendingmore » energy and Onsager interaction give rise to the elasticity. Under deep compression, the responsive behaviors of the nematic polymer brush depend on the chain rigidity. For the compressed rigid polymer brush, the chains incline to re-orientate randomly to maximize the orientational entropy and its nematic order is destroyed. For the compressed flexible polymer brush, the chains incline to fold back to keep the nematic order. A buckling-folding transition takes place during the compressing process. For the compressed semiflexible brush, the chains are collectively tilted to a certain direction, which leads to the breaking of the rotational symmetry in the lateral plane. These responsive behaviors of nematic brush relate to the properties of highly frustrated worm-like chain, which is hard to be studied by the traditional self-consistent field theory due to the difficulty to solve the modified diffusion equation. To overcome this difficulty, a single chain in mean-field theory incorporating Monte Carlo simulation and mean-field theory for the worm-like chain model is developed in present work. This method shows high performance for entire region of chain rigidity in the confined condition.« less

Gingival abrasion and recession in manual and oscillating–rotating power brush users

PubMed Central

Rosema, NAM; Adam, R; Grender, JM; Van der Sluijs, E; Supranoto, SC; Van der Weijden, GA

2014-01-01

Objective To assess gingival recession (GR) in manual and power toothbrush users and evaluate the relationship between GR and gingival abrasion scores (GA). Methods This was an observational (cross-sectional), single-centre, examiner-blind study involving a single-brushing exercise, with 181 young adult participants: 90 manual brush users and 91 oscillating–rotating power brush users. Participants were assessed for GR and GA as primary response variables. Secondary response variables were the level of gingival inflammation, plaque score reduction and brushing duration. Pearson correlation was used to describe the relationship between number of recession sites and number of abrasions. Prebrushing (baseline) and post-brushing GA and plaque scores were assessed and differences analysed using paired tests. Two-sample t-test was used to analyse group differences; ancova was used for analyses of post-brushing changes with baseline as covariate. Results Overall, 97.8% of the study population had at least one site of ≥1 mm of gingival recession. For the manual group, this percentage was 98.9%, and for the power group, this percentage was 96.7% (P = 0.621). Post-brushing, the power group showed a significantly smaller GA increase than the manual group (P = 0.004); however, there was no significant correlation between number of recession sites and number of abrasions for either group (P ≥ 0.327). Conclusions Little gingival recession was observed in either toothbrush user group; the observed GR levels were comparable. Lower post-brushing gingival abrasion levels were seen in the power group. There was no correlation between gingival abrasion as a result of brushing and the observed gingival recession following use of either toothbrush. PMID:24871587

The effect of food location, heat load, and intrusive medical procedures on brushing activity in dairy cows.

PubMed

Mandel, R; Whay, H R; Nicol, C J; Klement, E

2013-10-01

Animals allocate time and effort to a range of core (e.g., sleeping, feeding, drinking) and "luxury" (e.g., playing, exploring) activities. A luxury activity is characterized by low resilience and, as such, will be reduced when time or energy resources are limited, including under conditions of stress or discomfort. One seemingly luxurious activity available to cows on an increasing number of dairy farms is rubbing against an automated brush. The current study examined the effect of distance from food, heat load, and an intrusive medical procedure (i.e., artificial insemination and transrectal pregnancy examination) on the resilience of brush usage. The probability of using the brush decreased significantly when food was located distantly from the brush (mean=0.53) compared with days when food was located closer to the brush (mean=0.81). Brush usage also decreased at high temperature and humidity levels, with an average decrease of 0.062 brushing events for an increase of 1 temperature-humidity index unit (95% confidence interval=-0.93-0.030). In addition, a significant reduction of approximately 50% in brushing activity was observed on days of artificial insemination compared with the preceding 3d and the following 3d. These findings show that brush usage is a low resilience activity that reduces under a range of conditions. It may thus have the potential to be used as an indicator of a range of health and welfare problems in cows. Further research should be conducted to assess the sensitivity and specificity of this suggested tool and its possible contribution to the early detection of morbidity. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

A comparative evaluation of the in vitro penetration performance of the improved Crest Complete toothbrush versus the Colgate Total toothbrush and the Oral-B Advantage toothbrush.

PubMed

Volpenhein, D W; Hartman, W L

1996-01-01

Removal of plaque and debris from interproximal surfaces during toothbrushing has generally been difficult to achieve, in large part because traditional flat-bristled toothbrushes do not offer good interproximal penetration. As a result, a number of varying bristle designs have been developed, with the rippled-design brush shown to be particularly effective at removing interproximal plaque. Recently, an existing rippled brush, the original Crest Complete, was modified to offer longer rippled outer tufts to clean along the gumline more effectively. Therefore, this study evaluated the overall and gumline interproximal penetration of three bristle designs: rippled, raised pattern (Improved Crest Complete); and two multi-level patterns (Colgate Total and Oral-B Advantage). The study used a previously reported in vitro model for determining interproximal penetration of manual toothbrushes (J Clin Dent 5:27-33, 1994). In order to effectively mimic the in-use characteristics of toothbrushing, this model is based on analysis of videotaped consumer brushing habits, tooth morphology, and in vivo plaque tenacity characteristics, and uses the three most predominantly used brushing techniques (circular, up-and-down, and back-and-forth with the brush held at both 45 degrees and 90 degrees to the tooth surface). In addition, the model's brush stroke length, brush force, and brush speed are likewise based on an analysis of consumer brushing patterns. The results of this study indicate that the Improved Crest Complete with longer rippled outer bristles provided significantly superior (p < 0.05) interproximal penetration overall and at the gumline than the Colgate Total and Oral-B Advantage brushes.

Factors Affecting Oral Hygiene and Tooth Brushing in Preschool Children, Shiraz/Iran.

PubMed

S, Shaghaghian; M, Zeraatkar

2017-06-01

Inadequate tooth brushing and inappropriate oral hygiene can lead to dental caries, the most common chronic diseases of childhood with several side effects. To evaluate factors affecting on preschool children's oral hygiene and tooth brushing in Shiraz, Iran. In this cross-sectional study, we selected 453 children registered in Shiraz kindergartens in 2013 by randomized cluster sampling. The children's tooth brushing and oral hygiene were assessed using a reliable and valid questionnaire and Simplified Debris Index (DI-S), respectively. A dental student examined all the children in each kindergarten to determine their DI-S. The relationship between the children's demographic variables and their oral hygiene and tooth brushing status were evaluated. Tooth brushing for 272 children (71.2%) had been started after the age of 2 years. The teeth in 96 children (24.2%) had been brushed lower than once daily. The mean of the children's DI-S was 1.19 ± (0.77). The DI-S of only 126 children (31.8%) was found to be good and very good. After controlling the effect of confounding factors, we found that the children's tooth brushing frequency was significantly associated with the number of children in the family and mothers' employment status. The age at which tooth brushing had been started was significantly associated with the fathers' education. Furthermore, the DI-S was associated with children's age, number of the children in the family, and their mothers' education. Oral hygiene and tooth brushing of the preschool children were not in a desirable status. Interventional procedures, especially educational programs, are recommended for children and their parents. These programs seem to be more necessary for older children, low socioeconomic families, and families with more than one child.

Does tooth brushing influence the development and progression of non-inflammatory gingival recession? A systematic review.

PubMed

Rajapakse, P Sunethra; McCracken, Giles I; Gwynnett, Erika; Steen, Nick D; Guentsch, Arndt; Heasman, Peter A

2007-12-01

The aim of this systematic review was to produce the best available evidence and pool appropriate data to evaluate the effect of tooth brushing on the initiation and progression of non-inflammatory gingival recession. A protocol was developed a priori for the question: "Do factors associated with tooth brushing predict the development and progression of non-inflammatory gingival recession in adults?" The search covered six electronic databases between January 1966 and July 2005. Hand searching included searches of the Journal of Clinical Periodontology, Journal of Periodontal Research and the Journal of Periodontology. Bibliographies of narrative reviews, conference proceedings and relevant texts known to the authors were also searched. Inclusion of titles, abstracts and ultimately full texts was based on consensus between three reviewers. The full texts of 29 papers were read and 18 texts were eligible for inclusion. One abstract from EuroPerio 5 reported a randomized-controlled clinical trial [Level I evidence] in which the authors concluded that the toothbrushes significantly reduced recessions on buccal tooth surfaces over 18 months. Of the remaining 17 observational studies, two concluded that there appeared to be no relationship between tooth brushing frequency and gingival recession. Eight studies reported a positive association between tooth brushing frequency and recession. Other potential risk factors were duration of tooth brushing, brushing force, frequency of changing the toothbrush, brush (bristle) hardness and tooth brushing technique. None of the observational studies satisfied all the specified criteria for quality appraisal and a valid appraisal of the quality of the randomized-controlled trial was not possible. The data to support or refute the association between tooth brushing and gingival recession are inconclusive.

Nanostructured bio-functional polymer brushes.

PubMed

Padeste, Celestino; Farquet, Patrick; Potzner, Christian; Solak, Harun H

2006-01-01

Structured poly(glycidyl methracrylate) (poly-GMA) brushes have been grafted onto flexible fluoro-polymer films using a radiation grafting process. The reactive epoxide of poly-GMA provides the basis for a versatile biofunctionalization of the grafted brushes. Structure definition by extreme ultraviolet (EUV) exposure allowed nanometer-scale resolution of periodic patterns. By variation of the exposure dose the height of the grafted structures can be adapted in a wide range. Derivatization of the grafted brushes included reaction with various amines with different side chains, hydrolysis of the epoxide to diols to increase protein resistance and introduction of ionic groups to yield poly-electrolytes. As an example for biofunctionalization, biotin was linked to the grafted brush and biofunctionality was demonstrated in a competitive biotin-streptavidin assay. In this article we also present a brief review of other approaches to obtain structured biofunctional polymer brushes.

Shunt attachment and method for interfacing current collection systems

DOEpatents

Denney, P.E.; Iyer, N.C.; Hannan, W.F. III.

1992-12-08

A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature. 6 figs.

Shunt attachment and method for interfacing current collection systems

DOEpatents

Denney, Paul E.; Iyer, Natraj C.; Hannan, III, William F.

1992-01-01

A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature.

Surface roughness of composite resin veneer after application of herbal and non-herbal toothpaste

NASA Astrophysics Data System (ADS)

Nuraini, S.; Herda, E.; Irawan, B.

2017-08-01

The aim of this study was to find out the surface roughness of composite resin veneer after brushing. In this study, 24 specimens of composite resin veneer are divided into three subgroups: brushed without toothpaste, brushed with non-herbal toothpaste, and brushed with herbal toothpaste. Brushing was performed for one set of 5,000 strokes and continued for a second set of 5,000 strokes. Roughness of composite resin veneer was determined using a Surface Roughness Tester. The results were statistically analyzed using Kruskal-Wallis nonparametric test and Post Hoc Mann-Whitney. The results indicate that the highest difference among the Ra values occurred within the subgroup that was brushed with the herbal toothpaste. In conclusion, the herbal toothpaste produced a rougher surface on composite resin veneer compared to non-herbal toothpaste.

Effect of saliva and blood contamination after etching upon the shear bond strength between composite resin and enamel

NASA Astrophysics Data System (ADS)

Armadi, A. S.; Usman, M.; Suprastiwi, E.

2017-08-01

The aim of this study was to find out the surface roughness of composite resin veneer after brushing. In this study, 24 specimens of composite resin veneer are divided into three subgroups: brushed without toothpaste, brushed with non-herbal toothpaste, and brushed with herbal toothpaste. Brushing was performed for one set of 5,000 strokes and continued for a second set of 5,000 strokes. Roughness of composite resin veneer was determined using a Surface Roughness Tester. The results were statistically analyzed using Kruskal-Wallis nonparametric test and Post Hoc Mann-Whitney. The results indicate that the highest difference among the Ra values occurred within the subgroup that was brushed with the herbal toothpaste. In conclusion, the herbal toothpaste produced a rougher surface on composite resin veneer compared to non-herbal toothpaste.

Friendship Network and Dental Brushing Behavior among Middle School Students: An Agent Based Modeling Approach.

PubMed

Sadeghipour, Maryam; Khoshnevisan, Mohammad Hossein; Jafari, Afshin; Shariatpanahi, Seyed Peyman

2017-01-01

By using a standard questionnaire, the level of dental brushing frequency was assessed among 201 adolescent female middle school students in Tehran. The initial assessment was repeated after 5 months, in order to observe the dynamics in dental health behavior level. Logistic Regression model was used to evaluate the correlation among individuals' dental health behavior in their social network. A significant correlation on dental brushing habits was detected among groups of friends. This correlation was further spread over the network within the 5 months period. Moreover, it was identified that the average brushing level was improved within the 5 months period. Given that there was a significant correlation between social network's nodes' in-degree value, and brushing level, it was suggested that the observed improvement was partially due to more popularity of individuals with better tooth brushing habit. Agent Based Modeling (ABM) was used to demonstrate the dynamics of dental brushing frequency within a sample of friendship network. Two models with static and dynamic assumptions for the network structure were proposed. The model with dynamic network structure successfully described the dynamics of dental health behavior. Based on this model, on average, every 43 weeks a student changes her brushing habit due to learning from her friends. Finally, three training scenarios were tested by these models in order to evaluate their effectiveness. When training more popular students, considerable improvement in total students' brushing frequency was demonstrated by simulation results.

Tooth brushing frequency in Mexican schoolchildren and associated socio-demographic, socioeconomic, and dental variables

PubMed Central

Casanova-Rosado, Alejandro José; Medina-Solís, Carlo Eduardo; Casanova-Rosado, Juan Fernando; Vallejos-Sánchez, Ana Alicia; Minaya-Sánchez, Mirna; Mendoza-Rodríguez, Martha; Márquez-Rodríguez, Sonia; Maupomé, Gerardo

2014-01-01

Background Tooth brushing (with fluoridated toothpaste) is the most cost-effective intervention in dentistry and it is widely recommended to preserve good oral health. We aimed to determine the frequency of tooth brushing and the variables associated with this practice in schoolchildren living in southeast Mexico. Material/Methods A cross-sectional study was carried out in 1644 schoolchildren, 6 to 13 years old. Questionnaires with socio-demographic, socioeconomic, and dental variables were administered to mothers/guardians of children. The dependent variable was the frequency of tooth brushing, which was categorized as 0 = tooth brushing less than once a day and 1 = tooth brushing at least once a day. A logistic regression model was used to evaluate the final results. Results Mean age was 9.06±2.02 years and 49.1% were girls. The prevalence of tooth brushing at least once a day was 49.8%. In the multivariate model, characteristics related to tooth brushing frequency (p<0.05) were: older age (OR=1.11), being female (OR=1.64), having a larger family (OR=0.87), having had a visit to a dentist during the year preceding the study (OR=1.37), and having had fluoride applications by a professional (OR=1.39). Conclusions The results suggested that different variables (demographic, socioeconomic and dental) are associated with the frequency of tooth brushing. Family size (proxy variable for socioeconomic status) may indicate certain oral health inequalities in this population. PMID:24907713

Tooth brushing frequency in Mexican schoolchildren and associated socio-demographic, socioeconomic, and dental variables.

PubMed

Casanova-Rosado, Alejandro José; Medina-Solís, Carlo Eduardo; Casanova-Rosado, Juan Fernando; Vallejos-Sánchez, Ana Alicia; Minaya-Sánchez, Mirna; Mendoza-Rodríguez, Martha; Márquez-Rodríguez, Sonia; Maupomé, Gerardo

2014-06-07

Tooth brushing (with fluoridated toothpaste) is the most cost-effective intervention in dentistry and it is widely recommended to preserve good oral health. We aimed to determine the frequency of tooth brushing and the variables associated with this practice in schoolchildren living in southeast Mexico. A cross-sectional study was carried out in 1644 schoolchildren, 6 to 13 years old. Questionnaires with socio-demographic, socioeconomic, and dental variables were administered to mothers/guardians of children. The dependent variable was the frequency of tooth brushing, which was categorized as 0 = tooth brushing less than once a day and 1 = tooth brushing at least once a day. A logistic regression model was used to evaluate the final results. Mean age was 9.06±2.02 years and 49.1% were girls. The prevalence of tooth brushing at least once a day was 49.8%. In the multivariate model, characteristics related to tooth brushing frequency (p<0.05) were: older age (OR=1.11), being female (OR=1.64), having a larger family (OR=0.87), having had a visit to a dentist during the year preceding the study (OR=1.37), and having had fluoride applications by a professional (OR=1.39). The results suggested that different variables (demographic, socioeconomic and dental) are associated with the frequency of tooth brushing. Family size (proxy variable for socioeconomic status) may indicate certain oral health inequalities in this population.

Design and Testing of High Performance Brushes.

DTIC Science & Technology

1982-03-01

specific types, namely metal fiber brushes and met- al foil brushes, have been constructed and tested, and a theory has been developed which accounts for...combining electric- al measurements with mechanical investigations and optical observations. Since we now have reason to rely confidently on the theory of...reasonable requirements. packing densities between a few % and up to 20%, have been made of various materi- Brushes with gold, platinum, niobium als by the

Polyelectrolyte brushes grafted from cellulose nanocrystals using Cu-mediated surface-initiated controlled radical polymerization.

PubMed

Majoinen, Johanna; Walther, Andreas; McKee, Jason R; Kontturi, Eero; Aseyev, Vladimir; Malho, Jani Markus; Ruokolainen, Janne; Ikkala, Olli

2011-08-08

Herein we report the synthesis of cellulose nanocrystals (CNCs) grafted with poly(acrylic acid) (PAA) chains of different lengths using Cu-mediated surface initiated-controlled radical polymerization (SI-CRP). First, poly(tert-butylacrylate) (PtBA) brushes were synthesized; then, subsequent acid hydrolysis was used to furnish PAA brushes tethered onto the CNC surfaces. The CNCs were chemically modified to create initiator moieties on the CNC surfaces using chemical vapor deposition (CVD) and continued in solvent phase in DMF. A density of initiator groups of 4.6 bromine ester groups/nm(2) on the CNC surface was reached, suggesting a dense functionalization and a promising starting point for the controlled/living radical polymerization. The SI-CRP of tert-butylacrylate proceeded in a well-controlled manner with the aid of added sacrificial initiator, yielding polymer brushes with polydispersity values typically well below 1.12. We calculated the polymer brush grafting density to almost 0.3 chains/nm(2), corresponding to high grafting densities and dense polymer brush formation on the nanocrystals. Successful rapid acid hydrolysis to remove the tert-butyl groups yielded pH-responsive PAA-polyelectrolyte brushes bound to the CNC surface. Individually dispersed rod-like nanoparticles with brushes of PtBA or PAA were clearly visualized by AFM and TEM imaging.

The theory of reasoned action in describing tooth brushing, dental caries and diabetes adherence among diabetic patients.

PubMed

Syrjälä, Anna-Maija H; Niskanen, Mirka C; Knuuttila, Matti L E

2002-05-01

Preventive oral health behaviour is important among diabetic patients, as it has been found that dental diseases and insulin-dependent diabetes mellitus (IDDM) have some psychological and biological factors in common. The aim here was to analyze the variables of Ajzen and Fishbein's theory of reasoned action to explain the reported frequency of tooth brushing, dental caries, HbA1c level and diabetes adherence. Cross-sectional data were gathered from 149 IDDM patients by means of a quantitative questionnaire, clinical examination and patient records. The results showed that a firmer intention to brush the teeth was related to a higher reported frequency of tooth brushing (p < 0.001). The attitude to and the subjective norm of tooth brushing were related to the intention to brush(p < 0.001) and to the reported frequency of tooth brushing. A better dental attitude was related to better diabetes adherence (p = 0.002) and fewer decayed surfaces (p = 0.01), and a firmer intention to brush the teeth was related to a lower HbA1c level (p = 0.015). Our results suggest that in oral health promotion among diabetic patients, both subjective norm and attitude are important and that diabetes adherence may be influenced by promoting dental attitude.

Combined carbon mesh and small graphite fiber brush anodes to enhance and stabilize power generation in microbial fuel cells treating domestic wastewater

NASA Astrophysics Data System (ADS)

Wu, Shijia; He, Weihua; Yang, Wulin; Ye, Yaoli; Huang, Xia; Logan, Bruce E.

2017-07-01

Microbial fuel cells (MFCs) need to have a compact architecture, but power generation using low strength domestic wastewater is unstable for closely-spaced electrode designs using thin anodes (flat mesh or small diameter graphite fiber brushes) due to oxygen crossover from the cathode. A composite anode configuration was developed to improve performance, by joining the mesh and brushes together, with the mesh used to block oxygen crossover to the brushes, and the brushes used to stabilize mesh potentials. In small, fed-batch MFCs (28 mL), the composite anode produced 20% higher power densities than MFCs using only brushes, and 150% power densities compared to carbon mesh anodes. In continuous flow tests at short hydraulic retention times (HRTs, 2 or 4 h) using larger MFCs (100 mL), composite anodes had stable performance, while brush anode MFCs exhibited power overshoot in polarization tests. Both configurations exhibited power overshoot at a longer HRT of 8 h due to lower effluent CODs. The use of composite anodes reduced biomass growth on the cathode (1.9 ± 0.2 mg) compared to only brushes (3.1 ± 0.3 mg), and increased coulombic efficiencies, demonstrating that they successfully reduced oxygen contamination of the anode and the bio-fouling of cathode.

The Effects of Tooth Brushing on Whole Salivary Flow Rate in Older Adults

PubMed Central

Trottier, K.; Garrick, R.; Mascarenhas, T.; Jang, Y.

2018-01-01

Objectives (1) To determine whether manual (MTB), or electric, tooth brushing (ETB) modulates whole salivary flow rate in older adults who are free of systemic disease. (2) To determine the duration of the brushing-related modulation of salivary flow rate. (3) To compare salivary flow rate modulation associated with MTB and ETB. Method Twenty-one adults aged 60 years and older participated in two experimental sessions during which they used a manual, or electric, toothbrush to brush their teeth, tongue, and palate. Whole salivary flow rates were determined using the draining method before, during, and after brushing. Differences in salivary flow rates across time periods, and between conditions, were examined using paired samples t-tests applying a Holm-Bonferroni sequential procedure (pcorr < 0.0045). The relationship between tooth brushing and age with respect to maximum salivary flow rate increase was examined using Pearson's correlation coefficient (p < 0.05). Results/Conclusion Whole salivary flow rates increased during, and for up to 5 minutes following, tooth brushing in adults aged 60 years and older who were free of systemic disease. The salivary effects of MTB and ETB were not significantly different. A moderate, positive correlation was observed between tooth-brushing-related maximum salivary flow rate increase and age. PMID:29682540

Expression and effect of inhibition of aminopeptidase-A during nephrogenesis.

PubMed

Dijkman, Henry B P M; Assmann, Karel J M; Steenbergen, Eric J; Wetzels, Jack F M

2006-02-01

Aminopeptidase-A (APA) is a metalloprotease that cleaves N-terminal aspartyl and glutamyl residues from peptides. Its best-known substrate is angiotensin II (Ang II), the most active compound of the renin-angiotensin system (RAS). The RAS is involved in renal development. Most components of the RAS system are expressed in the developing kidney. Thus far, APA has not been studied in detail. In the present study we have evaluated the expression of APA at the protein, mRNA, and enzyme activity (EA) level in the kidney during nephrogenesis. Furthermore, we have studied the effect of inhibiting APA EA by injection of anti-APA antibodies into 1-day-old mice. APA expression was observed from the comma stage onwards, predominantly in the developing podocytes and brush borders of proximal tubular cells. Notably, APA was absent in the medulla or the renal arterioles. Inhibition of APA EA caused temporary podocyte foot-process effacement, suggesting a minimum role for APA during nephrogenesis.

Study of enzyme activities in the descending part of the duodenum in patients of duodenal ulcer.

PubMed

Fernandes, V L C; Bhasin, D K; Rana, S V

2006-03-01

The aim of this study was to measure the levels of lactase, sucrase, maltase, leucine amino peptidase and gamma-glutamyl transpeptidase in duodenum of Indian patients with duodenal ulcer. The effect of duodenum inflammation on these brush border enzymes has also been analysed in this study. Levels of lactase, sucrase, maltase, leucine amino peptidase and gamma-glutamyl transpeptidase were assessed in duodenal biopsies of 20 patients of duodenal ulcer and 20 non-ulcer dyspepsia. The duodenal biopsy specimens were also examined histopathologically for presence or absence of inflammation. There was no significant difference (p>0.05) in the activity of above mentioned enzyme levels in both the groups. Only levels of gamma-glutamyl transpeptidase were significantly decreased in patients of duodenal ulcer with duodenal inflammation. This study shows that only the levels of gamma-glutamyl transpeptidase were significantly decreased in patients of duodenal ulcer with inflammation but no change in duodenal enzymes due to duodenal ulcer as compared to non-ulcer dyspepsia.

Effect of andrographolide on cysteamine-induced duodenal ulcer in rats.

PubMed

Panneerselvam, Saranya; Arumugam, Geetha; Karthikeyan, Narmadha Selvamathy Selvaperumal Munis

2011-09-01

The aim of this study was to evaluate the gastroprotective efficacy of andrographolide isolated from Andrographis paniculata in rats induced with duodenal ulcers. Duodenal ulcers were induced by cysteamine administration in rats pretreated with 3 mg kg⁻¹ BW day⁻¹ of andrographolide for 30 days. Ulcer score, myeloperoxidase activity, TBARS level, GSH/GSSG ratio and enzyme antioxidants were measured in the duodenal tissue. Brush border and basolateral membranes were isolated to assay sucrase, maltase, alkaline phosphatase and total ATPases. Ulcer score was significantly minimised in rats pretreated with andrographolide. Elevation in myeloperoxidase and TBARS levels were found to be minimised significantly due to andrographolide treatment. Membrane-bound enzyme activities and the thiol redox status of glutathione were significantly maintained in duodenal mucosa of rats that received andrographolide. This study reveals that the major component of A. paniculata, andrographolide, has potent antiulcer properties that are most likely caused by minimising inflammatory changes, counteracting free radical formation and maintaining the thiol redox status in the duodenum.

The Diverse Forms of Lactose Intolerance and the Putative Linkage to Several Cancers

PubMed Central

Amiri, Mahdi; Diekmann, Lena; von Köckritz-Blickwede, Maren; Naim, Hassan Y.

2015-01-01

Lactase-phlorizin hydrolase (LPH) is a membrane glycoprotein and the only β-galactosidase of the brush border membrane of the intestinal epithelium. Besides active transcription, expression of the active LPH requires different maturation steps of the polypeptide through the secretory pathway, including N- and O-glycosylation, dimerization and proteolytic cleavage steps. The inability to digest lactose due to insufficient lactase activity results in gastrointestinal symptoms known as lactose intolerance. In this review, we will concentrate on the structural and functional features of LPH protein and summarize the cellular and molecular mechanism required for its maturation and trafficking. Then, different types of lactose intolerance are discussed, and the molecular aspects of lactase persistence/non-persistence phenotypes are investigated. Finally, we will review the literature focusing on the lactase persistence/non-persistence populations as a comparative model in order to determine the protective or adverse effects of milk and dairy foods on the incidence of colorectal, ovarian and prostate cancers. PMID:26343715

The Diverse Forms of Lactose Intolerance and the Putative Linkage to Several Cancers.

PubMed

Amiri, Mahdi; Diekmann, Lena; von Köckritz-Blickwede, Maren; Naim, Hassan Y

2015-08-28

Lactase-phlorizin hydrolase (LPH) is a membrane glycoprotein and the only β-galactosidase of the brush border membrane of the intestinal epithelium. Besides active transcription, expression of the active LPH requires different maturation steps of the polypeptide through the secretory pathway, including N- and O-glycosylation, dimerization and proteolytic cleavage steps. The inability to digest lactose due to insufficient lactase activity results in gastrointestinal symptoms known as lactose intolerance. In this review, we will concentrate on the structural and functional features of LPH protein and summarize the cellular and molecular mechanism required for its maturation and trafficking. Then, different types of lactose intolerance are discussed, and the molecular aspects of lactase persistence/non-persistence phenotypes are investigated. Finally, we will review the literature focusing on the lactase persistence/non-persistence populations as a comparative model in order to determine the protective or adverse effects of milk and dairy foods on the incidence of colorectal, ovarian and prostate cancers.

The Green Gut: Chlorophyll Degradation in the Gut of Spodoptera littoralis.

PubMed

Badgaa, Amarsanaa; Büchler, Rita; Wielsch, Natalie; Walde, Marie; Heintzmann, Rainer; Pauchet, Yannik; Svatos, Ales; Ploss, Kerstin; Boland, Wilhelm

2015-11-01

Chlorophylls, the most prominent natural pigments, are part of the daily diet of herbivorous insects. The spectrum of ingested and digested chlorophyll metabolites compares well to the pattern of early chlorophyll-degradation products in senescent plants. Intact chlorophyll is rapidly degraded by proteins in the front- and midgut. Unlike plants, insects convert both chlorophyll a and b into the corresponding catabolites. MALDI-TOF/MS imaging allowed monitoring the distribution of the chlorophyll catabolites along the gut of Spodoptera littoralis larvae. The chlorophyll degradation in the fore- and mid-gut is strongly pH dependent, and requires alkaline conditions. Using LC-MS/MS analysis we identified a lipocalin-type protein in the intestinal fluid of S. littoralis homolog to the chlorophyllide a binding protein from Bombyx mori. Widefield and high-resolution autofluorescence microscopy revealed that the brush border membranes are covered with the chlorophyllide binding protein tightly bound via its GPI-anchor to the gut membrane. A function in defense against gut microbes is discussed.

Identification of Escherichia coli F4ac-binding proteins in porcine milk fat globule membrane

PubMed Central

Novakovic, Predrag; Huang, Yanyun Y.; Lockerbie, Betty; Shahriar, Farshid; Kelly, John; Gordon, John R.; Middleton, Dorothy M.; Loewen, Matthew E.; Kidney, Beverly A.; Simko, Elemir

2015-01-01

F4ac-positive enterotoxigenic Escherichia coli (ETEC) must attach to the intestinal mucosa to cause diarrhea in piglets. Prevention of bacterial attachment to the intestinal mucosa is the most effective defense against ETEC-induced diarrhea. Porcine milk fat globule membranes (MFGM) were shown to be able to inhibit attachment of ETEC to the intestinal brush border; however, the specific components of porcine MFGM that inhibited attachment of ETEC to enterocytes were not identified. Accordingly, the purpose of this study was to identify F4ac-binding MFGM proteins by overlay Western blot and affinity chromatography. The proteome of porcine MFGM was characterized and the following F4ac-binding proteins were detected by overlay Western blot and affinity chromatography: lactadherin, butyrophilin, adipophilin, acyl-CoA synthetase 3, and fatty acid-binding protein 3. The biological function of these proteins was not investigated but it is possible that their interaction with F4ac fimbria interferes with bacterial attachment and colonization. PMID:25852227

Localization of a renal sodium-phosphate cotransporter gene to human chromosome 5q35

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kos, C.H.; Tenenhouse, H.S.; Tihy, F.

1994-01-01

Several Mendelian disorders of renal phosphate reabsorption, associated with hypophosphatemia and bone disease, have been described. These include X-linked hypophosphatemia (XLH), hereditary hypophosphatemic rickets with hypercalciuria, hypophosphatemic bone disease, and autosomal dominant and autosomal recessive hypophosphatemic rickets. The underlying mechanisms for renal phosphate wasting in these disorders remain unknown. The proximal tubule is the major site of renal phosphate reabsorption. Thus, mutations in genes that participate in the transepithelial transport of phosphate in this segment of the nephron may be responsible for these disorders. Recently, a cDNA encoding a renal proximal tubular, brush-border membrane Na[sup +]-phosphate cotransporter (NaP[sub i]-3) wasmore » cloned from human kidney cortex. As a first step in establishing whether mutations in the NaP[sub i]-3 gene are the cause of inherited disorders in phosphate homeostasis, the authors sought to determine its chromosomal localization. 9 refs., 1 fig.« less

A monoclonal IgM smooth muscle antibody reactive with fibroblast stress fibres produced by immunization with Treponema pallidum.

PubMed Central

Strugnell, R A; Underwood, J R; Clarke, F M; Pedersen, J S; Chalmers, P J; Faine, S; Toh, B H

1983-01-01

A monoclonal IgM smooth muscle antibody secreted by a hybrid (MMI-1) of mouse plasmacytoma NS-1 with spleen cells from mouse immunized with Treponema pallidum was detected by indirect immunofluorescence tests on frozen tissue sections and on acetone fixed monolayers of rat and human fibroblasts. The antibody did not react with acetone fixed smears of T. pallidum but reacted with smooth muscle fibres and with striations of skeletal and cardiac muscle. In non-muscle cells, the antibody stained liver in a 'polygonal' pattern, thymus with accentuated staining of the thymic medulla, renal glomeruli and the brush border and peritubular fibrils of renal tubules. In fibroblast monolayers, the antibody stained stress fibres in an interrupted pattern. Immunoblotting with muscle proteins and the antibody showed labelling of a 100K molecule. The cellular distribution of the mouse monoclonal antibody is similar to that obtained with anti-actin antibody suggesting that the corresponding antigen may be an actin binding protein. Images Fig. 3 PMID:6347470

Systemic and anti-neuronal auto-antibodies in patients with paraneoplastic neurological disease.

PubMed

Moll, J W; Hooijkaas, H; van Goorbergh, B C; Roos, L G; Henzen-Logmans, S C; Vecht, C J

1996-01-01

Sera from 23 patients with paraneoplastic disease of the central nervous system (PNS) were examined for the presence of anti-neuronal (anti-Hu, anti-Yo/PCA) and anti-Ri) and systemic auto-antibodies, including antibodies against DNA, centromeres, nRNP, Sm antigen, Scl-70, Ro(SS-A), La(SS-B), mitochondria, thyroid antigens, parietal calls, brush border antigen and rheumatoid factor. As controls, sera from 33 patients with small cell lung cancer, 33 with ovarian cancer and 7 with breast cancer and from 107 aged-matched healthy persons were used. Systemic auto-antibodies were found in 52% of patients with paraneoplastic neurological syndromes compared with only 16% (P = 0.001) in the control group with cancer only and 15% in the group of healthy controls. The relatively high percentage of systemic auto-antibodies in patients with PNS indicates that there is a genetic susceptibility to the development of auto-immune phenomena. This may provide an explanation for the relatively rare occurrence of PNS in patients with cancer.

Intestinal alkaline phosphatase detoxifies lipopolysaccharide and prevents inflammation in zebrafish in response to the gut microbiota.

PubMed

Bates, Jennifer M; Akerlund, Janie; Mittge, Erika; Guillemin, Karen

2007-12-13

Vertebrates harbor abundant lipopolysaccharide (LPS) in their gut microbiota. Alkaline phosphatases can dephosphorylate and detoxify the endotoxin component of LPS. Here, we show that expression of the zebrafish intestinal alkaline phosphatase (Iap), localized to the intestinal lumen brush border, is induced during establishment of the gut microbiota. Iap-deficient zebrafish are hypersensitive to LPS toxicity and exhibit the excessive intestinal neutrophil influx characteristic of wild-type zebrafish exposed to LPS. Both of these Iap mutant phenotypes are dependent on Myd88 and Tumor Necrosis Factor Receptor (Tnfr), proteins also involved in LPS sensitivity in mammals. When reared germ-free, the intestines of Iap-deficient zebrafish are devoid of neutrophils. Together, these findings demonstrate that the endogenous microbiota establish the normal homeostatic level of neutrophils in the zebrafish intestine through a process involving Iap, Myd88, and Tnfr. Thus, by preventing inflammatory responses, Iap plays a crucial role in promoting mucosal tolerance to resident gut bacteria.

An Apical MRCK-driven Morphogenetic Pathway Controls Epithelial Polarity

PubMed Central

Zihni, Ceniz; Vlassaks, Evi; Terry, Stephen; Carlton, Jeremy; Leung, Thomas King Chor; Olson, Michael; Pichaud, Franck; Balda, Maria Susana; Matter, Karl

2017-01-01

Polarized epithelia develop distinct cell surface domains, with the apical membrane acquiring characteristic morphological features such as microvilli. Cell polarization is driven by polarity determinants including the evolutionarily conserved partitioning defective (PAR) proteins that are separated into distinct cortical domains. PAR protein segregation is thought to be a consequence of asymmetric actomyosin contractions. The mechanism of activation of apically polarized actomyosin contractility is unknown. Here we show that the Cdc42 effector MRCK activates Myosin-II at the apical pole to segregate aPKC-Par6 from junctional Par3, defining the apical domain. Apically polarized MRCK-activated actomyosin contractility is reinforced by cooperation with aPKC-Par6 downregulating antagonistic RhoA-driven junctional actomyosin contractility, and drives polarization of cytosolic brush border determinants and apical morphogenesis. MRCK-activated polarized actomyosin contractility is required for apical differentiation and morphogenesis in vertebrate epithelia and Drosophila photoreceptors. Our results identify an apical origin of actomyosin-driven morphogenesis that couples cytoskeletal reorganization to PAR polarity signalling. PMID:28825699

Mechanisms involved in the intestinal digestion and absorption of dietary vitamin A.

PubMed

Harrison, E H; Hussain, M M

2001-05-01

Dietary retinyl esters are hydrolyzed in the intestine by the pancreatic enzyme, pancreatic triglyceride lipase (PTL), and intestinal brush border enzyme, phospholipase B. Recent work on the carboxylester lipase (CEL) knockout mouse suggests that CEL may not be involved in dietary retinyl ester digestion. The possible roles of the pancreatic lipase-related proteins (PLRP) 1 and 2 and other enzymes require further investigation. Unesterified retinol is taken up by the enterocytes, perhaps involving both diffusion and protein-mediated facilitated transport. Once in the cell, retinol is complexed with cellular retinol-binding protein type 2 (CRBP2) and the complex serves as a substrate for reesterification of the retinol by the enzyme lecithin:retinol acyltransferase (LRAT). Retinol not bound to CRBP2 is esterified by acyl-CoA acyltransferase (ARAT). The retinyl esters are incorporated into chylomicrons, intestinal lipoproteins that transport other dietary lipids such as triglycerides, phospholipids, and cholesterol. Chylomicrons containing newly absorbed retinyl esters are then secreted into the lymph.

Thermomechanical Properties and Glass Dynamics of Polymer-Tethered Colloidal Particles and Films.

PubMed

Cang, Yu; Reuss, Anna N; Lee, Jaejun; Yan, Jiajun; Zhang, Jianan; Alonso-Redondo, Elena; Sainidou, Rebecca; Rembert, Pascal; Matyjaszewski, Krzysztof; Bockstaller, Michael R; Fytas, George

2017-11-14

Polymer-tethered colloidal particles (aka "particle brush materials") have attracted interest as a platform for innovative material technologies and as a model system to elucidate glass formation in complex structured media. In this contribution, Brillouin light scattering is used to sequentially evaluate the role of brush architecture on the dynamical properties of brush particles in both the individual and assembled (film) state. In the former state, the analysis reveals that brush-brush interactions as well as global chain relaxation sensitively depend on grafting density; i.e., more polymer-like behavior is observed in sparse brush systems. This is interpreted to be a consequence of more extensive chain entanglement. In contrast, the local relaxation of films does not depend on grafting density. The results highlight that relaxation processes in particle brush-based materials span a wider range of time and length scales as compared to linear chain polymers. Differentiation between relaxation on local and global scale is necessary to reveal the influence of molecular structure and connectivity on the aging behavior of these complex systems.

PRDA-2 and 3 Brush Seal Development Programs at EG and G

NASA Technical Reports Server (NTRS)

Loewenthal, Robert G.

1996-01-01

EG&G Mechanical Components Technology Group R&D completed a Brush Seal Development Program under PRDA-2 in late 1992. We started the Advanced Brush Seal Development program, under PRDA-3, in 1993 and will complete it in 1996. Both programs have been funded by the United States Air Force. In the first program, we made significant gains in the area of tribopairs (bristle materials vs. shaft coatings) and the 'Low Hysteresis' design for brush seals. These were reported in two AIAA Propulsion Conference papers, and the 'Low Hysteresis' design has been patented. Seals were delivered for test in an Air Force demonstrator at Allison. In PRDA-3, goals are to increase the pressure sealing capability, and the surface speeds and temperatures at which brush seals can be used. We have conducted part of the design and testing and have tested brush seals successfully at more severe conditions than in the previous program. We are continuing with the program, and will complete it in time to furnish brush seals for an Air Force Demonstrator test in 1997.

Assembly and Characterization of Well Defined High Molecular Weight Poly(p-phenylene) Polymer Brushes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alonzo Calderon, Jose E; Kilbey, II, S Michael; Ankner, John Francis

2011-01-01

The assembly and characterization of well-defined, end-tethered poly(p-phenylene) (PPP) brushes having high molecular weight, low polydispersity and high 1,4-stereoregularity are presented. The PPP brushes are formed using a precursor route that relies on either self-assembly or spin coating of high molecular weight (degrees of polymerizations 54, 146, and 238) end-functionalized poly(1,3-cyclohexadiene) (PCHD) chains from benzene solutions onto silicon or quartz substrates, followed by aromatization of the end-attached PCHD chains on the surface. The approach allows the thickness (grafting density) of the brushes to be easily varied. The dry brushes before and after aromatization are characterized by ellipsometry, atomic force microscopy,more » grazing angle attenuated total reflectance Fourier transform infrared spectroscopy, and UV-Vis spectroscopy. The properties of the PPP brushes are compared with those of films made using oligo-paraphenylenes and with ab initio density functional theory simulations of optical properties. Our results suggest conversion to fully aromatized, end-tethered PPP polymer brushes having effective conjugation lengths of 5 phenyl units.« less

Endoscopic transpapillary brush cytology and forceps biopsy in patients with hilar cholangiocarcinoma.

PubMed

Weber, Andreas; von Weyhern, Claus; Fend, Falko; Schneider, Jochen; Neu, Bruno; Meining, Alexander; Weidenbach, Hans; Schmid, Roland M; Prinz, Christian

2008-02-21

To evaluate the sensitivity of brush cytology and forceps biopsy in a homogeneous patient group with hilar cholangiocarcinoma. Brush cytology and forceps biopsy were routinely performed in patients with suspected malignant biliary strictures. Fifty-eight consecutive patients undergoing endoscopic retrograde cholangio-pancreatography (ERCP) including forceps biopsy and brush cytology in patients with hilar cholangiocarcinoma between 1995-2005. Positive results for malignancy were obtained in 24/58 patients (41.4%) by brush cytology and in 31/58 patients (53.4%) by forceps biopsy. The combination of both techniques brush cytology and forceps biopsy resulted only in a minor increase in diagnostic sensitivity to 60.3% (35/58 patients). In 20/58 patients (34.5%), diagnosis were obtained by both positive cytology and positive histology, in 11/58 (19%) by positive histology (negative cytology) and only 4/58 patients (6.9%) were confirmed by positive cytology (negative histology). Brush cytology and forceps biopsy have only limited sensitivity for the diagnosis of malignant hilar tumors. In our eyes, additional diagnostic techniques should be evaluated and should become routine in patients with negative cytological and histological findings.

Nanoscale evaluation of lubricity on well-defined polymer brush surfaces using QCM-D and AFM.

PubMed

Kitano, Kazuhiko; Inoue, Yuuki; Matsuno, Ryosuke; Takai, Madoka; Ishihara, Kazuhiko

2009-11-01

For preparing a "highly lubricated biointerface", which has both excellent lubricity and biocompatibility, we investigated the factors responsible for resistance to friction during polymer grafting. We prepared poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(methyl methacrylate) (PMMA) brush layers with high graft density and well-controlled thickness using atom transfer radical polymerization (ATRP). We measured the water absorptivity in the polymer brush layers and the viscoelasticity of the polymer-hydrated layers using a quartz crystal microbalance with dissipation monitoring (QCM-D) measurements. The PMPC brush layer had the highest water absorptivity, while the PMPC-hydrated layer had the highest fluidity. The friction properties of the polymer brush layers were determined in air, water, and toluene by atomic force microscopy (AFM). The friction on each polymer brush decreased only when a good solvent was chosen for each polymer. In conclusion, the brush layer possessing high water absorptivity and fluidity in water contributes to reduce friction. PMPC grafting is an effective and promising method for obtaining highly lubricated biointerfaces.

Polyelectrolyte brushes in mixed ionic medium studied via intermolecular forces

NASA Astrophysics Data System (ADS)

Farina, Robert; Laugel, Nicolas; Pincus, Philip; Tirrell, Matthew

2011-03-01

The vast uses and applications of polyelectrolyte brushes make them an attractive field of research especially with the growing interest in responsive materials. Polymers which respond via changes in temperature, pH, and ionic strength are increasingly being used for applications in drug delivery, chemical gating, etc. When polyelectrolyte brushes are found in either nature (e.g., surfaces of cartilage and mammalian lung interiors) or commercially (e.g., skin care products, shampoo, and surfaces of medical devices) they are always surrounded by mixed ionic medium. This makes the study of these brushes in varying ionic environments extremely relevant for both current and future potential applications. The polyelectrolyte brushes in this work are diblock co-polymers of poly-styrene sulfonate (N=420) and poly-t-butyl styrene (N=20) which tethers to a hydrophobic surface allowing for a purely thermodynamic study of the polyelectrolyte chains. Intermolecular forces between two brushes are measured using the SFA. As multi-valent concentrations are increased, the brushes collapse internally and form strong adhesion between one another after contact (properties not seen in a purely mono-valent environment).

Comparison of the clinical effects of white brand toothbrushes versus Vitis Suave®

PubMed Central

Segarra-Vidal, Marta; Lucas-Alcahuz, Eduardo; López-Roldán, Andrés; Gil-Loscos, Francisco; Alpiste-Illueca, Francisco

2015-01-01

Background There has been an increase in the use of white label manual toothbrushes and a greater increase in inquiries for discomfort of the gingiva and mucosa. Material and Methods A randomized, double-blind, cross-over clinical trial was made of four white brand toothbrushes versus a control brush (Vitis Suave®), with the recording of plaque index, bleeding upon probing, and gingival abrasions following utilization of the different brushes. Results All the brushes except Deliplus® were equally effective in terms of plaque removal (p<0.05). Vitis Suave® and Veckia® were the brushes associated to the greatest increase in minor abrasions (p<0.01), while Veckia®, Carrefour® and Deluxe® significantly increased the number of medium intensity abrasions (p<0.05). These brushes also increased the number of large abrasions, though statistical significance was not reached in this case. Conclusions The white brand brushes proved effective in controlling bacterial plaque, but were associated to more intense soft tissue abrasion. Key words:Gingival abrasions, manual tooth brushing, white brand, clinical effects. PMID:26535095

Covariates of Tooth-brushing Frequency in Low-income African Americans From Grades 5 to 8

PubMed Central

Koerber, A.; Graumlich, S.; Punwani, I.C.; Berbaum, M.L.; Burns, J.L.; Levy, S.R.; Cowell, J.M.; Flay, B.R.

2009-01-01

Purpose The purpose of this study was to examine tooth-brushing frequency in 575 urban and nearby suburban African American children as part of a comprehensive risk-reduction study for students at high risk for violence, drugs, school delinquency, and unsafe sexual behaviors to determine which covariates predicted tooth-brushing frequency. Methods Students were surveyed 5 times, from the beginning of grade 5 and the end of each year through grade 8, and parents were surveyed at the beginning of grade 5. Peer influence, importance of being liked, self-esteem, attitudes towards tooth-brushing, oral health knowledge, self-efficacy, parental attitudes, and other covariates were examined for the ability to predict self-reporting of tooth-brushing frequency. Results In the fifth grade, peer influence, the importance of being liked, and physical self-esteem were the significant predictors, and peer influence continued to predict tooth-brushing in the eighth grade. Oral health knowledge and parental influence were not significant. Conclusion Peer influence is an important factor in tooth-brushing behavior in metropolitan African American preadolescent children. PMID:17249434

Covariates of tooth-brushing frequency in low-income African Americans from grades 5 to 8.

PubMed

Koerber, A; Graumlich, S; Punwani, I C; Berbaum, M L; Burns, J L; Levy, S R; Cowell, J M; Flay, B R

2006-01-01

The purpose of this study was to examine tooth-brushing frequency in 575 urban and nearby suburban African American children as part of a comprehensive risk-reduction study for students at high risk for violence, drugs, school delinquency, and unsafe sexual behaviors to determine which covariates predicted tooth-brushing frequency. Students were surveyed 5 times, from the beginning of grade 5 and the end of each year through grade 8, and parents were surveyed at the beginning of grade 5. Peer influence, importance of being liked, self-esteem, attitudes towards tooth-brushing, oral health knowledge, self-efficacy, parental attitudes, and other covariates were examined for the ability to predict self-reporting of tooth-brushing frequency. In the fifth grade, peer influence, the importance of being liked, and physical self-esteem were the significant predictors, and peer influence continued to predict tooth-brushing in the eighth grade. Oral health knowledge and parental influence were not significant. Peer influence is an important factor in tooth-brushing behavior in metropolitan African American preadolescent children.

Magnetically Activated Self-Cleaning Membranes

DTIC Science & Technology

2010-06-01

potassium phthalimide was reacted with the brushes to attach the phthalimide group to the end of the brushes. Hydralization then yields a primary amine...Synthesis reaction For the first step of the Gabriel Synthesis, 1 g potassium phthalimide was dissolved into 20 mL of ethanol. This solution (4.5 mL...resulting polyacrylic acid (pAA) brushes 12 through an amide linkage. Grafting of pAA brushes was confirmed using two types of spectroscopy

Phase behavior of ternary polymer brushes

DOE PAGES

Simocko, Chester K.; Frischknecht, Amalie L.; Huber, Dale L.

2016-01-07

Ternary polymer brushes consisting of polystyrene, poly(methyl methacrylate), and poly(4-vinylpyridine) have been synthesized. These brushes laterally phase separate into several distinct phases and can be tailored by altering the relative polymer composition. Self-consistent field theory has been used to predict the phase diagram and model both the horizontal and vertical phase behavior of the polymer brushes. As a result, all phase behaviors observed experimentally correlate well with the theoretical model.

Single molecule spectroscopy reveals heterogeneous transport mechanisms for molecular ions in a polyelectrolyte polymer brush.

PubMed

Reznik, Carmen; Estillore, Nicel; Advincula, Rigoberto C; Landes, Christy F

2009-11-05

Single molecule polarization and fluorescence correlation spectroscopy were used to evaluate heterogeneous transport mechanisms of molecular ions within supported polyelectrolyte brushes. Modes of diffusive transport include periods of significantly restricted rotational motion, often maintained over tens of milliseconds; periods of fast molecular rotation; and occasional adsorption of fluorescent probe molecules in the brush. The studies reveal rapid switching between orientational states during each observed mode of motion. Through quantitative analysis of state occupation times, the rate constants for transitions from weakly associated to strongly associated states were extracted. Additionally, the pH dependence of the ion transport rates in the brush exhibits an abrupt, rather than continuous, trend. These single molecule studies demonstrate the presence of dynamic anisotropic interactions between the charged molecular probe and the polymer brush and provide experimental evidence of stimuli responsive switchable transport functionality in the polyelectrolyte brush.

Tandem catalysis for the preparation of cylindrical polypeptide brushes.

PubMed

Rhodes, Allison J; Deming, Timothy J

2012-11-28

Here, we report a method for synthesis of cylindrical copolypeptide brushes via N-carboxyanhydride (NCA) polymerization utilizing a new tandem catalysis approach that allows preparation of brushes with controlled segment lengths in a straightforward, one-pot procedure requiring no intermediate isolation or purification steps. To obtain high-density brush copolypeptides, we used a "grafting from" approach where alloc-α-aminoamide groups were installed onto the side chains of NCAs to serve as masked initiators. These groups were inert during cobalt-initiated NCA polymerization and gave allyloxycarbonyl-α-aminoamide-substituted polypeptide main chains. The alloc-α-aminoamide groups were then activated in situ using nickel to generate initiators for growth of side-chain brush segments. This use of stepwise tandem cobalt and nickel catalysis was found to be an efficient method for preparation of high-chain-density, cylindrical copolypeptide brushes, where both the main chains and side chains can be prepared with controlled segment lengths.

Real-time x-ray scattering study of the initial growth of organic crystals on polymer brushes

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, Sung Yup; Ahn, Kwangseok; Kim, Doris Yangsoo

2014-04-21

We studied the early-stage growth structures of pentacene organic crystals grown on polymer brushes using real-time x-ray scattering techniques. In situ x-ray reflectivity and atomic force microscopy analyses revealed that at temperatures close to the glass transition temperature of polymer brush, the pentacene overlayer on a polymer brush film showed incomplete condensation and 3D island structures from the first monolayer. A growth model based on these observations was used to quantitatively analyze the real-time anti-Bragg x-ray scattering intensities measured during pentacene growth to obtain the time-dependent layer coverage of the individual pentacene monolayers. The extracted total coverage confirmed significant desorptionmore » and incomplete condensation in the pentacene films deposited on the polymer brushes. These effects are ascribed to the change in the surface viscoelasticity of the polymer brushes around the glass transition temperature.« less

Microsecond MD Simulations of Nano-patterned Polymer Brushes on Self-Assembled Monolayers

NASA Astrophysics Data System (ADS)

Buie, Creighton; Qiu, Liming; Cheng, Kwan; Park, Soyeun

2010-03-01

Nano-patterned polymer brushes end-grafted onto self-assembled monolayers have gained increasing research interests due to their unique thermodynamic properties and their chemical and biomedical applications in colloids, biosensing and tissue engineering. So far, the interactions between the polymer brushes with the surrounding environments such as the floor and solvent at the nanometer length scale and microsecond time scale are still difficult to obtained experimentally and computationally. Using a Coarse-Grained MD approach, polymer brushes of different monomeric lengths, grafting density and hydrophobicity of the monomers grafted on self-assembled monolayers and in explicit solvent were studied. Molecular level information, such as lateral diffusion, transverse height and volume contour of the brushes, were calculated from our microsecond-MD simulations. Our results demonstrated the significance of the hydration of the polymer in controlling the conformational arrangement of the polymer brushes.

In Situ Infrared Ellipsometry for Protein Adsorption Studies on Ultrathin Smart Polymer Brushes in Aqueous Environment

DOE PAGES

Kroning, Annika; Furchner, Andreas; Aulich, Dennis; ...

2015-02-10

The protein-adsorbing and -repelling properties of various smart nanometer-thin polymer brushes with high potential for biosensing and biomedical applications are studied by in-situ infrared-spectroscopic ellipsometry (IRSE). IRSE as a highly sensitive non-destructive technique allows us to investigate protein adsorption on polymer brushes in aqueous environment in dependence of external stimuli like temperature and pH. These stimuli are, for instance, relevant in switchable mixed brushes containing poly(N-isopropyl acrylamide) and poly(acrylic acid), respectively. We use such brushes as model surfaces for controlling protein adsorption of human serum albumin and human fibrinogen. IRSE can distinguish between polymer-specific vibrational bands, which yield insights intomore » the hydration state of the brushes, and changes in the protein-specific amide bands, which are related to changes of the protein secondary structure.« less

Importance of filament diameter when using bass brushing technique.

PubMed

Vowles, A D; Wade, A B

1977-08-01

A comparative study using a crossover experimental construction was made of the effectiveness of brushes containing 6/10 nylon filaments of 0.132 mm mean diameter using a Bass technique with those containing filaments of the same type of nylon but 0.280 mm diameter. Each type of brush was used for a 2-week period. Even though the finer filament brushes contained more than three times as many filaments, they were inferior in cleaning achievement to the brushes with the broader filaments. The difference was particularly marked on the facial aspect, but was largely nullified lingually. The effectiveness of the Bass technique in the gingival zone demonstrated in a previous investigation when brushes containing filaments of 0.18 and 0.20 mm were used, was not found in this investigation. It is concluded that filament diameter is critical in achieving effective cleaning using the Bass technique.

Influence of cutting time on brush response: implications for herbivory in linear (transportation) corridors.

PubMed

Rea, Roy V; Child, Kenneth N; Spata, David P; MacDonald, Douglas

2007-08-01

An experiment was conducted to determine the influence the time of brush-cutting can have on plant regrowth and attractiveness to herbivores that browse in linear corridors. The influence of cutting time on leaf flush and senescence, shoot morphometry, and biomass was measured for 3 consecutive years after initial brush-cutting. Results indicate that morphological and phenological attributes of three woody deciduous plants were influenced by the timing of brush-cutting for up to 3 years after initial cutting. Brush-cutting generally stimulated plants to produce larger than normal shoots and delay leaf senescence. The degree to which plants were affected, however, varied with the timing of initial cutting and the species in question. Generally, plants cut later in the year resprouted more vigorously and were taller in the third year after cutting but produced less overall biomass than when cut earlier. In the years following brush-cutting, plants cut earlier flushed leaves earlier in the spring but delayed leaf senescence in the fall when compared to uncut controls. Results of these trials suggest that brush-cutting time influences plant response and several plant attributes known to influence plant attractiveness to moose and other herbivores. We therefore recommend that roadside and railside vegetation management plans consider the influence of cutting time on plant regrowth. Such considerations can ensure that brush is cut to reduce the attractiveness of plant regrowth in these linear corridors, reduce the utilization of such brush by herbivores, and, as such, mitigate collision risk between motorists and herbivores such as moose.

Plaque-left-behind after brushing: intra-oral reservoir for antibacterial toothpaste ingredients.

PubMed

Otten, Marieke P T; Busscher, Henk J; Abbas, Frank; van der Mei, Henny C; van Hoogmoed, Chris G

2012-10-01

Plaque is never fully removed by brushing and may act as a reservoir for antibacterial ingredients, contributing to their substantive action. This study investigates the contribution of plaque-left-behind and saliva towards substantivity of three antibacterial toothpastes versus a control paste without antibacterial claims. First, volunteers brushed 2 weeks with a control or antibacterial toothpaste. Next, plaque and saliva samples were collected 6 and 12 h after brushing and bacterial concentrations and viabilities were measured. The contributions of plaque and saliva towards substantivity were determined by combining control plaques with experimental plaque or saliva samples and subsequently assessing their viabilities. Bacterial compositions in the various plaque and saliva samples were compared using denaturing gradient gel electrophoresis. The viabilities of plaques after brushing with Colgate-Total® and Crest-Pro-Health® were smaller than of control plaques and up to 12 h after brushing with Crest-Pro-Health® plaques still contained effective, residual antibacterial activity against control plaques. No effective, residual antibacterial activity could be measured in saliva samples after brushing. There was no significant difference in bacterial composition of plaque or saliva after brushing with the different toothpastes. Plaque-left-behind after mechanical cleaning contributes to the substantive action of an antibacterial toothpaste containing stannous fluoride (Crest-Pro-Health®). The absorptive capacity of plaque-left-behind after brushing is of utmost clinical importance, since plaque is predominantly left behind in places where its removal and effective killing matter most. Therewith this study demonstrates a clear and new beneficial effect of the use of antibacterial toothpastes.

A profilometry-based dentifrice abrasion Method for V8 brushing machines. Part I: Introduction to RDA-PE.

PubMed

White, Donald J; Schneiderman, Eva; Colón, Ellen; St John, Samuel

2015-01-01

This paper describes the development and standardization of a profilometry-based method for assessment of dentifrice abrasivity called Radioactive Dentin Abrasivity - Profilometry Equivalent (RDA-PE). Human dentine substrates are mounted in acrylic blocks of precise standardized dimensions, permitting mounting and brushing in V8 brushing machines. Dentin blocks are masked to create an area of "contact brushing." Brushing is carried out in V8 brushing machines and dentifrices are tested as slurries. An abrasive standard is prepared by diluting the ISO 11609 abrasivity reference calcium pyrophosphate abrasive into carboxymethyl cellulose/glycerin, just as in the RDA method. Following brushing, masked areas are removed and profilometric analysis is carried out on treated specimens. Assessments of average abrasion depth (contact or optical profilometry) are made. Inclusion of standard calcium pyrophosphate abrasive permits a direct RDA equivalent assessment of abrasion, which is characterized with profilometry as Depth test/Depth control x 100. Within the test, the maximum abrasivity standard of 250 can be created in situ simply by including a treatment group of standard abrasive with 2.5x number of brushing strokes. RDA-PE is enabled in large part by the availability of easy-to-use and well-standardized modern profilometers, but its use in V8 brushing machines is enabled by the unique specific conditions described herein. RDA-PE permits the evaluation of dentifrice abrasivity to dentin without the requirement of irradiated teeth and infrastructure for handling them. In direct comparisons, the RDA-PE method provides dentifrice abrasivity assessments comparable to the gold industry standard RDA technique.

Glucose monitoring using a polymer brush modified polypropylene hollow fiber-based hydraulic flow sensor.

PubMed

Fortin, Nicolas; Klok, Harm-Anton

2015-03-04

Tight regulation of blood glucose levels of diabetic patients requires durable and robust continuous glucose sensing schemes. This manuscript reports the fabrication of ultrathin, phenylboronic acid (PBA) functionalized polymer brushes that swell upon glucose binding and which were integrated as the sensing interface in a new polypropylene hollow fiber (PPHF)-based hydraulic flow glucose sensor prototype. The polymer brushes were prepared via surface-initiated atom transfer radical polymerization of sodium methacrylate followed by postpolymerization modification with 3-aminophenyl boronic acid. In a first series of experiments, the glucose-response of PBA-functionalized poly(methacrylic acid) (PMAA) brushes grafted from planar silicon surfaces was investigated by quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM) experiments. The QCM-D experiments revealed a more or less linear change of the frequency shift for glucose concentrations up to ∼10 mM and demonstrated that glucose binding was completely reversible for up to seven switching cycles. The AFM experiments indicated that glucose binding was accompanied by an increase in the film thickness of the PBA functionalized PMAA brushes. The PBA functionalized PMAA brushes were subsequently grafted from the surface of PPHF membranes. The hydraulic permeability of these porous fibers depends on the thickness and swelling of the PMAA brush coating. PBA functionalized brush-coated PPHFs showed a decrease in flux upon exposure to glucose, which is consistent with swelling of the brush coating. Because they avoid the use of enzymes and do not rely on an electrochemical transduction scheme, these PPHF-based hydraulic flow sensors could represent an interesting alternative class of continuous glucose sensors.

Prebrushing rinse with water on plaque removal: a split-mouth design.

PubMed

Van der Sluijs, E; Slot, D E; Hennequin-Hoenderdos, N L; Van Leeuwen, Mpc; Van der Weijden, G A

2017-11-01

The aim was to evaluate whether there is an additional beneficial effect on dental plaque removal of rinsing the oral cavity with water before toothbrushing. In total, 48 non-dental, systemically healthy participants ≥18 years were included in this randomized controlled clinical trial using a split-mouth design. The participants were requested to refrain from any form of oral hygiene for 48 h. First dental plaque scores (PI) were assessed full mouth. Two randomly assigned contra-lateral quadrants were brushed. Next the participant rinsed for 1 min with 15 ml water. Subsequently, the opposite two contra-lateral quadrants were brushed. Brushing was performed without toothpaste. Subsequently the second full-mouth PI assessment was performed. The brushing and rinsing procedure was performed under supervision and brushing time was tracked by a timer, each quadrant was brushed for 30 s. For the buccal, lingual, and approximal surfaces and tooth type, a subanalysis was performed. At baseline there was no statistically significantly difference between the two sets of contra-lateral quadrants. When a water rinse was used before toothbrushing the PI-score was reduced by 58%. If water rinse was used post-brushing the PI-score reduced by 57%. The difference of 0.04 in mean plaque index score reduction between the two brushing regimens was not significant(P = 0.162). When a 2 min brushing exercise was performed, on average more than 55% dental plaque was removed. Prerinsing with water did not contribute significantly to toothbrush efficacy. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Stages and transitions in the development of tooth brushing skills in children of Mexican immigrant families: a qualitative study.

PubMed

Benadof, Dafna; Polk, Deborah; Documet, Patricia

2015-01-01

Compared with white children, the oral health of Latino children in the United States is much worse. One factor contributing to oral health is tooth brushing. Few studies have addressed the formation of the tooth brushing habit in children, and only one of them studied a Latino population. The purpose of this study is to explore the development of the tooth brushing habit in children of Mexican immigrant families and develop hypothesis based on its results. This is an exploratory qualitative study, with a case study design based on 20 in-depth interviews. Participants were Mexican immigrant mothers living in Pittsburgh and Philadelphia, PA. Participants had at least one child six-years-old or younger. Interviews were recorded, transcribed verbatim, and analyzed using qualitative analysis procedures. Four stages were identified in the tooth brushing learning process: initiation and entirely dependent tooth brushing, assisted tooth brushing, road to tooth brushing independence, and independent tooth brushing. Two factors influenced parents' teaching approaches: parents' perceptions of their child's achievement of physical, cognitive, and motor developmental milestones and parents' knowledge about oral hygiene. We identified four distinct stages and found evidence to hypothesize that transitions from one stage to the next are triggered not by the age of the child but by parents' knowledge about oral hygiene and their perceptions of their child's achievement of physical, cognitive, and motor developmental milestones. Future quantitative research studies should be conducted to test this hypothesis in larger groups of Latinos as well as other ethnic groups. © 2015 American Association of Public Health Dentistry.

Unique Tuft Test Facility Dramatically Reduces Brush Seal Development Costs

NASA Technical Reports Server (NTRS)

Fellenstein, James A.

1997-01-01

Brush seals have been incorporated in the latest turbine engines to reduce leakage and improve efficiency. However, the life of these seals is limited by wear. Studies have shown that optimal sealing characteristics for a brush seal occur before the interference fit between the brush and shaft is excessively worn. Research to develop improved tribopairs (brush and coating) with reduced wear and lower friction has been hindered by the lack of an accurate, low-cost, efficient test methodology. Estimated costs for evaluating a new material combination in an engine company seal test program are on the order of $100,000. To address this need, the NASA Lewis Research Center designed, built, and validated a unique, innovative brush seal tuft tester that slides a single tuft of brush seal wire against a rotating shaft under controlled loads, speeds, and temperatures comparable to those in turbine engines. As an initial screening tool, the brush seal tuft tester can tribologicaly evaluate candidate seal materials for 1/10th the cost of full-scale seal tests. Previous to the development of the brush seal tuft tester facility, most relevant tribological data had been obtained from full-scale seal tests conducted primarily to determine seal leakage characteristics. However, from a tribological point of view, these tests included the confounding effects of varying contact pressures, bristle flaring, high-temperature oxidation, and varying bristle contact angles. These confounding effects are overcome in tuft testing. The interface contact pressures can be either constant or varying depending on the tuft mounting device, and bristle wear can be measured optically with inscribed witness marks. In a recent cooperative program with a U.S. turbine engine manufacturer, five metallic wire candidates were tested against a plasma-sprayed Nichrome-bonded chrome carbide. The wire materials used during this collaboration were either nickel-chrome- or cobaltchrome-based superalloys. These tests corroborated full-scale seal test results and provided insight into previously untested combinations. As the cycle temperature for improved efficiency turbine engines increases, new brush seal materials combinations must be considered. Future brush seal tuft testing will include both metallic and ceramic bristles versus commercial and NASA-developed shaft coatings. The ultimate goal of this work is to expand the current data base so that seal designers can tailor brush seal materials to specific applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Liang; Akgun, Bulent; Narayanan, Suresh

Swollen polymer brushes are found in many systems where the brush is intended to mediate interactions with the surroundings. The surface height fluctuations of planar polystyrene brushes (0.04 – 0.63 chains/nm2) highly swollen in toluene vapor are so strongly slowed by the tethering of the chains that they are unobservable in the current experimental window of length and time. This is the case despite the fact that the segmental dynamics of the brush chains should be very fast due to the substantial plasticization by the solvent. With respect to thermally stimulated fluctuations, the surfaces of these swollen brushes are solid-likemore » on time scales and length scales pertinent to many practical applications.« less

Tooth brushing inhibits oral bacteria in dogs.

PubMed

Watanabe, Kazuhiro; Hayashi, Kotaro; Kijima, Saku; Nonaka, Chie; Yamazoe, Kazuaki

2015-10-01

In this study, scaling, polishing and daily tooth brushing were performed in 20 beagle dogs, and the number of oral bacteria was determined using a bacterial counter. The dogs were randomized into the scaling (S), scaling + polishing (SP), scaling + tooth daily brushing (SB) and scaling + polishing + tooth daily brushing (SPB) groups. Samples were collected from the buccal surface of the maxillary fourth premolars of the dogs immediately after scaling and every week thereafter from weeks 1 to 8. Throughout the study, the number of bacteria was significantly lower in the SB and SPB groups compared with the S group. The findings suggest that daily tooth brushing inhibited oral bacterial growth in the dogs.

Autonomous multifunctional nanobrushes-autonomous materials

NASA Astrophysics Data System (ADS)

Ghasemi-Nejhad, Mehrdad N.; Tius, Marcus A.

2007-04-01

In this work, taking advantage of carbon nanotubes' small size, and exceptional mechanical, chemical and electrical properties, we report on a series of nano-synthesis procedures that combine conventional chemical vapor deposition and selective substrate area growth followed by chemical functionalizations to fabricate functionalized nano-brushes from aligned carbon nanotube arrays and chemically selective functional groups. The high aspect ratio and small dimension, mechanical stability and flexibility, surface chemical and adhesive characteristics of carbon nanotubes provide opportunities to create nano-brushes with selected chemical functionalities. The nano-brushes are made from aligned multi-walled carbon nanotube bristles grafted onto long SiC fiber handles in various configurations and functionalized with various chemical functional groups. These nano-brushes can easily be manipulated physically, either manually or with the aid of motors. Here, we explain the autonomous characteristics of the functionalized nano-brushes employing functional chemical groups such that the nano-brush can potentially collect various metal particles, ions, and contaminants from liquid solutions and the air environment, autonomously. These functionalized multiwalled carbon nanotube based nano-brushes can work swiftly in both liquid and air environments. With surface modification and functionalization, the nanotube nano-brushes can potentially become a versatile nano-devices in many chemical and biological applications, where they can autonomously pick up the particles they encounter since they can be chemically programmed to function as Autonomous Chemical Nano Robots (ACNR).

Spectroscopic study of a DNA brush synthesized in situ by surface initiated enzymatic polymerization.

PubMed

Khan, M Nuruzzaman; Tjong, Vinalia; Chilkoti, Ashutosh; Zharnikov, Michael

2013-08-29

We used a combination of synchrotron-based X-ray photoelectron spectroscopy (XPS) and angle-resolved near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to study the chemical integrity, purity, and possible internal alignment of single-strand (ss) adenine deoxynucleotide (poly(A)) DNA brushes. The brushes were synthesized by surface-initiated enzymatic polymerization (SIEP) on a 25-mer of adenine self-assembled monolayer (SAM) on gold (A25-SH), wherein the terminal 3'-OH of the A25-SH serve as the initiation sites for SIEP of poly(A). XPS and NEXAFS spectra of poly(A) brushes were found to be almost identical to those of A25-SH initiator, with no unambiguous traces of contamination. Apart from the well-defined chemical integrity and contamination-free character, the brushes were found to have a high degree of orientational order, with an upright orientation of individual strands, despite their large thickness up to ~55 nm, that corresponds to a chain length of at least several hundred nucleotides for individual ssDNA molecules. The orientational order exhibited by these poly(A) DNA brushes, mediated presumably by base stacking, was found to be independent of the brush thickness as long as the packing density was high enough. The well-defined character and orientational ordering of the ssDNA brushes make them a potentially promising system for different applications.

The dynamics of complex formation between amylose brushes on gold and fatty acids by QCM-D.

PubMed

Cao, Zheng; Tsoufis, Theodoros; Svaldo-Lanero, Tiziana; Duwez, Anne-Sophie; Rudolf, Petra; Loos, Katja

2013-10-14

Amylose brushes were synthesized by enzymatic polymerization with glucose-1-phosphate as monomer and rabbit muscle phosphorylase b as catalyst on gold-covered surfaces of a quartz crystal microbalance. Fourier transform infrared (FT-IR) spectra confirmed the presence of the characteristic absorption peaks of amylose between 3100 cm(-1) and 3500 cm(-1). The thickness of the amylose brushes-measured by Spectroscopic Ellipsometry--can be tailored from 4 to 20 nm, depending on the reaction time. The contour length of the stretched amylose chains on gold surfaces has been evaluated by single molecule force spectroscopy, and a total chain length of about 20 nm for 16.2 nm thick amylose brushes was estimated. X-ray photoelectron spectroscopy (XPS) was employed to characterize the amylose brushes before and after the adsorption of fatty acids. The dynamics of inclusion complex formation between amylose brushes and two fatty acids (octanoic acid and myristic acid) with different chain length was investigated as a function of time using a quartz crystal microbalance with dissipation monitoring (QCM-D) immersed in the liquid phase. QCM-D signals including the frequency and dissipation shifts elucidated the effects of the fatty acid concentration, the solvent types, the chain length of the fatty acids and the thickness of the amylose brushes on the dynamics of fatty acid molecule adsorption on the amylose brush-modified sensor surfaces.

Efficacy of plaque removal and learning effect of a powered and a manual toothbrush.

PubMed

Lazarescu, D; Boccaneala, S; Illiescu, A; De Boever, J A

2003-08-01

Subjects with high plaque and gingivitis scores can profit most from the introduction of new manual or powered tooth brushes. To improve their hygiene, not only the technical characteristics of new brushes but also the learning effect in efficient handling are of importance. : The present study compared the efficacy in plaque removal of an electric and a manual toothbrush in a general population and analysed the learning effect in efficient handling. Eighty healthy subjects, unfamiliar with electric brushes, were divided into two groups: group 1 used the Philips/Jordan HP 735 powered brush and group 2 used a manual brush, Oral-B40+. Plaque index (PI) and gingival bleeding index (GBI) were assessed at baseline and at weeks 3, 6, 12 and 18. After each evaluation, patients abstained from oral hygiene for 24 h. The next day a 3-min supervised brushing was performed. Before and after this brushing, PI was assessed for the estimation of the individual learning effect. The study was single blinded. Over the 18-week period, PI reduced gradually and statistically significantly (p<0.001) in group 1 from 2.9 (+/-0.38) to 1.5 (+/-0.24) and in group 2 from 2.9 (+/-0.34) to 2.2 (+/-0.23). From week 3 onwards, the difference between groups was statistically significant (p<0.001). The bleeding index decreased in group 1 from 28% (+/-17%) to 7% (+/-5%) (p<0.001) and in group 2 from 30% (+/-12%) to 12% (+/-6%) (p<0.001). The difference between groups was statistically significant (p<0.001) from week 6 onwards. The learning effect, expressed as the percentage of plaque reduction after 3 min of supervised brushing, was 33% for group 1 and 26% for group 2 at week 0. This percentage increased at week 18 to 64% in group 1 and 44% in group 2 (difference between groups statistically significant: p<0.001). The powered brush was significantly more efficient in removing plaque and improving gingival health than the manual brush in the group of subjects unfamiliar with electric brushes. There was also a significant learning effect that was more pronounced with the electric toothbrush.

[Pathologico-anatomic contribution to antibody detection in immunopathologic diseases].

PubMed

Nozicka, Z

1991-01-01

Results of twenty years experience with identification of anti organ autoantibodies occurring mainly during autoimmune diseases are presented. Cryostat sections from human cadaver tissue and albino-rat kidneys were used for the detection of the above mentioned antibodies, by method of two-step (indirect) immunofluorescence. The study describes working schedule of a newly established subspeciality of pathological anatomy--the "histoserology". The main aim of the study was investigate the occurrence of autoantibodies and to asses the correlation between these findings and health condition of patients. The following antibodies were evaluated: antibodies against epithelia and colloid of thyroid gland, the antibody against parietal cells of stomach mucosa, antibodies against striated ducts of salivary gland and basal elements in its excretory ducts, the antibody against suprarenal cortical elements, the antibody against parathyreoidea, the antibody against smooth muscle cells, anti brush-border antibody, and the anti-nuclear factor as well as the antibodies against intercellular substance and basement membrane of epidermis. Antibody against thyroid gland coloid appears to be of diagnostic value for recognizing of Hashimoto and focal thyroiditis. The finding of antibody against parietal cells indicates the probability of pernicious trait in diagnostically unclear anaemias. On the other hand the finding of such antibody is not very useful in classification of gastritis and its subtyping. The appearance of the phenomenon of "shaggy rim" during the assay for antinuclear factor seems to be very reliable for verification of systemic lupus. The antibody against salivary gland striated ducts does not give fundamental support for diagnosis of Sjögren's disease. Very interesting immunopathological phenomenon is an occurrence of antibody binding to basal cells of salivary gland excretory ducts. To our knowledge, this phenomenon is rather typical for the antibody against cytokeratin polypeptide No 13 and 16. The finding of the antibody against suprarenal gland cortical elements seems to be essential for diagnosis of chronic nonspecific epinephritis since its appearance is mostly without false positivities. Also the antibodies against epidermal intercellular and basement membrane show similar high specificity. Both these antibodies unfortunately often fail and for their high number of false negative results are solely of affirmative importance, since their lack is evidently unwarranted for exclusion of considered disease. Both the findings of antibody against smooth muscle cells and against mitochondria are usefull for the diagnosis of liver lesions especially those of primary biliary cirrhosis. Anti brush-border antibody essentially assists the diagnosis of Crohn's disease and works to differentiate it from ulcerative colitis. Antireticulin antibodies counts frequently for the diagnosis of celiakia.(ABSTRACT TRUNCATED AT 400 WORDS)

Prevalence of adhesin and toxin genes in E. coli strains isolated from diarrheic and non-diarrheic pigs from smallholder herds in northern and eastern Uganda.

PubMed

Ikwap, Kokas; Larsson, Jenny; Jacobson, Magdalena; Owiny, David Okello; Nasinyama, George William; Nabukenya, Immaculate; Mattsson, Sigbrit; Aspan, Anna; Erume, Joseph

2016-08-05

Enterotoxigenic E. coli (ETEC) significantly contribute to diarrhea in piglets and weaners. The smallholder pig producers in Uganda identified diarrhea as one of the major problems especially in piglets. The aim of this study was to; i) characterize the virulence factors of E. coli strains isolated from diarrheic and non-diarrheic suckling piglets and weaners from smallholder herds in northern and eastern Uganda and ii) identify and describe the post-mortem picture of ETEC infection in severely diarrheic piglets. Rectal swab samples were collected from 83 piglets and weaners in 20 herds and isolated E. coli were characterized by PCR, serotyping and hemolysis. The E. coli strains carried genes for the heat stable toxins STa, STb and EAST1 and adhesins F4 and AIDA-I. The genes for the heat labile toxin LT and adhesins F5, F6, F18 and F41 were not detected in any of the E. coli isolates. Where the serogroup could be identified, E. coli isolates from the same diarrheic pig belonged to the same serogroup. The prevalence of EAST1, STb, Stx2e, STa, AIDA-I, and F4 in the E. coli isolates from suckling piglets and weaners (diarrheic and non-diarrheic combined) was 29, 26.5, 2.4, 1.2, 16, and 8.4 %, respectively. However the prevalence of F4 and AIDA-I in E. coli from diarrheic suckling piglets alone was 22.2 and 20 %, respectively. There was no significant difference in the prevalence of the individual virulence factors in E. coli from the diarrheic and non-diarrheic pigs (p > 0.05). The main ETEC strains isolated from diarrheic and non-diarrheic pigs included F4/STb/EAST1 (7.2 %), F4/STb (1.2 %), AIDA/STb/EAST1 (8 %) and AIDA/STb (8 %). At post-mortem, two diarrheic suckling piglets carrying ETEC showed intact intestinal villi, enterocytes and brush border but with a layer of cells attached to the brush border, suggestive of ETEC infections. This study has shown that the F4 fimbriae is the most predominant in E. coli from diarrheic piglets in the study area and therefore an F4-based vaccine should be considered one of the preventive measures for controlling ETEC infections in the piglets in northern and eastern Uganda.

A Brush Seals Program Modeling and Developments

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Flower, Ralph; Howe, Harold

1996-01-01

Some events of a U.S. Army/NASA Lewis Research Center brush seals program are reviewed, and the development of ceramic brush seals is described. Some preliminary room-temperature flow data are modeled and compare favorably to the results of Ergun.

Factors Affecting Oral Hygiene and Tooth Brushing in Preschool Children, Shiraz/Iran

PubMed Central

S, Shaghaghian; M, Zeraatkar

2017-01-01

Statement of Problem: Inadequate tooth brushing and inappropriate oral hygiene can lead to dental caries, the most common chronic diseases of childhood with several side effects. Objectives: To evaluate factors affecting on preschool children’s oral hygiene and tooth brushing in Shiraz, Iran Materials and Methods: In this cross-sectional study, we selected 453 children registered in Shiraz kindergartens in 2013 by randomized cluster sampling. The children’s tooth brushing and oral hygiene were assessed using a reliable and valid questionnaire and Simplified Debris Index (DI-S), respectively. A dental student examined all the children in each kindergarten to determine their DI-S. The relationship between the children’s demographic variables and their oral hygiene and tooth brushing status were evaluated. Results: Tooth brushing for 272 children (71.2%) had been started after the age of 2 years. The teeth in 96 children (24.2%) had been brushed lower than once daily. The mean of the children’s DI-S was 1.19 ± (0.77). The DI-S of only 126 children (31.8%) was found to be good and very good. After controlling the effect of confounding factors, we found that the children’s tooth brushing frequency was significantly associated with the number of children in the family and mothers’ employment status. The age at which tooth brushing had been started was significantly associated with the fathers’ education. Furthermore, the DI-S was associated with children’s age, number of the children in the family, and their mothers’ education. Conclusions: Oral hygiene and tooth brushing of the preschool children were not in a desirable status. Interventional procedures, especially educational programs, are recommended for children and their parents. These programs seem to be more necessary for older children, low socioeconomic families, and families with more than one child. PMID:28959771

Stereoregular polyacrylamide and its copolymer brushes: Preparation and surface characters

NASA Astrophysics Data System (ADS)

Jiang, Jianguo; Wang, Xiaoshu; Lu, Xiaoyan; Lu, Yun

2008-12-01

Two kinds of polymer brushes, the single one with stereospecific polyacrylamide (PAAM) chains and the dual-component one with random poly(methyl methacrylate) (PMMA) segments grafting from stereospecific PAAM chains, were prepared on silicon wafer for the first time by combining the immobilization of initiator and the stereospecific living radical in situ polymerization. With the addition of the Lewis acid AlCl 3 into the polymerization system, the PAAM brushes obtained exhibited an increased stereospecificity as well as a decreased hydrophilicity, which might attribute to the reduced thickness of PAAM brushes on the silicon wafer and the handicap of the free rotation of the stereospecific molecular chain. The smoother surface morphology of the stereospecific PAAM brushes shown in AFM images was in good agreement with the experimental data of water contact angle. Also, block amphiphilic copolymer brushes were prepared with the stereospecific PAAM formed first on silicon wafer as the anchored-initiator and revealed a novel surface self-assembly behavior after being treated with different solvent such as toluene or water. The stereospecificity of PAAM chains in the polymer brushes could be modulated by adjusting reaction conditions according to the requirement of applications for surface hydrophilicity.

Endoscopic transpapillary brush cytology and forceps biopsy in patients with hilar cholangiocarcinoma

PubMed Central

Weber, Andreas; von Weyhern, Claus; Fend, Falko; Schneider, Jochen; Neu, Bruno; Meining, Alexander; Weidenbach, Hans; Schmid, Roland M; Prinz, Christian

2008-01-01

AIM: To evaluate the sensitivity of brush cytology and forceps biopsy in a homogeneous patient group with hilar cholangiocarcinoma. METHODS: Brush cytology and forceps biopsy were routinely performed in patients with suspected malignant biliary strictures. Fifty-eight consecutive patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) including forceps biopsy and brush cytology in patients with hilar cholangiocarcinoma between 1995-2005. RESULTS: Positive results for malignancy were obtained in 24/58 patients (41.4%) by brush cytology and in 31/58 patients (53.4%) by forceps biopsy. The combination of both techniques brush cytology and forceps biopsy resulted only in a minor increase in diagnostic sensitivity to 60.3% (35/58 patients). In 20/58 patients (34.5%), diagnosis were obtained by both positive cytology and positive histology, in 11/58 (19%) by positive histology (negative cytology) and only 4/58 patients (6.9%) were confirmed by positive cytology (negative histology). CONCLUSION: Brush cytology and forceps biopsy have only limited sensitivity for the diagnosis of malignant hilar tumors. In our eyes, additional diagnostic techniques should be evaluated and should become routine in patients with negative cytological and histological findings. PMID:18286693

Evaluation of Brushing as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

NASA Technical Reports Server (NTRS)

Gaier, James R.; Journey, Khrissaundra; Christopher, Steven; Davis, Shanon

2011-01-01

Evaluation of brushing to remove lunar simulant dust from thermal control surfaces is described. First, strip brushes made with nylon, PTFE, or Thunderon (Nihon Sanmo Dyeing Company Ltd.) bristles were used to remove JSC-1AF dust from AZ93 thermal control paint or aluminized FEP (AlFEP) thermal control surface under ambient laboratory conditions. Nylon and PTFE bristles removed a promising amount of dust from AZ93, and nylon and Thunderon bristles from AlFEP. But when these were tested under simulated lunar conditions in the lunar dust adhesion bell jar (LDAB), they were not effective. In a third effort, seven brushes made up of three different materials, two different geometries, and different bristle lengths and thicknesses were tested under laboratory conditions against AZ93 and AlFEP. Two of these brushes, the Zephyr fiberglass fingerprint brush and the Escoda nylon fan brush, removed over 90 percent of the dust, and so were tested in the fourth effort in the LDAB. They also performed well under these conditions recovering 80 percent or more of the original thermal performance (solar absorptance/thermal emittance) of both AZ93 and AgFEP after 20 strokes, and 90 or more percent after 200 strokes

Evaluation of Brushing as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

NASA Technical Reports Server (NTRS)

Gaier, James R.; Journey, Hhrissaundra; Christopher, Steven; Davis, Shanon

2011-01-01

Evaluation of brushing to remove lunar simulant dust from thermal control surfaces is described. First, strip brushes made with nylon, PTFE, or Thunderon bristles were used to remove JSC-1AF dust from AZ93 thermal control paint or aluminized FEP (AlFEP) thermal control surface under ambient laboratory conditions. Nylon and PTFE bristles removed a promising amount of dust from AZ93, and nylon and Thunderon bristles from AlFEP. But when these were tested under simulated lunar conditions in the lunar dust adhesion bell jar (LDAB), they were not effective. In a third effort, seven brushes made up of three different materials, two different geometries, and different bristle lengths and thicknesses were tested under laboratory conditions against AZ93 and AlFEP. Two of these brushes, the Zephyr fiberglass fingerprint brush and the Escoda nylon fan brush, removed over 90 percent of the dust, and so were tested in the fourth effort in the LDAB. They also performed well under these conditions recovering 80 percent or more of the original thermal performance (solar absorptance/thermal emittance) of both AZ93 and AgFEP after 20 strokes, and 90 or more percent after 200 strokes.

Tension amplification in tethered layers of bottle-brush polymers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leuty, Gary M.; Tsige, Mesfin; Grest, Gary S.

2016-02-26

In this paper, molecular dynamics simulations of a coarse-grained bead–spring model have been used to study the effects of molecular crowding on the accumulation of tension in the backbone of bottle-brush polymers tethered to a flat substrate. The number of bottle-brushes per unit surface area, Σ, as well as the lengths of the bottle-brush backbones N bb (50 ≤ N bb ≤ 200) and side chains N sc (50 ≤ N sc ≤ 200) were varied to determine how the dimensions and degree of crowding of bottle-brushes give rise to bond tension amplification along the backbone, especially near the substrate.more » From these simulations, we have identified three separate regimes of tension. For low Σ, the tension is due solely to intramolecular interactions and is dominated by the side chain repulsion that governs the lateral brush dimensions. With increasing Σ, the interactions between bottle-brush polymers induce compression of the side chains, transmitting increasing tension to the backbone. For large Σ, intermolecular side chain repulsion increases, forcing side chain extension and reorientation in the direction normal to the surface and transmitting considerable tension to the backbone.« less

Cavitation during wire brushing

NASA Astrophysics Data System (ADS)

Li, Bo; Zou, Jun; Ji, Chen

2016-11-01

In our daily life, brush is often used to scrub the surface of objects, for example, teeth, pots, shoes, pool, etc. And cleaning rust and stripping paint are accomplished using wire brush. Wire brushes also can be used to clean the teeth for large animals, such as horses, crocodiles. By observing brushing process in water, we capture the cavitation phenomenon on the track of moving brush wire. It shows that the cavitation also can affect the surface. In order to take clear and entire pictures of cavity, a simplified model of one stainless steel wire brushing a boss is adopted in our experiment. A transparent organic tank filled with deionized water is used as a view box. And a high speed video camera is used to record the sequences. In experiment, ambient pressure is atmospheric pressure and deionized water temperature is kept at home temperature. An obvious beautiful flabellate cavity zone appears behind the moving steel wire. The fluctuation of pressure near cavity is recorded by a hydrophone. More movies and pictures are used to show the behaviors of cavitation bubble following a restoring wire. Beautiful tracking cavitation bubble cluster is captured and recorded to show.

Poor oral health, that is, decreased frequency of tooth brushing, is associated with endothelial dysfunction.

PubMed

Kajikawa, Masato; Nakashima, Ayumu; Maruhashi, Tatsuya; Iwamoto, Yumiko; Iwamoto, Akimichi; Matsumoto, Takeshi; Hidaka, Takayuki; Kihara, Yasuki; Chayama, Kazuaki; Goto, Chikara; Taguchi, Akira; Noma, Kensuke; Higashi, Yukihito

2014-01-01

 Poor oral health is an independent predictor of cardiovascular outcome. Endothelial dysfunction is the initial step of atherosclerosis, resulting in cardiovascular outcomes; but there is no information on the association between oral health and endothelial function. The purpose of this study was to determine the relationships between oral health and endothelial function.  A total of 190 subjects who underwent health examinations (mean age, 57±18 years), including patients with cardiovascular disease, completed a questionnaire on oral health and frequency of tooth brushing, and underwent measurement of vascular function, flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation. The subjects were divided into 2 groups according to frequency of tooth brushing (≥twice/day and

Dual wound dc brush motor gearhead

NASA Technical Reports Server (NTRS)

Henson, Barrie W.

1986-01-01

The design requirements, the design, development tests and problems, the qualification and life test and the findings of the strip examination of a dual wound DC brushed motor gearhead are described. It is the only space qualified dual wound dc brushed motor gearhead in Europe.

Applications of functional polymer brushes for nanoparticle uptake and prevention of protein adsorption

NASA Astrophysics Data System (ADS)

Arifuzzaman, Shafi M.

The central theme of this Ph.D. dissertation is to develop novel multifunctional polymer coatings for understanding partition of proteins and nanoparticles on polymers grafted to flat surfaces (so-called brushes). Systematic investigation of the adsorption phenomena is accomplished by utilizing surface-anchored assemblies comprising grafted polymers with variation in physical properties (i.e., length or/and grafting density) and chemical functionality. The chemical composition of the brush is tailored by either "chemical coloring" of a parent homopolymer brush with selective chemical moieties or by sequential growth of two chemically dissimilar polymer blocks. We present preparation of two types of tailor-made, surface-grafted copolymers: (1) those composed of hydrophilic and hydrophobic blocks (so-called amphiphilic polymer brushes), and (2) those comprising of anionic and cationic polymer segments (so-called polyampholyte brushes). We describe the organization of functionality in the grafted polymer brushes and the partitioning of proteins and nanoparticles using a battery of complementary analytical probes. Specifically, we address how varying the molecular weight, grafting density, and chemical composition of the brush affects adsorbtion and desorbtion of model proteins and gold nanoparticles. Our observations indicate densely-populated responsive amphiphilic polymers are very efficient in suppressing protein adsorption. In addition, we have established that the length of poly(ethylene glycol) spacers attached to a parent homopolymer brush is a key factor governing uptake of gold nanoparticles. Both grafting density and molecular weight of the coating are important in controlling the kinetics and thermodynamics of protein adsorption on surfaces. Our findings and methodologies can lead to the development of next generation environmentally friendly antifouling surfaces and will find application in medical devices, antifouling coatings and anti reflection finishes.

Changes to Glazed Dental Ceramic Shade, Roughness, and Microhardness after Bleaching and Simulated Brushing.

PubMed

Rodrigues, Carlos Roberto Teixeira; Turssi, Cecilia Pedroso; Amaral, Flávia Lucisano Botelho; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes

2017-09-05

To evaluate shade stability, surface roughness, microhardness, and compressive strength of a glazed feldspathic ceramic subjected to bleaching and simulated brushing. Eighty-eight glazed feldspathic ceramic specimens were made from microparticulate leucite and divided into eight groups (n = 10). The whitening products used were: Opalescence Trèswhite Supreme (Ultradent), Opalescence®\\ PF 15% (Ultradent), and Oral-B 3D White Whitestrips. All substances for whitening were used for 4 hours/day for a period of 14 days; the control group was not bleached. Next, half of the specimens were individually brushed. Microhardness and surface roughness data were subjected to three-way ANOVA and Tukey test. The diametrical tensile strength data were subjected to two-way ANOVA. The shade change data were analyzed using Kruskal-Wallis, Mann-Whitney, and the Student-Newman-Keuls test. The significance level was set at 5%. Glazed feldspathic ceramic surface microhardness was significantly affected by bleaching agents (p = 0.007). Initially, glazed ceramic microhardness was significantly higher than that observed after contact with the bleaching agents, whether or not brushing was performed. The specimens submitted to bleaching in preloaded trays presented lower surface roughness values after brushing (p = 0.037). The surface roughness was significantly lower in the brushed specimens (p = 0.044). The diametrical tensile strength was not significantly affected by the application of bleaching agents (p = 0.563) or by brushing (p = 0.477). When the specimens were brushed, however, shade change was significantly influenced by the bleaching agent used (p = 0.041). Bleaching agents associated with brushing cycles can alter surface properties and shade stability of glazed feldspathic ceramics, though such findings may not reflect the performance of unglazed feldspathic ceramics. © 2017 by the American College of Prosthodontists.

Association of tongue brushing with the number of fungiform taste buds and taste perception: A preliminary study using confocal laser scanning microscopy in combination with a filter-paper disc method.

PubMed

Kobayashi, Junichi; Saito, Takehisa; Ito, Tetsufumi; Yoshimura, Hitoshi; Matsuda, Shinpei; Yoshida, Hisato; Fujita, Ryousuke; Sano, Kazuo

2017-12-01

The aim of this study was to investigate the association of tongue brushing with the number of fungiform taste buds and taste perception using a confocal laser scanning microscopy in combination with a filter-paper disc method (FPDM). Twenty-four subjects with or without a habit of tongue brushing (11 males and 13 females, 20-46 years old) participated in this study. Nine of the 24 subjects had no habit of tongue brushing (Group 1, n=9). Fifteen subjects had a habit of tongue brushing, and the brushing regions of the tongue were as follows: central region (Group 2, n=7), or entire region (Group 3, n=8) of the tongue dorsum. Using confocal laser scanning microscopy, the average number of taste buds per fungiform papilla (FP) was counted. Taste perception was evaluated using an FPDM. These observations were performed in the midlateral region of the tongue since the distribution of fungiform papillae is large in the midlateral region compared to that in the central region. The subjects in Group 3 showed a significantly decreased number of fungiform taste buds compared to Group 1 and Group 2. Group 3 also showed significantly higher FPDM scores than the other two groups. Excessive tongue brushing of the entire tongue dorsum, including the midlateral region, may have an association with the decreased number of FP and taste buds and decreased taste sensation. To avoid these conditions, instituting proper tongue brushing methods, such as limiting it to the central region of the tongue and using a light touch, is suggested and is important for the subjects who are eager to participate in tongue brushing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Regular Tooth Brushing is Associated with a Decreased Risk of Metabolic Syndrome According to a Medical Check-Up Database.

PubMed

Tsutsumi, Chiyo; Kakuma, Tatsuyuki

2015-01-01

Associations have been reported between periodontal disease and increased cardiovascular disease risk, as well as between healthy self-reported tooth brushing behavior and reduced cardiovascular disease risk. We examined the association between self-reported tooth brushing behavior and the risk of metabolic syndrome (MetS) using a large medical check-up database. A total of 12,548 medical checkup records from a medical screening center in a city in southwest Japan were assessed. Subjects were aged 30 to 59 years. As lifestyle is associated with both tooth brushing and MetS, many lifestyle variables were considered as potential confounders. Logistic regression model were employed with a list of 127 lifestyle variables. Twenty variables associated with both tooth brushing and MetS were selected for both males and females. Furthermore, final confounding variables were selected by principal component analysis to avoid collinearity problems. The association of tooth brushing and MetS was evaluated for males and females separately by calculating adjusted odds ratios (ORs) with selected confounders plus age. The association between daily tooth brushing frequency and MetS risk for both genders was significant after adjusting for confounders, with the risk of MetS decreasing with increased frequency of daily tooth brushing (adjusted OR = 0.57 (95%Cl:0.48-0.81), 0.50 (95%Cl:0.35-0.71), 0.42 (95%Cl: 0.29-0.61) for males and adjusted OR = 0.65 (95%Cl:0.48-0.87), 0.44 (95%Cl:0.32-0.62) for females). Therefore, oral hygiene, including the frequency of tooth brushing as a significant component, may be an important factor in preventing MetS.

[Brushing abrasion of the enamel surface after erosion].

PubMed

Lipei, Chen; Xiangke, Ci; Xiaoyan, Ou

2017-08-01

Objective A study was conducted to compare the effect of different enamel remineralization periods after erosion on the depth of brushing abrasion. Methods Ten volunteers were selected for a 4-day experiment. A total of 60 enamels were randomly assigned into six groups (A-F) and placed in intraoral palatal devices. On the first day, the palatal devices were placed in oral cavity (24 h) . On the following three days, brushing experiments were performed extraorally, two times per day. The specific experimental method of brushing follows these next steps. First, the group F specimens were covered with a film of wax, and then acid etched for 2 min. Subsequently, the film of wax was detached. The groups from A to D were brushed after remineralization at the following time intervals: group A, 0 min; group B, 20 min; group C, 40 min; group D, 60 min. Erosion and remineralization were performed on group E, but without brushing. Remineralization was performed on group F, but without acid etching and brushing. The depth of enamel abrasion was determined by a mechanical profilometer. The surface morphology of the enamel blocks was observed using a scanning electron microscope. Results 1) The depth of abrasion was different in varied enamel remineralization time after acid etching. The statistical significant differences between groups were as follows. 2) When the time of enamel remineralization after acid etching was short, the surface depression in the electron microscope was deep, and the surface morphology was rough. Conclusion Brushing immediately after acid etching would cause much serious abrasion to the enamel surface. Brushing after 60 min can effectively reduce the abrasion of acid etching enamel.

Smoking, tooth brushing and oral cleanliness among 15-year-olds in Tehran, Iran.

PubMed

Yazdani, Reza; Vehkalahti, Miira M; Nouri, Mahtab; Murtomaa, Heikki

2008-01-01

To assess smoking, tooth brushing and oral cleanliness and their relationships among 15-year-olds in Tehran, Iran. A cross-sectional study based on World Health Organization criteria and the methods of the Second International Collaborative Study was carried out in autumn 2004 among 15-year-olds (n=502) in Tehran. Data were based on a self-administered questionnaire and a clinical dental examination. Smokers comprised 5% of the boys and 2% of the girls (p = 0.02). Smoking was more common among students of less-educated parents (50% vs. 30%, p < 0.05). Of all students, 26% reported twice-daily tooth brushing; those of higher socio-economic backgrounds and girls did so more frequently. Of the smokers, 11% reported no tooth brushing compared to 6% of the non-smokers. Oral cleanliness was good for 13%, moderate for 32%, and poor for 55%; the rates associated positively with female gender (p = 0.002), having higher-educated parents (p = 0.03), and reporting a higher frequency of tooth brushing (p < 0.001). Those students reporting twice-daily tooth brushing had less dental plaque and gingival bleeding (p < or = 0.01) on both anterior and posterior teeth. In multivariable analyses, the best predictors for a good level of oral cleanliness were female gender (OR = 2.0) or twice-daily tooth brushing (OR = 1.7). Oral cleanliness and tooth brushing among 15-year-olds were at poor levels, particularly among boys. Such poor levels call for intensive attempts to enhance rates of twice-daily tooth brushing and to improve its quality. For this age group, anti-smoking purposes should be combined into school-based oral health promotion programmes as well.

Osmotic and Salted Brush Phase of Polyelectrolyte Brushes

NASA Astrophysics Data System (ADS)

Helm, Christane A.; Ahrens, Heiko; Förster, Stephan

2004-03-01

Amphiphilic block copolymers consisting of a fluid hydrophobic Poly(ethyletylene) (PEE), and a Poly(styrenesulfonate) (PSS) part form monolayers at the air/water interface. With x-ray reflectivity it is shown that the hydrophobic blocks of PEE_114PSS_83 and PEE_144PSS_136 constitute a nm-thick melt, while the polyelectrolyte forms an osmotically swollen brush with counterion incorporation. A slight thickness increase on monolayer compression is found which can be explained by the strong stretching of the brushes. Only at high salt conditions (above 0.1 M), the brush shrinks and the thickness scales with the molecular area (exponent -1/3), and with the salt concentration (exponent ca. -1/5). With Grazing Incidence Diffraction, the lateral order of the polyelectrolyte chains can be detected.

Damage of target edges in brush-like geometry in the course of ELM-like plasma pulses in QSPA Kh-50

NASA Astrophysics Data System (ADS)

Makhlaj, V. A.; Garkusha, I. E.; Aksenov, N. N.; Bazylev, B.; Byrka, O. V.; Chebotarev, V. V.; Landman, I.; Herashchenko, S. S.; Staltsov, V. V.

2015-08-01

Castellated edges of macro-brush armour elements of ITER divertor can be a source of molten/solid dust particles which are injected into the plasma. The targets that combined in brush-like geometry have been irradiated under different inclination angles in QSPA Kh-50. The cubic brushes element has typical size of 1 cm. The titanium was used to investigate dynamics of mountains' formation. The onset of dust particles ejection from the exposed castellated targets has been studied. Formation of resolidified bridges through the gaps of brush-like targets due to the melt motion is studied in dynamics. With following plasma impacts such resolidified bridges became additional source of dust.

Trends in Social Inequality in Tooth Brushing among Adolescents: 1991-2014.

PubMed

Holstein, Bjørn E; Bast, Lotus Sofie; Brixval, Carina Sjöberg; Damsgaard, Mogens Trab

2015-01-01

This study examines whether social inequality in tooth brushing frequency among adolescents changed from 1991 to 2014. The data material was seven comparable cross-sectional studies of nationally representative samples of 11- to 15-year-olds in Denmark with data about frequency of tooth brushing and occupation of parents. The total number of participants was 31,464, of whom 21.7% brushed their teeth less than the recommended 2 times a day. The absolute social inequality measured as prevalence difference between low and high social class increased from 7.7% in 1991 to 14.6% in 2014. The relative social inequality assessed by odds ratios for infrequent tooth brushing also increased from 1991 to 2014. © 2015 S. Karger AG, Basel.

Rapid cortical oscillations and early motor activity in premature human neonate.

PubMed

Milh, Mathieu; Kaminska, Anna; Huon, Catherine; Lapillonne, Alexandre; Ben-Ari, Yehezkel; Khazipov, Rustem

2007-07-01

Delta-brush is the dominant pattern of rapid oscillatory activity (8-25 Hz) in the human cortex during the third trimester of gestation. Here, we studied the relationship between delta-brushes in the somatosensory cortex and spontaneous movements of premature human neonates of 29-31 weeks postconceptional age using a combination of scalp electroencephalography and monitoring of motor activity. We found that sporadic hand and foot movements heralded the appearance of delta-brushes in the corresponding areas of the cortex (lateral and medial regions of the contralateral central cortex, respectively). Direct hand and foot stimulation also reliably evoked delta-brushes in the same areas. These results suggest that sensory feedback from spontaneous fetal movements triggers delta-brush oscillations in the central cortex in a somatotopic manner. We propose that in the human fetus in utero, before the brain starts to receive elaborated sensory input from the external world, spontaneous fetal movements provide sensory stimulation and drive delta-brush oscillations in the developing somatosensory cortex contributing to the formation of cortical body maps.

What information can frictional properties of polymer brushes tell us?

NASA Astrophysics Data System (ADS)

Zhang, Zhenyu; Moxey, Mark; Morse, Andrew; Armes, Steven; Lewis, Andrew; Geoghegan, Mark; Leggett, Graham

2013-03-01

We have used friction force microscopy (FFM) to quantitatively examine surface grown zwitterionic polymer brushes: poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC), and to establish the correlation between its frictional behaviour to other intrinsic properties. In a good solvent, it was found that the coefficient of friction (μ) decreased with increasing film thickness. We conclude that the amount of bound solvent increases as the brush length increases, causing the osmotic pressure to increase and yielding a reduced tendency for the brush layer to deform under applied load. When measured in a series of alcohol/water mixtures, a significant increase in μ was observed for ethanol/water mixtures at a volume fraction of 90%. This is attributed to brush collapse due to co-nonsolvency, leading to loss of hydration of the brush chains and hence substantially reduced lubrication. We show that single asperity contact mechanics is strongly dependent on solvent quality. Friction-load relationship was found linear in methanol (good solvent), but sub-linear in water and ethanol (moderate solvent).

Some metallographic results for brush bristles and brush segments of a shroud ring brush seal tested in a T-700 engine

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Griffin, Thomas A.; Bobula, George A.; Bill, Robert C.; Hull, David R.; Csavina, Kristine R.

1994-01-01

Post-test investigation of a T-700 engine brush seal found regions void of bristles ('yanked out'), regions of bent-over bristles near the inlet, some 'snapped' bristles near the fence, and a more uniform smeared bristle interface between the first and last axial rows of bristles. Several bristles and four brush segments were cut from the brush seal, wax mounted, polished, and analyzed. Metallographic analysis of the bristle near the rub tip showed tungsten-rich phases uniformly distributed throughout the bristle, no apparent change within 1 mu m of the interface, and possibly a small amount of titanium, which would represent a transfer from the rotor. Analysis of the bristle wear face showed nonuniform tungsten, which is indicative of material resolidification. The cut end contained oxides and internal fractures; the worn end was covered with oxide scale. Material losses due to wear and elastoplastic deformation within the shear zone and third-body lubrication effects in the contact zone are discussed.

Monomer volume fraction profiles in pH responsive planar polyelectrolyte brushes

DOE PAGES

Mahalik, Jyoti P.; Yang, Yubo; Deodhar, Chaitra V.; ...

2016-03-06

Spatial dependencies of monomer volume fraction profiles of pH responsive polyelectrolyte brushes were investigated using field theories and neutron reflectivity experiments. In particular, planar polyelectrolyte brushes in good solvent were studied and direct comparisons between predictions of the theories and experimental measurements are presented. The comparisons between the theories and the experimental data reveal that solvent entropy and ion-pairs resulting from adsorption of counterions from the added salt play key roles in affecting the monomer distribution and must be taken into account in modeling polyelectrolyte brushes. Furthermore, the utility of this physics-based approach based on these theories for the predictionmore » and interpretation of neutron reflectivity profiles in the context of pH responsive planar polyelectrolyte brushes such as polybasic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and polyacidic poly(methacrylic acid) (PMAA) brushes is demonstrated. The approach provides a quantitative way of estimating molecular weights of the polymers polymerized using surface-initiated atom transfer radical polymerization.« less

Polymer absorption in dense polymer brushes vs. polymer adsorption on the brush-solvent interface

NASA Astrophysics Data System (ADS)

Milchev, Andrey; Binder, Kurt

2014-06-01

Molecular-dynamics simulations of a coarse-grained model of a dense brush of flexible polymers (of type A) interacting with a long flexible macromolecule (of type B) are presented, considering the case of an attractive AB interaction, while effective interactions between AA and BB pairs of monomers are repulsive. Varying the strength \\varepsilon_{AB} of the attraction between unlike monomers, an adsorption transition at some critical value \\varepsilon^c_{AB} is found, where the B-chain is bound to the brush-solvent interface, similar to the adsorption on a planar solid substrate. However, when \\varepsilon_{AB} is much higher than \\varepsilon^c_{AB} , the long macromolecule is gradually “sucked in” the brush, developing many pieces that are locally stretched in the z-direction perpendicular to the substrate, in order to fit between the brush chains. The resulting hairpin-like structures of the absorbed chain shows up via oscillatory decay of the bond vector autocorrelation function. Chain relaxation is only possible via reptation.

Molecular dynamics simulations of polyelectrolyte brushes under poor solvent conditions: origins of bundle formation.

PubMed

He, Gui-Li; Merlitz, Holger; Sommer, Jens-Uwe

2014-03-14

Molecular dynamics simulations are applied to investigate salt-free planar polyelectrolyte brushes under poor solvent conditions. Starting above the Θ-point with a homogeneous brush and then gradually reducing the temperature, the polymers initially display a lateral structure formation, forming vertical bundles of chains. A further reduction of the temperature (or solvent quality) leads to a vertical collapse of the brush. By varying the size and selectivity of the counterions, we show that lateral structure formation persists and therefore demonstrate that the entropy of counterions being the dominant factor for the formation of the bundle phase. By applying an external compression force on the brush we calculate the minimal work done on the polymer phase only and prove that the entropy gain of counterions in the bundle state, as compared to the homogeneously collapsed state at the same temperature, is responsible for the lateral microphase segregation. As a consequence, the observed lateral structure formation has to be regarded universal for osmotic polymer brushes below the Θ-point.

Evaluation of Internal Brushing on Pinch Weld Quality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korinko, P

2005-12-01

Post machining operations such as borescope inspection can cause linear indications down the length of the bore of fill stems. Often these indications are removed or obscured using rotary wire brushing. This study evaluated the effect this mechanical operation may have on pinch weld quality when relatively cold welds were made. A total of four stems with two levels of brushing of both Type 304L and 21-6-9 stainless steels were tested. In addition, two each of the Type 304L stems were Nitradd cleaned and the other two were aqueously cleaned; all four 21-6-9 stems were aqueously cleaned. All of themore » brushed stem areas exhibited more surface anomalies based on borescope evaluation. On average, the bond rating was a higher value (worse) for the brushed areas than the unadulterated areas for both Type 304L and 21-6-9 stems. The test method used may have biased the results towards a lesser quality bond for the brushed areas so additional testing is recommended.« less

Emerging Technologies for the Diagnosis of Perihilar Cholangiocarcinoma.

PubMed

Rizvi, Sumera; Eaton, John; Yang, Ju Dong; Chandrasekhara, Vinay; Gores, Gregory J

2018-05-01

The diagnosis of malignant biliary strictures remains problematic, especially in the perihilar region and in primary sclerosing cholangitis (PSC). Conventional cytology obtained during endoscopic retrograde cholangiography (ERC)-guided brushings of biliary strictures is suboptimal due to limited sensitivity, albeit it remains the gold standard with a high specificity. Emerging technologies are being developed and validated to address this pressing unmet patient need. Such technologies include enhanced visualization of the biliary tree by cholangioscopy, intraductal ultrasound, and confocal laser endomicroscopy. Conventional cytology can be aided by employing complementary and advanced cytologic techniques such as fluorescent in situ hybridization (FISH), and this technique should be widely adapted. Interrogation of bile and serum by examining extracellular vesicle number and cargo, and exploiting next-generation sequencing and proteomic technologies, is also being explored. Examination of circulating cell-free deoxyribonucleic acid (cfDNA) for differentially methylated regions is a promising test which is being rigorously validated. The special expertise required for these analyses has to date hampered their validation and adaptation. Herein, we will review these emerging technologies to inform the reader of the progress made and encourage further studies, as well as adaptation of validated approaches. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

PubMed

Cao, Zi-Quan; Wang, Guo-Jie

2016-06-01

Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cloning strategy for producing brush-forming protein-based polymers.

PubMed

Henderson, Douglas B; Davis, Richey M; Ducker, William A; Van Cott, Kevin E

2005-01-01

Brush-forming polymers are being used in a variety of applications, and by using recombinant DNA technology, there exists the potential to produce protein-based polymers that incorporate unique structures and functions in these brush layers. Despite this potential, production of protein-based brush-forming polymers is not routinely performed. For the design and production of new protein-based polymers with optimal brush-forming properties, it would be desirable to have a cloning strategy that allows an iterative approach wherein the protein based-polymer product can be produced and evaluated, and then if necessary, it can be sequentially modified in a controlled manner to obtain optimal surface density and brush extension. In this work, we report on the development of a cloning strategy intended for the production of protein-based brush-forming polymers. This strategy is based on the assembly of modules of DNA that encode for blocks of protein-based polymers into a commercially available expression vector; there is no need for custom-modified vectors and no need for intermediate cloning vectors. Additionally, because the design of new protein-based biopolymers can be an iterative process, our method enables sequential modification of a protein-based polymer product. With at least 21 bacterial expression vectors and 11 yeast expression vectors compatible with this strategy, there are a number of options available for production of protein-based polymers. It is our intent that this strategy will aid in advancing the production of protein-based brush-forming polymers.

Binary Polymer Brushes of Strongly Immiscible Polymers.

PubMed

Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

2015-06-17

The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

Comparison of diagnostic performances among bronchoscopic sampling techniques in the diagnosis of peripheral pulmonary lesions.

PubMed

Boonsarngsuk, Viboon; Kanoksil, Wasana; Laungdamerongchai, Sarangrat

2015-04-01

There are many sampling techniques dedicated to radial endobronchial ultrasound (R-EBUS) guided flexible bronchoscopy (FB). However, data regarding the diagnostic performances among bronchoscopic sampling techniques is limited. This study was conducted to compare the diagnostic yields among bronchoscopic sampling techniques in the diagnosis of peripheral pulmonary lesions (PPLs). A prospective study was conducted on 112 patients who were diagnosed with PPLs and underwent R-EBUS-guided FB between Oct 2012 and Sep 2014. Sampling techniques-including transbronchial biopsy (TBB), brushing cell block, brushing smear, rinsed fluid of brushing, and bronchoalveolar lavage (BAL)-were evaluated for the diagnosis. The mean diameter of the PPLs was 23.5±9.5 mm. The final diagnoses included 76 malignancies and 36 benign lesions. The overall diagnostic yield of R-EBUS-guided bronchoscopy was 80.4%; TBB gave the highest yield among the 112 specimens: 70.5%, 34.8%, 62.5%, 50.0% and 42.0% for TBB, brushing cell block, brushing smear, rinsed brushing fluid, and BAL fluid (BALF), respectively (P<0.001). TBB provided high diagnostic yield irrespective of the size and etiology of the PPLs. The combination of TBB and brushing smear achieved the maximum diagnostic yield. Of 31 infectious PPLs, BALF culture gave additional microbiological information in 20 cases. TBB provided the highest diagnostic yield; however, to achieve the highest diagnostic performance, TBB, brushing smear and BAL techniques should be performed together.

Comparison of the tooth brushing habits of primary school age children and their parents.

PubMed

Ozbek, Ceren Damla; Eser, Didem; Bektas-Kayhan, Kivanc; Unur, Meral

2015-01-01

As they grow, children develop their attitude and behavior related to tooth brushing by taking their parents' oral-dental health behavior as an example. The purpose of this study was to assess whether there was a similarity in tooth brushing between primary school-age children and their parents presenting to the Department of Oral, Dental and Jaw Diseases and Surgery and the Department of Pedodontics, School of Dental Medicine, Istanbul University. The study included 126 children and their parents, as totally 252 subjects. The data on oral hygiene of the subjects were obtained using a questionnaire form including questions on the qualitative-quantitative tooth brushing habits of the children and their parents and the socio-demographic characteristics of their families. In most of the cases, there was a similarity between children and their parents in terms of the frequency of dentist visits, the therapy they underwent in their last dentist visit, the cause of caries, the frequency of tooth brushing, the material used for oral hygiene, the duration of tooth brushing, method of tooth brushing, and tooth sites most brushed, which showed a significant association between children and their parents (p<0.01). Correct knowledge given to the children by their families will positively affect the oral-dental health of the children. Thus, firstly, correct knowledge should be given to the parents so that they can successfully carry out their responsibility in being the correct model for their children in oral-dental health.

Experience of maintaining tooth brushing for children born with a cleft lip and/or palate.

PubMed

Lin, Yin-Ling; Davies, Karen; Callery, Peter

2017-08-24

Children with a Cleft Lip and/or Palate (CL/P) have been reported to have poorer oral health than those without the condition. The consequences for these children can be particularly problematic due to implications for future treatments. Tooth brushing is an important behaviour contributing to children's oral health, but is under researched in the CL/P population. The aim of the study is to explore the experience of maintaining tooth brushing among children in the United Kingdom (UK) with a CL/P and their parents. Semi-structured interviews were carried out with twenty-two parents and sixteen children with a CL/P (5-11 years), recruited at a cleft centre in the UK. Thematic analysis was used for data analysis. Three key themes were drawn from the qualitative data: first, parents of children with a CL/P generally had strong motivation to look after their children's teeth but children's motivation was inconsistent. Second, parents were primary enablers of children's tooth brushing behaviour, often employing approaches adapted to their child's characteristics to encourage tooth brushing. Third, a range of obstacles were encountered by parents and children in maintaining regular tooth brushing behaviours. They reported obstacles such as issues related to CL/P, 'forgetting' and childhood illness. The paper suggests that parents of children with a CL/P need support to enact their intention to maintain regular tooth brushing and prioritise tooth brushing within the context of demanding and dynamic family life.

Wildlife responses to brush management: a contemporary evaluation

USDA-ARS?s Scientific Manuscript database

Brush management has been widely practiced with the general intent of curtailing or reversing the proliferation of shrubs and trees in grasslands and savannas. The traditional aim of brush management has been to increase livestock forage or to improve water yield. Its potential role for restoring h...

75 FR 39706 - Natural Bristle Paint Brushes From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-12

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-244 (Third Review)] Natural Bristle Paint Brushes From China AGENCY: United States International Trade Commission. ACTION: Revised schedule for the... natural bristle paint brushes from China (75 FR 21347, April 23, 2010). On April 23, 2010, the domestic...

A four-week clinical study to evaluate and compare the effectiveness of a baking soda dentifrice and an antimicrobial dentifrice in reducing plaque.

PubMed

Ghassemi, Annahita; Vorwerk, Linda M; Hooper, William J; Putt, Mark S; Milleman, Kimberly R

2008-01-01

To evaluate and compare the effectiveness in reducing plaque of a fluoride dentifrice containing baking soda and a non-baking soda fluoride dentifrice containing an antimicrobial (triclosan/copolymer) system after a single brushing and over a four-week period of daily brushing. A total of 207 subjects completed this randomized, blinded, parallel-group clinical study. Twenty-four hour plaque buildup was scored at baseline and after two and four weeks of twice-daily use of the products. Additionally, controlled single brushing with the assigned dentifrice, followed by post-brushing plaque assessment, was performed at the start (baseline visit) and end (Week-4 visit) of the study. Plaque was scored using the Turesky, et al. modification of Quigley-Hein Index at six sites per tooth, according to Soparkar's modification. Mean baseline whole mouth plaque scores for the baking soda and triclosan dentifrice groups were 2.90 +/- 0.40 and 2.90 +/- 0.39, respectively, and the difference was not statistically significant. Within-group analysis showed that both products significantly reduced the amount of plaque over the four-week period (p < 0.001). Between-group analysis showed that brushing with the baking soda dentifrice exhibited significantly greater reduction in plaque scores (p < 0.001) after two and four weeks of brushing as compared to the triclosan dentifrice. After four weeks, the mean plaque reduction for the baking soda dentifrice group (0.34 +/- 0.32) was 2.22-fold greater than that observed for the triclosan dentifrice group (0.15 +/- 0.24). Similarly, single brushing with the baking soda dentifrice showed a 1.88- to 2.08-fold greater pre- to post-brushing plaque difference as compared to the triclosan dentifrice at the baseline visit (mean plaque reduction: baking soda 0.54 +/- 0.26; triclosan 0.28 +/- 0.18; ratio 1.88X) and Week-4 visit (baking soda 0.47 +/- 0.21; triclosan 0.23 +/- 0.15; ratio 2.08X). Similar to the whole mouth scores, evaluation of various tooth sites (facial, lingual, proximal, and gingival) showed a significantly greater reduction in plaque scores for brushing with the baking soda dentifrice as compared to brushing with the triclosan dentifrice. The results of this study indicate that the baking soda dentifrice was more effective than the non-baking soda, antimicrobial dentifrice in plaque removal after a single tooth brushing, and in maintaining significantly lower plaque levels during a four-week period of twice daily, unsupervised tooth brushing.

Tension Amplification in Molecular Brushes in Solutions and on Substrates

PubMed Central

Panyukov, Sergey; Zhulina, Ekaterina B.; Sheiko, Sergei S.; Randall, Greg C.; Brock, James; Rubinstein, Michael

2009-01-01

Molecular bottle-brushes are highly branched macromolecules with side chains densely grafted to a long polymer backbone. The brush-like architecture allows focusing of the side-chain tension to the backbone and its amplification from the picoNewton to nanoNewton range. The backbone tension depends on the overall molecular conformation and the surrounding environment. Here we study the relation between the tension and conformation of the molecular brushes in solutions, melts, and on substrates. In solutions, we find that the backbone tension in dense brushes with side chains attached to every backbone monomer is on the order of f0N3/8 in athermal solvents, f0N1/3 in θ-solvents, and f0 in poor solvents and melts, where N is the degree of polymerization of side chains, f0≃ kBT/b is the maximum tension in side chains, b is the Kuhn length, kB is Boltzmann constant, and T is absolute temperature. Depending on the side chain length and solvent quality, molecular brushes in solutions develop tension on the order of 10–100 picoNewtons, which is sufficient to break hydrogen bonds. Significant amplification of tension occurs upon adsorption of brushes onto a substrate. On a strongly attractive substrate, maximum tension in the brush backbone is ~ f0N, reaching values on the order of several nanoNewtons which exceed the strength of a typical covalent bond. At low grafting density and high spreading parameter the cross-sectional profile of adsorbed molecular brush is approximately rectangular with thicknes ~bA/S, where A is the Hamaker constant and S is the spreading parameter. At a very high spreading parameter (S > A), the brush thickness saturates at monolayer ~ b. At a low spreading parameter, the cross-sectional profile of adsorbed molecular brush has triangular tent-like shape. In the cross-over between these two opposite cases, covering a wide range of parameter space, the adsorbed molecular brush consists of two layers. Side chains in the lower layer gain surface energy due to the direct interaction with the substrate, while the second layer spreads on the top of the first layer. Scaling theory predicts that this second layer has a triangular cross-section with width R ~ N3/5 and height h ~ N2/5. Using self-consistent field theory we calculate the cap profile y (x) = h (1 − x2/R2)2, where x is the transverse distance from the backbone. The predicted cap shape is in excellent agreement with both computer simulation and experiment. PMID:19673133

Induction of a reversible cardiac lipidosis by a dietary long-chain fatty acid (erucic acid). Relationship to lipid accumulation in border zones of myocardial infarcts.

PubMed Central

Chien, K. R.; Bellary, A.; Nicar, M.; Mukherjee, A.; Buja, L. M.

1983-01-01

Previous studies have demonstrated that cardiac myocytes in the border zone of acute myocardial infarction become markedly overloaded with neutral lipid during the transition from reversible to irreversible injury. To examine directly the role of these changes in neutral lipid metabolism in the development of irreversible cellular injury and associated increases in tissue Ca2+ content, the authors fed rats large amounts of a fatty acid (erucic acid) that is poorly oxidized by the heart and that subsequently accumulates as neutral lipid. Rats fed a high erucic acid (C22:1) diet in the form of 20% rapeseed oil for 3-5 days had a fourfold increase in triglyceride (49.5 +/- 3.8 SEM mg/g wet wt versus 13.6 +/- 13, n = 4) and a 60% increase in long-chain acyl CoA content (166.0 +/- 21.9 versus 91.5 +/- 9.0 nM/g wet wt, n = 4), compared with controls. However, there was no change in long-chain acyl carnitine or total phospholipid content. Histochemical studies showed accumulation of numerous lipid droplets in the myocytes, and electron microscopy revealed localization of lipid vesicles in direct contact with mitochondria, thus mimicking the lipid-laden cells in the border zone regions of acute myocardial infarcts. The acute lipidosis was reversible with either continued feeding of erucic acid for several weeks or conversion to a normal diet. It was not associated with an increased tissue Ca2+ content, nor with cell necrosis. However, continued erucic acid intake for 3 months was associated with focal myocardial degeneration and loss of myocytes. These results suggest that acute increases in neutral lipids, as found in the border zone of acute myocardial infarction, may not be the cause of progression to irreversible damage during acute myocardial injury, but that the persistent presence of similar lipid material over months may result in focal myocardial degeneration. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:6859230

Prognostic value of seminal vesicle involvement due to prostate cancer in radical prostatectomy specimens.

PubMed

Algarra, R; Barba, J; Merino, I; Tienza, A; Tolosa, E; Robles, J E; Zudaire, J

2015-04-01

To study the influence, in terms of prognosis, of the finding of seminal vesicle involvement in patients with prostate adenocarcinoma treated with radical prostatectomy. We reviewed a series of patients with seminal vesicle involvement with clinically localized prostate adenocarcinoma who underwent radical prostatectomy between 1989 and 2009, focusing on their clinical-pathological characteristics, biochemical progression-free survival (BPFS) and specific survival (SS). We assessed the variables that influenced BPFS and designed a risk model. A total of 127 out of 1,132 patients who underwent surgery (11%) presented seminal vesicle invasion (i.e., pT3b). In the multivariate study of the entire series (Cox model), pT3b affects the BPFS (HR: 2; 95% CI: 1.4-3.3; P=.001). Other influential factors were the affected borders, initial prostate-specific antigen levels, pathological Gleason score and the presence of palpated tumor. The pT3b tumors have poorer clinical-pathological variables when compared with pT2 and pT3a tumors. Sixty-five percent of the patients evidenced biochemical progression. The BPFS was significantly poorer for pT3b (40 ± 4% and 28 ± 4% at 5 and 10 years, respectively) than for pT2 and pT3a (P<.0001). The SS was also poorer in patients with pT3b tumors (91 ± 2% and 76 ± 4% at 5 and 10 years, respectively) (P<.0001). The predictors within the pT3b patient group were: PSA levels >10 ng/mL (HR: 1.9; 95% CI: 1.04-3.6; P=.04) and pathological Gleason score 8-10 (HR: 2.1; 95% CI: 1.2-3.5; P=.03). We designed a risk model that accounts for the variables involved, which entails 2 groups with different BPFS (P=.004): Group 1 (0-1 variable), with a BPFS of 46 ± 7% and 27 ± 8% at 5 and 10 years, respectively; and Group 2 (2 variables), with a BPFS of 14 ± 7% and 5 ± 5% at 5 and 10 years, respectively. Seminal vesicle involvement severely and negatively affects the BPFS and SS. We designed a risk model with the independent influential variables in BPFS (pathological Gleason score 8-10 and PSA levels >10 ng/mL). This model confirms that pT3b tumors are a heterogeneous group, which includes an important group with better prognosis when surgical treatment is performed. Copyright © 2014 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

Improved Steam Turbine Leakage Control with a Brush Seal Design

NASA Astrophysics Data System (ADS)

Turnquist, Norman; Chupp, Raymond E.; Pastrana, Ryan; Wolfe, Chris; Burnett, Mark

2002-10-01

This paper presents an improved steam turbine leakage control system with a brush seal design. The contents include: 1) Typical Design Characteristics; 2) Typical Brush Seal Locations; 3) Reduced Leakage Rates; 4) Performance Benefits; 5) System Considerations; 6) Rotor Dynamics; 7) Laboratory Tests and 8) Field Experience.

A Critique of the Brushing for Life Programme

ERIC Educational Resources Information Center

Downer, Martin C.; Drugan, Caroline S.; Blinkhorn, Anthony S.

2006-01-01

Background and objective: Brushing for Life is intended to promote regular brushing of children's teeth with fluoride toothpaste. The programme is delivered by health visitors who provide toothbrushes, toothpaste and dental health education material at children's 8, 18 and 36 month development checks. The purpose of the present paper was to…

40 CFR 141.805 - Notification to passengers and crew.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and should not be used for drinking, food or beverage preparation, hand washing, teeth brushing, or... beverage preparation, hand washing, teeth brushing, or any other consumptive use; (ii) A description of the... for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use...

40 CFR 141.805 - Notification to passengers and crew.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and should not be used for drinking, food or beverage preparation, hand washing, teeth brushing, or... beverage preparation, hand washing, teeth brushing, or any other consumptive use; (ii) A description of the... for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use...

40 CFR 141.805 - Notification to passengers and crew.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and should not be used for drinking, food or beverage preparation, hand washing, teeth brushing, or... beverage preparation, hand washing, teeth brushing, or any other consumptive use; (ii) A description of the... for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use...

Effect of dielectric discontinuity on a spherical polyelectrolyte brush

NASA Astrophysics Data System (ADS)

Tergolina, Vinicius B.; dos Santos, Alexandre P.

2017-09-01

In this paper we perform molecular dynamics simulations of a spherical polyelectrolyte brush and counterions in a salt-free medium. The dielectric discontinuity on the grafted nanoparticle surface is taken into account by the method of image charges. Properties of the polyelectrolyte brush are obtained for different parameters, including valency of the counterions, radius of the nanoparticle, and the brush total charge. The monovalent counterions density profiles are obtained and compared with a simple mean-field theoretical approach. The theory allows us to obtain osmotic properties of the system.

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor.

PubMed

Munirathinam, Rajesh; Ricciardi, Roberto; Egberink, Richard J M; Huskens, Jurriaan; Holtkamp, Michael; Wormeester, Herbert; Karst, Uwe; Verboom, Willem

2013-01-01

Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS). XPS revealed the presence of one gallium per 2-3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-functionalized brushes in a microreactor was demonstrated for the dehydration of oximes, using cinnamaldehyde oxime as a model substrate, and for the formation of oxazoles by ring closure of ortho-hydroxy oximes. The catalytic activity of the microreactor could be maintained by periodic reactivation by treatment with GaCl3.

Polymer Brushes as Functional, Patterned Surfaces for Nanobiotechnology.

PubMed

Welch, M Elizabeth; Xu, Youyong; Chen, Hongjun; Smith, Norah; Tague, Michele E; Abruña, Héctor D; Baird, Barbara; Ober, Christopher K

2013-01-01

Polymer brushes have many desirable characteristics such as the ability to tether molecules to a substrate or change the properties of a surface. Patterning of polymer films has been an area of great interest due to the broad range of applications including bio-related and medicinal research. Consequently, we have investigated patterning techniques for polymer brushes which allow for two different functionalities on the same surface. This method has been applied to a biosensor device which requires both polymer brushes and a photosensitizer to be polymerized on a patterned gold substrate. Additionally, the nature of patterned polymer brushes as removable thin films was explored. An etching process has enabled us to lift off very thin membranes for further characterization with the potential of using them as Janus membranes for biological applications.

Polyacrylic acid polymer brushes as substrates for the incorporation of anthraquinone derivatives. Unprecedented application of decorated polymer brushes on organocatalysis

NASA Astrophysics Data System (ADS)

Ruiz-Muelle, Ana Belén; Contreras-Cáceres, Rafael; Oña-Burgos, Pascual; Rodríguez-Dieguez, Antonio; López-Romero, Juan Manuel; Fernández, Ignacio

2018-01-01

The synthesis of amino-terminated anthraquinone derivatives and their incorporation onto polymer brushes for the fabrication of silicon-based nanometric functional coatings are described for the first time. The general process involves the covalent grafting of anthraquinone 1 onto two different polymer-brushes by amidation reactions. They are composed by amino- and carboxy-terminated poly(acrylic acid) chains (PAA-NH2- and PAA-COOH, respectively) tethered by one end to an underlying silicon oxide (SiO2) substrate in a polymer brush configuration. A third substrate is fabricated by UV induced hydrosilylation reaction using undecenoic acid as adsorbate on hydrogen-terminated Si(111) surfaces. One- and two-dimensional nuclear magnetic resonance (NMR), FT-IR, MS and X-ray diffraction (XRD) were used to characterize anthraquinone 1. Ellipsometric and X-ray photoelectron spectroscopy (XPS) measurements demonstrated the presence of the polymer brushes on the silicon wafers, and atomic force microscopy (AFM) was used to study its surface morphology. The covalent linkage between anthraquinone and polymer brushes was proven by XPS and confocal fluorescence microscopy. The resulting surfaces were assayed in the heterogenous organocatalytic transformation of (1H)-indole into 3-benzyl indole with moderate yields but with high recyclability.

Evaluation of tablet PC as a tool for teaching tooth brushing to children.

PubMed

Salama, F; Abobakr, I; Al-Khodair, N; Al-Wakeel, M

2016-12-01

This study evaluated the effect of a single time tooth brushing instruction using video on a tablet PC (Apple iPad) compared to operator presentation using jaw model for plaque removal. This cross-sectional study included a convenience sample of 100 children divided into two groups. For Group 1 brushing was demonstrated to the child by the operator with the use of a jaw model. This demonstration was videotaped for subsequent use in Group 2 using a tablet PC (Apple iPad). Plaque index was recorded before and after demonstration of the assigned method of teaching tooth brushing. The results showed a significant difference using the two methods. The difference between the mean plaque index values with the jaw model and tablet PC at baseline and after tooth brushing represented 17.27% (50% improvement) and 11.56% (34% improvement) respectively. Boys showed a 18.3%. higher improvement in tooth brushing compared to girls. Seventy-five percent of the children reported using tablet computers in their daily life. CONCLUSION Teaching children by using a jaw model was more effective in improving plaque index score than using video on tablet PC by 16%. Both methods of tooth brushing teaching were fully accepted by all children.