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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The adhesion of the S fimbriae of meningitis-associated Escherichia coli O18ac:K1:H7 to the cellular and the plasma forms of human fibronectin was studied. E. coli HB101(pAZZ50) expressing the complete S-fimbria II gene cluster of E. coli O18 adhered to cellular fibronectin (cFn) on glass but not to plasma fibronectin (pFn). Adhesion to cFn was specifically inhibited by neuraminidase treatment of cFn as well as by incubation of the bacteria with sialyl-alpha2-3-lactose, a receptor analog of the S fimbriae. No significant adhesion to cFn or pFn was detected with E. coli HB101(pAZZ50-67) expressing S fimbriae lacking the SfaS lectin subunit. Strain HB101(pAZZ50) also adhered to a human fibroblast cell culture known to be rich in cFn, and the adhesion was specifically inhibited in the presence of polyclonal antibodies to cFn. The results show that the SfaS lectin of the S fimbriae mediates the adherence of meningitis-associated E. coli to sialyl oligosaccharide chains of cFn.
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PMID:The cellular form of human fibronectin as an adhesion target for the S fimbriae of meningitis-associated Escherichia coli. 1022 41

The ability of a Bacillus cereus strain, isolated from spoiled milk, to adhere to the surface of stainless steel chips was evaluated during its growth in diluted tryptic soy broth (DTSB). The number of cells that adhered to the surface increased markedly as the culture reached the end of the log phase and entered stationary phase, and continued to increase with further incubation. The surface properties of cells from the log, stationary, and late stationary phases were measured by hydrophobic interaction chromatography (HIC) and electrostatic interaction chromatography (ESIC). It was found that surface hydrophobicity of B. cereus vegetative cells from the late stationary phase was the highest followed by those from the stationary phase and the log phase cultures. While the vegetative cells prepared from stationary phase and log phase cultures, respectively, had the highest and the lowest surface charges. Adhesion of B. cereus vegetative cells to stainless steel was positively correlated with the cell surface hydrophobicity (R = 0.979). Surface hydrophobicity and surface positive charge noted on the spores harvested from diluted tryptic soy agar (DTSA) and Mn2+-tryptone glucose extract agar were higher than those harvested from the sucrose or lactose-added DTSA. A wide variation in the surface charge values was noted on the surface of various spores prepared from cultures grown on the four different media tested, while their ability to adhere to stainless steel chips in phosphate buffered saline (PBS) showed no significant difference (p > 0.05). Similarly, the number of spores or vegetative cells adhering to stainless steel suspended in PBS, milk or diluted milk (1000 x) did not differ significantly (p > 0.05).
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PMID:Surface characteristics of Bacillus cereus and its adhesion to stainless steel. 1132 92

The atomic force microscopy (AFM) colloid probe technique was investigated as a method for the characterisation of adhesional properties of pharmaceutical powder surfaces. Lactose carriers used in dry powder inhaler (DPI) formulations were chosen for investigation since adhesion between the carrier surface and drug particles has been proposed to affect the dispersion of drug particles. Individual adhesion forces were determined by measuring the detachment forces in air between the colloid probe and the lactose particle surface. The colloid probe consisted of a silica sphere (10 microm diameter) attached to a V-shaped silicon nitride cantilever (spring constant, k=0.42 N/m). Adhesion forces were calculated from individual force-distance curves using Hooke's Law. Individual forces measured at various adhesion sites were observed to be reproducible and stable over 10 min (coefficient of variation, CV below 5%). The adhesion force distribution determined from measurements at multiple sites (n>50) on each sample followed a log-normal relationship (regression coefficient, r(2) ranged between 0.95 and 0.99). This enabled characterisation in terms of the geometric mean adhesion force and a geometric standard deviation (GSD). Significant differences (P<0.001) in adhesion force were observed between samples, ranging from 37.47+/-1.95 to 117.48+/-2.20 nN. This study demonstrates the suitability of AFM as sensitive technique for the characterisation of adhesional properties of pharmaceutical particles.
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PMID:Characterisation of adhesional properties of lactose carriers using atomic force microscopy. 1137 36

Adherence of the opportunistic pathogen Candida albicans to basement membrane (BM) proteins is considered a crucial step in the development of candidiasis. In this study the interactions of C. albicans yeast cells with the three main domains of type IV collagen, a major BM glycoprotein, were analysed. C. albicans adhered to the three immobilized domains by different mechanisms. Adhesion to the N-terminal cross-linking domain (7S) required the presence of divalent cations, whereas interaction with the central collagenous domain (CC) was cation-independent. Recognition of the C-terminal non-collagenous domain (NC1) was partially cation-dependent. Binding inhibition assays with the corresponding domains in soluble form showed that these interactions were specific. Both Ca(2+) and Mg(2+) promoted adhesion to the 7S domain and the interaction was completely abolished by EDTA. Treatment of the 7S domain, or its subunits, with N-glycosidase F reduced yeast binding by approximately 70%. Moreover, several sugars known to be part of the N-linked oligosaccharide chains of collagen IV inhibited adhesion to immobilized 7S; N-acetylglucosamine, L-fucose and methylmannoside caused a similar inhibition whereas N-acetyllactosamine was a more effective inhibitor. In contrast, glucose, galactose, lactose or heparan sulfate did not affect yeast binding. Combinations of the inhibitory sugars at suboptimal inhibition concentrations did not reduce C. albicans adhesion more than the individual sugars, pointing to a single lectin as responsible for the interaction. These results taken together show that C. albicans utilizes several adhesins for interacting with type IV collagen, and that at least one of them is a lectin which recognizes the 7S(IV) oligosaccharide residues as its receptor.
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PMID:Different adhesins for type IV collagen on Candida albicans: identification of a lectin-like adhesin recognizing the 7S(IV) domain. 1142 74

Adhesion of 19 Bifidobacterium strains to native maize, potato, oat, and barley starch granules was examined to investigate links between adhesion and substrate utilization and to determine if adhesion to starch could be exploited in probiotic food technologies. Starch adhesion was not characteristic of all the bifidobacteria tested. Adherent bacteria bound similarly to the different types of starch, and the binding capacity of the starch (number of bacteria per gram) correlated to the surface area of the granules. Highly adherent strains were able to hydrolyze the granular starches, but not all amylolytic strains were adherent, indicating that starch adhesion is not a prerequisite for efficient substrate utilization for all bifidobacteria. Adhesion was mediated by a cell surface protein(s). For the model organisms tested (Bifidobacterium adolescentis VTT E-001561 and Bifidobacterium pseudolongum ATCC 25526), adhesion appeared to be specific for alpha-1,4-linked glucose sugars, since adhesion was inhibited by maltose, maltodextrin, amylose, and soluble starch but not by trehalose, cellobiose, or lactose. In an in vitro gastric model, adhesion was inhibited both by the action of protease and at pH values of < or =3. Adhesion was not affected by bile, but the binding capacity of the starch was reduced by exposure to pancreatin. It may be possible to exploit adhesion of probiotic bifidobacteria to starch granules in microencapsulation technology and for synbiotic food applications.
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PMID:Adhesion of bifidobacteria to granular starch and its implications in probiotic technologies. 1147 21

The surface energies of film coating formulations based on hydroxypropyl methylcellulose and containing microcrystalline cellulose, lactose and Tween 20, respectively, have been assessed. The approach taken allowed the components of the surface energy, in terms of the Lifshitz-van der Waals and the acid-base contributions, to be determined. Spreading coefficients of these coating formulations were determined on a model tablet surface whose surface energy had been similarly characterised. The determined spreading coefficients were high and positive indicating that spreading and wetting would not be a controlling factor in the formation of an adequate film coat. The adhesion of the coats to the core was measured and showed that the inclusion of additives influenced the adhesion of the film. Maximum adhesion was obtained when microcrystalline cellulose was included in the coating formulation that presumably allowed a strong interaction with the same component in the tablet core. Adhesion was enhanced when the tablet cores were made at a higher compaction force. Atomising air pressure had little influence on the adhesion.
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PMID:The influence of additives on the spreading coefficient and adhesion of a film coating formulation to a model tablet surface. 1156 45

The aim of this study was to establish a correlation between carrier characteristics and the dispersibility of drug from the blend. The influence of the roughness of a commonly used carrier material, lactose monohydrate, on the adhesion, dose uniformity, and aerodynamic properties of a model drug, terbutaline sulphate was investigated. Evaluation of adhesion was carried out with a mechanical sieve and an Alpine air-jet sieve. For the characterisation of lactose roughness, we used image analysis software. Aerodynamic evaluation of fine particle dose and emitted dose was obtained using a twin stage impinger. The study with the mechanical sieve demonstrated that at least 60% of drug adheres to lactose. The Alpine air-jet sieve assays showed there was a correlation between drug separation from a carrier by sieving and that obtained from longer in vitro deposition studies. Adhesion, blend homogeneity and stability are related to the surface roughness of the lactose used as carrier. There is a linear relationship between the parameters "fine particle fraction" and "roughness". A compromise between homogeneity and drug liberation must be found: a certain roughness is necessary to allow for drug adhesion and blend homogeneity, but if too high it will prevent drug liberation after inhalation.
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PMID:The influence of carrier roughness on adhesion, content uniformity and the in vitro deposition of terbutaline sulphate from dry powder inhalers. 1508 Nov 50

Adhesion force distributions of silica spheres (5 and 20 microm) and salmeterol xinafoate (4 microm) particles with inhalation grade lactose surfaces and spin coated lactose films were determined by atomic force microscopy (AFM) to investigate the influence of surface roughness on the force distributions. The roughness of lactose particles and films was determined by both AFM and confocal microscopy (CM); the lactose particles showed RMS R(q) values between 0.93 and 2.2 microm. The adhesion force distributions for silica and SX probes were significantly different for the different lactose carriers and broad, e.g., the adhesion force distribution between a 5 microm silica sphere and lactose particles ranged from 5 to 105 nN. This contrasted with distributions on smooth spin coated lactose films (RMS R(q) of 0.28 nm) which were not significantly different and were narrow, e.g., the adhesion force distribution between a 5 microm silica sphere and spin coated lactose films was between 42 and 68 nN. In addition, no significant difference in adhesion force distribution occurred with silica probe size on the lactose carrier surface. The use of X-ray photoelectron spectroscopic analysis confirmed that the lactose surfaces were free of impurities that might contribute to variation in adhesion. Although the almost atomically flat films showed some adhesion variability, the surface roughness of the lactose particles was a major contributing factor to the broad distributions seen in this study.
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PMID:Surface roughness contribution to the adhesion force distribution of salmeterol xinafoate on lactose carriers by atomic force microscopy. 1592 47

Poly(vinyl pyrrolidone) (PVP) is widely used for bioengineering and pharmaceutical applications, and its adhesion characteristics are critical. When used as a binder in pharmaceutical granulation, it covers the resultant granules and governs their surface properties. The intrinsic adhesion forces of PVP toward common hydrophobic (magnesium stearate) and hydrophilic (lactose) pharmaceutical materials have been studied as a function of relative humidity (RH). The effect of RH on adhesion force was more significant for the PVP/hydrophilic material than the PVP/hydrophobic material. Adhesion was lowest between 20 and 40% RH, and it increased at RH above 40% and below 20%. This is likely to be due to the development of capillary and triboelectrification forces, respectively. In a nano-indentation experiment using a silicon tip at room temperature, the PVP surface underwent a glass transition at 70% RH. This result suggests that surface softening contributes to the increased PVP adhesion at RH above 70%. To adjust the adhesion properties of PVP, humidity control should be an essential part of research and development. Effect of humidity on the adhesion forces between PVP and lactose (LT) or magnesium stearate (MS).
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PMID:Intrinsic adhesion properties of poly(vinyl pyrrolidone) to pharmaceutical materials: humidity effect. 1624 67

Dry powder inhalers mostly contain carrier based formulations where micronized drug particles are adhered to coarse carrier particles. The performance of the dry powder inhaler depends on the inhaler device, the inhalation manoeuvre and the formulation. The most important factor influencing the behaviour of the formulation is the adhesion force acting between the active ingredient and the carrier particles, which can be measured using different methods, for example the centrifuge technique or atomic force microscopy. In this study the tensile strength method, usually applied to determine cohesion forces between powder particles of one material, is optimized for adhesion force measurements between powder particles of unlike materials. Adhesion force measurements between the carrier materials lactose or mannitol and the drug substance salbutamol sulphate using the tensile strength method and the atomic force microscopy show higher values with increasing relative humidity. Consequently, the fine particle fraction determined using the Next Generation Impactor decreases with increasing relative humidity as a result of the enhanced interparticle interactions.
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PMID:Adhesion forces in interactive mixtures for dry powder inhalers--evaluation of a new measuring method. 1741 48


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