Molecular cloning and characterization of spiggin. An androgen-regulated extraorganismal adhesive with structural similarities to von Willebrand Factor-related proteins.
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One of the most definitive examples of a vertebrate extraorganismal structural protein can be found in three-spined sticklebacks (Gasterosteus aculeatus). In the breeding male the kidney hypertrophies and synthesizes an adhesive protein called "spiggin," which is secreted into the urinary bladder from where it is employed as a structural thread for nest building. This paper describes the first molecular characterization of spiggin and demonstrates that this adhesive is a protein complex assembled from a potential of three distinct subunits (alpha, beta, and gamma). These subunits arise by alternative splicing, and 11-ketoandrogens induce their expression in stickleback kidneys. Analysis of the predicted amino acid sequence of each subunit reveals a modular organization whose structural elements display a similarity to the multimerization domains found within von Willebrand Factor-related proteins. These results implicate that spiggin utilizes a conserved multimerization mechanism for the formation of a viscous agglutinate from its constituent subunits in the urinary bladders of male sticklebacks. This novel extraorganismal structural protein is therefore ideally suited to its function as an adhesive thread. (+info)
Analgesic-induced asthma caused by 2.0% ketoprofen adhesive agents, but not by 0.3% agents.
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A 74-year-old woman was admitted with an asthma attack. She had a 40-year history of sinusitis, nasal polyp and analgesic-induced asthma; however, asthma had never occurred when she used a 0.3% ketoprofen adhesive patch (Mohrus) for stiff shoulder or lumbago. In the hospital, a life-threatening asthma attack suddenly occurred two and a half hours after application of a 2.0% ketoprofen adhesive tape (Mohrus tape) to her shoulder. She was treated with bronchodilator and glucocorticoid and extubated after 20 hours. A drug lymphocyte stimulating test (DLST) was strongly positive for ketoprofen. We suspected that drug-induced hypersensitivity coexisted in the present case, but it was not clear whether or not the hypersensitivity was related to the pathogenesis of analgesic-induced asthma. (+info)
Novel barnacle underwater adhesive protein is a charged amino acid-rich protein constituted by a Cys-rich repetitive sequence.
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Barnacle cement is an underwater adhesive that is used for permanent settlement, and is an insoluble protein complex. A method for rendering soluble the cement of Megabalanus rosa has been developed, and three major proteins have been identified in a previous study. To survey the M. rosa cement proteins in a lower molecular mass range, the cement proteins were separated by reversed-phase HPLC and a previously unidentified protein named 20 kDa M. rosa cement protein (Mrcp-20k) was found. Mrcp-20k cDNA was cloned to reveal its primary structure. This cDNA was 902 bp long and encoded a 202 amino acid-long open reading frame, including 19 amino acids of the signal sequence. The molecular mass in the disulphide form was calculated to be 20357 Da and the isoelectric point of the mature polypeptide was 4.72. Mrcp-20k was characterized by an abundance of Cys residues and charged amino acids. The most common amino acid was Cys (17.5%), with Asp (11.5%), Glu (10.4%) and His (10.4%) following in order of magnitude. The alignment of the Cys residues indicated the primary structure of this protein to consist of six degenerated repeats, each about 30 residues long. Mrcp-20k has no intermolecular disulphide bonds and no free thiol groups of Cys in the insoluble cement complex. Abundant Cys is thought to play a role in maintaining the topology of charged amino acids on the molecular surface by intramolecular disulphide-bond formation. The possible function of abundant charged amino acids, including the interaction with a variety of surface metals on the substratum, is discussed. (+info)
Conformational and quantum analysis of dental adhesive carboxylic acid and carboxylic acid anhydride monomers.
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The conformational and quantum analyses of dental adhesive carboxylic acid and carboxylic acid anhydride monomers were preformed. Conformational analyses were carried out by a molecular mechanics calculation. 4-META and 4-AETA showed more compact conformation than 4-MET. Quantum analyses were performed by semi-empirical molecular orbital calculation. 4-MET had a higher dipole moment, polarizability, and HOMO and LUMO energy than 4-META and 4-AETA. The bond lengths and bond orders of the carbonyl groups of the trimellitic acid moiety of 4-MET were different from those of carbonyl groups of the trimellitate anhydride moieties of 4-META and 4-AETA. Oxygen of the methacryloyl or acryloyl groups showed the highest electron densities among the oxygen atoms for all monomers. The superdelocalizabilities of oxygen atoms of the trimellitic acid moiety of 4-MET were greater than that of oxygen of the methacryloyl group. A small change in the bond length of the Ca-O bond showed a large difference in the steric energies of 4-MET/Ca salt. (+info)
An approach to enhance the interface adhesion between an orthodontic plastic bracket and adhesive.
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For the purpose of improving the degree of success of plastic bracket bonding, based on the analysis of the chemical components of plastic brackets, a systematic method for the treatment of the adhesive surface of plastic brackets was introduced in this study. After sandblasting the adhesive surfaces of two commercially available plastic brackets (Spirit and Clear Bracket), a favourable surface treatment was obtained with the application of a silane coupling agent, gamma-methacryloxy propyl trimethoxy silane. The findings showed that (i) the fillers added to the plastic brackets were glass fillers with Si-OH groups distributed on their surfaces; (ii) sandblasting of the bracket surface resulted in exposure of the glass fillers; (iii) combined with sandblasting, silane coupling treatment significantly increased the bond strength (P < 0.05), which was adequate to withstand the forces generated during orthodontic therapy; and (iv) treatment with sandblasting and silane coupling 24 hours before direct bonding did not cause a significant reduction in bond strength. It is concluded that sandblasting and silane coupling treatment offers the benefit of increasing the in vitro bond strength of plastic brackets for orthodontic application. (+info)
Comparative prospective study of foreign body removal from external auditory canals of cadavers with right angle hook or cyanoacrylate glue.
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OBJECTIVES: Foreign bodies of the external auditory canal are a relatively common problem in emergency departments. Repeated attempts at removal with standard instrumentation can lead to significant ear injury. Recent case reports of using cyanoacrylate impregnated cotton buds suggest this is less traumatic and well tolerated by patients. No studies on this method have been performed. The objectives of this study were to identify whether there were significant differences in success rate, duration and injury caused by extracting beads from the external auditory canals of adult cadaveric ears using two different methods. This is the first study in a planned series of anatomical and clinical studies relating to foreign body extraction from the external auditory canal. METHODS: In this study the success rate, time taken and injury rate were assessed for removal of impacted spherical foreign bodies in the external auditory canals of cadavers using both a blunt right angle hook and cotton buds impregnated with cyanoacrylate glue. This process was performed by a specialist registrar in otolaryngology and repeated by a specialist registrar in emergency medicine. RESULTS: It was shown that both methods had a statistically similar success rate (two tailed binomial test p=0.5) and no injury was identified for either method. In addition the median extraction time for a right angle hook was 6 seconds and 42 seconds for cyanoacrylate. It was also noted that failed extraction was associated with a poor view of the foreign body in the external canal. This was caused by hair, a large tragus or tortuous external canal. CONCLUSIONS: The authors feel that cyanoacrylate impregnated cotton buds are as effective at removing impacted foreign bodies as a right angle hook but the process takes longer. It is believed that patients could tolerate this longer time as the cyanoacrylate method is in theory less traumatic. (+info)
Influence of solvent exposure and aging on cognitive functioning: an 18 year follow up of formerly exposed floor layers and their controls.
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OBJECTIVES: To extend our knowledge of how exposure to neurotoxic substances during working life affects cognitive functioning in the long term. Does long term occupational exposure to organic solvents lead to aggravated cognitive impairment later in life? METHODS: A follow up was conducted of floor layers exposed to solvents and their unexposed referents (carpenters) 18 years after the baseline assessment. The pattern of cognitive changes in the two groups was compared, with the same 10 neuropsychological tests from the test battery for investigating functional disorders (TUFF) that were used at baseline. The study included 41 floor layers and 40 carpenters. A medical examination focused on health at the present and during the past 18 years. An extensive exposure assessment made in the initial study included questionnaires, interviews, and measurements. Additional exposure during the follow up period was minor, as explored in interviews at follow up. RESULTS: The entire group of floor layers did not deteriorate significantly more over time than did the carpenters. However, among the oldest subjects (>60 years), only floor layers showed decline in visual memory. Moreover, the most highly exposed floor layers deteriorated significantly more than their referents in visual memory and perceptual speed, and they tended to display larger decrements in motor speed. Significant dose effect relations were found; higher cumulative exposure was associated with decrements in visual episodic memory, perceptual speed and attention, and visuospatial skill. CONCLUSIONS: The hypothesis that floor layers would deteriorate more in cognitive performance than their unexposed referents over a period of 18 years was partly supported by the results of this study. The results are consistent with the view that the negative effects of exposure to solvents may interact with the normal aging process, primarily at heavy exposure. (+info)
Moisture-insensitive adhesives: reactivity with water and bond strength to wet and saliva-contaminated enamel.
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The purpose of this study was to investigate the reactivity with water of a moisture-insensitive orthodontic primer (Transbond MIP), in conjunction with a no-mix orthodontic adhesive (Unite), and a moisture-insensitive adhesive (Smartbond), and to assess their bond strength to wet and saliva-contaminated enamel relative to the conventional application of the no-mix adhesive. The reactivity of the moisture-insensitive products with water was investigated by micro-multiple internal reflectance Fourier transform infrared spectroscopy (micro-MIR FTIR). Sixty premolars were divided into two groups of 30 teeth each and, on the buccal enamel surfaces, a standardized volume (0.1 ml) of water or fresh whole saliva was applied. Standard edgewise stainless steel brackets were then bonded to enamel surfaces as follows: (a) Unite, (b) Unite with the Transbond MIP, and (c) Smartbond. The brackets were debonded under shear force at a speed of 2 mm/min and the debonded enamel surfaces were subjected to fractographic analysis. The statistical analysis of the bond strength values was performed by two-way ANOVA with condition (water, saliva) and adhesive type serving as discriminating variables (n = 10, alpha = 0.05). The results of the fractographic analysis were evaluated by chi 2 test (alpha = 0.05). FTIR analysis showed that only Smartbond set in the presence of water. Application of water in Transbond MIP increased the extent of carboxyl ionization without inducing any setting reaction. Transbond MIP did not improve bond strength values when combined with the no-mix adhesive. Most adhesive-enamel condition combinations showed a trend to present lower bond strength in the presence of saliva; however, this was not confirmed statistically. Fractography of enamel and bracket base surfaces showed that Unite + Transbond MIP resulted in the most adhesive fractures (leaving no resin on enamel surface), whereas Smartbond presented the highest frequency of cohesive fractures (adhesive left on bracket and enamel surfaces). (+info)