Control Material (control + material)

Distribution by Scientific Domains


Selected Abstracts


Modified Oligosaccharides as Potential Dental Plaque Control Materials

BIOTECHNOLOGY PROGRESS, Issue 5 2004
Eun-Seong Seo
Metabolic acids produced by oral pathogens demineralize tooth surfaces, leading to dental caries. Glucosyltransferases are the key factor in this process. We synthesized various modified oligosaccharides and tested them for their inhibitory effects on glucosyltransferase activity. Oligosaccharides were produced using a mixed-culture fermentation of Lipomyces starkeyi and Leuconostoc mesenteroides and then further modified as iron- and sulfate-oligosaccharides. Iron- and sulfate-oligosaccharides reduced glucosyltransferase activity of Streptococci from 17% to 43% and prevented the formation of insoluble biomass on the surface of glass vials or stainless steel wires in the presence of sucrose. They also reduced the growth and acid productions of oral pathogens including S. mutans, S. sobrinus, Eikenella corrodens, Prevotella intermedia, and Actinobacillus actinomycetemcmitans. [source]


Biopsy of the posterior interosseous nerve: a low morbidity method for assessment of peripheral nerve disorders

DIABETIC MEDICINE, Issue 1 2009
N. O. B. Thomsen
Abstract Aims The sural nerve is the commonest peripheral nerve biopsied to help in the diagnosis of peripheral neuropathy of unknown cause. However, associated complications limit its use. The aim was, as an alternative, to asses biopsy of the terminal branch of the posterior interosseous nerve (PIN) in the forearm. Methods PIN pathology was morphometrically quantified in 10 male patients with Type 2 diabetes and compared with six PIN biopsy specimens taken post mortem from male cadavers with no history of neuropathy or trauma. Results The PIN biopsy procedure provides a long (approximately 3 cm) mono- or bifascicular nerve biopsy with generous epineurial tissue and adjacent vessels. Our results show a significantly lower myelinated fibre density in subjects with diabetes [5782 (3332,9060)/mm2] compared with autopsy control material [9256 (6593,12 935)/mm2, P < 0.007]. No postoperative discomfort or complications were encountered. Conclusions A reduction in myelinated fibre density has previously been shown to be a clinically meaningful measure of neuropathy in diabetic patients. We demonstrate similar findings using the PIN biopsy. The PIN biopsy procedure fulfils the criteria for nerve biopsy and was well tolerated by the patients. It may be a possible alternative to sural nerve biopsy to allow for diagnosis of neuropathy. [source]


Evaluation and use of a synthetic quality control material, included in the European external quality assessment scheme for cystic fibrosis,

HUMAN MUTATION, Issue 8 2008
Sarah Berwouts
Abstract Assuring high quality within the field of genetic testing is fundamental, as the results can have considerable impact on the patient and his or her family. The use of appropriate quality control (QC) samples is therefore essential. Diagnostic laboratories mainly use patient samples as QC material, which of course include a maximum of two mutations per sample. Bearing in mind that some assays (such as for cystic fibrosis [CF] testing) can test for more than 100 mutations, multiplex QC materials including more than two mutations could save valuable time and reagents. Based on this need, synthetic multiplex controls have been developed by Maine Molecular Quality Controls, Inc. (MMQCI) for CF. A synthetic control, containing six homozygous mutations and one polymorphism for CF transmembrane conductance regulator (CFTR), was evaluated by distributing it through the CF external quality assessment (EQA) scheme, along with the EQA samples in 2005. A total of 197 participants returned results of the yearly EQA scheme and 133 laboratories participated in the evaluation of the synthetic sample. Respectively, 76% and 73% of the participants were assigned as successful. This evaluation study revealed that the multiplex QC material performed well in the majority of assays and could be useful in method validation, as a tool to challenge interpretation skills, and as potential proficiency testing (PT) material. Hum Mutat 0, 1,8, 2008. © 2008 Wiley-Liss, Inc. [source]


A sample distribution programme for erythropoietin

INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 4 2006
J. T. MARSDEN
Summary A survey was sent to laboratories participating in the United Kingdom External Quality Assessment Service (UKNEQAS) Haematinics Scheme about the measurement of serum erythropoietin (EPO). Six laboratories, from a total of 120 that returned the survey, were measuring serum EPO concentrations by commercially available immunoassays on site in the United Kingdom. The workload of the laboratories varied from up to 100 specimens per month to more than 100 specimens analysed per week. All laboratories included control material in the assays and none of the laboratories was participating in an external quality assessment scheme for serum EPO. Four laboratories agreed to take part in the first sample distribution programme, with five and six laboratories participating in distributions 2 and 3 respectively. The results from eight kits were compared from the three distributions over a 2-year period. The serum EPO concentrations for the methods showed some variation across the range of 2.9,200 U/l when the serum EPO concentrations for each method were compared with the whole method mean. The results from this scheme have identified a role for an external quality assessment scheme for serum EPO measurements. [source]


Formation and resolution of ankylosis under application of recombinant human bone morphogenetic protein-2 (rhBMP-2) to class III furcation defects in cats

JOURNAL OF PERIODONTAL RESEARCH, Issue 4 2005
D. Takahashi
Objectives:, Periodontal regeneration under application of bone morphogenetic protein (BMP) is compromised by ankylosis. Ankylosis disappearance following application of BMP has been observed in the case of a small defect, which might be beneficial change for periodontal regeneration. However, the histological observation of ankylosis disappearance has not been demonstrated in a large defect. The purpose of this present study was to confirm resolution of ankylosis during periodontal regeneration by recombinant human BMP-2 (rhBMP-2) applied to class III furcation defects. Material and methods:, Class III furcation defects were created in the premolars of six adult cats. The rhBMP-2 material, prepared by applying rhBMP-2 to a combination of polylactic acid,polygricolic copolymer and gelatin sponge (PGS; 0.33 µg rhBMP-2/mm3 PGS) or control material containing only PGS, was implanted into each defect. The cats were killed at 3, 6 or 12 weeks after surgery and serial sections were prepared for histological and histometrical observation. Results:, Ankylosis was observed in some of the rhBMP-2/PGS group at 3 and 6 weeks, but not at 12 weeks. At 6 weeks, osteoclast-like cells were visible in the rhBMP-2/PGS group with ankylosis. Residual PGS was evident between the bone and root surface in the rhBMP-2/PGS group without ankylosis at 3 weeks. Conclusions:, Resolution of ankylosis by osteoclast-like cells possibly occurred under application of rhBMP-2. Residual PGS might play an important role in preventing ankylosis formation. [source]


Change in sugar, sterol and fatty acid composition in banana meristems caused by sucrose-induced acclimation and its effects on cryopreservation

PHYSIOLOGIA PLANTARUM, Issue 1 2006
Guo-Yu Zhu
To understand the mechanisms of sucrose-induced acclimation in relation to plant cryopreservation, sugars, sterols, fatty acids of different lipid fractions (neutral lipids, glycolipids and sphingolipids and phospholipids), as well as free fatty acids were analyzed in proliferating meristem cultures of different banana varieties. The four banana varieties that were selected show different post-thaw shoot regeneration rates (0,53.4%). All mentioned parameters were analyzed using (1) control meristems that were cultured on a normal sucrose concentration (0.09 M), which resulted in low survival after cryopreservation; and (2) 2-week sucrose precultured meristems (0.4 M). This sucrose preculture, essential for regeneration after cryopreservation, resulted in a significant increase of each of seven sugars detected. The ratio of stigmasterol/sitosterol (St/Si) in sucrose-pretreated meristems significantly increased. The sucrose pretreatment also resulted in a significant increase of total fatty acid content of the neutral lipid fraction and of the glycolipid and sphingolipid fraction, as well as the total free fatty acid content. The individual fatty acid content of the phospholipids was differently changed by the sucrose pretreatment for the given varieties studied. In most cases, sucrose pretreatment resulted in an increase of the double bond index (DBI) in the neutral lipids and a decrease of DBI in the glycolipids and sphingolipids, in phospholipids as well as in free fatty acids. Principal component analysis of all collected data revealed that (1) for the control material, sucrose and total sugar contents were closely linked to the post-thaw shoot regeneration, suggesting that sucrose and total sugar may be main limiting factors to survive cryopreservation; (2) accumulation of large quantities of sugars (glucose, fructose, sucrose and total sugar) in sucrose-pretreated material cannot explain the differences in survival after cryopreservation of the four banana varieties. We assume that a minimal amount of sugars is needed in meristem cultures to survive cryopreservation. Still, other limiting factors do influence the survival following the sucrose pretreatment. We observed that the parameters which are closely linked to the post-thaw shoot regeneration are a minimal change in the ratios of St/Si, the minimal change of the DBI of phospholipids and free fatty acids, as well as linoleic acid content (C18:2); and (3) inositol, raffinose, myristic acid (C14:0) and oleic acid (C18:1) were present in small quantities; however, they could be correlated to survival after cryopreservation, suggesting that they may be also involved in cryopreservation process. [source]


Wood-thermoplastic composites manufactured using beetle-killed spruce from Alaska

POLYMER ENGINEERING & SCIENCE, Issue 1 2009
Vikram Yadama
The primary objectives of the study were to characterize the critical properties of wood flour produced using highly deteriorated beetle-killed spruce for wood-plastic composite (WPC) production and evaluate important mechanical and physical properties of WPC extruded using an industry standard formulation. Chemical composition analysis indicated no significant differences in wood constituents between highly deteriorated and sound wood. Preliminary investigation with Fourier transform infrared spectroscopy (FTIR), however, indicated partial degradation or depolymerization of carbohydrate components in highly deteriorated wood compared to sound wood from green trees; effects of these changes could be seen in cell collapse and poor interaction between thermoplastic matrix and deteriorated wood fiber. Physical and mechanical properties of extruded WPCs manufactured from highly deteriorated material were comparable to WPC properties produced using pine wood flour that served as a control material. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers [source]


The effects of urea-treated potato pulp (PP) ensiled with beet pulp or wheat bran pellets to reduce moisture of PP and flake density of corn grain supplemented with the PP silage on digestibility and ruminal fermentation in beef steers

ANIMAL SCIENCE JOURNAL, Issue 3 2010
Masahito SUGIMOTO
ABSTRACT The effects of adding beet pulp or wheat bran to urea-treated potato pulp (PP) in order to reduce moisture of PP silage and flake density of corn grain on digestibility and ruminal fermentation in beef steers were studied in a split-plot design experiment. The whole-plot treatments were PP silage mixed with 0% added pellets (CON), 9% (as-fed basis) beet pulp pellets (BP) or 9% (as-fed basis) wheat bran pellets (WB) as water-absorbing materials. The subplot treatments consisted of supplements formulated to contain either high-density corn (HDC) or low-density corn (LDC). BP steers consumed more (BP vs WB, P = 0.011) concentrate than did WB steers, whereas hay intake did not differ between the treatments. Dry matter (BP vs WB, P = 0.023) and organic matter (BP vs WB, P = 0.029) digestibility were higher for BP steers than for WB steers. Starch digestibility was higher (P = 0.006) for LDC than for HDC. There were no differences in the concentration of ruminal ammonia nitrogen among the treatments. Molar proportions of ruminal acetate were higher for BP steers than for WB steers (BP vs WB, P = 0.030). Conversely, molar proportions of propionate were lower for BP steers than for WB steers (BP vs WB, P = 0.044). Flake density of corn did not affect ruminal characteristics. In conclusion, from the viewpoint of feed intake and digestibility, BP is superior to WB as a moisture control material for urea-treated PP silage, and flake density of corn supplemented with urea-treated PP silage does not alter ruminal fermentation. [source]


Comparison of static automated perimetry and semi-automated kinetic perimetry in patients with bilateral visible optic nerve head drusen

ACTA OPHTHALMOLOGICA, Issue 7 2009
Katarzyna Nowomiejska
Abstract. Purpose:, Until now there has been no standardized, systemic approach to diagnostics in patients with optic nerve head drusen (ONHD). This study compares visual field (VF) results obtained with static automated perimetry (SAP) and semi-automated kinetic perimetry (SKP) in patients with bilateral visible ONHD. Methods:, Visual fields in 26 eyes (13 patients) with ONHD were obtained by Humphrey Field Analyser II (SAP) and Octopus 101 (SKP) equipment and classified by three masked observers. Pairs of VFs were considered equivalent if the descriptions given by both methods matched. Individual reaction time (RT) was assessed during SKP. Fifteen healthy volunteers were examined as control material. Results:, Visual field pairs matched in 19 eyes (three normal VFs, 16 arcuate defects). In the remaining eight eyes SKP provided more information in concentric constriction of the VF (two eyes) and SAP provided more information on paracentral scotomas (five eyes). Sensitivity was 69% for SKP, 80% for SAP and 88% for both methods together. Mean RT assessed using SKP amounted to 909 ms in eyes with ONHD and 568 ms in normal subjects (p < 0.0003). The median examination duration was 13 mins with SKP and 11 mins with SAP (p = 0.05) in eyes with ONHD, and 8 mins in control eyes (p < 0.0001). Conclusions:, In clinical practice it is necessary to perform both SAP and SKP in patients with ONHD because the VF defects are diverse. In SKP, RT is prolonged in eyes with ONHD compared with normal eyes and SKP takes longer than SAP in ONHD eyes. [source]


Bicanalicular double silicone intubation in external dacryocystorhinostomy and canaliculoplasty for distal canalicular obstruction

ACTA OPHTHALMOLOGICA, Issue 4 2009
Sang Won Hwang
Abstract. Purpose:, We aimed to evaluate the effectiveness of bicanalicular double silicone intubation in dacryocystorhinostomy (DCR) and canaliculoplasty for distal or common canalicular obstruction. Methods:, We reviewed the medical records of patients with distal or common canalicular obstruction who had undergone bicanalicular double silicone intubation (insertion of two tubes into each canaliculus) during external DCR and canaliculoplasty. We reviewed the records of subjects who had undergone the same surgery with a bicanalicular single intubation as control material. The tubes were removed at around 6 months after surgery. Anatomical and functional success rates of patients who were followed up for > 2 months after the removal of tube(s) were evaluated. In addition, complications related to the silicone tube were evaluated. Results:, Data for 60 eyes of 45 patients in the double-intubation group and 69 eyes of 65 patients in the single-intubation group were retrieved. The double-intubation group showed higher anatomical success rates (96.5%) than the single-intubation group (85.5%). Functional success was achieved by 53 (88.3%) of 60 eyes in the double-intubation group and 56 (81.2%) of 69 eyes in the single-intubation group. There was no significant difference in complication rates between the two groups. Conclusions:, Bicanalicular double silicone intubation for DCR and canaliculoplasty may be an effective mode of treatment for patients with distal or common canalicular obstruction. [source]