Fracture resistance of endodontically treated teeth restored with intra-radicular post: The effects of post system and dentine thickness

To investigate the influence of post system and amount of remaining root tissue on the fracture resistance of endodontically treated teeth. Seventy upper canine teeth were divided into seven groups (n=10), one control (sound teeth) and six experimental groups resulting from the interaction between the two study factors: post system (FB, fiber post; FPC, fiber post relined with resin composite; CPC, cast Ni–Cr alloy post and core) and amount of remaining root tooth tissue (2 or 1 mm of thick root). All teeth were restored with metal crowns and exposed to 250,000 cycles in a controlled chewing simulator. The samples were submitted to the fracture resistance test in a universal testing machine, at an angle of 135° and speed of 0.5 mm/min, until fracture occurred. Failure modes were observed, and the data of fracture resistance, in Newtons, were submitted to the analysis of variance (ANOVA), followed by Tukey′s test (α=0.05). Roots restored with FPC had the highest fracture strength of the experimental groups, being statistically similar to the intact teeth group (P>0.05). FP and CPC did not differ statistically (P>0.05) and were statistically lower than those of FPC (P<0.05). No statistically significant difference was observed between amounts of remaining root tooth tissue to the same post systems (P>0.05). A prevalence of irreparable failures was observed in specimens restored with CPC, whereas FP and FPC posts showed more repairable failures. The post system had an influence significant on fracture resistance. However, the remaining dentine with 2- or 1-mm thickness was not an important factor for the fracture resistance.     

Fracture prevention in COPD patients; a clinical 5-step approach

Although osteoporosis and its related fractures are common in patients with COPD, patients at high risk of fracture are poorly identified, and consequently, undertreated. Since there are no fracture prevention guidelines available that focus on COPD patients, we developed a clinical approach to improve the identification and treatment of COPD patients at high risk of fracture. We organised a round-table discussion with 8 clinical experts in the field of COPD and fracture prevention in the Netherlands in December 2013. The clinical experts presented a review of the literature on COPD, osteoporosis and fracture prevention. Based on the Dutch fracture prevention guideline, they developed a 5-step clinical approach for fracture prevention in COPD. Thereby, they took into account both classical risk factors for fracture (low body mass index, older age, personal and family history of fracture, immobility, smoking, alcohol intake, use of glucocorticoids and increased fall risk) and COPD-specific risk factors for fracture (severe airflow obstruction, pulmonary exacerbations and oxygen therapy). Severe COPD (defined as postbronchodilator FEV₁ < 50% predicted) was added as COPD-specific risk factor to the list of classical risk factors for fracture. The 5-step clinical approach starts with case finding using clinical risk factors, followed by risk evaluation (dual energy X-ray absorptiometry and imaging of the spine), differential diagnosis, treatment and follow-up. This systematic clinical approach, which is evidence-based and easy-to-use in daily practice by pulmonologists, should contribute to optimise fracture prevention in COPD patients at high risk of fracture.     

Protein primary structure using orthogonal fragmentation techniques in Fourier transform mass spectrometry

Proteomics analysis using tandem mass spectrometry requires informative backbone fragmentation of peptide ions. Collision-activated dissociation (CAD) of cations alone is not sufficiently informative to satisfy all requirements. Thus, there is a need to supplement CAD with a complementary fragmentation technique. Electron capture dissociation (ECD) is complementary to collisional excitation in terms of the cleavage of a different bond (N-C_α versus C-N bond) and other properties. CAD-ECD combination improves protein identification and enables high-throughput de novo sequencing of peptides. ECD and its variants are also useful in mapping labile post-translational modifications in proteins and isomer differentiation; for example, distinguishing Ile from Leu, iso-Asp from Asp and even D- from L-amino acid residues.     

Evaluating stripe rust resistance in Indian wheat genotypes and breeding lines using molecular markers

Stripe rust (yellow rust), caused by Puccinia striiformis f. sp. tritici (Pst), is a serious disease of wheat worldwide, including India. Growing resistant cultivars is the most cost-effective and eco-friendly approach to manage the disease. In this study, 70 publically available molecular markers were used to identify the distribution of 35 Yr genes in 68 wheat genotypes. Out of 35 Yr genes, 25 genes amplified the loci associated with Yr genes. Of the 35, 18 were all-stage resistance ASR (All-stage resistance) genes and 7 (Yr16, Yr18, Yr29, Yr30, Yr36, Yr46 & Yr59) were APR (Adult-plant resistance) genes. In the field tests, evaluation for stripe rust was carried out under artificial inoculation of Pst. Fifty-three wheat genotypes were found resistant to yellow rust (ITs 0), accounting for 77.94% of total entries. Coefficients of infection ranged from 0 to 60 among all wheat genotypes. Two genotypes (VL 1099 & VL 3002) were identified with maximum 15 Yr genes followed by 14 genes in VL 3010 and HI8759, respectively. Maximum number of all-stage resistance genes were identified in RKD 292 (11) followed by ten genes in DBW 216, WH 1184 and VL 3002. Maximum number of adult-plant resistance gene was identified in VL 3009 (6), HI 8759 (5) and Lassik (4) respectively. Genes Yr26 (69.2%), Yr2 (69.1%), Yr64 (61.7%), Yr24 (58.9%), Yr7 (52.9%), Yr10 (50%) and Yr 48 (48.5%) showed high frequency among selected wheat genotypes, while Yr9 (2.94%), Yr36 (2.94%), Yr60 (1.47%) and Yr32 (8.8%) were least frequent in wheat genotypes. In future breeding programs, race specific genes and non-race specific genes should be utilised to pyramid with other effective genes to develop improved wheat cultivars with high-level and durable resistance to stripe rust. Proper deployment of Yr genes and utilizing the positive interactions will be helpful for resistance breeding in wheat.     

Monitoring of microbial souring in chemically treated, produced-water biofilm systems using molecular techniques

The identification of bacteria in oil production facilities has previously been based on culture techniques. However, cultivation of bacteria from these often-extreme environments can lead to errors in identifying the microbial community members. In this study, molecular techniques including fluorescence in situ hybridization, PCR, denaturing gradient gel electrophoresis, and sequencing were used to track changes in bacterial biofilm populations treated with nitrate, nitrite, or nitrate + molybdate as agents for the control of sulfide production. Results indicated that nitrite and nitrate + molybdate reduced sulfide production, while nitrate alone had no effect on sulfide generation. No long-term effect on sulfide production was observed. Initial sulfate-reducing bacterial numbers were not influenced by the chemical treatments, although a significant increase in sulfate-reducing bacteria was observed after termination of the treatments. Molecular analysis showed a diverse bacterial population, but no major shifts in the population due to treatment effects were observed.     

Assessment of blue-stain resistance according to the EN 152 and a reverse test method using visual and computer-aided techniques

A computer technique for assessing blue-stained coated wood has been implemented for evaluating the discoloration of coatings and analysing the interior wood staining of samples subjected to testing according to European Standard EN 152. The comparison of visual assessment and computer-evaluated percentages of blue staining is based on a combination of correlation measures, principal components and cluster analysis. It appears difficult to imitate human evaluation with image processing, since computer ratings represent exact percentages, while subjective evaluations do not. Additionally, more specific techniques for exploring fungal growth in coated wood have been described. As EN 152 was specifically developed for testing efficacy of wood preservatives, a modified test methodology was elaborated for testing the efficacy of wood coatings, called here as the EN 152-reverse method. Furthermore three-dimensional (3D) reconstruction is validated as a tool for in-depth analysis of blue-stain disfigurement. This 3D visualisation indicates important differences in fungal infestation and proves its suitability for blue-stain resistance testing.     

Number of teeth in relation to oral health behaviour in dentate elderly patients in Lithuania

Aim: To describe oral self‐care practices and the use of dental services among dentate elderly patients attending public dental service in Kédainiai, Lithuania, and relate these parameters to the number of remaining teeth. Design: Cross‐sectional questionnaire study. Setting: Two public dental offices in Kédainiai, Lithuania. Participants: Dentate patients aged 60+. Methods: A self‐administered questionnaire covering oral hygiene practices, use of sugar, utilisation of dental services, and number of teeth. Age, gender, and education served as background factors. Results: In all, 174 dentate elderly people responded, their mean age being 69.2 years (CI 95% 68.2–70.2) and mean number of teeth reported 16.2 (CI 95% 15.4–17.1). Of these respondents, 30% reported that they brushed their teeth twice daily and 57% that they always used fluoridated tooth paste. Having 21+ teeth was strongly associated (p < 0.001) with these habits, with brushing in the evening, and with enrolment in higher education, but not with gender. After controlling for various self‐care and background factors, frequent tooth brushing remained as the only significant factor in the logistic regression model (OR 2.0, CI 95% 1.2–3.3, p = 0.01) to explain subjects’ retention of 21+ teeth. Conclusions: Elderly Lithuanians’ oral self‐care is far from meeting recommendations. To preserve their natural teeth, dentate elderly people should improve their oral self‐care practices, in particular as regards tooth brushing. To reach that goal, all efforts by the community and dental profession are welcomed.     

Enhanced resistance to infection with Haemonchus contortus in sheep treated with a corticosteroid

Adams D. B. and Davies H. I. 1982. Enhanced resistance to infection with Haemonchus contortus in sheep treated with a corticosteroid. International Journal for Parasitology12: 523–529. Fewer worms established from experimental infections with Haemonchus contortus in either immune or naive sheep or in sheep of undefined immune status given the corticosteroid, dexamethasone, around the time of challenge. In four experiments, the number of adult worms present in sheep treated with dexamethasone ranged from 32 to 36% of that in untreated animals. That the phenomenon did not stem from direct action of dexamethasone on the worms themselves was demonstrated by comparing continuous treatment with the drug from infection until patency with treatment given at infection and four days later. Sheep continuously treated with dexamethasone harboured similar numbers of worms as the infection controls whereas fewer parasites were found in sheep given dexamethasone around the time of infection. The results imply that active regulation of immunological unresponsiveness operates in sheep during infection with H. contortus and that disruption of immunoregulation by dexamethasone released protective responses thereby decreasing worm burdens. Because suppressor lymphocytes are implicated, cellular perturbations following treatment with dexamethasone were investigated. Dexamethasone did not cause marked lymphopenia. It, however, reduced blastogenic responses by lymphocytes to con A but not PHA. Comparison of responses to these mitogens in cells from blood and lymph demonstrates that con A and PHA-reactivity resides in identifiably different cell populations in sheep.     

A procedure to estimate okadaic acid in whole dinoflagellate cells using immunological techniques

A single procedure to detect and estimate okadaic acid in isolated whole cells was developed based on immunofluorescence and microscope photometry. This procedure allows the study of variations in okadaic acid concentration per cell although it is no substitute for HPLC procedures. Cells from mid-log exponential and stationary phase from two different clonal cultures of the okadaic-acid-producing dinoflagellate Prorocentrum lima (PI 5V and PI 7V) were analyzed. The results showed that: (1) cells from saturated phase cultures contain more okadaic acid than those from exponentially-growing mid-log phase; (2) genetic differences exist in okadaic acid production between the clones used; (3) okadaic acid is synthesized continuously during the whole cell cycle.     

Variability and resistance mutations in the hepatitis C virus NS3 protease in patients not treated with protease inhibitors

The goal of treatment of chronic hepatitis C is to achieve a sustained virological response, which is defined as exhibiting undetectable hepatitis C virus (HCV) RNA levels in serum following therapy for at least six months. However, the current treatment is only effective in 50% of patients infected with HCV genotype 1, the most prevalent genotype in Brazil. Inhibitors of the serine protease non-structural protein 3 (NS3) have therefore been developed to improve the responses of HCV-infected patients. However, the emergence of drug-resistant variants has been the major obstacle to therapeutic success. The goal of this study was to evaluate the presence of resistance mutations and genetic polymorphisms in the NS3 genomic region of HCV from 37 patients infected with HCV genotype 1 had not been treated with protease inhibitors. Plasma viral RNA was used to amplify and sequence the HCV NS3 gene. The results indicate that the catalytic triad is conserved. A large number of substitutions were observed in codons 153, 40 and 91; the resistant variants T54A, T54S, V55A, R155K and A156T were also detected. This study shows that resistance mutations and genetic polymorphisms are present in the NS3 region of HCV in patients who have not been treated with protease inhibitors, data that are important in determining the efficiency of this new class of drugs in Brazil.     

Screening of high-risk Gaucher disease patients in Brazil using miniaturized dried blood spots and leukocyte techniques

This study investigates the miniaturization of the screening technique using dried blood spots on filter paper (DBS) to measure GBA and CT activities, and GBA and β-galactosidase activities in leukocytes. 274 DBS from individuals with suspected GD were screened for 1.5years. Of these, we confirmed the diagnosis in 13.5%. The miniaturization of the DBS and leukocyte techniques afforded to reduce costs and sample size appropriate for a reliable diagnosis.     

Family association between immune parameters and resistance to Aeromonas hydrophila infection in the Indian major carp, Labeo rohita

Seven innate immune parameters were investigated in 64 full-sib families (the offspring of 64 sires and 45 dams) from two year-classes of farmed rohu carp (Labeo rohita). Survival rates were also available from Aeromonas hydrophila infection (aeromoniasis) recorded in controlled challenge tests on a different sample of individuals from the same families. Due to strong confounding between the animal additive genetic effect and the family effects (common environmental + non-additive genetic), reliable additive (co)variance components and hence heritabilities and genetic correlations could not be obtained for the investigated parameters. Therefore, estimates of the association of challenge test survival with the studied immune parameters were obtained as product moment correlations between family least square means. These correlations revealed statistically significant (p < 0.05) negative correlations of survival with bacterial agglutination titre (−0.48), serum haemolysin titre (−0.29) and haemagglutination titre (−0.34); and significant positive correlation with ceruloplasmin level (0.51). The correlations of survival to aeromoniasis with myeloperoxidase activity, superoxide production and lysozyme activity were found to be not significantly different from zero (p > 0.05). Assuming that the negatively correlated candidate traits are not favourable as indirect selection criteria, the results suggest that ceruloplasmin level could potentially be a marker for resistance to aeromoniasis in rohu. The use of this immune parameter as an indirect selection criterion for increased resistance to aeromoniasis in rohu will, however, require that the parameter shows significant additive genetic variation and a significant genetic correlation with survival. Further studies are therefore needed to obtain a reliable heritability estimate for ceruloplasmin and its genetic correlation with survival from aeromoniasis.     

小菜蛾对阿维菌素抗性基因的AFLP连锁图谱的构建

世界性害虫小菜蛾Plutella xylostella (L.) 田间种群已对阿维菌素药剂产生了高抗药性。本研究以小菜蛾对阿维菌素的抗性品系、敏感品系和回交群体组建作图家系,再利用AFLP技术构建小菜蛾对阿维菌素抗性基因的连锁图谱。用10组AFLP引物组合对未经药剂处理的小菜蛾成虫DNA选择性扩增,共获得1 044条可区分的DNA条带,271条带具有多态性,χ²检验表明只有123个位点符合1∶1 （P=0.05）,其中的112个构成28个连锁群,其总长度为1 222.7 cM; 用10组AFLP引物对经药剂处理后存活的小菜蛾成虫DNA扩增,所得的DNA条带中有54个条带符合分离比1∶1,经Mapmaker 3.0对多态性位点分析,只有E1M4-15、E1M1-4和E1M4-2标记位点位于同一连锁群,3个AFLP标记与抗性基因的遗传距离分别为0 cM,8.3 cM和13.1 cM。比较分析得出,抗性基因所在的连锁群是第5连锁群。结果显示AFLP连锁图谱对小菜蛾对阿维菌素的抗性监测具有很好的应用潜力。     

Improved distance analysis in RNA using network-editing techniques for overcoming errors due to spin diffusion

Multispin magnetization transfer, or spin diffusion, is a significant source of error in NOESY-derived distance measurements for the determination of nucleic acid solution structures. The BD-NOESY and CBD-NOESY experiments, which allow the measurement of interproton distances with greatly reduced contributions from spin diffusion, have been adapted to structural analysis in RNA oligonucleotides. The techniques are applied to a lead-dependent ribozyme (LZ2). We demonstrate the measurement of both aromatic proton–aromatic proton NOEs free of spin diffusion involving the intervening ribose moieties and aromatic proton–ribose proton NOEs free of the efficient cross-relaxation within the ribose ring. In LZ2, the accuracy and precision of the resulting distances are significantly improved. We also find that, by allowing the use of longer mixing times with greater sensitivity, the experimental attenuation of spin diffusion in RNA increases the distance range of interactions that can be analyzed. This effect permits measurement of important long-range distances in LZ2 that are not accessible with standard techniques. Thus, these techniques allow the simultaneous optimization of the number, accuracy, and precision of distance constraints used for RNA structure determinations.     

QTL mapping of resistance to Fusarium ear rot using a RIL population in maize

Fusarium ear rot is a prevalent disease in maize, reducing grain yields and quality. Resistance breeding is an efficient way to minimize losses caused by the disease. In this study, 187 lines from a RIL population along with the resistant (87-1) and susceptible (Zong 3) parents were planted in Zhengzhou and Beijing with three replications in years 2004 and 2006. Each line was artificially inoculated using the nail-punch method. Significant genotypic variation in response to Fusarium ear rot was detected in both years. Based on a genetic map containing 246 polymorphic SSR markers with average genetic distances of 9.1 cM, the ear-rot resistance QTL were firstly analyzed by composite interval mapping (CIM). Three QTL were detected in both Zhengzhou and Beijing in 2004; and three and four QTL, respectively, were identified in 2006. The resistant parent contributed all resistance QTL. By using composite interval mapping and a mixed model (MCIM), significant epistatic effects on Fusarium ear rot as well as interactions between mapped loci and environments were observed across environments. Two QTL on chromosome 3 (3.04 bin) were consistently identified across all environments by the two methods. The major resistant QTL with the largest effect was flanked by markers umc1025 and umc1742 on chromosome 3 (3.04 bin), explaining 13–22% of the phenotypic variation. The SSR markers closely flanking the major resistance QTL will facilitate marker-assisted selection (MAS) of resistance to Fusarium ear rot in maize breeding programs.     

Pyramiding multiple genes for resistance to soybean mosaic virus in soybean using molecular markers

Seven strains of Soybean mosaic virus (SMV) and three independent resistance loci (Rsv1, Rsv3, and Rsv4) have been identified in soybean. The objective of this research was to pyramid Rsv1, Rsv3, and Rsv4 for SMV resistance using molecular markers. J05 carrying Rsv1 and Rsv3 and V94-5152 carrying Rsv4 were used as the donor parents for gene pyramiding. A series of F_2:3, F_3:4, and F_4:5 lines derived from J05 × V94-5152 were developed for selecting individuals carrying all three genes. Eight PCR-based markers linked to the three SMV resistance genes were used for marker-assisted selection. Two SSR markers (Sat_154 and Satt510) and one gene-specific marker (Rsv1-f/r) were used for selecting plants containing Rsv1; Satt560 and Satt063 for Rsv3; and Satt266, AI856415, and AI856415-g for Rsv4. Five F_4:5 lines were homozygous for all eight marker alleles and presumably carry all three SMV resistance genes that would potentially provide multiple and durable resistance to SMV.     

Development of markers linked to Diuraphisnoxia resistance in wheat using a novel PCR-RFLP approach

Through random amplified polymorphic DNA (RAPD) analysis we identified a putative marker linked to the Dn5 resistance gene. This marker was converted to a more reliable sequence-characterised-amplified regions (SCAR) marker. The initial SCAR marker amplified the correct amplification product but failed to discern between the susceptible and resistant individuals. Hence, it was utilised to sequence the internal fragment. All nested primers designed from the internal sequences were also unable to produce any polymorphism between the susceptible and resistant cultivars. Restriction digests were then performed on these fragments, and the restriction enzyme EcoRI was able to discern between the susceptible and resistant F₂ individuals of the Dn5 population. This granted one marker amplified with the internal SCAR primer set OPF14₁₀₈₃ the ability to differentiate between parental individuals carrying the Dn5 genes. This marker was tested in a segregating F₂ population carrying the Dn5 resistance gene and proved able to differentiate between the segregating individuals. This marker may prove useful in marker assisted selection (MAS), although performing restriction digests may hamper the throughput of a high number of samples. Received: 4 August 1999 / Accepted: 27 August 1999