189 research outputs found

    Endophytic fungi in Canada wild rye in natural grasslands

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    Some grasses harbor endophytic fungi living in intercellular spaces in the leaves, stems and reproductive organs. The fungi can dramatically affect the physiology and ecology of plants. For example, fungi may produce toxins that deter herbivores and they may alter the water status of the plant to increase drought tolerance. The distribution of fungal infection in natural plant populations is unknown for many host species. We investigated the occurrence of endophytic fungi in Elymus canadensis L. (Canada wild rye) from 13 remnant prairie sites in the midwest and 23 sites in the southern Great Plains. Collections of plant tissue came from Nebraska, Kansas, Minnesota, Iowa, Missouri, Illinois, Oklahoma, and Texas. All midwest plants were grown in a common garden site in eastern Nebraska. Seeds collected from Oklahoma and Texas accessions were planted in the greenhouse. At least 3 tillers from 2 plants of each accession were screened for endophytes, using light microscopy. The endophytic fungus was found in seed of all accessions and in plants from all but 4 accessions. The functional significance of the fungus is unclear, but it may affect plants by enhancing productivity or deterring herbivores. The widespread occurrence of endophytic fungi in natural populations of E. canadensis suggests that the plant-fungal association may be long-standing and important in the evolution and success of this native prairie species. Algunos zacates albergan hongos endofiticos que viven en los espacios intracelulares de las hojas, tallos y órganos reproductivos. Los hongos pueden afectar dramáticamente la fisiología y ecología de las plantas. Por ejemplo, el hongo puede producir toxinas que desalientan a los herbívoros y ellos pueden alterar el estado hídrico de la planta para incrementar la tolerancia a sequía. La distribución de la infección fungal en poblaciones de plantas naturales es desconocida para muchas de las especies hospederas. Investigamos la ocurrencia de hongos endofiticos en Elymus canadensis L. (Canada wild rye) en 13 sitios de pradera en el medio oeste y en 23 sitios en las Grandes Planicies del Sur. Colecciones de tejidos de plantas arribaron de Nebraska, Kansas, Minnesota, Iowa, Missouri, Illinois, Oklahoma, and Texas. Todas las plantas provenientes del medio oeste se cultivaron en un sitio de jardín común en el este de Nebraska. Las semillas colectadas de las entradas de Oklahoma and Texas se plantaron en invernadero. Al menos 3 hijuelos de dos plantas de cada entrada se inspeccionaron mediante luz microscópica para determinar los endófitos. El hongo endófito se encontró en las semillas de todas las entradas y en plantas de todas menos 4 entradas. El significado funcional del hongo no es claro, pero puede afectar las plantas aumentando su productividad o desalentando a los herbívoros. La ocurrencia tan amplia y dispersa de los hongos endofiticos en las poblaciones naturales de E. Canadiensis sugiere que la asociación planta-hongo puede ser importante en la evolución y éxito de esta especie nativa de las prader

    The Importance of Time Congruity in the Organisation.

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    In 1991 Kaufman, Lane, and Lindquist proposed that time congruity in terms of an individual's time preferences and the time use methods of an organisation would lead to satisfactory performance and enhancement of quality of work and general life. The research reported here presents a study which uses commensurate person and job measures of time personality in an organisational setting to assess the effects of time congruity on one aspect of work life, job-related affective well-being. Results show that time personality and time congruity were found to have direct effects on well-being and the influence of time congruity was found to be mediated through time personality, thus contributing to the person–job (P–J) fit literature which suggests that direct effects are often more important than indirect effects. The study also provides some practical examples of ways to address some of the previously cited methodological issues in P–J fit research

    Neural circuitry engaged during unsuccessful motor inhibition in pediatric bipolar disorder

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    Objective: Deficits in motor inhibition may contribute to impulsivity and irritability in children with bipolar disorder (BPD). Therefore, studies of the neural circuitry engaged during failed motor inhibition in pediatric BPD may contribute to our understanding of the pathophysiology of the illness. We tested the hypothesis that children with BPD and controls would differ in ventral prefrontal cortex (vPFC), striatal, and anterior cingulate activation during unsuccessful motor inhibition. We also compared activation in medicated vs. unmedicated children with BPD, and in children with BPD and ADHD (BPD+ADHD) vs. those with BPD but without ADHD (BPD-ADHD). Method: Event-related fMRI study comparing neural activation in children with BPD and controls while they performed a motor inhibition task. The sample included 26 children with BPD (13 unmedicated, 15 with ADHD) and 17 age, gender, and IQ matched controls. Results: On failed inhibitory trials, controls showed greater bilateral striatal and right vPFC activation than did patients. While our findings were somewhat more prominent in unmedicated than medicated, patients, and in BPD+ADHD than BPD-ADHD, the findings did not differ significantly (?) among these subgroups of children with BPD. Conclusions: Compared to controls, children with BPD may have deficits in their ability to engage striatal structures and right vPFC during unsuccessful inhibition. (this reads confusingly to me—they’re deficient in their capacity to engage structures when they’re behaviorally unsuccessful? Perhaps reword?) Further research is needed to determine whether these deficits play a role in the emotional and behavioral dysregulation characteristic of BPD

    The Current State of Performance Appraisal Research and Practice: Concerns, Directions, and Implications

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    On the surface, it is not readily apparent how some performance appraisal research issues inform performance appraisal practice. Because performance appraisal is an applied topic, it is useful to periodically consider the current state of performance research and its relation to performance appraisal practice. This review examines the performance appraisal literature published in both academic and practitioner outlets between 1985 and 1990, briefly discusses the current state of performance appraisal practice, highlights the juxtaposition of research and practice, and suggests directions for further research

    Efficacy of tissue brushing as measured by the prosthodontic tissue index

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    This study was conducted to determine the efficacy of brushing the oral mucosa supporting complete dentures with a soft brush to see if this treatment would reduce inflammation. The oral mucosa health status of 60 patients was monitored for 120 days using the PTI to measure inflammation. For comparison the patients were divided into two groups, and every effort was made to balance the groups for those variables that may effect inflammation. The patients were also compared with themselves. The experiment consisted of three phases; Phase 1 established baseline data, and Phases 2 and 3 were information-gathering sessions. Each patient received brushing instructions at the start of the brushing test period and additional brushing instruction during a reinforcement session after 30 days. Tissue brushing did reduce the inflammation index of the oral mucosa examined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74782/1/j.1754-4505.1984.tb00150.x.pd

    Diagnosis and follow-up of treatment of latent tuberculosis; the utility of the QuantiFERON-TB Gold In-tube assay in outpatients from a tuberculosis low-endemic country

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    <p>Abstract</p> <p>Background</p> <p>Interferon-gamma (IFN-γ) Release Assays (IGRA) are more specific than the tuberculosis skin test (TST) in the diagnosis of latent tuberculosis (TB) infection (LTBI). We present the performance of the QuantiFERON<sup>®</sup>-TB Gold In-tube (QFT-TB) assay as diagnostic test and during follow-up of preventive TB therapy in outpatients from a TB low-endemic country.</p> <p>Methods</p> <p>481 persons with suspected TB infection were tested with QFT-TB. Thoracic X-ray and sputum samples were performed and a questionnaire concerning risk factors for TB was filled. Three months of isoniazid and rifampicin were given to patients with LTBI and QFT-TB tests were performed after three and 15 months.</p> <p>Results</p> <p>The QFT-TB test was positive in 30.8% (148/481) of the total, in 66.9% (111/166) of persons with origin from a TB endemic country, in 71.4% (20/28) previously treated for TB and in 100% (15/15) of those diagnosed with active TB with no inconclusive results. The QFT-TB test was more frequently positive in those with TST ≥ 15 mm (47.5%) compared to TST 11-14 mm (21.3%) and TST 6-10 mm (10.5%), (p < 0.001). Origin from a TB endemic country (OR 6.82, 95% CI 1.73-26.82), recent stay in a TB endemic country (OR 1.32, 95% CI 1.09-1.59), duration of TB exposure (OR 1.59, 95% CI 1.14-2.22) and previous TB disease (OR 11.60, 95% CI 2.02-66.73) were all independently associated with a positive QFT-TB test. After preventive therapy, 35/40 (87.5%) and 22/26 (84.6%) were still QFT-TB positive after three and 15 months, respectively. IFN-γ responses were comparable at start (mean 6.13 IU/ml ± SD 3.99) and after three months (mean 5.65 IU/ml ± SD 3.66) and 15 months (mean 5.65 IU/ml ± SD 4.14), (p > 0.05).</p> <p>Conclusion</p> <p>Only one third of those with suspected TB infection had a positive QFT-TB test. Recent immigration from TB endemic countries and long duration of exposure are risk factors for a positive QFT-TB test and these groups should be targeted through screening. Since most patients remained QFT-TB positive after therapy, the test should not be used to monitor the effect of preventive therapy. Prospective studies are needed in order to determine the usefulness of IGRA tests during therapy.</p

    Predictors of persistently positive Mycobacterium-tuberculosis-specific interferon-gamma responses in the serial testing of health care workers

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    <p>Abstract</p> <p>Background</p> <p>Data on the performance of Mycobacterium-tuberculosis-specific interferon-(IFN)-γ release assays (IGRAs) in the serial testing of health care workers (HCWs) is limited. The objective of the present study was to determine the frequency of IGRA conversions and reversions and to identify predictors of persistent IGRA positivity among serially tested German HCWs in the absence of recent extensive tuberculosis (TB) exposure.</p> <p>Methods</p> <p>In this observational cohort-study HCWs were prospectively recruited within occupational safety and health measures and underwent a tuberculin skin test (TST) and the IGRA QuantiFERON<sup>®</sup>-TB Gold In-Tube (QFT-GIT) at baseline. The QFT-GIT was repeated 18 weeks later in the median. QFT-GIT conversions (and reversions) were defined as baseline IFN-γ < 0.35 IU/ml and follow-up IFN-γ ≥ 0.35 IU/ml (and vice versa). Predictors of persistently positive QFT-GIT results were calculated by logistic regression analysis.</p> <p>Results</p> <p>In total, 18 (9.9%) and 15 (8.2%) of 182 analyzed HCWs were QFT-GIT-positive at baseline and at follow-up, respectively. We observed a strong overall agreement between baseline and follow-up QFT-GIT results (κ = 0.70). Reversions (6/18, 33.3%) occurred more frequently than conversions (3/162, 1.9%). Age and positive prior and recent TST results independently predicted persistent QFT-GIT positivity. Furthermore, the chance of having persistently positive QFT-GIT results raised about 3% with each additional 0.1 IU/ml increase in the baseline IFN-γ response (adjusted odds ratio 1.03, 95% confidence interval 1.01-1.04). No active TB cases were detected within an observational period of more than two years.</p> <p>Conclusions</p> <p>The QFT-GIT's utility for the application in serial testing was limited by a substantial proportion of reversions. This shortcoming could be overcome by the implementation of a borderline zone for the interpretation of QFT-GIT results. However, further studies are needed to clearly define the within-subject variability of the QFT-GIT and to confirm that increasing age, concordantly positive TST results, and the extend of baseline IFN-γ responses may predict the persistence of QFT-GIT positivity over time in serially tested HCWs with only a low or medium TB screening risk in a TB low-incidence setting.</p

    'MRI-negative PET-positive' temporal lobe epilepsy (TLE) and mesial TLE differ with quantitative MRI and PET: a case control study

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    Background: \u27MRI negative PET positive temporal lobe epilepsy\u27 represents a substantial minority of temporal lobe epilepsy (TLE). Clinicopathological and qualitative imaging differences from mesial temporal lobe epilepsy are reported. We aimed to compare TLE with hippocampal sclerosis (HS+ve) and non lesional TLE without HS (HS-ve) on MRI, with respect to quantitative FDG-PET and MRI measures.Methods: 30 consecutive HS-ve patients with well-lateralised EEG were compared with 30 age- and sex-matched HS+ve patients with well-lateralised EEG. Cerebral, cortical lobar and hippocampal volumetric and co-registered FDG-PET metabolic analyses were performed.Results: There was no difference in whole brain, cerebral or cerebral cortical volumes. Both groups showed marginally smaller cerebral volumes ipsilateral to epileptogenic side (HS-ve 0.99, p = 0.02, HS+ve 0.98, p &lt; 0.001). In HS+ve, the ratio of epileptogenic cerebrum to whole brain volume was less (p = 0.02); the ratio of epileptogenic cerebral cortex to whole brain in the HS+ve group approached significance (p = 0.06). Relative volume deficits were seen in HS+ve in insular and temporal lobes. Both groups showed marked ipsilateral hypometabolism (p &lt; 0.001), most marked in temporal cortex. Mean hypointensity was more marked in epileptogenic-to-contralateral hippocampus in HS+ve (ratio: 0.86 vs 0.95, p &lt; 0.001). The mean FDG-PET ratio of ipsilateral to contralateral cerebral cortex however was low in both groups (ratio: HS-ve 0.97, p &lt; 0.0001; HS+ve 0.98, p = 0.003), and more marked in HS-ve across all lobes except insula.Conclusion: Overall, HS+ve patients showed more hippocampal, but also marginally more ipsilateral cerebral and cerebrocortical atrophy, greater ipsilateral hippocampal hypometabolism but similar ipsilateral cerebral cortical hypometabolism, confirming structural and functional differences between these groups.<br /

    Axillary lymph node dissection for breast cancer utilizing Harmonic Focus®

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    <p>Abstract</p> <p>Background</p> <p>For patients with axillary lymph node metastases from breast cancer, performance of a complete axillary lymph node dissection (ALND) is the standard approach. Due to the rich lymphatic network in the axilla, it is necessary to carefully dissect and identify all lymphatic channels. Traditionally, these lymphatics are sealed with titanium clips or individually sutured. Recently, the Harmonic Focus<sup>®</sup>, a hand-held ultrasonic dissector, allows lymphatics to be sealed without the utilization of clips or ties. We hypothesize that ALND performed with the Harmonic Focus<sup>® </sup>will decrease operative time and reduce post-operative complications.</p> <p>Methods</p> <p>Retrospective review identified all patients who underwent ALND at a teaching hospital between January of 2005 and December of 2009. Patient demographics, presenting pathology, treatment course, operative time, days to drain removal, and surgical complications were recorded. Comparisons were made to a selected control group of patients who underwent similar surgical procedures along with an ALND performed utilizing hemostatic clips and electrocautery. A total of 41 patients were included in this study.</p> <p>Results</p> <p>Operative time was not improved with the use of ultrasonic dissection, however, there was a decrease in the total number of days that closed suction drainage was required, although this was not statistically significant. Complication rates were similar between the two groups.</p> <p>Conclusion</p> <p>In this case-matched retrospective review, there were fewer required days of closed suction drainage when ALND was performed with ultrasonic dissection versus clips and electrocautery.</p
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