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Little Role (little + role)
Selected AbstractsThe role of surveillance endoscopy and endosonography after endoscopic ablation of high-grade dysplasia and carcinoma of the esophagusDISEASES OF THE ESOPHAGUS, Issue 2 2008A. D. Savoy SUMMARY., Barrett's esophagus (BE) with high-grade dysplasia (HGD) or early carcinoma treated with surgery or photodynamic therapy (PDT) is at risk of recurrence. The efficacy of endoscopic ultrasound (EUS) for surveillance after PDT is unknown. Our objective was to determine if EUS is superior to esophagogastroduodenoscopy (EGD) and/or CT scan for surveillance of BE neoplasia after PDT. The study was designed as a retrospective review with the setting as a tertiary referral center. Consecutive patients with BE with HGD or carcinoma in situ treated with PDT were followed with EUS, CT scan and EGD with jumbo biopsies every 1 cm at 3, 4, or 6-month intervals. Exclusion criteria was < 6 months of follow up and/or < 2 EUS procedures. Main outcome measurements were residual or recurrent disease discovered by any method. Results showed that 67/97 patients met the inclusion criteria (56 men and 11 women). Median follow-up was 16 months. Recurrent or residual adenocarcinoma (ACA) was detected in four patients during follow-up. EGD with random biopsies or targeted nodule biopsies detected three patients. EUS with endoscopic mucosal resection of the nodule confirmed T1 recurrence in one of these three. In the fourth patient, CT scan revealed perigastric lymphadenopathy and EUS-FNA (fine needle aspiration) confirmed adenocarcinoma. There were two deaths, one related to disease progression and one unrelated. The rate of recurrent/persistent ACA after PDT was 4/67 = 6%. EUS did not detect disease when EGD and CT were normal. Limitations of this study include non-blinding of results and preferential status of non-invasive imaging (CT) over EUS. Our experience suggests that EUS has little role in the surveillance of these patients, unless discrete abnormalities are found on EGD or cross-sectional imaging. [source] Role of GABAA inhibition in modulation of pyramidal tract neuron activity during postural correctionsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2007Zinaida A. Tamarova Abstract In a previous study we demonstrated that the activity of pyramidal tract neurons (PTNs) of the motor cortex is modulated in relation to postural corrections evoked by periodical tilts of the animal. The modulation included an increase in activity in one phase of the tilt cycle and a decrease in the other phase. It is known that the motor cortex contains a large population of inhibitory GABAergic neurons. How do these neurons participate in periodic modulation of PTNs? The goal of this study was to investigate the role of GABAA inhibitory neurons of the motor cortex in the modulation of postural-related PTN activity. Using extracellular electrodes with attached micropipettes, we recorded the activity of PTNs in cats maintaining balance on a tilting platform both before and after iontophoretic application of the GABAA receptor antagonists gabazine or bicuculline. The tilt-related activity of 93% of PTNs was affected by GABAA receptor antagonists. In 88% of cells, peak activity increased by 75 ± 50% (mean ± SD). In contrast, the trough activity changed by a much smaller value and almost as many neurons showed a decrease as showed an increase. In 73% of the neurons, the phase position of the peak activity did not change or changed by no more than 0.1 of a cycle. We conclude that the GABAergic system of the motor cortex reduces the posture-related responses of PTNs but has little role in determining their response timing. [source] Effects of structural variations of APOBEC3A and APOBEC3B genes in chronic hepatitis B virus infectionHEPATOLOGY RESEARCH, Issue 12 2009Hiromi Abe Aim:, Human APOBEC3 deaminases induce G to A hypermutation in nascent DNA strand of hepatitis B virus (HBV) genomes and seem to operate as part of the innate antiviral immune system. We analyzed the importance of APOBEC3A (A3A) and APOBEC3B (A3B) proteins, which are potent inhibitors of adeno-associated-virus and long terminal repeat (LTR)-retrotransposons, in chronic HBV infection. Methods:, We focused on the common deletion polymorphism that spans from the 3, part of A3A gene to the 3, portion of A3B gene. An association study was carried out in 724 HBV carriers and 469 healthy control subjects. We also analyzed hypermutated genomes detected in deletion and insertion (non-deletion) homozygous patients to determine the effect of APOBEC3 gene deletion. Further, we performed functional analysis of A3A gene by transient transfection experiments. Results:, The association study showed no significant association between deletion polymorphism and chronic HBV carrier state. Context analysis also showed a negligible effect for the deletion. Rather, mild liver fibrosis was associated with APOBEC gene deletion homozygosity, suggesting that A3B deletion is not responsible for chronic HBV infection. Functional analysis of A3A showed that overexpression of A3A induced hypermutation in HBV genome, although the levels of hypermutants were less than those introduced by A3G. However, overexpression of A3A did not decrease replicative intermediates of HBV. Conclusion:, These results suggest that A3A and A3B play little role in HBV elimination through anti-viral defense mechanisms. The significance of hypermutation induced by A3A should be investigated further. [source] The clinical features of dermatomyositis in a South Australian populationINTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 2 2007Vidya LIMAYE Abstract Aim:, To review the clinical features of dermatomyositis (DM) in a South Australian population. Methods:, Retrospective review of medical records of patients with biopsy-proven DM in South Australia from 1990 to 2005. Results:, There were 21 cases of biopsy-proven DM in SA (62% F, mean age 49.7 ± 18.4 years) and clinical details were available in 20 of these. Malignancy was identified in 9/20 patients; in five this followed the diagnosis of DM, with three malignancies seen within 3 months of disease onset. Three patients had a clearly defined immune insult prior to the diagnosis of DM; one patient had Mycoplasma pneumoniae infection 23 days prior to DM, two had pneumococcal and influenza vaccinations 5 and 14 days prior to the onset of DM, respectively. Two of three patients with anti-Jo-1 antibody experienced thromboembolism within 2 months of DM onset and three patients had interstitial lung disease (2 with anti-Jo-1 antibody). Creatine kinase (CK) was elevated in 15/20 cases and showed strong correlation with transaminases, and notably not with traditional inflammatory markers. Conclusions:, This retrospective review of patients with biopsy-proven DM suggests a role for infection/vaccination in triggering disease onset. A particularly strong association with malignancy was observed and it is suggested that DM may predispose to thrombosis. Transaminases, in addition to CK may be used to monitor disease activity, and traditional inflammatory markers have little role in this. [source] Demographic models and the management of endangered species: a case study of the critically endangered Seychelles magpie robinJOURNAL OF APPLIED ECOLOGY, Issue 5 2003Ken Norris Summary 1Demographic models are assuming an important role in management decisions for endangered species. Elasticity analysis and scope for management analysis are two such applications. Elasticity analysis determines the vital rates that have the greatest impact on population growth. Scope for management analysis examines the effects that feasible management might have on vital rates and population growth. Both methods target management in an attempt to maximize population growth. 2The Seychelles magpie robin Copsychus sechellarum is a critically endangered island endemic, the population of which underwent significant growth in the early 1990s following the implementation of a recovery programme. We examined how the formal use of elasticity and scope for management analyses might have shaped management in the recovery programme, and assessed their effectiveness by comparison with the actual population growth achieved. 3The magpie robin population doubled from about 25 birds in 1990 to more than 50 by 1995. A simple two-stage demographic model showed that this growth was driven primarily by a significant increase in the annual survival probability of first-year birds and an increase in the birth rate. Neither the annual survival probability of adults nor the probability of a female breeding at age 1 changed significantly over time. 4Elasticity analysis showed that the annual survival probability of adults had the greatest impact on population growth. There was some scope to use management to increase survival, but because survival rates were already high (> 0·9) this had a negligible effect on population growth. Scope for management analysis showed that significant population growth could have been achieved by targeting management measures at the birth rate and survival probability of first-year birds, although predicted growth rates were lower than those achieved by the recovery programme when all management measures were in place (i.e. 1992,95). 5Synthesis and applications. We argue that scope for management analysis can provide a useful basis for management but will inevitably be limited to some extent by a lack of data, as our study shows. This means that identifying perceived ecological problems and designing management to alleviate them must be an important component of endangered species management. The corollary of this is that it will not be possible or wise to consider only management options for which there is a demonstrable ecological benefit. Given these constraints, we see little role for elasticity analysis because, when data are available, a scope for management analysis will always be of greater practical value and, when data are lacking, precautionary management demands that as many perceived ecological problems as possible are tackled. [source] Juvenile shrubs show differences in stress tolerance, but no competition or facilitation, along a stress gradientJOURNAL OF ECOLOGY, Issue 1 2000Lisa A. Donovan Summary 1,We investigated experimentally differences in abiotic stress tolerance and the effects of plant,plant interactions for two desert shrubs, Chrysothamnus nauseosus and Sarcobatus vermiculatus, along a soil salinity (NaCl) and boron (B) gradient at Mono Lake, California, USA. Based on differences in natural distribution, and the classical expectation of a trade-off between competitive ability and stress tolerance, we hypothesized that (i) Chrysothamnus would have greater competitive ability than Sarcobatus at the low salinity end of the gradient, and that (ii) Sarcobatus would be more stress tolerant than Chrysothamnus. 2,Juvenile target plants of Chrysothamnus and Sarcobatus were planted into four sites along the gradient. Biomass was determined by destructive harvests over two growing seasons. At each site, interspecific relative competitive ability was assessed as the effect of Sarcobatus neighbours on Chrysothamnus targets compared to the effect of Chrysothamnus neighbours on Sarcobatus targets. Stress tolerance was assessed as the ability of each species to survive and grow, in the absence of neighbours, at different sites along the gradient. 3,The two species did not differ in the relative strength of plant,plant interactions, providing no support for the expectation that Chrysothamnus had greater competitive ability than Sarcobatus. Furthermore, there was no evidence for competition or facilitation, either interspecific or intraspecific, at any site in either year of the study. However, fertilization treatments demonstrated nutrient limitations, soil water reached limiting levels and root systems of targets and neighbours overlapped substantially. It is therefore surprising that plant,plant interactions among juveniles apparently play little role in the growth and survival of shrubs in this saline desert habitat. 4,Sarcobatus was more stress tolerant than Chrysothamnus and the two species performed optimally at different sites along the gradient. Sarcobatus juveniles grew best at the two most saline sites and survived at all sites, whereas Chrysothamnus juveniles grew best at a low-salinity site and did not survive at the most saline site. The difference in site of optimal performance may be due to differences in nutrient limitations or to interactions between nutrient availability and sodium (Na) and B tolerance. [source] Improving Construct Validity With Cognitive Psychology PrinciplesJOURNAL OF EDUCATIONAL MEASUREMENT, Issue 4 2001Susan Embretson Cognitive psychology principles have been heralded as possibly central to construct validity. In this paper, testing practices are examined in three stages: (a) the past, in which the traditional testing research paradigm left little role for cognitive psychology principles, (b) the present, in which testing research is enhanced by cognitive psychology principles, and (c) the future, for which we predict that cognitive psychology's potential will be fully realized through item design. An extended example of item design by cognitive theory is given to illustrate the principles. A spatial ability test that consists of an object assembly task highlights how cognitive design principles can lead to item generation. [source] Disentangling the racial test score gap: Probing the evidence in a large urban school districtJOURNAL OF POLICY ANALYSIS AND MANAGEMENT, Issue 1 2007Leanna Stiefel We examine the size and distribution of the gap in test scores across races within New York City public schools and the factors that explain these gaps. While gaps are partially explained by differences in student characteristics, such as poverty, differences in schools attended are also important. At the same time, substantial within-school gaps remain and are only partly explained by differences in academic preparation across students from different race groups. Controlling for differences in classrooms attended explains little of the remaining gap, suggesting little role for within-school inequities in resources. There is some evidence that school characteristics matter. Race gaps are negatively correlated with school size,implying small schools may be helpful. In addition, the trade-off between the size and experience of the teaching staff in urban schools may carry unintended consequences for within-school race gaps. © 2006 by the Association for Public Policy Analysis and Management. [source] An Assessment of the Dental Public Health Infrastructure in the United StatesJOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 1 2006Scott L. Tomar DMD Abstract Objectives: The National Institute of Dental and Craniofacial Research commissioned an assessment of the dental public health infrastructure in the United States as a first step toward ensuring its adequacy. This study examined several elements of the US dental public health infrastructure in government, education, workforce, and regulatory issues, focused primarily at the state level. Methods: Data were drawn from a wide range of sources, including original surveys, analysis of existing databases, and compilation of publicly available information. Results: In 2002, 72.5% of states had a full-time dental director and 65% of state dental programs had total budgets of $1 million or less. Among U.S. dental schools, 68% had a dental public health academic unit. Twelve and a half percent of dental schools and 64.3% of dental hygiene programs had no faculty member with a public health degree. Among schools of public health, 15% offered a graduate degree in a dental public health concentration area, and 60% had no faculty member with a dental or dental hygiene degree. There were 141 active diplomates of the American Board of Dental Public Health as of February 2001; 15% worked for state, county, or local governments. In May 2003, there were 640 US members of the American Association of Public Health Dentistry with few members in most states. In 2002, 544 American Dental Association members reported their specialty as Dental Public Health, which ranged from 0 in five states to 41 in California. Just two states had a public health dentist on their dental licensing boards. Conclusions: Findings suggest the US dental public health workforce is small, most state programs have scant funding, the field has minimal presence in academia, and dental public health has little role in the regulation of dentistry and dental hygiene. Successful efforts to enhance the many aspects of the US dental public health infrastructure will require substantial collaboration among many diverse partners. [source] Lead promotes abasic site accumulation and co-mutagenesis in mammalian cells by inhibiting the major abasic endonuclease Ape1,MOLECULAR CARCINOGENESIS, Issue 2 2007Daniel R. McNeill Abstract Lead is a widespread environmental toxin, found in contaminated water sources, household paints, and certain occupational settings. Classified as a probable carcinogen by the International Agency for Research on Cancer (IARC), lead promotes mutagenesis when combined with alkylating and oxidizing DNA-damaging agents. We previously reported that lead inhibits the in vitro repair activity of Ape1, the major endonuclease for repairing mutagenic and cytotoxic abasic sites in DNA. We investigated here whether lead targets Ape1 in cultured mammalian cells. We report a concentration-dependent inhibition of apurinic/apyrimidinic (AP) site incision activity of Chinese hamster ovary (CHO) AA8 whole cell extracts by lead. In addition, lead exposure results in a concentration-dependent accumulation of AP sites in the genomic DNA of AA8 cells. An increase in the oxidative base lesion 8-oxoguanine was observed only at high lead levels (500 µM), suggesting that non-specific oxidation plays little role in the production of lead-related AP lesions at physiological metal concentrations,a conclusion corroborated by "thiobarbituric acid reactive substances" assays. Notably, Ape1 overexpression in AA8 (hApe1-3 cell line) abrogated the lead-dependent increase in AP site steady-state levels. Moreover, lead functioned cooperatively to promote a further increase in abasic sites with agents known to generate AP sites in DNA (i.e., methyl methansulfonate (MMS) and hydrogen peroxide (H2O2)), but not the DNA crosslinking agent mitomycin C. Hypoxanthine guanine phosphoribosyltransferase (hprt) mutation analysis revealed that, whereas lead alone had no effect on mutation frequencies, mutagenesis increased in MMS treated, and to a greater extent lead/MMS treated, AA8 cells. With the hApe1-3 cell line, the number of mutant colonies in all treatment groups was found to be equal to that of the background level, indicating that Ape1 overexpression reverses MMS- and lead-associated hprt mutagenesis. Our studies in total indicate that Ape1 is a member of an emerging group of DNA surveillance proteins that are inhibited by environmental heavy metals, and suggest an underlying mechanism by which lead promotes co-carcinogenesis. Published 2006 Wiley-Liss, Inc., [source] Genetic divergence and migration patterns in a North American passerine bird: implications for evolution and conservationMOLECULAR ECOLOGY, Issue 8 2006LESLIE A. DAVIS Abstract Like many other migratory birds, the black-throated blue warbler (Dendroica caerulescens) shows pronounced differences in migratory behaviour and other traits between populations: birds in the southern part of the breeding range have darker plumage and migrate to the eastern Caribbean during the winter, whereas those in the north have lighter plumage and migrate to the western Caribbean. We examined the phylogeography of this species, using samples collected from northern and southern populations, to determine whether differentiation between these populations dates to the Pleistocene or earlier, or whether differences in plumage and migratory behaviour have arisen more recently. We analysed variation at 369 bp of the mitochondrial control region domain I and also at seven nuclear microsatellites. Analyses revealed considerable genetic variation, but the vast majority of this variation was found within rather than between populations, and there was little differentiation between northern and southern populations. Phylogeographic analyses revealed a very shallow phylogenetic tree, a star-like haplotype network, and a unimodal mismatch distribution, all indicative of a recent range expansion from a single refugium. Coalescent modelling approaches also indicated a recent common ancestor for the entire group of birds analysed, no split between northern and southern populations, and high levels of gene flow. These results show that Pleistocene or earlier events have played little role in creating differences between northern and southern populations, suggesting that migratory and other differences between populations have arisen very recently. The implications of these results for the evolution of migration and defining taxonomic groups for conservation efforts are discussed. [source] Interleukin-5 deficient mice exhibit impaired host defence against challenge Trichinella spiralis infectionsPARASITE IMMUNOLOGY, Issue 10 2000B.A. Vallance Enteric nematode infections are characterized by both peripheral and tissue eosinophilia. The cytokine interleukin (IL)-5 is considered a critical factor in the proliferation and recruitment of eosinophils, however, studies suggest it plays little role in host defence, at least during primary Trichinella spiralis infections. Less is known concerning its role in host defence or in the inflammatory response that develops against challenge infections with the same parasite. We examined these questions by infecting IL-5 deficient and wild-type mice, with T. spiralis parasites. Both strains expelled the primary infection by day 21. Forty days after the primary infection, we challenged the mice with a second T. spiralis infection and counted tissue eosinophils and worms in the intestine. While wild-type mice developed a large tissue eosinophilia, IL-5 deficient mice showed little increase in eosinophil numbers within the intestine. Throughout the challenge infection, significantly larger worm burdens were recovered from IL-5 deficient mice, and worm expulsion was also significantly slower (day 21) compared to wild-type mice (day 14). Thus, unlike in a primary infection, IL-5 is not only essential for the onset of intestinal eosinophilia, but also makes a significant contribution to enteric host defence during challenge T. spiralis infections. [source] From international sports to international competition: Longitudinal study of the Beijing Olympic GamesASIAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 2 2010Yan-mei Li To investigate whether and how the Beijing Olympic Games influenced the Chinese competitiveness towards foreigners, we conducted a three-wave longitudinal study and found that participants' competitiveness towards foreigners from five comparison target nations, particularly towards Japanese, South Koreans and Kenyans, was higher during the Games than before and/or after. We further found that nationalism predicted the competitiveness toward Japanese and South Koreans, but did not predict the competitiveness toward Americans, Russians and Kenyans. Additionally, we found that patriotism played little role in the effects of the Games on competitiveness towards foreigners. We herein discuss the relationship between national comparisons, nationalism and national conflict. [source] Granulosa cell tumours of the ovaryAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 3 2010Puliyath GEETHA Granulosa cell tumours are rare, potentially malignant sex cord stromal tumours of the ovary. They are unique in their presentation and histological features. Many of them are hormone-producing and this property helps them to present early unlike other epithelial ovarian cancers. As a result, most of them will be in an early stage at the time of initial diagnosis. The tumour can manifest in young girls as a juvenile form and conservative management with unilateral salpingo-opherectomy may be an option in them as 95% are unilateral. Surgery is the treatment of choice and initial staging laparatomy a determinant recurrence. Advance stage of the tumour, its size (>5 cm), mitotic figures (>10/hpf), nuclear atypia and absence of call-exner bodies are poor prognostic factors. Such tumours are characterised by late recurrences and this necessitates a prolonged follow-up. Tumour markers such as inhibin and estradiol are useful in follow-up. Chemotherapy, radiotherapy and hormone replacement therapy have very little role in the initial treatment and may be suggested in case of recurrences. With appropriate treatment, a better survival rate can be achieved as against other ovarian malignancies. Methods used for locating, selecting and synthesising data:, A search of Medline and Cochrane data base for the period from 1999 to 2010 was carried out to include relevant systematic reviews, meta-analysis, randomised controlled and other clinical and rare case reports. The date of the last search was January 2010. [source] | |||||||||||||