1,993 research outputs found
The origins of intensive marine fishing in medieval Europe: the English evidence
The catastrophic impact of fishing pressure on species such as cod and herring is well documented. However, the antiquity of their intensive exploitation has not been established. Systematic catch statistics are only available for ca. 100 years, but large-scale fishing industries existed in medieval Europe and the expansion of cod fishing from the fourteenth century (first in Iceland, then in Newfoundland) played an important role in the European colonization of the Northwest Atlantic. History has demonstrated the scale of these late medieval and post-medieval fisheries, but only archaeology can illuminate earlier practices. Zooarchaeological evidence shows that the clearest changes in marine fishing in England between AD 600 and 1600 occurred rapidly around AD 1000 and involved large increases in catches of herring and cod. Surprisingly, this revolution predated the documented post-medieval expansion of England's sea fisheries and coincided with the Medieval Warm Period-when natural herring and cod productivity was probably low in the North Sea. This counterintuitive discovery can be explained by the concurrent rise of urbanism and human impacts on freshwater ecosystems. The search for 'pristine' baselines regarding marine ecosystems will thus need to employ medieval palaeoecological proxies in addition to recent fisheries data and early modern historical records
Experience with posttransplant lymphoproliferative disorders in solid organ transplant recipients
Nearly 6000 solid organ transplants have been performed at the University of Pittsburgh since 1981. Posttransplant lymphoproliferative disorders (PTLD) have occurred in 131 patients, at a frequency of 2.2%. The majority of cases manifest within 6 months following allograft, but individual lesions may arise several years thereafter. From 1981 to 1989, cyclosporine-A (CsA) served as the primary immunosuppressant in this population. In March of 1989, FK506 was introduced for clinical trials. Since that time, 1421 patients have received FK506 either for primary immunosuppression or as rescue therapy. The frequency of PTLD in this subpopulation is 1.5%. PTLD arising under FK506-containing regimens have clinicopathologic features similar to those arising with CsA immunosuppression. The frequency of PTLD at this point in time is approximately 1%, in kidney allograft patients, 2.7% in liver, 3.3% in heart and 3.8%, in heart/lung or lung recipients. An understanding of the range of histologic appearance is important for the diagnosis of PTLD, especially when it involves the allograft itself. Immunoglobulin heavy chain gene analysis shows that lesions with no rearrangements or with a rearrangement in only a small proportion of cells are more likely to respond to reduced immunosuppression than are those with clonal rearrangement involving a high proportion of cells. However, this distinction is not absolute, and a trial of reduced immunosuppression appears to be indicated regardless of clonal status
Effectiveness and reach of a directed-population approach to improving dental health and reducing inequalities: a cross sectional study
Background
Childsmile School adopts a directed-population approach to target fluoride varnish applications to 20% of the primary one (P1) population in priority schools selected on the basis of the proportion of enrolled children considered to be at increased-risk of developing dental caries. The study sought to compare the effectiveness of four different methods for identifying individuals most in need when a directed-population approach is taken. <p></p>
Methods
The 2008 Basic National Dental Inspection Programme (BNDIP) cross-sectional P1 Scottish epidemiological survey dataset was used to model four methods and test three definitions of increased-risk. Effectiveness was determined by the positive predictive value (PPV) and explored in relation to 1-sensitivity and 1-specificity. <p></p>
Results
Complete data was available on 43470 children (87% of the survey). At the Scotland level, at least half (50%) of the children targeted were at increased-risk irrespective of the method used to target or the definition of increased-risk. There was no one method across all definitions of <i>increased-risk</i> that maximised PPV. Instead, PPV was highest when the targeting method complimented the definition of <i>increased-risk</i>. There was a higher percentage of children at <i>increased-risk</i> who were not targeted (1-sensitivity) when caries experience (rather than deprivation) was used to define <i>increased-risk</i>, irrespective of the method used for targeting. Over all three definitions of <i>increased-risk</i>, there was no one method that minimised (1-sensitivity) although this was lowest when the method and definition of <i>increased-risk</i> were complimentary. The false positive rate (1-specificity) for all methods and all definitions of <i>increased-risk</i> was consistently low (<20%), again being lowest when the method and definition of <i>increased-risk</i> were complimentary. <p></p>
Conclusion
Developing a method to reach all (or even the vast majority) of individuals at <i>increased-risk</i> defined by either caries experience or deprivation is difficult using a directed-population approach at a group level. There is a need for a wider debate between politicians and public health experts to decide how best to reach those most at need of intervention to improve health and reduce inequalities. <p></p>
Expression of Epstein–Barr Virus–Encoded Small RNA (by the EBER-1 Gene) in Liver Specimens from Transplant Recipients with Post-Transplantation Lymphoproliferative Disease
Epstein-Barr virus (EBV)—associated post-transplantation lymphoproliferative disease (PTLD) develops in 1 to 10 percent of transplant recipients, in whom it can be treated by a reduction in the level of immunosuppression. We postulated that the tissue expression of the small RNA transcribed by the EBER-1 gene during latent EBV infection would identify patients at risk for PTLD. We studied EBER-1 gene expression in liver specimens obtained from 24 patients 2 days to 22 months before the development of PTLD, using in situ hybridization with an oligonucleotide probe. Control specimens were obtained from 20 recipients of allografts with signs of injury due to organ retrieval, acute graft rejection, or viral hepatitis in whom PTLD had not developed 9 to 71 months after the biopsy. Of the 24 patients with PTLD, 17 (71 percent) had specimens in which 1 to 40 percent of mononuclear cells were positive for the EBER-1 gene. In addition, 10 of these 17 patients (59 percent) had specimens with histopathological changes suggestive of EBV hepatitis. In every case, EBER-1—positive cells were found within the lymphoproliferative lesions identified at autopsy. Only 2 of the 20 controls (10 percent) had specimens with EBER-1—positive cells (P<0.001), and such cells were rare. EBER-1 gene expression in liver tissue precedes the occurrence of clinical and histologic PTLD. The possibility of identifying patients at risk by the method we describe here and preventing the occurrence of PTLD by a timely reduction of immunosuppression needs to be addressed by future prospective studies. (N Engl J Med 1992;327:1710–4.), POST-TRANSPLANTATION lymphoproliferative disease (PTLD), either polyclonal or monoclonal, complicates the clinical course of 1 to 10 percent of organ-transplant recipients.123 Immunohistochemical studies have demonstrated that the lymphoid cells within the lesions of PTLD almost invariably contain Epstein–Barr virus (EBV), primarily in a state of latent infection.4,5 The EBER-1 gene is expressed early during latent EBV infection and codes for a small messenger RNA (mRNA) expressed at up to 107 copies per cell.6 We and others have previously demonstrated the value of the detection of EBER-1 RNA for identifying EBV-infected cells in formalin-fixed paraffin-embedded tissues.7,8 In the current investigation, we used… © 1992, Massachusetts Medical Society. All rights reserved
IR Spectrum of the O-HO Hydrogen Bond of Phthalic Acid Monomethylester in Gas Phase and in CCl Solution
The absorption spectrum of the title compound in the spectral range of the
Hydrogen-bonded OH-stretching vibration has been investigated using a
five-dimensional gas phase model as well as a QM/MM classical molecular
dynamics simulation in solution. The gas phase model predicts a Fermi-resonance
between the OH-stretching fundamental and the first OH-bending overtone
transition with considerable oscillator strength redistribution. The anharmonic
coupling to a low-frequency vibration of the Hydrogen bond leading to a
vibrational progression is studied within a diabatic potential energy curve
model. The condensed phase simulation of the dipole-dipole correlation function
results in a broad band in the 3000 \cm region in good agreement with
experimental data. Further, weaker absorption features around 2600 \cm have
been identified as being due to motion of the Hydrogen within the Hydrogen
bond.Comment: Contribution to Horizons in Hydrogen Bond Research Conference, Paris
200
The pathology of posttransplant lymphoproliferative disorders occurring in the setting of cyclosporine A-prednisone immunosuppression
Posttransplant lymphoproliferative disorders (PTLDs) were diagnosed in 43 patients from the Pittsburgh-Denver series between June 1980 and March 1987. This constitutes a detection rate of 1.7%. Major categories of clinical presentation included a mononucleosis-like syndrome, gastrointestinal/abdominal disease, and solid organ disease. The median time of onset in patients initially immunosuppressed with cyclosporine-A (CsA)-containing regimens was 4.4 months after transplant, regardless of tumor clonality. A strong association of PTLD with Epstein-Barr virus (EBV) was observed. A histologic spectrum of lesions from polymorphic to monomorphic was observed. Whereas polymorphic lesions could be either clonal or non-clonal, monomorphic lesions appeared to be clonal in composition. The presence of large atypical cells (atypical immunoblasts) or necrosis did not appreciably worsen the prognosis. Twelve patients had clonal, 13 had nonclonal, and five had both clonal and nonclonal tumors. Clonality was indeterminate in 13 cases. Most patients were treated with a regimen based on reduced immunosuppression and supportive surgery. Almost all nonclonal and about half of the clonal lesions respond to this conservative therapy, indicating that it is an appropriate first line of treatment. This behavior suggests that a spectrum of lesions ranging from infectious mononucleosis to malignant lymphoma constitutes the entity known as PTLD. Some monoclonal tumors can undergo regression, however, apparently in response to host immune control mechanisms. Because of its short latency and strong association with EBV, PTLD is an important model for the study of virus-associated tumor progression in humans
The development and psychometric properties of the Arabic version of the child oral health impact profile-short form (COHIP- SF 19)
BACKGROUND: This study aims to cross-culturally adapt the original English-language COHIP-SF 19 to Arabic culture and to test its psychometric properties in a community sample. METHODS: The Arabic COHIP-SF 19 was developed and its psychometric properties were examined in a population-based sample of 876 schoolchildren who were aged 12 years of age, in Benghazi, Libya. The Arabic COHIP-SF 19 was tested for its internal consistency, reproducibility, construct validity, factorial validity and floor as well as ceiling effects. A Mann-Whitney U test was used to compare the mean scores of COHIP-SF 19 by participants' caries status and self-reported oral health rating, satisfaction and treatment need. RESULTS: The Arabic COHIP-SF 19 was successfully and smoothly developed. It showed an acceptable level of equivalence to the original version. Overall, the internal consistency and reproducibility were acceptable to excellent, with a Cronbach's alpha of 0.84 and an intra-class correlation coefficient (ICC) of 0.76. All hypotheses predefined to test construct validity were confirmed. That is, children who had active dental caries, and who rated their oral health as poor, were not satisfied with their oral health or indicated the need of treatment had lower COHIP-SF 19 scores (P < 0.05). Floor or ceiling effects were not observed. The exploratory Factorial analysis suggested a 4-component solution and deletion of one item. CONCLUSION: The Arabic COHIP-SF 19 was successfully developed. The measure demonstrated satisfactory reliability and validity to estimate OHRQoL in a representative sample of 12-year-old schoolchildren
HCV IRES manipulates the ribosome to promote the switch from translation initiation to elongation.
The internal ribosome entry site (IRES) of the hepatitis C virus (HCV) drives noncanonical initiation of protein synthesis necessary for viral replication. Functional studies of the HCV IRES have focused on 80S ribosome formation but have not explored its role after the 80S ribosome is poised at the start codon. Here, we report that mutations of an IRES domain that docks in the 40S subunit's decoding groove cause only a local perturbation in IRES structure and result in conformational changes in the IRES-rabbit 40S subunit complex. Functionally, the mutations decrease IRES activity by inhibiting the first ribosomal translocation event, and modeling results suggest that this effect occurs through an interaction with a single ribosomal protein. The ability of the HCV IRES to manipulate the ribosome provides insight into how the ribosome's structure and function can be altered by bound RNAs, including those derived from cellular invaders
Direct access:how is it working?
AimThe aim of this study was to identify and survey dental hygienists and therapists working in direct access practices in the UK, obtain their views on its benefits and disadvantages, establish which treatments they provided, and what barriers they had encountered.MethodThe study used a purposive sample of GDC-registered hygienists and therapists working in practices offering direct access, identified through a ‘Google’ search. An online survey was set up through the University of Edinburgh, and no-responses followed up by post.ResultsThe initial search identified 243 individuals working in direct access practices. Where a practice listed more than one hygienist/therapist, one was randomly selected. This gave a total of 179 potential respondents. Eighty six responses were received, representing a response rate of 48%. A large majority of respondents (58, 73%) were favourable in their view of the GDC decision to allow direct access, and most thought advantages outnumbered disadvantages for patients, hygienists, therapists and dentists. There were no statistically significant differences in views between hygienists and therapists. Although direct access patients formed a small minority of their caseload for most respondents, it is estimated that on average respondents saw approximately 13 per month. Treatment was mainly restricted to periodontal work, irrespective of whether the respondent was singly or dually qualified. One third of respondents reported encountering barriers to successful practice, including issues relating to teamwork and dentists’ unfavourable attitudes. However, almost two thirds(64%) felt that direct access had enhanced their job satisfaction, and 45% felt their clinical skills had increased.DiscussionComments were mainly positive, but sometimes raised worrying issues, for example in respect to training, lack of dental nurse support and the limited availability of periodontal treatment under NHS regulations
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