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PubMed2005

Impacts of stable element intake on 14C and 129I dose estimates.

The purpose of this study was to evaluate and provide insights related to the influence of the intake of stable isotopes of carbon and iodine on the committed doses due to the ingestion of (14)C and (129)I. This was accomplished through the application of two different computational approaches. The first was based on the assumption that ground (drinking) water was the only source of intake of (14)C and (129)I, as well as stable carbon and stable iodine. In the second, the intake of (14)C and (129)I was still assumed to be restricted to that in the ground (drinking) water, but the intake of stable carbon and stable iodine was expanded to include that in other components of the diet. The doses were estimated using either a conversion formula or the applicable dose coefficients in Federal Guidance Reports No. 11 and No. 13. Serving as input for the analyses was the estimated maximum concentrations of (14)C or (129)I that would be present in the ground water due to potential releases from the proposed Yucca Mountain high-level radioactive waste repository during the first 10,000 y after closure. The estimated contributions of stable carbon and iodine through the consumption of ground water were based on analyses of samples collected in the Amargosa Valley, NV. The contributions through dietary intake were based on surveys conducted in the United States. Based on the accompanying analyses, it was noted that stable isotope intake has a significant effect on the estimated doses due to the intake of radioactive isotopes of the same element. While this is a well-known fact, this observation has international implications in terms of dose estimates for key radionuclides, such as (14)C and (129)I, a primary reason being the wide variations in the intakes of stable carbon and iodine in various countries. For this reason, analysts planning to apply the dose coefficients developed by the International Commission on Radiological Protection (ICRP) should either confirm that the average total intake in their country of stable isotope(s) of the radioactive isotope being evaluated is in reasonable agreement with the value assumed by the ICRP or suitably modify the ICRP dose coefficients to account for any differences. If such a procedure is to be implemented, there is a need for periodic updates of the dietary intakes of various stable elements in countries throughout the world. The importance of this is documented by recent surveys in Asia that revealed that their average total daily intake of stable iodine was less than half of the ICRP value for Reference Man. In this case, application of the ICRP dose coefficients, without modification, would underestimate the dose due to ingested (129)I by a factor of more than two. A related situation exists in the United States where the latest surveys indicate that the daily intake of stable iodine is 75% of the ICRP value.

Administration, Oral↗
PubMed2005

Understanding the toxicity of buried radioactive waste and its impacts.

The oral ingestion toxicities of buried high level radioactive waste from nuclear power plants and of the natural radioactivity in the ground are calculated and expressed as cancer doses, the number of fatal cancers predicted by the linear no-threshold theory if all of the material were fed to people. Unless the size of the U.S. nuclear power industry is greatly expanded, there will probably never be more than 2 trillion cancer doses (CD) in U.S. repositories, as compared with 31 trillion CD in the ground above them. Measurements of the uranium, thorium, and radium in human bodies indicate that the latter cause 500 deaths per year in U.S. The great majority of this material is derived from the top few meters of soil that are penetrated by plant roots. It is concluded that the annual number of U.S. deaths from buried nuclear wastes will be about 1.0 (or less), orders of magnitude less than the number from coal burning electricity generation, the principal competitor of nuclear power.

Algorithms↗
PubMed2005

ISCORS Catalog of References to Parameter Values and Distributions Used in Environmental Pathway Modeling for Cleanup of Sites Contaminated with Radioactivity.

Federal and state regulatory agencies that are concerned with issues of environmental management have adopted approaches toward policy-making that are dose- and risk-informed. To that end they (and others) have developed environmental models and computer codes to mimic the transport of contaminants along air, water, food-chain, and related pathways for estimating potential exposures, doses, and risks to individuals, populations, and ecosystems. Their calculations commonly find application in the planning of remediation, and thereafter in the demonstration of compliance with federal and state cleanup standards. As the models and codes have become more sophisticated, so also have requirements on the accuracy and level of detail of the numerical point values and probability distributions of environmental transfer factors and other parameters that serve as input parameters to them. In response to this growing need, the federal Interagency Steering Committee On Radiation Standards (ISCORS) and the Argonne National Laboratory have developed an on-line, national repository of information on parameter values and distributions of known provenance and demonstrated utility. The ISCORS Catalog of References to Parameter Values and Distributions Used in Environmental Pathway Modeling for Cleanup of Sites Contaminated with Radioactivity is a web-based, indexed compilation of references, compendia, databases, and other sources of peer-reviewed information on parameters. It does not itself contain numerical point values or distributions for any particular parameter, but rather it provides links or directions to sites or other published materials where such information can be obtained. Designed to be user-friendly, easily searchable, and readily up-dateable, the Catalog is being filled, after some initial priming, mainly through on-line submissions of proposed references by the Catalog users themselves. The relevant information on a proposed reference is submitted to ISCORS in a simple, standardized format; it is vetted (with acceptance criteria such as publication in a peer-reviewed technical journal, or appearance in a formally-issued federal agency report) and then added semi-automatically to the Catalog. Built around a relational database, the system offers subject- and text-search capabilities, provides information on parameter definitions and methods of measurement, on transport/exposure pathways, and on standard models and codes. The Catalog is intended for use by (and being populated by) the professionals, managers, and others involved or interested in the application of pathway modeling to estimate doses and risks associated with sites contaminated with radioactive or other hazardous materials.

Databases as Topic↗
PubMed2006

Comparison of natural background dose rates for residents of the Amargosa Valley, NV, to those in Leadville, CO, and the states of Colorado and Nevada.

In the latter half of 2005, the U.S. Environmental Protection Agency (U.S. EPA) published a Proposed Rule (40 CFR Part 197) for establishing a dose rate standard for limiting radionuclide releases from the proposed Yucca Mountain high-level radioactive waste repository during the time period from 10 to 10 years after closure. The proposed standard was based on the difference in the estimated dose rate from natural background in the Amargosa Valley and the "average annual background radiation" for the State of Colorado. As defined by the U.S. EPA, "natural background radiation consists of external exposures from cosmic and terrestrial sources, and internal exposures from indoor exposures to naturally-occurring radon." On the basis of its assessments, the U.S. EPA estimated that the difference in the dose rate in the two identified areas was 3.5 mSv y. The purpose of this paper is to provide an independent evaluation and review of this estimate. One of the first observations was that, because site-specific dose rate measurements for the Amargosa Valley "were not available," the dose rates for various sources of natural background in that area, used by the U.S. EPA in its assessment, were based on modifications of the average values for the State of Nevada. A second observation was that the conversion coefficient applied in estimating the dose rates due to exposures to indoor radon and its decay products was a factor of >2 higher than the currently internationally accepted value. Further review revealed that site-specific data for many natural background sources in the Amargosa Valley were available. One particularly important observation was that about 91% of the residents of that area live in mobile homes which, due to their construction and design, have indoor radon concentrations comparable to, or less than, those outdoors. For that reason, alone, the U.S. EPA estimate of the average dose rate for residents of the Amargosa Valley, due to exposures to indoor radon, was not valid. For purposes of the comparisons in this paper, site-specific dose rates were estimated for all major natural background sources of exposure to residents of the Amargosa Valley, and those in Leadville, CO. The latter community was selected for comparison because of its altitude (3,200 m) and accompanying relatively high cosmic radiation dose rate, and the fact the size of its population is comparable to that of the Amargosa Valley. Another reason for this selection was that a comparison of the average natural background dose rate in the Amargosa Valley to that for the State of Colorado is not suitable because it fails to consider those locations within the State that have dose rates that are higher than the average. Nonetheless, for completeness, and to provide a number that could be compared to the U.S. EPA estimated difference, similar comparisons of the estimated dose rate in the Amargosa Valley to those for average residents of the States of Colorado and Nevada were included in the assessments that follow. The outcome showed that the estimated dose rates in Leadville, the State of Colorado, and the State of Nevada, were higher than those in the Amargosa Valley by 3.94 +/- 1.09, 2.54 +/- 2.18, and 0.95 +/- 0.82 mSv y, respectively. Associated uncertainties were highest for the estimated dose rates due to exposures to radon and its decay products. Had the systematic errors in the radon dose conversion coefficient and the random distribution in radon concentrations been included, the overall uncertainty in the total dose rate estimates could have been as high as 150%.

Air Pollution, Indoor↗
PubMed2006

Warren K. Sinclair keynote address: contemporary issues in risk-informed decision making on the disposition of radioactive waste.

A consistent and transparent risk-informed approach to managing nuclear waste is plagued with different regulators, different rules and regulations for different waste types, different compliance requirements, and indecisions about probabilistic vs. deterministic models. Low-activity waste management is particularly void of a path forward with respect to being risk-informed. Risk assessment is not referenced in the statutes on low-activity waste even though both the U.S. Environmental Protection Agency and U.S. Nuclear Regulatory Commission (U.S. NRC) have policies to apply consistent risk management approaches to all of their programs. The U.S. NRC has developed guidance on the preparation of probabilistic performance assessments for low-activity waste facilities, but there have been no serious takers and a lack of initiative on the part of licensees. Thus, little to no experience exists on risk-informing low-activity waste. The missed opportunities include establishing a risk basis that would allow for simpler, safer, and much less costly alternatives for low-activity waste disposal while enabling society to have the full benefit of radiation technologies. There is hope that congressional action or regulatory rule making will address some of these issues with the result being the adoption of a more general and unified approach to risk-informed regulation of all types of waste. Just as much of the initiative for risk-informed nuclear power came from industry, it must also be the case for nuclear waste. A start would be the adoption of a basic framework of risk assessment in waste management applicable to all types of waste--radioactive and nonradioactive. The "set of triplets" risk assessment framework that is applicable to any kind of risk is an established alternative. It is believed that such a framework with the support of a regulatory structure made compatible through appropriate rulemaking or congressional action, and the experience of the probabilistic performance assessments for the Waste Isolation Pilot Plant and the proposed Yucca Mountain high-level waste repository, could result in the right path forward for the regulation and management of low-activity waste.

Decision Making↗
PubMed2007

Optimization of radioactive waste storage.

In several countries, low-level radioactive wastes are treated and stored awaiting construction and operation of a final repository. In some cases, interim storage may be extended for decades requiring special attention regarding security issues. The International Atomic Energy Agency (IAEA) recommends segregation of wastes that may be exempted from interim storage or ultimate disposal. The paper presents a method to optimize the decision making process regarding exemption vs. interim storage or ultimate disposal of these wastes.

Radioactive Waste↗
PubMedDate not supplied

Evaluation of erectile dysfunction therapy in patients previously nonadherent to long-term medications: a retrospective analysis of prescription claims.

Erectile dysfunction (ED) can lead to treatment noncompliance in patients taking medications for chronic health conditions. Using the Intelligent Health Repository, NDCHealth's longitudinal, United States health care claims database, we examined the impact of treating ED on adherence to long-term therapies in previously nonadherent patients. Male patients >or=18 years of age were identified who received antidepressant (AD), antihypertensive (AH), oral hypoglycemic (OHG), or lipid-lowering (LL) agents and initiated therapy with sildenafil citrate (Viagra) between January and June 2003. Treatment adherence was determined using medication possession ratios (MPRs) for the 12 months before and after the first prescription of sildenafil. Prior to initiation of therapy for ED with sildenafil, 64% of patients with comorbid medications were not adherent (MPR <0.8). Among these patients, 728 (27%) received AD, 2112 (78%) received AH, 984 (18%) received OHG, and 1078 (40%) received LL agents, with 66% of patients receiving multiple therapeutic classes. During the 12-month period after the first sildenafil prescription, patients had a significant increase in medication adherence compared with the 12 months before the first prescription of sildenafil (P < 0.0001). The percentage of patients who became adherent (MPR >or=0.8) with medications after sildenafil treatment was from 22% to 36%. With the exception of the LL group, there was a significant relationship between >or=3 sildenafil prescriptions and change in MPR (P < 0.05). Patients aged >or=65 years had similar improvement in MPR as patients <or=65 years. Treatment of ED with sildenafil improved adherence in patients taking common long-term medications who were previously nonadherent.

Adult↗
PubMed2006

Low frequency of telomerase RNA mutations among children with aplastic anemia or myelodysplastic syndrome.

Mutations in TERC, the RNA component of telomerase, result in autosomal dominant dyskeratosis congenita (DC), a rare bone marrow failure syndrome. TERC mutations have been detected in a subset of patients previously diagnosed with aplastic anemia and myelodysplastic syndrome (MDS), and these TERC mutations are clinically relevant as patients with DC respond poorly to conventional therapies. We aimed to determine the frequency of TERC mutations in pediatric patients with aplastic anemia and MDS who required a hematopoietic stem cell transplant. We obtained 284 blood samples from the National Donor Marrow Program Research Sample Repository from children and adolescents with bone marrow failure who underwent an unrelated stem cell transplant. We screened these samples for mutations in the TERC gene using direct DNA sequencing. We found 2 patients with sequence alterations in TERC. We identified a 2 base pair deletion (-240delCT) in a 4-year-old child with MDS and a single nucleotide alteration (-99-->CG) in a 1-year-old child with juvenile myelomonocytic leukemia. Screening for TERC gene mutations is unlikely to diagnose occult DC in children with severe bone marrow failure who require a hematopoietic stem cell transplant.

Adolescent↗
PubMed2004

Ten year experience of burn, trauma, and combined burn/trauma injuries comparing outcomes.

BACKGROUND: Percent total body surface area (TBSA) burn, inhalation injury (INH), and age all have been shown to be independent predictors of mortality in burn victims. Little is known regarding patients sustaining combined thermal and mechanical injuries in relation to either injury sustained in isolation or with regard to these variables. This descriptive study profiles the 10-year experience of a single American Burn Association/American College of Surgeons verified Level I trauma and burn center and the treatment of this patient population. METHODS: A retrospective review of all burn and trauma patients admitted between 1990 and 2000. Patients were divided into three groups; Burn only (B), Trauma only (T), and combined Burn/Trauma (B/T). Groups were compared with respect to age, TBSA burn, length of stay (LOS), Injury Severity Score (ISS), INH and mortality. These groups were then compared with B, T and B/T patients from the National Burn Repository (NBR) and National Trauma Data Bank (NTDB). Student's t test and chi tests were performed, as well as multiple logistic regression to identify independent predictors of mortality. p <0.05 was considered significant. RESULTS: Through our trauma registry, 24,093 patients were identified (T=22,284, B=1717 and B/T=92). When comparing B and T, there was no difference in age, LOS, ISS, or mortality to those patients in the NBR or NTDB. B/T patients showed significantly increased percentage with INH (B/T=44.5% versus 11%), increased LOS (B/T=18 days versus 13.7 B and 5.3 T) and increased mortality (B/T=28.3% versus 9.8% B and 4.3% T). B/T were also significantly older (B/T=40.1 years versus 31.0 B and 35.1 T). When these variables are compared with the NBR and the NTDB benchmarks, mortality (28.3% versus 11.6% NBR and 7.0% NTDB) and ISS (23 versus 11.7 NTDB) were significantly higher with no difference in age (40.1 versus 33.4 NTDB, 35.9 NBR), LOS (18 days versus 23.3 NBR) or TBSA (20.8% versus 19.5% NBR). Multiple logistic regression comparing TBSA, age, ISS and INH of survivors versus non-survivors identified only ISS as an independent predictor of mortality. CONCLUSION: B combined with T presents a rare injury pattern that has a synergistic effect on mortality. Physicians and caregivers should be aware of a 2-3 fold increase in the incidence of INH in this population, and increased mortality despite similar TBSA burned when compared with patients with B as the sole mechanism; ISS appears to be an independent predictor of mortality in this combined injury pattern.

Adolescent↗
PubMed2006

Longitudinal study of suicide after traumatic injury.

BACKGROUND: Suicide risk after discharge among trauma patients could be influenced by multiple factors. The aim of this study is to establish whether patients discharged from a trauma center experience an increased suicide rate and whether this can be explained by defined demographic, injury, or alcohol abuse risk factors. METHODS: Patients admitted between July 1, 1983, and June 30, 1995, and discharged alive from a Level I trauma center (n = 27,399) were followed for 1.5 to 14.5 years to determine whether they had died. Death determination was made by an epidemiologic support service, which had created a repository of death certificates. Variables used in the analyses included age, gender, race, Injury Severity Score, discharge disposition, mechanism of injury, and alcohol toxicology. General and trauma populations were compared using standard mortality rates. Risk factors for suicide within the trauma population were explored using Pearson's chi2, Mantel-Haenszel chi2, Cox proportional hazards, and Mantel-Cox log-rank methodology. RESULTS: Suicide was more common in the trauma than in the general population (standard mortality rate = 1.71). This difference may be attributed primarily to alcohol use problems. Suicide risk in the trauma population increased with age from 25 to 44 years, male gender, Caucasian race, and positive alcohol toxicology. Disability (as measured by discharge disposition), but not injury severity, also seemed to have an influence on suicide rates. CONCLUSION: Interventions that address modifiable risk factors for suicide (substance abuse, psychiatric disorders, hopelessness, and social isolation) could benefit trauma patients known to be at higher risk for suicide, particularly those abusing alcohol.

Adolescent↗
PubMed2004

Preservation of human pancreatic islet in vivo function after 6-month culture in serum-free media.

BACKGROUND: Culturing human islets in Memphis serum-free media (M-SFM) is associated with excellent postculture recovery, in vitro function, and in vivo survival. The authors investigate the possibility of preserving islet function for extended periods (6 months) in culture and describe the in vitro and in vivo functional outcomes associated with these extended culture times. METHODS: Human islets isolated from three cadaveric donor organs were cultured in M-SFM for 1, 3, or 6 months before transplantation under the kidney capsule of nonobese diabetic (NOD)-severe combined immunodeficiency (SCID) mice. In vitro function was measured by static incubation at the time of transplantation. In vivo function was assessed by measuring human insulin and C-peptide production, and by the ability of 6-month cultured islets to cure streptozotocin-induced diabetes in this mouse model. RESULTS: Islet recovery ratios after 1 month in culture ranged from 85% to 88% and declined to 28% to 53% after 6 months of culture (P <0.01). Insulin stimulation indices did not differ among the fresh or the 6-month cultured preparations. All preparations cultured for 1 to 3 months functioned in the NOD-SCID mice. After 6 months of culture, two of the three preparations demonstrated in vivo function and were able to cure streptozotocin-induced diabetes. CONCLUSIONS: These data demonstrate that human islets can be cultured in M-SFM for extended periods and still retain in vitro and in vivo function and the ability to cure experimental diabetes. The ability to maintain islets in culture for prolonged periods is an important step toward the development of islet tissue repositories and distribution centers.

Animals↗
PubMed1990

Discharge planning for the child with infantile spasms.

Infantile spasms is a type of seizure disorder usually occurring within the first 24 months of life. The standard treatment is intramuscular injections of repository corticotropin (HP ACTHAR gel). The child with infantile spasms is at risk for developmental delay, even if the seizures are controlled. The parents' grief reaction to this prognosis may affect their ability to learn and implement the treatment plan. Discharge planning for children and families is extensive and must begin at the time of the child's admission to the hospital.

Adaptation, Psychological↗
PubMedDate not supplied

The National Institute on Disability and Rehabilitation Research burn model system database: a tool for the multicenter study of the outcome of burn injury.

Advances in critical care and surgical management have significantly improved survival after burn injury over the past several decades. However, today, survival alone is an insufficient outcome. In 1994, the National Institute on Disability and Rehabilitation Research (NIDRR) created a burn model system program to evaluate the long-term sequelae of burn injuries. As part of this multicenter program, a comprehensive demographic and outcome database was developed to facilitate the study of a number of functional and psychosocial outcomes after burns. The purpose of this study is to review the database design and structure as well as the data obtained during the last 10 years. This is a descriptive study of the NIDRR database structure as well as the patient data obtained from the four participating burn centers from 1994 to 2004. Data obtained during hospitalization and at 6, 12, and 24 months after discharge were reviewed and descriptive statistics were calculated for select database fields. The database is divided into several subsections, including demographics, injury complications, patient disposition, and functional and psychological surveys. A total of 4600 patients have been entered into the NIDRR database. To date, 3449 (75%) patients were alive at discharged and consented to follow-up data collection. The NIDRR database provides an expansive repository of patient, injury, and outcome data that can be used to analyze the impact of burn injury on physical and psychosocial function and for the design of interventions to enhance the quality of life of burn survivors.

Adolescent↗
PubMed2025

Construction and accuracy assessment of an efferocytosis-related prognostic model for ovarian cancer: A diagnostic accuracy study.

The study aimed to investigate the prognostic significance of efferocytosis-related genes in ovarian cancer (OC) with regard to cancer development, progression, invasion, and metastasis. OC cohorts were assembled from bioinformatics repositories. Utilizing consensus clustering analysis, distinct clusters were delineated based on the intersection of OC-related genes and efferocytosis-related genes. A prognostic signature specific to efferocytosis in OC was developed using data from The Cancer Genome Atlas, validated against the gene expression omnibus database, and subjected to independent prognostic analysis. Subsequently, a nomogram model was formulated. Moreover, investigations encompassed the immune microenvironment, immunotherapy, mutation profiling, drug sensitivity assessments, drug prediction models, and molecular docking analyses. Finally, quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays were employed to ascertain the mRNA expression levels of key genes. Five key genes, FCGBP, BTN3A3, WDR91, SLC25A45, and BTNL3, were identified as significantly associated with OC. Both datasets and qRT-PCR demonstrated elevated expression levels of FCGBP and WDR91 in OC. Notably, AFLATOXIN B1 exhibited strong binding affinity to SLC25A45, ciclopirox to BTN3A3, and irinotecan to WDR91. The risk score, age, and stage were identified as independent prognostic factors, with the nomogram displaying efficacy in predicting OC patient survival. Variations in the immune cell infiltration profiles, including naive B cells, and expression levels of 6 immune checkpoint genes, such as CTLA4, were notable. High tumor mutation burden scores were associated with improved survival outcomes. Additionally, significant differences in the IC50 values of 123 anticancer drugs were observed between the 2 risk groups. This findings of this study highlight the efficacy of the efferocytosis-associated risk model in predicting the survival outcomes of OC patients, thus providing a novel reference for prognostic prediction in OC patients.

Humans↗
PubMed2026

The role of ferroptosis in juvenile idiopathic arthritis: Causal inference and mediation by immune phenotypes.

This study employed a bidirectional 2-step, two-sample Mendelian randomization approach to investigate the causal relationships between ferroptosis-related genes and juvenile idiopathic arthritis (JIA) and to explore the mediating role of immune cells. Ferroptosis genes were identified from the deCODE database and matched with protein quantitative trait locus data as exposures to evaluate their causal effects on JIA, while immune cell traits were similarly assessed. For genes showing positive Mendelian randomization results, further analyses were conducted to determine whether immune cells mediated the effects on JIA, with mediation analysis performed only in the presence of causal associations. Data were sourced from the GWAS, FerrDb, and other public repositories. Nine ferroptosis-related genes were found to have causal links with JIA: HSPB1, DECR1, LIFR, and CTSB increased JIA risk, whereas PIEZO1, DPP4, BID, and others were protective. Forty immune cell traits were also causally associated with JIA. Mediation analysis revealed that several immune cells, including CD127- CD8+ T cells, partially mediated the genetic effects, with mediation proportions reaching up to 18.6%. Collectively, these results point to a ferroptosis-immune-JIA axis, suggesting that ferroptosis-related genes contribute to JIA pathogenesis through immune cell mediation and offering new mechanistic insights and potential therapeutic targets.

Arthritis, Juvenile↗
PubMed2007

Prevalence, risk factors, and outcomes for occult hepatitis B virus infection among HIV-infected patients.

BACKGROUND: Occult hepatitis B virus (HBV) is defined by the presence of HBV DNA in individuals with HBV core antibodies (anti-HBc) but without HBV surface antigen (HBsAg). The prevalence of occult HBV in HIV-infected patients remains controversial, and the risk factors and clinical significance are unknown. OBJECTIVES: To determine the prevalence, risk factors, and clinical significance of occult HBV among HIV-infected patients. Hypothesized risk factors include chronic hepatitis C virus (HCV), CD4 count < 200 cells/mm, HIV RNA level >1000 copies/mL, and lack of use of anti-HBV antiretrovirals. METHODS: We examined randomly selected HBsAg/anti-HBc HIV-infected patients in the Penn Center for AIDS Research Adult/Adolescent Database and Specimen Repository. HBV DNA was qualitatively detected using a transcription-mediated amplification assay. Risk factors and transaminases were ascertained at the time sera were collected. RESULTS: A total of 699 HBsAg/anti-HBc HIV-infected patients were identified. Of 179 randomly selected subjects, 17 (10%; 95% confidence interval [CI]: 5% to 14%) had occult HBV. Differences in the prevalence of HBV surface antibody (anti-HBs) between those with (7 [41%]) and without (94 [58%]) occult HBV were not statistically significant (P = 0.3). An HIV RNA level >1000 copies/mL (adjusted odds ratio [OR] = 4.88, 95% CI: 1.01 to 30.26) and the absence of chronic HCV (adjusted OR = 0.26, 95% CI: 0.05 to 0.95) were associated with occult HBV. Occult HBV did not increase the risk of transaminitis (adjusted OR = 0.42, 95% CI: 0.12 to 1.45). CONCLUSIONS: Occult HBV occurred in a sizable proportion of HIV-infected patients and was associated with detectable HIV and the absence of chronic HCV. It did not increase the risk of transaminitis. The presence of anti-HBs does not rule out occult HBV. Future studies should examine the long-term clinical implications of occult HBV in HIV-infected patients.

Adult↗
PubMed2002

'Ancient' DNA in the resting egg bank of a microcrustacean can serve as a palaeolimnological database.

Recent work on the diapausing egg banks of zooplankton, such as Daphnia (Crustacea: Anomopoda), indicates that these eggs can remain viable for decades while, theoretically, DNA can remain intact for even longer periods (i.e. centuries or millennia). We isolated diapausing eggs of Daphnia from a 30 m long sediment core taken from a hypereutrophic, northern German lake (Belauer See), with some eggs found in dated core material as old as 4500 years. Using microsatellite markers, we analysed the genetic structure of the resting eggs dated as old as ca. 200 years, and found that, although levels of heterozygosity remained remarkably stable, significant genetic differentiation (Nei's D = 0.36; F(ST) = 0.15) between recent and 'ancient' resting eggs (including allele frequency shifts and private alleles) was detected. These shifts represent either species-level changes in this complex (i.e. species-specific characters of ephippia are not always robust), or intraspecific shifts in genetic variation, or a combination of both. This study demonstrates that the egg banks of aquatic zooplankton can serve as repositories of both genetic (intrapopulational) and ecological (interspecific) information. The use of molecular markers, such as microsatellites, on diapausing egg/seed banks may open new avenues of enquiry related to tracking the long-term genetic (and/or species) shifts that are associated with long-term environmental changes.

Alleles↗
PubMed2001

The Functional Magnetic Resonance Imaging Data Center (fMRIDC): the challenges and rewards of large-scale databasing of neuroimaging studies.

The Functional Magnetic Resonance Imaging Data Center (fMRIDC) (http://www.fmridc.org) was established in the Autumn of 1999 with the objective of creating a mechanism by which members of the neuroscientific community may more easily share functional neuroimaging data. Examples in other sciences offer proof of the usefulness and benefit that sharing data provides through encouraging growth and development in those fields. By building a publicly accessible repository of raw data from peer-reviewed studies, the Data Center hopes to create a similarly successful environment for the neurosciences. In this article, we discuss the continuum of data-sharing efforts and provide an overview of the scientific and practical difficulties inherent in managing various fMRI data-sharing approaches. Next, we detail the organization, design and foundation of the fMRIDC, ranging from its current capabilities to the issues involved in the submitting and requesting of data. We discuss how a publicly accessible database enables other fields to develop relevant tools that can aid in the growth of understanding of cognitive processes. Information retrieval and meta-analytic techniques can be used to search, sort and categorize study information with a view towards subjecting study data to secondary 'meta-' and 'mega-analyses'. In addition, we detail the technical and policy challenges that have had to be addressed in the formation of the Data Center. Among others, these include: human subject confidentiality issues; ensuring investigator's rights; heterogeneous data description and organization; development of search tools; and data transfer issues. We conclude with comments concerning the future of the fMRIDC effort, its role in promoting the sharing of neuroscientific data, and how this may alter the manner in which studies are published.

Brain↗