Using emerging science to inform risk characterizations for wildlife within current regulatory frameworks

Many jurisdictions have regulatory frameworks that seek to reduce the effects of environmental exposures of anthropogenic chemicals on terrestrial wildlife (i.e., mammals, birds, reptiles, and amphibians). The frameworks apply for new and existing chemicals, including pesticides (prospective assessments), and to environmental contamination from releases (retrospective risk assessments). Relatively recently, there have been many scientific advances that could improve risk estimates for wildlife. Here, we briefly describe current regulations from North America (United States and Canada) and from Europe that include risk assessments for wildlife to ascertain whether they are conducive to the use of emerging science and new methods. We also provide examples where new and emerging science may be used to improve wildlife risk characterization and identify areas in need of future research. Integr Environ Assess Manag 2024;20:765-779. © 2024 His Majesty the King in Right of Canada and The Authors. Integrated Environmental Assessment and Management © 2024 Society of Environmental Toxicology & Chemistry (SETAC). Reproduced with the permission of the Minister of Environment and Climate Change Canada. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

In situ sediment treatment using activated carbon: a demonstrated sediment cleanup technology

This paper reviews general approaches for applying activated carbon (AC) amendments as an in situ sediment treatment remedy. In situ sediment treatment involves targeted placement of amendments using installation options that fall into two general approaches: 1) directly applying a thin layer of amendments (which potentially incorporates weighting or binding materials) to surface sediment, with or without initial mixing; and 2) incorporating amendments into a premixed, blended cover material of clean sand or sediment, which is also applied to the sediment surface. Over the past decade, pilot- or full-scale field sediment treatment projects using AC-globally recognized as one of the most effective sorbents for organic contaminants-were completed or were underway at more than 25 field sites in the United States, Norway, and the Netherlands. Collectively, these field projects (along with numerous laboratory experiments) have demonstrated the efficacy of AC for in situ treatment in a range of contaminated sediment conditions. Results from experimental studies and field applications indicate that in situ sequestration and immobilization treatment of hydrophobic organic compounds using either installation approach can reduce porewater concentrations and biouptake significantly, often becoming more effective over time due to progressive mass transfer. Certain conditions, such as use in unstable sediment environments, should be taken into account to maximize AC effectiveness over long time periods. In situ treatment is generally less disruptive and less expensive than traditional sediment cleanup technologies such as dredging or isolation capping. Proper site-specific balancing of the potential benefits, risks, ecological effects, and costs of in situ treatment technologies (in this case, AC) relative to other sediment cleanup technologies is important to successful full-scale field application. Extensive experimental studies and field trials have shown that when applied correctly, in situ treatment via contaminant sequestration and immobilization using a sorbent material such as AC has progressed from an innovative sediment remediation approach to a proven, reliable technology.

Report on World Workshops on Oral Medicine (WWOM) IV and V: research themes and citation impact: WWOM VI steering committee

The first World Workshop on Oral Medicine (WWOM) was held in 1988. The portfolio has continued to expand in scope and impact over the past 26 years. Five World Workshops were conducted between 1988 and 2010, focusing on creation of systematic reviews in biomedicine and health care of importance to the international oral medicine community. WWOM VI was conducted in April 2014 and further extended this modeling. This most recent Workshop also fostered creation of the inaugural joint meeting between the American Academy of Oral Medicine and the European Association of Oral Medicine, together with The British Society for Oral Medicine and the Oral Medicine Academy of Australasia. The goal of the WWOM portfolio is to strategically enhance international oral medicine research, education, and clinical practice. To this end, this report summarizes subject areas for WWOM IV (2004) and research recommendations for WWOM V (2010), as well as citation metrics relative to publications from these two conferences. The information is designed to provide research and clinical context for key issues in oral medicine as delineated by the WWOM portfolio over the past 10 years, as well as for projected outcomes of WWOM VI over the next 12 months.

Regulatory considerations for the potential development and application of metal cleanup values

This article addresses the regulatory issues associated with the application of recent data to support Registration, Evaluation, Authorisation and Restriction of Chemical substances (REACH) requirements in Europe and the use of metal-specific parameters by other countries to generate remediation values for metals in soil. The purposes of this article are to: 1) present approaches and advances developed over the last decade in Europe for the REACH regulation and proposed in Australia by the National Environment Protection Council, 2) review current US and Canadian regulatory practices on ecological soil cleanup values, and 3) evaluate the application of new scientific approaches, methods, and soil criteria development processes used in other countries.

Passive sampling methods for contaminated sediments: risk assessment and management

This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree ), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal ) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree ) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed.

A sediment ecotoxicity assessment platform for in situ measures of chemistry, bioaccumulation and toxicity. Part 2: Integrated application to a shallow estuary

A comprehensive, weight-of-evidence based ecological risk assessment approach integrating laboratory and in situ bioaccumulation and toxicity testing, passive sampler devices, hydrological characterization tools, continuous water quality sensing, and multi-phase chemical analyses was evaluated. The test site used to demonstrate the approach was a shallow estuarine wetland where groundwater seepage and elevated organic and inorganic contaminants were of potential concern. Although groundwater was discharging into the surficial sediments, little to no chemical contamination was associated with the infiltrating groundwater. Results from bulk chemistry analysis, toxicity testing, and bioaccumulation, however, suggested possible PAH toxicity at one station, which might have been enhanced by UV photoactivation, explaining the differences between in situ and laboratory amphipod survival. Concurrently deployed PAH bioaccumulation on solid-phase micro-extraction fibers positively correlated (r(2) ≥ 0.977) with in situ PAH bioaccumulation in amphipods, attesting to their utility as biomimetics, and contributing to the overall improved linkage between exposure and effects demonstrated by this approach.

A sediment ecotoxicity assessment platform for in situ measures of chemistry, bioaccumulation and toxicity. Part 1: System description and proof of concept

In situ-based testing using aquatic organisms has been widely reported, but is often limited in scope and practical usefulness in making decisions on ecological risk and remediation. To provide this capability, an integrated deployment system, the Sediment Ecotoxicity Assessment (SEA) Ring was developed, which incorporates rapid in situ hydrological, chemical, bioaccumulation, and toxicological Lines-of-Evidence (LoE) for assessing sediment and overlying water contamination. The SEA Ring system allows for diver-assisted, or diverless, deployment of multiple species of ecologically relevant and indigenous organisms in three different exposures (overlying water, sediment-water interface, and bulk sediment) for periods ranging from two days to three weeks, in a range of water systems. Measured endpoints were both sublethal and lethal effects as well as bioaccumulation. In addition, integrated passive sampling devices for detecting nonpolar organics (solid phase micro-extraction fibers) and metals (diffusive gradients in thin films) provided gradient measures in overlying waters and surficial sediments.

Local drug delivery for oral mucosal diseases: challenges and opportunities

There are few topical formulations used for oral medicine applications most of which have been developed for the management of dermatological conditions. As such, numerous obstacles are faced when utilizing these preparations in the oral cavity, namely enzymatic degradation, taste, limited surface area, poor tissue penetration and accidental swallowing. In this review, we discuss common mucosal diseases such as oral cancer, mucositis, vesiculo-erosive conditions, infections, neuropathic pain and salivary dysfunction, which could benefit from topical delivery systems designed specifically for the oral mucosa, which are capable of sustained release. Each condition requires distinct penetration and drug retention profiles in order to optimize treatment and minimize side effects. Local drug delivery may provide a more targeted and efficient drug-delivery option than systemic delivery for diseases of the oral mucosa. We identify those mucosal diseases currently being treated, the challenges that must be overcome and the potential of novel therapies. Novel biological therapies such as macromolecular biological drugs, peptides and gene therapy may be of value in the treatment of many chronic oral conditions and thus in oral medicine if their delivery can be optimized.

Persistent orofacial muscle pain

The pathophysiology of persistent orofacial myalgia has been the centre of much controversy. In this article we suggest a novel descriptive term; 'persistent orofacial muscle pain' (POMP) and review current evidence that supports the hypothesis that the induction of POMP involves the interplay between a peripheral nociceptive source in muscle, a faulty central nervous system component and decreased coping ability. In this context it is widely accepted that a complex interaction of variable intrinsic and extrinsic factors act to induce POMP and dysfunction.

Spatially explicit ecological exposure models: a rationale for and path toward their increased acceptance and use

Spatially explicit wildlife exposure models have been developed to integrate chemical concentrations dispersed in space and time, heterogeneous habitats of varying qualities, and foraging behaviors of wildlife to give more realistic wildlife exposure estimates for ecological risk assessments. These models not only improve the realism of wildlife exposure estimates, but also increase the efficiency of remedial planning. However, despite being widely available, these models are rarely used in baseline (definitive) ecological risk assessments. A lack of precedent for their use, misperceptions about models in general and spatial models in particular, non-specific or no enabling regulations, poor communication, and uncertainties regarding inputs are all impediments to greater use of such models. An expert workshop was convened as part of an Environmental Security Technology Certification Program Project to evaluate current applications for spatially explicit models and consider ways such models could bring increased realism to ecological exposure assessments. Specific actions (e.g., greater accessibility and innovation in model design, increased communication with and training opportunities for decision makers and regulators, explicit consideration during assessment planning and problem formulation) were discussed as mechanisms to increase the use of these valuable and innovative modeling tools. The intent of this workshop synopsis is to highlight for the ecological risk assessment community both the value and availability of a wide range of spatial models and to recommend specific actions that may help to increase their acceptance and use by ecological risk assessment practitioners.

Aspirin and recurrent intracerebral hemorrhage in cerebral amyloid angiopathy

OBJECTIVE

To identify and compare clinical and neuroimaging predictors of primary lobar intracerebral hemorrhage (ICH) recurrence, assessing their relative contributions to recurrent ICH.

METHODS

Subjects were consecutive survivors of primary ICH drawn from a single-center prospective cohort study. Baseline clinical, imaging, and laboratory data were collected. Survivors were followed prospectively for recurrent ICH and intercurrent aspirin and warfarin use, including duration of exposure. Cox proportional hazards models were used to identify predictors of recurrence stratified by ICH location, with aspirin and warfarin exposures as time-dependent variables adjusting for potential confounders.

RESULTS

A total of 104 primary lobar ICH survivors were enrolled. Recurrence of lobar ICH was associated with previous ICH before index event (hazard ratio [HR] 7.7, 95% confidence interval [CI] 1.4-15.7), number of lobar microbleeds (HR 2.93 with 2-4 microbleeds present, 95% CI 1.3-4.0; HR = 4.12 when >or=5 microbleeds present, 95% CI 1.6-9.3), and presence of CT-defined white matter hypodensity in the posterior region (HR 4.11, 95% CI 1.01-12.2). Although aspirin after ICH was not associated with lobar ICH recurrence in univariate analyses, in multivariate analyses adjusting for baseline clinical predictors, it independently increased the risk of ICH recurrence (HR 3.95, 95% CI 1.6-8.3, p = 0.021).

CONCLUSIONS

Recurrence of lobar ICH is associated with previous microbleeds or macrobleeds and posterior CT white matter hypodensity, which may be markers of severity for underlying cerebral amyloid angiopathy. Use of an antiplatelet agent following lobar ICH may also increase recurrence risk.

Case study of contaminated groundwater discharge: how in situ tools link an evolving conceptual site model with management decisions

In this paper, we show how simple in situ tools provide key insights into groundwater transport and exposure pathways. We illustrate how integration between managers, hydrogeologists, and ecologists, through the use of an evolving conceptual site model, helps direct management decisions. An initial conceptual site model was used to guide a preliminary investigation to determine the extent to which contaminant exposure from discharging groundwater occurs in a waterway. Regulatory agency managers, informed by phased input of data, supported extending the site investigation subtidally to identify the nature and extent of waterway contamination and to provide the basis for developing remedial alternatives. Approaches and tools used in this reconnaissance investigation included monitoring ambient surface water for groundwater signatures, installing minipiezometers within the sediment, and installing diffusion samplers and seepage meters. Despite high concentrations of contaminants in nearby piezometer samples, the diffusion sampler array indicated few locations with contaminant accumulation in the top 20 cm of the sediment. At the location where deployed, seepage meters demonstrated a high degree of connectivity and the potential for mass loading in the waterway. In the collective experience of the authors, this is one of the 1st sites where this comprehensive suite of tools has been applied in a regulatory setting to evaluate the movement of industrial contaminants beneath and into a waterway. This approach was effective because of integration of disciplines, unification of previously separate groundwater and sediment investigations, and collaboration across separate agencies and programs. In large part because of the results, the facility and agency managers agreed, and have begun a comprehensive subtidal investigation, to characterize the distribution of sediment and groundwater contamination and to quantify the groundwater flux to the surface water.

Review of aquatic in situ approaches for stressor and effect diagnosis

Field-based (in situ) approaches are used increasingly for measuring biological effects and for stressor diagnoses in aquatic systems because these assessment tools provide realistic exposure environments that are rarely replicated in laboratory toxicity tests. Providing realistic exposure scenarios is important because environmental conditions can alter toxicity through complex exposure dynamics (e.g., multiple stressor interactions). In this critical review, we explore the information provided by aquatic in situ exposure and monitoring methods when compared with more traditional approaches and discuss the associated strengths and limitations of these techniques. In situ approaches can, under some circumstances, provide more valuable information to a decision maker than information from surveys of resident biota, laboratory toxicity tests, or chemical analyses alone. A decision tree is provided to assist decision makers in determining when in situ approaches can add value.

In situ exposures using caged organisms: a multi-compartment approach to detect aquatic toxicity and bioaccumulation

An in situ toxicity and bioaccumulation assessment approach is described to assess stressor exposure and effects in surface waters (low and high flow), the sediment-water interface, surficial sediments and pore waters (including groundwater upwellings). This approach can be used for exposing species, representing major functional and taxonomic groups. Pimephales promelas, Daphnia magna, Ceriodaphnia dubia, Hyalella azteca, Hyalella sp., Chironomus tentans, Lumbriculus variegatus, Hydra attenuatta, Hexagenia sp. and Baetis tibialis were successfully used to measure effects on survival, growth, feeding, and/or uptake. Stressors identified included chemical toxicants, suspended solids, photo-induced toxicity, indigenous predators, and flow. Responses varied between laboratory and in situ exposures in many cases and were attributed to differing exposure dynamics and sample-processing artifacts. These in situ exposure approaches provide unique assessment information that is complementary to traditional laboratory-based toxicity and bioaccumulation testing and reduce the uncertainties of extrapolating from the laboratory to field responses.

Desorption kinetics of fluoranthene and trifluralin from Lake Huron and Lake Erie, USA, sediments

Desorption kinetics were determined for fluoranthene (FLU) and trifluralin (TF) spiked onto Lake Erie and Lake Huron, USA, sediments at three concentrations (10, 40, 100 mg/kg dry wt). Following four months of equilibration, desorption was measured by extraction with Tenax and the data were fit to a first-order three-compartment kinetic model. The rate constants of the rapidly (k(rap)), slowly (k(slow)), and very slowly (k(vs)) desorbing fractions were on the order of 10(-1)/h, 10(-2-3)/h, and 10(-4)/h, respectively. The t99.9 (time required for 99.9% of the FLU and TF to desorb from each pool value) for each compartment indicated that FLU and TF desorption from rapid, slow, and very slow compartments were on the order of hours, days, and years, respectively. Higher rates of desorption were observed for FLU and TF from the Lake Huron sediments and this was not apparently related to the total organic carbon (TOC), particle size distribution, or polarity (carbon-to-nitrogen ratio) of the sediments. In general, the total fraction of the initial contaminant amounts that desorbed over the time course was directly related to concentration, which we hypothesized was due to the combined effects of saturation of high-energy (slow and very slow) binding sites in the organic carbon matrix and hysteresis. In extrapolations to field conditions, FLU and TF were predicted to persist in the sediments for years due to the very slow desorption of an estimated 31 to 53% of the bulk concentrations. Based on the rapidly desorbing fractions, the bioavailable amounts of the contaminants were predicted to be between 31 to 55% of bulk sediment concentrations.

Investigating the role of desorption on the bioavailability of sediment-associated 3,4,3',4'-tetrachlorobiphenyl in benthic invertebrates

Only a fraction of all sediment-associated hydrophobic organic contaminants are bioavailable, and a simple Tenax extraction procedure may estimate this fraction. Bioavailability is assumed to coincide with the rapidly and, possibly, slowly desorbing sediment-associated contaminant. River sediment was spiked with radiolabeled (14C) and nonradiolabeled (12C) 3,4,3',4'-tetrachlorobiphenyl (TCBP), and desorption kinetics using Tenax extraction were obtained at 10 degrees C and 22 degrees C. Bioaccumulation was measured in Lumbriculus variegatus, Chironomus tentans, and Hyalella azteca. Desorption of TCBP was triphasic at 22 degrees C and slowed at 10 degrees C to show only biphasic kinetics. The rapidly desorbing fractions decreased with increasing TCBP sediment concentration. The biota sediment accumulation factors, biota accumulation factors, and sediment clearance coefficients (ks) also decreased with increasing sediment TCBP concentration. The rapidly plus slowly desorbing fractions and the total TCBP desorbed when 99.9% of the rapidly desorbing fraction had desorbed were used to estimate bioavailable TCBP. These Tenax-based fractions did not explain the decreasing bioavailability with increasing TCBP load. Several factors, such as animal behavior and TCBP water solubility limitations, were evaluated to explain the concentration effect, but the most likely cause was severe diffusion limitations in whole sediment that were not predicted by the fully mixed Tenax extraction. Therefore, desorbing fractions determined by Tenax extraction overestimated the bioavailable fractions in sediments.

Biological responses of Lumbriculus variegatus exposed to fluoranthene-spiked sediment

Lumbriculus variegatus was used as a bioassay organism to examine the impact of the sediment-associated polycyclic aromatic hydrocarbon (PAH) fluoranthene on behavior, reproduction, and toxicokinetics. The number of worms increased between the beginning and end of the experiment at 59 microg x g(-1) fluoranthene, but at the next higher treatment (108 microg x g(-1)) the number of worms found was lower and not different from the control. Worms exposed to 95 microg x g(-1) also exhibited increased reproduction when fed a yeast-cerophyl-trout chow mixture. On a total biomass basis, only the 95 microg x g(-1) exposure with food exhibited a statistically significant increase over the nonfed control. Evaluation of reproduction at the two highest treatments was compromised by a brief aeration failure 2 days before the end of the experiment. The behavioral responses were followed as changes in biological burial rate (sediment reworking rate) of a 137Cs-labeled marker layer. The biological burial rate increased toward a plateau as the concentration increased from the control (3.9 microg x g(-1) dry weight total PAH) to 355 microg x g(-1) dry weight fluoranthene in sediment. The aeration failure had minimal impact on the determination of reworking rate because all the data for the rate determination were collected prior to the aeration failure. Uptake and elimination rates declined with increasing treatment concentration across the range of fluoranthene concentrations, 59-355 microg x g(-1) dry weight sediment. The disconnect between the increasing biological burial rates and the decreasing toxicokinetics rates with increasing exposure concentration demonstrates that the toxicokinetic processes are dominated by uptake and elimination to interstitial water. The bioaccumulation factor (concentration in the organisms on a wet weight basis divided by the concentration in sediment on a dry weight basis) ranged from 0.92 to 1.88 on day 10 and declined to a range of 0.52 to 0.99 on day 28 with the lowest value at the highest dose.

Optimizing interpretation of in situ effects of riverine pollutants: impact of upwelling and downwelling

In situ toxicity and bioaccumulation tests with Ceriodaphnia dubia (48 h), Chironomus tentans (96 h), Hyalella azteca (96 h), and Lumbriculus variegatus (96 h) were conducted at three stations on a river that was contaminated primarily with chlorobenzenes (CBs), and results were compared to a nearby reference site. Exposures were characterized by using minipiezometers for contaminant profiling and determination of hydraulic heads and vertical flow direction within the sediments and measuring contaminants in sediment, surface water, and exposure chamber water samples. Localized zones of upwelling and downwelling existed in the exposure areas at contaminated sites 5 and 18, while site 23 was downwelling at all measurement positions. Pore-water samples from minipiezometers contained CBs at the three contaminated sites that were highest at site 23. However, sediment and water samples from exposure chambers at site 23 contained the lowest levels of CBs among the contaminated sites. The CBs were not detected at the reference site, but other organic contaminants and metals were detected at all sites, with the highest concentrations occurring at sites 5 and 18. In water column exposures, no significant (p > 0.05) differences were observed in species survival between the contaminated sites and the reference. Mean percentage survival of H. azteca, C. dubia, and C. tentans exposed to surficial sediments (SS) at sites 5 and 18 was significantly (p < 0.05) reduced compared to the reference, whereas only C. tentans survival was significantly reduced at site 23. Body residues of total CB congeners in L. variegatus exposed to SS were highest at site 18 (618 micromol/kg lipid) and lowest at site 23 (21 micromol/kg lipid). The data suggest that downwelling reduced the bioavailability of CBs in surficial sediments, most likely by mobilizing the freely dissolved and colloid-bound fractions to deeper sediments. Overall, downwelling conditions reduced the in situ exposure of organisms in surficial sediments and hence the toxicity and bioaccumulation of CBs. Hydrologic and chemistry data from nested minipiezometers improved the interpretation of exposure-effects relationships.

A retrospective study of the management of oral mucous membrane pemphigoid with dapsone

OBJECTIVE

The purpose of this retrospective study was to investigate the efficacy of dapsone therapy in the management of mucous membrane pemphigoid.

STUDY DESIGN

The charts of 29 patients who had been diagnosed with mucous membrane pemphigoid by means of routine histologic analysis and direct immunofluorescence were reviewed. The oral features were graded according to severity of disease from 1 to 3. Each patient was assigned to one of 4 groups according to his or her response to therapy.

RESULTS

Nine patients were treated successfully with topical corticosteroids alone. Eleven patients with moderate to severe disease who were treated initially with topical steroids showed minimal improvement; after dapsone was added, 7 of the 11 had total resolution of their lesions and 4 had greater than 75% improvement. Two patients had to discontinue dapsone because of side effects.

CONCLUSIONS

In this group of 20 patients with moderate to severe mucous membrane pemphigoid, the use of dapsone in combination with topical corticosteroids caused greater than 75% resolution of oral lesions in all patients studied.

Physiologically based pharmacokinetic modeling of inhaled trichloroethylene and its oxidative metabolites in B6C3F1 mice

A physiologically based pharmacokinetic (PBPK) model for inhaled trichloroethylene (TCE) was developed for B6C3F1 mice. Submodels described four P450-mediated metabolites of TCE, which included chloral hydrate (CH), free and glucuronide-bound trichloroethanol (TCOH-f and TCOH-b), trichloroacetic acid (TCA), and dichloroacetic acid (DCA). Inhalation time course studies were carried out for calibration of the model by exposing mice to TCE vapor concentrations of either 100 or 600 ppm for 4 h. At several time points, mice were euthanized and blood, liver, kidney, lung, and fat were collected and analyzed for TCE and its oxidative metabolites. Peak blood TCE concentrations were 0.86 and 7.32 microgram/mL, respectively, in mice exposed to 100 and 600 ppm TCE. The model overpredicted the mixed venous blood and tissue concentrations of TCE for mice of both exposure groups. Fractional absorption of inhaled TCE was proposed to explain the discrepancy between the model predictions and the TCE blood time course data. When fractional absorption (53%) of inhaled TCE was incorporated into the model, a comprehensive description of the uptake, distribution, and clearance of TCE in the blood was obtained. Fractional uptake of inhaled TCE was further verified by collecting TCE in exhaled breath following a 4-h constant concentration exposure to TCE and validation was provided by testing the model against TCE blood concentrations from an independent data set. The submodels adequately simulated the distribution and clearance kinetics of CH and TCOH-f in blood and the lungs, TCOH-b in the blood, and TCA and DCA, which were respectively detected for up to 43 and 14 h postexposure in blood and livers of mice exposed to 600 ppm TCE. This is the first extensive tissue time course study of the major metabolites of TCE following an inhalation exposure to TCE and the PBPK model predictions were in good general agreement with the observed kinetics of the oxidative metabolites formed in mice exposed to TCE concentrations of 100 and 600 ppm.

When believing is seeing: the effect of scripts on eyewitness memory

Two studies examined the conditions under which event schema or scripts produce gap-filling errors in eyewitness accounts of a robbery. In Study 1, scripts for the robbery of a convenience store were identified. Results revealed high agreement among the 120 participants concerning the sequence of actions for such a robbery. Based on the information obtained in Study 1, participants in Study 2 (N = 144) viewed one of two sequences of slides depicting a robbery of a convenience store by a lone robber. In one sequence, three central script actions were omitted and in the other, three peripheral script actions were omitted. In addition, rate of exposure was varied (2 vs. 8 sec) as was the length of the retention interval (5 min vs. 1 week). As predicted, there was a higher rate of false recognition for central as opposed to peripheral actions, and this tendency was exaggerated for the longer retention interval. The theoretical and practical implications of the findings are discussed.

Intraoral contact allergy: a literature review and case reports

Signs and symptoms of contact allergic reactions affecting the oral mucosa may mimic other common oral disorders, making diagnosis difficult. Patients frequently seek multiple consultations and do not receive the correct diagnosis or effective management. As intraoral contact allergy may be more prevalent than previously believed, a review of this topic is warranted. This article emphasizes signs and symptoms that suggest intraoral contact allergy, and the authors discuss the allergens that most frequently affect the oral mucosa.

Comprehensive health data systems spanning the public-private divide: the Massachusetts experience

As systems of health care delivery have evolved from claims-based fee-for-service to capitated or managed care, with its emphasis on cost-effectiveness, quality, and performance measurement, some states have begun to experiment with new ways to collect, organize, and share health information. In many cases, the drivers of these changes have been purchasers of health care, including large and small private employers and public agencies such as Medicaid. One of the results of these changes is the increased interest in the sharing of health information, between health plans and employers, and, in some instances, between private plans and public agencies such as public health. Massachusetts, which has one of the highest rates of managed care penetration in the United States, has brought together the various parties involved in the collection and utilization of health information, to craft agreements on standards and protocols that will allow the sharing of health data. While much of the activity involves business transactions between private sector health plans, the Department of Medical Assistance (Medicaid) has joined with its private sector purchasing partners in demanding cost-effective, high-quality care; it is these demands that have helped stimulate the need to reorganize previously proprietary health information systems. The activities of two public-private coalitions, the Massachusetts Healthcare Purchaser Group and the Massachusetts Health Data Consortium, have been critical in initiating and supporting the complex processes that have led to significant changes in state-based systems of health information.

Prevalence of hereditary hemochromatosis in a Massachusetts corporation: is Celtic origin a risk factor?

The prevalence of homozygous hereditary hemochromatosis (HHC) is estimated at 1:250 in Caucasian adults. Little is known about ethnic subpopulations that might be at increased risk for this disease. HLA data have suggested a Celtic origin for HHC. Screening for HHC was offered to all employees of the Massachusetts Polaroid Corporation. Participants with a transferrin saturation of >55% or >45% and an elevated serum ferritin concentration on two screenings were referred for liver biopsy. The diagnosis of HHC was based on histological criteria, quantitative hepatic iron determination, hepatic iron index, and the phlebotomy requirement for iron depletion. Participants completed a questionnaire regarding their ethnic background. Two thousand two hundred ninety-four employees were screened, and 5 cases of HHC were detected. All 5 cases involved Caucasian men, yielding a prevalence of 1:395 for the Caucasian population. Four of the 5 cases were of 100% British-Irish ancestry based on the country of origin of their grandparents. Additional analysis revealed that the majority of grandparents of all 4 individuals came from Ireland or Wales. The exact two-tailed trend test showed a significant association of HHC with Celtic background (P = .012). The estimated cost of screening per patient identified was $18,041. Polaroid Corporation has a high representation of employees of British-Irish ancestry. Our data suggest that they are at high risk for developing HHC. A significant association of HHC with Celtic ancestry was found in this subpopulation, supporting the concept of a Celtic origin for this disease.

Relationship of cytomegalovirus to salivary gland dysfunction in HIV-infected patients

In a previous retrospective study of HIV-infected patients we detected a relationship between xerostomia and the presence of cytomegalovirus in saliva. This prospective study compares 13 patients with HIV and a complaint of xerostomia and low salivary flow rates with a control group of 7 patients with HIV without xerostomia and normal salivary flow rates. Both groups were evaluated for the presence of cytomegalovirus in saliva, peripheral blood mononuclear cells, and labial minor salivary glands. Viral cultures, polymerase chain reaction, and histopathologic examination were used to detect cytomegalovirus. Xerostomia and low salivary flow rates were associated with the presence of CMV in saliva. The virus was detected in 10 of 13 xerostomia patients and 2 of 7 controls (p = 0.05, Fisher's exact test). Cytomegalovirus was detected in the saliva of patients who did not also have it in their blood suggesting a local source of virus replication such as the salivary glands. The minor salivary glands were not a major site of cytomegalovirus. Culture was more sensitive then polymerase chain reaction in detecting salivary cytomegalovirus as a result of the presence of inhibitors to the reaction in saliva. These results suggest a link between cytomegalovirus in saliva and salivary gland dysfunction in HIV-infected patients.

Toward standardization of health information

NCVHS has made recommendations to the DHHS to standardize 42 core health data elements, a number of which relate to medical conditions and services. The committee has asked the DHHS Data Council to actively promote, both within the department and externally, standardization of data elements and definitions where substantial consensus already exists. For those elements that have been recognized as significant core data elements, but for which there is not consensus on approach or definition, the NCVHS is recommending that the Data Council support the formation of a public-private working group to conduct further study and evaluation. This group, or a separate group, could also be the focus for evaluating additions to the list of core data elements and for setting up methods for testing and promulgating the final products. The coming 12-18 months will be exceedingly important for health data standardization efforts in the US as the DHHS responds to both the NCVHS recommendations and the legislation recently enacted by Congress.

(1S,2R)-D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol as an inhibitor of ceramidase

In this study, we have examined the cellular and biochemical activities of the ceramide analog (1S,2R)-D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol (D-erythro-MAPP). Addition of 5 microM D-e-MAPP to HL-60 human promyelocytic leukemia cells resulted in a concentration- and time-dependent growth suppression accompanied by an arrest in the G0/G1 phase of the cell cycle; thus mimicking the action of exogenous ceramides. Its enantiomer L-e-MAPP was without effect. Two lines of evidence suggested that D-e-MAPP may not function as a direct analog of ceramide. First, D-e-MAPP possesses a stereochemical configuration opposite to that of D-erythro-ceramide. Second, D-e-MAPP failed to activate ceramide-activated protein phosphatase in vitro. Therefore, we examined if D-e-MAPP functioned indirectly by modulating endogenous ceramide levels. The addition of D-e-MAPP to cells, but not L-e-MAPP, caused a time- and concentration-dependent elevation in endogenous ceramide levels reaching greater than 3-fold over baseline following 24 h of treatment. Both D-e-MAPP and L-e-MAPP underwent similar uptake by HL-60 cells. D-e-MAPP was poorly metabolized, and remained intact in cells, whereas L-e-MAPP underwent a time- and concentration-dependent metabolism; primarily through N-deacylation. In vitro, L-e-MAPP was metabolized by alkaline ceremidase to an extent similar to that seen with C16-ceramide. D-e-MAPP was not metabolized. Instead, D-e-MAPP inhibited alkaline ceramidase activity in vitro with an IC50 of 1-5 microM. D-e-MAPP did not modulate the activity of other ceramide metabolizing enzymes in vitro or in cells, and it was a poor inhibitor of acid ceramidase (IC50>500 microM). Finally, D-e-MAPP inhibited the metabolism of L-e-MAPP in cells. These studies demonstrate that D-e-MAPP functions as an inhibitor of alkaline ceramidase in vitro and in cells resulting in elevation in endogenous levels of ceramide with the consequent biologic effects of growth suppression and cell cycle arrest. These studies point to an important role for ceramidases in the regulation of endogenous levels of ceramide.

Herpesvirus infections

There are presently seven known herpes viruses that infect humans. Those viruses are important in the fields of oral medicine and dentistry because they cause oral lesions, infect saliva, and cause serious and potentially life-threatening infections in patients whose immune systems are compromised by cancer chemotherapy, immunosuppressive drugs, or HIV infection. This article reviews the basic virology and clinical manifestations of the herpes viruses while highlighting the clinical aspects of herpes-related diseases important to dentistry.

HIV-associated lesions

Oral lesions are common in HIV infection and may be the first sign of AIDS. This article reviews the oral fungal and viral infections commonly detected in HIV-infected patients, particularly candidiasis, deep fungal infections, herpes simplex virus infections, cytomegalovirus infections, and oral hairy leukoplakia. The neoplasms associated with AIDS such as oral Kaposi's sarcoma and lymphoma are related periodontal diseases. Each disorder is discussed by clinical appearance, diagnosis, and management. Recent advances in therapy are stressed.

Relationship of oral disease to the presence of cytomegalovirus DNA in the saliva of AIDS patients

Cytomegalovirus is an important pathogen in persons infected with human immunodeficiency virus. In this study a thorough oral examination was done and blood and urine cultures for cytomegalovirus were obtained from a group of 31 patients with acquired immunodeficiency syndrome with CD4 lymphocyte counts less than 150 cells/mm3. Whole saliva was also collected for detection of cytomegalovirus deoxyribonucleic acid (DNA) via the polymerase chain reaction. The presence of cytomegalovirus DNA in the saliva specimens was not related to the presence of cytomegalovirus in the urine, which suggests a local source of cytomegalovirus from salivary gland and kidney parenchyma. There was also a strong statistical relationship between salivary cytomegalovirus DNA and xerostomia (p = 0.0004), which suggests that cytomegalovirus may be a cause of salivary gland dysfunction in patients with acquired immunodeficiency syndrome with low CD4 counts.

Evidence for construct validity of the TMJ scale in a sample of chronic post-traumatic headache patients

The construct validity of the TMJ Scale was examined in a sample of chronic post-traumatic headache patients. Clinical indicators of temporomandibular (TM) dysfunction and measures of psychosocial distress were compared with relevant scales of the TMJ Scale. The clinical indicators were first subjected to principal components analysis. The resulting factor scores correlated significantly with selected physical domain scales of the TMJ Scale. The factor scores also significantly predicted the TMJ Global Scale in a regression analysis. Selected psychosocial domain scales of the TMJ Scale correlated strongly with measures of depression and anger and a clinical diagnosis of post-traumatic stress disorder. The results support the validity of the TMJ Scale and demonstrates its utility with post-traumatic headache patients.

Plasma cell gingivitis. Report of two cases

Plasma cell gingivitis is a disorder first described in the 1960s and was believed to be caused by an allergic reaction to flavored chewing gum and toothpaste. The lesion was believed to have been largely eliminated by removing the allergens from the products. We report two additional cases, not related to a known allergen. One patient was allergy tested thoroughly and given a strict elimination diet without resolution. Immunofluorescence study suggests a reactive rather than a neoplastic process.

Unrecognized attention-deficit hyperactivity disorder in adults presenting for outpatient psychotherapy

ABSTRACT Adult patients with significant childhood and current symptoms of attention-deficit hyperactivity disorder (ADHD), but whose ADHD had not been previously recognized, were evaluated by three clinical consultants working with diverse referral populations. These 60 adults shared common characteristics of physical and mental restlessness, impulsivity, disabling distractibility, low self-esteem, self-loathing, and a gnawing sense of underachievement. Specific learning or behavior problems were often present. These patients were chronically disaffected. The diagnosis of ADHD appeared to be missed because these individuals presented with atypical symptoms or had found ways to compensate for their deficits. Descriptive generalizations are offered concerning their coping strategies. These adults had sought previous psychiatric care for non-ADHD symptoms but had numerous unsuccessful treatment attempts. Most patients had been treated for mood or anxiety disorders. Traditional defense analysis had little beneficial effect and aggravated problems of self-esteem; modifications of the psychotherapeutic process are recommended. In open clinical trials without formal measures, the majority of such patients appeared to respond to low doses of antidepressants (i.e., desipramine 10-30 mg daily) and seemed to lose the therapeutic effect at higher antidepressant doses.

Combination of treatments for attention deficit hyperactivity disorder in adults

Three adults with DSM-III-R diagnoses of attention deficit hyperactivity disorder were treated with a combination of a psychostimulant and nadolol. Previous treatment with only a psychostimulant had not been effective or had not been tolerated. The combination treatment resulted in an increase in attention and focusing capacities, along with a decrease in anxiety, impulsiveness, and somatic discomfort. These improvements suggest an effective regimen for treatment-resistant adults with attention deficit hyperactivity disorder.

The association between congenital syphilis and cocaine/crack use in New York City: a case-control study

From 1987 to 1989, an epidemic of congenital syphilis was observed in New York City. A case-control study was done to assess the association between various maternal risk factors and congenital syphilis. Independent of the effect of other factors, the odds of being exposed to cocaine were 3.9 times greater among cases than controls (95% confidence interval, 2.8-5.3). This study suggests that the epidemic of congenital syphilis may be related to the increase in cocaine/crack use among delivering mothers.

Management of cheilitis granulomatosa

Peripheral facial nerve palsy, recurrent or persistent oral or facial swelling, and fissured tongue constitute a triad of symptoms known as Melkersson-Rosenthal syndrome. Granulomatous labial enlargement, known as cheilitis granulomatosa, is considered the single most important diagnostic feature of this syndrome. This lesion has been difficult to treat. This article describes a case of 8 months' duration of cheilitis granulomatosa of the lower lip, which was successfully managed with intralesional steroid injections.

Diabetes mellitus--a newly described risk factor for infection from Salmonella enteritidis

Infections due to Salmonella serotype enteritidis have increased markedly in the northeastern United States. Due to the potential severity of these infections, host risk factors for infection were determined in the largest nosocomial S. enteritidis outbreak to have occurred in the United States. In a case-control study, patients in a New York City hospital who developed infection after exposure to an S. enteritidis-contaminated meal were more likely to be medication-dependent diabetics than were those who did not develop infection (17/75 vs. 7/80, Mantel-Haenszel adjusted odds ratio = 3.1, 95% confidence interval = 1.1, 8.6). Proposed mechanisms for diabetes as a risk factor for infection include decreased gastric acidity in diabetic patients and an autonomic neuropathy of the small bowel that reduces intestinal motility and prolongs gastrointestinal transit time.

Increasing the medical training of dentists

Dentists are entering complex diagnostic fields such as facial pain; carrying out advanced oral, periodontal, and maxillofacial procedures; and treating oral diseases by prescribing drugs with profound systemic effects. Concurrently, the population is living longer by taking multiple medications and undergoing sophisticated surgical procedures. The modern dentist requires more extrinsic and practical medical training to deal with these realities. This review advocates that courses in physical and laboratory diagnosis, pathophysiology, and internal medicine be expanded in the dental school curriculum and supplemented by practical clinical experience.

Maxillofacial plasmacytoma resulting in intraoral hemorrhage in a patient with multiple myeloma

Oral symptoms of multiple myeloma are common. A patient with refractory multiple myeloma is described because of this unusual orofacial manifestations, including severe intraoral hemorrhage, a massive, erosive maxillofacial lesion with extension into the cranial fossa, and rapid growth of a large intraoral mass.

Syphilis treatment response in HIV-infected individuals

The adequacy of treatment for syphilis has routinely been evaluated by the serological response, i.e. the rapid plasma reagin test (RPR). Since the description of AIDS and HIV aspects of both the natural history of syphilis and the response of Treponema pallidum to treatment have come under increased scrutiny. With concurrent epidemics of HIV and syphilis in New York City, a serological case-control study was done to determine whether HIV-infected individuals given treatment for primary or secondary syphilis have a modified serological response. All study participants had primary or secondary syphilis and paired specimens available for testing. Cases were defined as people who were HIV-positive and were compared with controls who were HIV-negative. HIV-infected patients with primary syphilis when compared with HIV-negative controls were less likely to have a fourfold or greater RPR decrease or seroreversion within 6 months of treatment [15 out of 28 versus 153 out of 210; odds ratio = 0.4, P less than 0.05]. Cases and controls with secondary syphilis had similar serological responses after treatment for syphilis. Although this study adds to the growing body of literature which suggests that HIV may alter the RPR response, prospective studies are needed to determine definitively whether HIV alters the serological response to therapy in patients with early syphilis.

Naloxone-reversible analgesic response to combat-related stimuli in posttraumatic stress disorder. A pilot study

We tested the hypothesis that exposure to a stimulus resembling the original traumatic event would induce naloxone-reversible analgesia in patients with posttraumatic stress disorder (PTSD). Eight medication-free Vietnam veterans with PTSD and eight veterans without PTSD, matched for age and combat severity, viewed a 15-minute videotape of dramatized combat under naloxone hydrochloride and placebo conditions in a randomized double-blind crossover design. In the placebo condition, the subjects with PTSD showed a 30% decrease in reported pain intensity ratings of standardized heat stimuli after the combat videotape. No decrease in pain ratings occurred in the subjects with PTSD in the naloxone condition. The subjects without PTSD did not show a decrease in pain ratings in either condition. The results are consistent with the induction of opioid-mediated stress-induced analgesia in the patients with PTSD.