Fear of Cancer Recurrence in Differentiated Thyroid Cancer Survivors: A Systematic Review.

Background: Despite excellent survival rates, health-related quality of life detriments are common in differentiated thyroid cancer survivors and can be driven by fear of cancer recurrence (FCR). This review aims to report the incidence of FCR in thyroid cancer survivors and synthesize evidence regarding contributing factors. An overview and appraisal of the range of tools used to measure FCR is presented. Methods: A systematic review of the English literature was performed. The search across six electronic databases generated 3414 studies. Two reviewers independently screened the citations and full-text articles, of which 31 were included. The data were extracted independently by two reviewers. Results: The incidence of FCR was reported in 27/31 studies and ranged from 15% to 91%. Direct comparisons regarding incidence and severity of FCR were not possible due to heterogeneity in cut-points used to define FCR. A total of eight validated tools were used to measure FCR across all studies, with five studies using self-developed nonvalidated items. There was minimal repetition of validated tools and no clear consensus as to a preferred survey tool. Factors influencing FCR were reported in 11 studies. There was minimal overlap of factors influencing FCR. Risk factors contributing to increased FCR reported in more than one study included young age and an upcoming clinical appointment. Male gender and higher education levels were reported in more than one article as protective. No literature evaluating interventions to address FCR in thyroid cancer survivors was found. Conclusion: FCR is common in thyroid cancer survivors, but significant heterogeneity in the current evidence base limits assessment of incidence, severity, or risk factors. There is a need to use validated tools to assess FCR in both research and clinical contexts. Reliable assessment of FCR may permit routine assessment of FCR in clinical practice and allow interventions to be prospectively evaluated to optimize the holistic well-being of thyroid cancer survivors.

Urine Drug Screening in a Telehealth Setting for the Treatment of Opioid Use Disorder.

Importance: Amid rapid and widespread adoption of telehealth-based opioid treatment (TBOT), there is an urgent need for rigorous studies exploring the feasibility and characteristics of urine drug screening (UDS). Objective: To investigate administration patterns and results of UDS to assess feasibility of UDS and patient outcomes in a TBOT setting. Design: This observational cohort study was conducted between January 1, 2021, and December 6, 2022, and included patients with opioid use disorder treated in Ophelia, a TBOT treatment platform in 14 states. Data analysis was performed from January to March 2023. Main Outcomes and Measures: Number and percentage of patients with UDS within 30, 90, and 180 days of intake, grouped by adherence to clinical protocols. Associations were assessed between baseline characteristics and UDS completion and opioid positivity in first 30 days using χ2 tests. Baseline and 180-day follow-up UDS results were compared using McNemar tests. Results: Among 3395 patients (mean [SD] age, 38.2 [9.3] years, mostly male [54.1%], non-Hispanic White [81.5%], urban-residing [80.3%], and cash-pay at intake [74.0%]), 2782 (83.3%) completed a UDS within 30 days (90.0% among protocol-adherent patients, 67.0% among protocol-nonadherent patients). A total of 2750 of 2817 (97.6%) patients retained more than 90 days completed 1 or more UDS, as did 2307 of 2314 (99.7%) patients retained more than 180 days. Younger patients, patients of a racial and ethnic minority group, those living in urban areas, and cash-pay patients were less likely to complete a UDS in the first 30 days. Buprenorphine positivity increased (from 96.9% to 98.4%, P = .004) and opioid positivity declined (from 7.9% to 3.3%, P < .001) over time. Conclusions and Relevance: In this cohort study of patients with opioid use disorder receiving buprenorphine in a remote care environment, UDS was highly feasible, though early UDS completion rates varied across demographic subgroups. The prevalence of unexpected UDS results was low and declined over time in treatment.

Hearing the Voices of Australian Thyroid Cancer Survivors: Qualitative Thematic Analysis of Semistructured Interviews Identifies Unmet Support Needs.

Background: Most thyroid cancer survivors regain their physical health-related quality of life, but psychological and social deficits persist. The nature of these detriments remains poorly understood and they are insufficiently captured by survey data alone. To address this, qualitative data exploring the breadth and depth of thyroid cancer survivors' experiences and priorities for supportive care are required. Methods: Twenty semistructured interviews were undertaken with a purposive, maximum variation sample of thyroid cancer survivors. Interviews were transcribed verbatim and coded independently by two researchers. A hybrid model of inductive and realistic codebook analysis was undertaken with themes developed. Results: Patient experiences centered around three themes: (1) impact of diagnosis and treatment, (2) thyroid cancer does not happen in isolation, and (3) role of clinicians and formalized support structures. The word "cancer" had negative connotations, but for many, the reality of their experience was more positive. Despite feeling "lucky" at the relative low-risk nature of thyroid cancer, many patients reported fatigue, weight gain, and difficulty returning to usual activities; concerns that were largely dismissed or minimized by clinicians. Few were offered any support beyond their treating doctors; where patients attempted to access formalized supportive care, little was available or appropriate. Life stage and concurrent family and social stressors greatly impacted patients' ability to cope with diagnosis and treatment. Addressing thyroid cancer in isolation felt inappropriate without appreciating the broader context of their lives. Interactions with clinicians were largely positive, particularly where information was communicated as a means of empowering patients to participate in shared decision-making and where clinicians "checked in" emotionally with patients. Information about initial treatments was largely adequate but information on longer term effects and follow-up was lacking. Many patients felt that clinicians focused on physical well-being and scan results, missing opportunities to provide psychological support. Conclusions: Thyroid cancer survivors can struggle to navigate their cancer journey, particularly with regard to psychological and social functioning. There is a need to acknowledge these impacts at the time of clinical encounters, as well as develop information resources and support structures that can be individualized to optimize holistic well-being for those in need.

Characterising Australian memory clinics: current practice and service needs informing national service guidelines.

BACKGROUND: Memory clinics (MCs) play a key role in accurate and timely diagnoses and treatment of dementia and mild cognitive impairment. However, within Australia, there are little data available on current practices in MCs, which hinder international comparisons for best practice, harmonisation efforts and national coordination. Here, we aimed to characterise current service profiles of Australian MCs. METHODS: The 'Australian Dementia Network Survey of Expert Opinion on Best Practice and the Current Clinical Landscape' was conducted between August-September 2020 as part of a larger-scale Delphi process deployed to develop national MC guidelines. In this study, we report on the subset of questions pertaining to current practice including wait-times and post-diagnostic care. RESULTS: Responses were received from 100 health professionals representing 60 separate clinics (45 public, 11 private, and 4 university/research clinics). The majority of participants were from clinics in metropolitan areas (79%) and in general were from high socioeconomic areas. While wait-times varied, only 28.3% of clinics were able to offer an appointment within 1-2 weeks for urgent referrals, with significantly more private clinics (58.3%) compared to public clinics (19.5%) being able to do so. Wait-times were less than 8 weeks for 34.5% of non-urgent referrals. Only 20.0 and 30.9% of clinics provided cognitive interventions or post-diagnostic support respectively, with 7.3% offering home-based reablement programs, and only 12.7% offering access to group-based education. Metropolitan clinics utilised neuropsychological assessments for a broader range of cases and were more likely to offer clinical trials and access to research opportunities. CONCLUSIONS: In comparison to similar countries with comprehensive government-funded public healthcare systems (i.e., United Kingdom, Ireland and Canada), wait-times for Australian MCs are long, and post-diagnostic support or evidence-based strategies targeting cognition are not common practice. The timely and important results of this study highlight a need for Australian MCs to adopt a more holistic service of multidisciplinary assessment and post-diagnostic support, as well as the need for the number of Australian MCs to be increased to match the rising number of dementia cases.

Factors Associated with Pain Treatment Satisfaction Among Patients with Chronic Non-Cancer Pain and Substance Use.

INTRODUCTION: A better understanding of pain treatment satisfaction in patients with chronic noncancer pain (CNCP) and substance use is needed, especially as opioid prescribing policies are changing. We sought to identify factors associated with pain treatment satisfaction in individuals with CNCP on recent opioid therapy and prior or active substance use. METHODS: An exploratory cross-sectional analysis using baseline data from a cohort study of 300 adults with CNCP receiving >20 morphine milligram equivalents of opioids for ≥3 of the preceding 12 months and prior or active substance use. Participants completed interviews, clinical assessments, urine drug screening, and medical chart review. RESULTS: Participants were predominantly middle-aged (mean age 57.5 years), Black (44%), and cisgender men (60%). One-third (33%) had high, 28% moderate, and 39% low pain treatment satisfaction. Post-traumatic stress disorder (PTSD), tobacco use, past-year opioid discontinuation, and higher average pain scores were associated with lower satisfaction. HIV and prescription cannabis use were associated with higher satisfaction. CONCLUSIONS: The relationship between PTSD and tobacco use with lower satisfaction should be explored to augment pain outcomes. Higher satisfaction among individuals with HIV and prescription cannabis use presents potential research areas to guide CNCP management and reduce reliance on opioid therapies.

High-dose preoperative cholecalciferol to prevent post-thyroidectomy hypocalcaemia: A randomized, double-blinded placebo-controlled trial.

OBJECTIVE: Post-thyroidectomy hypocalcaemia is a significant cause of morbidity and prolonged hospitalization, usually due to transient parathyroid gland damage, treated with calcium and vitamin D supplementation. We present a randomized, double-blinded placebo-controlled trial of preoperative loading with high-dose cholecalciferol (300 000 IU) to reduce post-thyroidectomy hypocalcaemia. PATIENTS AND MEASUREMENTS: Patients (n = 160) presenting for thyroidectomy at tertiary hospitals were randomized 1:1 to cholecalciferol (300 000 IU) or placebo 7 days prior to thyroidectomy. Ten patients withdrew prior to surgery. The primary outcome was post-operative hypocalcaemia (corrected calcium <2.1 mmol/L in first 180 days). RESULTS: The study included 150 patients undergoing thyroidectomy for Graves' disease (31%), malignancy (20%) and goitre (49%). Mean pre-enrolment vitamin D was 72 ± 26 nmol/L. Postoperative hypocalcaemia occurred in 21/72 (29%) assigned to cholecalciferol and 30/78 (38%) participants assigned to placebo (P = 0.23). There were no differences in secondary end-points between groups. In pre-specified stratification, baseline vitamin D status did not predict hypocalcaemia, although most individuals were vitamin D replete at baseline. Post-hoc stratification by day 1 parathyroid hormone (PTH) (<10 pg/mL, low vs ≥10 pg/mL, normal) was explored due to highly divergent rates of hypocalcaemia in these groups. Using a Cox regression model, the hazard ratio for hypocalcaemia in the cholecalciferol group was 0.56 (95%CI 0.32-0.98, P = 0.04) after stratification for Day 1 PTH. Further clinical benefits were observed in these subgroups. CONCLUSIONS: Pre-thyroidectomy treatment with high-dose cholecalciferol did not reduce the overall rate of hypocalcaemia following thyroidectomy. In subgroups stratified by day 1 PTH status, improved clinical outcomes were noted.

Cerebral quantitative susceptibility mapping predicts amyloid-ß-related cognitive decline.

See Derry and Kent (doi:10.1093/awx167) for a scientific commentary on this article.The large variance in cognitive deterioration in subjects who test positive for amyloid-ß by positron emission tomography indicates that convergent pathologies, such as iron accumulation, might combine with amyloid-ß to accelerate Alzheimer's disease progression. Here, we applied quantitative susceptibility mapping, a relatively new magnetic resonance imaging method sensitive to tissue iron, to assess the relationship between iron, amyloid-ß load, and cognitive decline in 117 subjects who underwent baseline magnetic resonance imaging and amyloid-ß positron emission tomography from the Australian Imaging, Biomarkers and Lifestyle study (AIBL). Cognitive function data were collected every 18 months for up to 6 years from 100 volunteers who were either cognitively normal (n = 64) or diagnosed with mild cognitive impairment (n = 17) or Alzheimer's disease (n = 19). Among participants with amyloid pathology (n = 45), higher hippocampal quantitative susceptibility mapping levels predicted accelerated deterioration in composite cognition tests for episodic memory [ß(standard error) = -0.169 (0.034), P = 9.2 × 10-7], executive function [ß(standard error) = -0.139 (0.048), P = 0.004), and attention [ß(standard error) = -0.074 (0.029), P = 0.012]. Deteriorating performance in a composite of language tests was predicted by higher quantitative susceptibility mapping levels in temporal lobe [ß(standard error) = -0.104 (0.05), P = 0.036] and frontal lobe [ß(standard error) = -0.154 (0.055), P = 0.006]. These findings indicate that brain iron might combine with amyloid-ß to accelerate clinical progression and that quantitative susceptibility mapping could be used in combination with amyloid-ß positron emission tomography to stratify individuals at risk of decline.

Dietary Accumulation of Inorganic Selenium by a Larval Amphibian (Hyla chrysoscelis) and Influence on Accumulation of Background Mercury.

Larval gray tree frogs (Hyla chrysoscelis) were exposed to inorganic Se (SeO2) added to the diet (10.2 and 86.3 ug/g dw) and monitored for accumulation and effect. Background concentrations of Hg were also measured in food and carcasses to assess possible effects of Se on Hg accumulation. Selenium was accumulated in a dose dependent manner, and life stages did not differ. No effects of Se exposure were observed on survival, growth, or time to metamorphosis. Mercury concentrations in carcasses, resulting from background concentrations in food, were significantly affected by the presence of Se. In the high Se treatment, Hg concentrations were significantly decreased relative to those in the low Se treatment and the control. Our study suggests that exposure to inorganic Se as SeO2 at the concentrations tested do not elicit adverse biological effects, but exposure to relatively high concentrations of Se may reduce accumulation of Hg from food.

Dietary exposure of BDE-47 and BDE-99 and effects on behavior, bioenergetics, and thyroid function in juvenile red-eared sliders (Trachemys scripta elegans) and common snapping turtles (Chelydra serpentina).

Juvenile red-eared sliders (Trachemys scripta elegans) and snapping turtles (Chelydra serpentina) were fed food dosed with brominated diphenyl ether-47 (BDE-47) or BDE-99 for 6 mo beginning approximately 9 mo posthatch. During the exposure period, measurements of growth, bioenergetics, and behavior were made; thyroid function and accumulation were quantified postexposure. Whole-body concentrations of both congeners were lower in red-eared sliders compared with snapping turtles after 6 mo of exposure. Snapping turtles receiving BDE-47 had significantly elevated standard metabolic rates after 3 mo and 4 mo of exposure (p = 0.014 and p = 0.019, respectively). When exposed to BDE-99, red-eared sliders were slower to right themselves after having been inverted (p < 0.0001). Total glandular thyroxine concentrations were significantly reduced in red-eared sliders exposed to BDE-47 (mean control, 8080 ng/g; mean BDE-47, 5126 ng/g; p = 0.034). These results demonstrate that dietary exposure to BDE-47 and BDE-99 can elicit a suite of responses in 2 species of turtles, but that the red-eared slider appears to be a more sensitive species to the measured end points.

Among vitamin B12 deficient older people, high folate levels are associated with worse cognitive function: combined data from three cohorts.

BACKGROUND: Folate fortification of food aims to reduce the number of babies born with neural tube defects, but has been associated with cognitive impairment when vitamin B12 levels are deficient. Given the prevalence of low vitamin B12 levels among the elderly, and the global deployment of food fortification programs, investigation of the associations between cognitive impairment, vitamin B12, and folate are needed. OBJECTIVE: To investigate the associations of serum vitamin B12, red cell folate, and cognitive impairment. METHODS: Data were collected on 1,354 subjects in two studies investigating cognitive impairment, and from patients attending for assessment or management of memory problems in the Barwon region of south eastern Australia between 2001 and 2011. Eligible subjects who had blood measurements of vitamin B12 and red cell folate taken within six months of cognitive testing were included. Subjects with stroke or neurodegenerative diseases other than Alzheimer's disease were excluded. A Mini-Mental State Examination score of <24 was used to define impaired cognitive function. RESULTS: Participants with low serum vitamin B12 (<250 pmol/L) and high red cell folate (>1,594 nmol/L) levels were more likely to have impaired cognitive performance (adjusted odds ratio (AOR) 3.45, 95% confidence interval (CI): 1.60-7.43, p = 0.002) when compared to participants with biochemical measurements that were within the normal ranges. Participants with high folate levels, but normal serum vitamin B12, were also more likely to have impaired cognitive performance (AOR 1.74, 95% CI: 1.03-2.95, p = 0.04). CONCLUSIONS: High folate or folic acid supplements may be detrimental to cognition in older people with low vitamin B12 levels. This topic is of global significance due to the wide distribution of food fortification programs, so prospective studies should be a high priority.

Increased risk of cognitive impairment in patients with diabetes is associated with metformin.

OBJECTIVE: To investigate the associations of metformin, serum vitamin B12, calcium supplements, and cognitive impairment in patients with diabetes. RESEARCH DESIGN AND METHODS: Participants were recruited from the Primary Research in Memory (PRIME) clinics study, the Australian Imaging, Biomarkers and Lifestyle (AIBL) study of aging, and the Barwon region of southeastern Australia. Patients with Alzheimer disease (AD) (n=480) or mild cognitive impairment (n=187) and those who were cognitively intact (n=687) were included; patients with stroke or with neurodegenerative diseases other than AD were excluded. Subgroup analyses were performed for participants who had either type 2 diabetes (n=104) or impaired glucose tolerance (n=22). RESULTS: Participants with diabetes (n=126) had worse cognitive performance than participants who did not have diabetes (n=1,228; adjusted odds ratio 1.51 [95% CI 1.03-2.21]). Among participants with diabetes, worse cognitive performance was associated with metformin use (2.23 [1.05-4.75]). After adjusting for age, sex, level of education, history of depression, serum vitamin B12, and metformin use, participants with diabetes who were taking calcium supplements had better cognitive performance (0.41 [0.19-0.92]). CONCLUSIONS: Metformin use was associated with impaired cognitive performance. Vitamin B12 and calcium supplements may alleviate metformin-induced vitamin B12 deficiency and were associated with better cognitive outcomes. Prospective trials are warranted to assess the beneficial effects of vitamin B12 and calcium use on cognition in older people with diabetes who are taking metformin.

Dietary selenomethionine exposure induces physical malformations and decreases growth and survival to metamorphosis in an amphibian (Hyla chrysoscelis).

Selenium (Se) is an essential micronutrient with a narrow therapeutic concentration range. The relative toxicity of Se increases as it is biotransformed into organic compounds, primarily selenomethionine (SeMet), within the aquatic food chain. Effects of aquatic Se contamination are well quantified for many freshwater fish and aquatic bird species, but impacts on amphibians are not well known. This study investigated the responses of larval Cope's gray tree frogs (Hyla chrysoscelis) fed a diet enriched with one of two concentrations of SeMet (50.1 and 489.9 µg Se g(-1) dw [low and high groups, respectively]) by way of a food-limited (ration) or ad libitum (ad lib) feeding regimen. The high dose caused 100 % mortality during the larval period independent of resource provision levels. Regardless of feeding regimen, the low dose decreased larval survival and successful metamorphosis relative to control treatments. The low dose also induced rear limb deformities in ≤73 % of individuals initiating metamorphosis. Providing low-dose food by way of a rationed feeding regimen decreased observed toxicity, likely because of decreased dietary exposure to SeMet relative to the low ad lib treatment. Individuals from the low ration treatment had decreased wet mass at initiation and completion of metamorphic climax (Gosner stages 42 through 46) compared with those from the control ad lib treatment, indicating that resource limitation combined with Se exposure might negatively affect energy stores after metamorphosis. However, lipid content analyses of recently metamorphosed individuals did not reveal any influence of treatment or resource provision on energy stored as lipids. The mean tissue Se concentration of individuals that received the low dose and completed metamorphosis was significantly greater than that of control ad lib or ration individuals at the same developmental stage. This study demonstrates that larval exposure to dietary SeMet can decrease growth and survival and induce deformities in a developing amphibian. Furthermore, retention of Se body burdens through metamorphosis suggests that surviving individuals can transport Se accumulated from contaminated aquatic environments into terrestrial food webs.

Differential patterns of accumulation and depuration of dietary selenium and vanadium during metamorphosis in the Gray Treefrog (Hyla versicolor).

Selenium (Se) and vanadium (V) are contaminants commonly found in aquatic systems affected by wastes derived from fossil fuels. To examine their effects on a widely distributed species of amphibian, we exposed gray tree frogs (Hyla versicolor) to Se (as SeO2) or V (as NaVO3) in their diet from the early larval period to metamorphosis. Concentrations of Se in Se-enriched food were 1.0 (Se control), 7.5 (Se low), and 32.7 (Se high) µg/g dw. Concentrations of V in V-enriched food were 3.0 (V control), 132.1 (V low), and 485.7 (V high) µg/g dw. Although we observed bioaccumulation of both metals throughout the larval period, no effects on growth, survival, metabolic rate, or lipid content were observed. Se concentrations in tissues did not vary among life stages, neither in Se low nor Se high treatments, such that maximum accumulation had occurred by the mid-larval period. In addition, there was no evidence of depuration of Se in either the Se low or the Se high treatments during metamorphosis. A strikingly different pattern of accumulation and depuration occurred in V-exposed individuals. In treatments V low and V high, maximum body burdens occurred in "premetamorphs" (i.e., animals with developed forelimbs but in which tail resorption had not begun), whereas body burdens in animals having completed metamorphosis were much lower and similar to those in larvae. These results suggest that compared with Se-exposed animals, V-exposed animals were able to depurate a substantial amount of accumulated V during the metamorphic period. In an ecologic context, it appears that amphibians exposed to Se during the larval period may serve as a vector of the metal to terrestrial predators, yet potential transfer of accumulated V to predators would largely be restricted to the aquatic habitat.

Lack of biological effects of water accommodated fractions of chemically- and physically-dispersed oil on molecular, physiological, and behavioral traits of juvenile snapping turtles following embryonic exposure.

Snapping turtle (Chelydra serpentina) eggs were exposed to two concentrations of chemically- or physically-dispersed water accommodated fractions of weathered Arabian light crude oil (Low=0.5 and High=10 g oil/L water). Solutions were passed through nest substrate to simulate alterations in composition during percolation to egg depth. Hatchlings were raised for 13 months during which numerous endpoints were measured. Prior to percolation, total PAH ("tPAH"; the sum of 52 PAHs measured) in physically-dispersed oil fractions were similar (High, 43; Low 67 mg/L). Following percolation, tPAH was also similar in physically-dispersed fractions (High, 14; Low 24 mg/L). Addition of dispersant increased tPAH prior to percolation in the High treatment (302 mg/L) relative to Low (13 mg/L), but percolation resulted in nearly equal concentrations in both treatments (High, 30; Low, 22 mg/L) due to physical trapping of dispersed oil by the nest substrate. In both chemically- and physically-dispersed fractions, percolation reduced low molecular weight (MW) compounds such that embryos were exposed to primarily mid- to high MW compounds. Total PAH in eggs differed 15-fold between the chemically-dispersed High and physically-dispersed High treatments (560 and 36 microg/kg respectively), the former characterized by higher MW compounds than the latter. While eggs accumulated up to 560 microg/kg tPAH, we observed no effects on hatching success or hatchling/juvenile traits (DNA integrity, survival, growth, metabolism, energy storage, or behavior), our results demonstrate that PAH profiles are altered during percolation, suggesting that experiments with subsurface organisms should be designed to account for compositional changes that occur as the solutions percolate through the substrate.

Bioenergetic effects of aqueous copper and cadmium on the grass shrimp, Palaemonetes pugio.

Adult grass shrimp (Palaemonetes pugio) were exposed to either aqueous copper (ranging from 7.54 to 41.29 microg Cu(2+)/L) or cadmium (2.48- 6.55 microg Cd(2+)/L) for 14 days in laboratory experiments to quantify effects on survival and bioenergetic processes, including respiration, somatic growth, energy (lipid) storage, and food consumption. The lowest observed effect concentrations for mortality were 41.29 microg Cu(2+)/L or 6.55 microg Cd(2+)/L, expressed as free metal ion concentrations. Both copper and cadmium caused a decrease in respiration rate at concentrations of 7.54 to 41.29 microg Cu(2+)/L or 6.55 microg Cd(2+)/L. Exposure to copper (>or=27.03 microg Cu(2+)/L) resulted in negative somatic growth (i.e., weight loss). Cadmium exposure (6.17 microg Cd(2+)/L) caused a decrease in growth rate, relative to the control, but growth remained positive. Nonpolar lipid content and food consumption were not significantly affected by exposure to either copper or cadmium. Our results suggest that both copper and cadmium result in overall metabolic depression, decreasing energy allocation to both maintenance and production.

Chronic exposure of Leptocheirus plumulosus to Baltimore Harbor sediment: bioenergetic and population-level effects.

We investigated the long-term effects of contaminants in sediment from Baltimore Harbor, MD, USA, on a burrowing amphipod (Leptocheirus plumulosus) via a full life-cycle laboratory exposure. Contaminants in the Baltimore Harbor sediment included PAHs (10,800 ng/g), PCBs (152 ng/g), and heavy metals (including As, Cd, Cu, Pb, Hg, Ni, and Zn). Exposures were initiated with neonate amphipods, placed in microcosms containing either contaminated or reference sediment, and were maintained for 42 days, allowing ample time for the initial cohort to mature and reproduce. At the end of the exposure period, the populations of amphipods were surveyed to ascertain the number and size of amphipods in each size class (neonate, juvenile, and adult), and bioenergetic measurements were performed on adults, including metabolic rate, lipid content, and fecundity. Contaminated sediment from Baltimore Harbor caused lower growth and reproductive rates; in Baltimore Harbor sediment, the average dry weight of amphipod offspring in each size class was significantly lower and there were less than one-third as many individuals in each size class, compared to reference sediment. By the end of the exposure, the total amphipod biomass in Baltimore Harbor sediment was less than one quarter of that in reference sediment. On average, gravid females in reference sediment produced at least twice as many viable offspring as those in contaminated sediment. Adult male amphipods in Baltimore Harbor sediment possessed significantly lower lipid concentrations. Lipid content in neonates also appeared to be negatively affected by parental exposure to contaminants. Metabolic rate was elevated in adult amphipods exposed to Baltimore Harbor sediment. Overall, the results suggest that contaminated sediment conditions in the urban estuary may chronically affect L. plumulosus by diverting energy from production to maintenance pathways, resulting in slower growth and reduced fecundity, and ultimately leading to retarded population growth rates. The results of this study reinforce the need for long-term toxicological exposures to reveal chronic effects.

Maternal transfer of selenium in Alligator mississippiensis nesting downstream from a coal-burning power plant.

Selenium (Se) is embryotoxic in many oviparous vertebrates, but little is known about maternal transfer of Se and its impact in reptiles. Over a four-year period, we collected three clutches of eggs of the American alligator (Alligator mississippiensis) from a single nest at a site contaminated with Se and compared egg and hatchling Se concentrations and clutch viability from this nest to nests downstream from the contaminated site (two clutches from two nests) and at a reference site (two clutches from two nests). Eggs and hatchlings from the nest at the Se-contaminated site and downstream nests had elevated Se concentrations (2.1-7.8 ppm) and lower viability (30-54%) compared to reference nests (1.4-2.3 ppm and 67-74% viability), but Se concentrations did not exceed reproductive toxicity thresholds established for other oviparous vertebrates. Selenium concentrations were higher in chorioallantoic membranes of eggs from Se-contaminated sites, suggesting that this tissue may be useful as a nondestructive index of Se exposure for embryos of A. mississippiensis. Examination of these data suggests that further studies on uptake, accumulation, and reproductive success of crocodilian embryos exposed to excessive Se are warranted.