Mercury concentrations in bald eagles across an impacted watershed in Maine, USA

Mercury (Hg) exposure was evaluated in bald eagles (Haliaeetus leucocephalus) in the lower Penobscot River watershed (PRW) in Maine to assess whether Hg discharges from a chlor-alkali plant (HoltraChem) influenced Hg concentrations in nestling tissues. Mean Hg concentrations in nestling blood and breast feathers sampled in marine and estuarine areas potentially contaminated with Hg from HoltraChem (the potential Hg impact zone) were significantly greater than those from reference sites spanning the Maine coast. To place Hg exposure in the potential Hg impact zone into a broader context, Hg exposure in bald eagle nestlings from four habitat types in the PRW was assessed. Mercury concentrations varied significantly across habitat types within the PRW, generally following the pattern: marine=estuarine<freshwater river<lake. While findings suggest that Hg inputs from HoltraChem elevated Hg concentrations in eagles in the potential Hg impact zone, those Hg concentrations were still significantly lower than those of nestlings raised in freshwater river and lake habitats in the PRW and elsewhere in Maine not contaminated by HoltraChem. Breast feathers had 31% higher statistical power to detect Hg differences among habitat types compared to nestling blood, demonstrating their higher value in biomonitoring efforts. Nestling tissue Hg concentrations in the PRW were within the range of reported Hg values for bald eagles, but were generally higher than most population comparisons within habitats. Mercury concentrations in lake-nesting bald eagles in the PRW were impacted primarily by inputs from atmospheric deposition, and Hg exposure in nestlings associated with this habitat type in the PRW often had similar or higher Hg exposure than those associated with point sources elsewhere. Mercury concentrations in bald eagle nestlings and a small sample of adults in our study commonly exceeded levels associated with adverse health effects in other bird species.

Changes in mercury exposure of marine birds breeding in the Gulf of Maine, 2008-2013

Mercury is a potent contaminant that can disrupt an organism's behavior and physiology, ultimately affecting reproductive success. Over the last 100 years, environmental deposition of anthropogenic sourced mercury has increased globally, particularly in the U.S. Northeast region. Marine birds are considered effective bioindicators of ecosystem health, including persistent marine contaminants. Goodale et al. (2008) found that mercury exposure exceeded adverse effects levels in some marine bird species breeding across the Gulf of Maine. We re-examined mercury contamination in four species identified as effective bioindicators. Compared with the previous sampling effort, inshore-feeding species showed significant increases in mercury exposure, while one pelagic-feeding species remained stable. This suggests that a major shift may have occurred in methylmercury availability in inshore waters of the Gulf of Maine. Understanding environmental mercury trends in the Gulf of Maine, and its significance to marine birds and other taxa will require a dedicated, standardized, long-term monitoring scheme.

Mitochondrial H2O2 regulates the angiogenic phenotype via PTEN oxidation

Recent studies have demonstrated that the tumor suppressor PTEN (phosphatase and tensin homolog deleted from chromosome 10), the antagonist of the phosphosphoinositol-3-kinase (PI3K) signaling cascade, is susceptible to H2O2-dependent oxidative inactivation. This study describes the use of redox-engineered cell lines to identify PTEN as sensitive to oxidative inactivation by mitochondrial H2O2. Increases in the steady state production of mitochondrial derived H2O2, as a result of manganese superoxide dismutase (Sod2) overexpression, led to PTEN oxidation that was reversed by the coexpression of the H2O2-detoxifying enzyme catalase. The accumulation of an oxidized inactive fraction of PTEN favored the formation of phosphatidylinositol 3,4,5-triphosphate at the plasma membrane, resulting in increased activation of Akt and modulation of its downstream targets. PTEN oxidation in response to mitochondrial H2O2 enhanced PI3K signaling, leading to increased expression of the key regulator of angiogenesis, vascular endothelial growth factor. Overexpression of PTEN prevented the H2O2-dependent increase in vascular endothelial growth factor promoter activity and immunoreactive protein, whereas a mutant PTEN (G129R), lacking phosphatase activity, did not. Furthermore, mitochondrial generation of H2O2 by Sod2 promoted endothelial cell sprouting in a three-dimensional in vitro angiogenesis assay that was attenuated by catalase coexpression or the PI3K inhibitor LY2949002. Moreover, Sod2 overexpression resulted in increased in vivo blood vessel formation that was H2O2-dependent as assessed by the chicken chorioallantoic membrane assay. Our findings provide the first evidence for the involvement of mitochondrial H2O2 in regulating PTEN function and the angiogenic switch, indicating that Sod2 can serve as an alternative physiological source of the potent signaling molecule, H2O2.

Rupture of the peroneus longus tendon in a military athlete

A 38-year-old active-duty Marine Corps officer with a history of ankle instability presented to the orthopedic clinic complaining of left lateral ankle and leg pain. A diagnosis of rupture of the tendon of the peroneus longus was made. This is an unusual diagnosis in an active Marine Corps officer. Surgical treatment markedly improved his symptoms.

Therapeutic recreation programmes for children with epilepsy

Amongst children with epilepsy, research has shown that most have a negative self-concept and consequently a low level of self-esteem. This elusive concept of the self is constantly being assessed and reassessed by each child throughout the process of social development. Early literature has suggested that children with disabilities, especially chronic medical or biological disabilities, typified by epilepsy and diabetes, are more susceptible to the development of psychopathology and negative self-concepts. This paper reports that intervention in the form of therapeutic recreation programmes can help rectify this problem of negative self-concept and low self-esteem in children with epilepsy. The Piers-Harris Self Concept Scale, a Self Report Inventory on six dimensions of self-concept, was assessed both pre- and post-therapeutic recreational intervention to show significant improvement in the child's self-concept and acceptance of their epilepsy. Educational components within the programme have demonstrated significant learning and increased treatment compliance--particularly with long-term medications. The Adolescent Psychosocial Seizure Inventory, an adolescent version of the Washington Psycho-Social Seizure Inventory (WPSI), both of which have been validated as a reliable clinical assessment for use in Australia, has provided further evidence to suggest that improvements occur in children's self-concept as a consequence of therapeutic recreation, however use of this protocol appears limited to adolescents over the age of 13 years.