Moderate reductions in dissolved oxygen may compromise performance in an ecologically-important estuarine invertebrate

Coastal ecosystems, including estuaries, are increasingly pressured by expanding hypoxic regions as a result of human activities such as increased release of nutrients and global warming. Hypoxia is often defined as oxygen concentrations below 2 mL O2 L−1. However, taxa vary markedly in their sensitivity to hypoxia and can be affected by a broad spectrum of low oxygen levels. To better understand how reduced oxygen availability impacts physiological and molecular processes in invertebrates, we investigated responses of an estuarine amphipod to an ecologically-relevant level of moderate hypoxia (~2.6 mL O2 L−1) or severe hypoxia (~1.3 mL O2 L−1). Moderate hypoxia elicited a reduction in aerobic scope, and widespread changes to gene expression, including upregulation of metabolic genes and stress proteins. Under severe hypoxia, a marked hyperventilatory response associated with maintenance of aerobic performance was accompanied by a muted transcriptional response. This included a return of metabolic genes to baseline levels of expression and downregulation of transcripts involved in protein synthesis, most of which indicate recourse to hypometabolism and/or physiological impairment. We conclude that adverse ecological effects may occur under moderate hypoxia through compromised individual performance and, therefore, even modest declines in future oxygen levels may pose a significant challenge to coastal ecosystems

Scarlet fever associated with hepatitis : a report of two cases

Infection with group A beta-hemolytic streptococci (GABHS) is the most common bacterial cause of acute pharyngitis and tonsillitis beyond infancy. We report on two patients with scarlet fever associated with hepatitis. The patients (boys aged 6 and 7 years) both presented with a scarlatiniform rash, dark urine and light-colored stools. Laboratory studies revealed elevated liver transaminases and negative antibody tests against hepatitis viruses A, B and C, cytomegalovirus and Epstein-Barr virus. Both patients were treated with antibiotics and recovered completely within a few days. Although the association between scarlet fever and hepatitis has been known for many decades, the pathogenesis is still unknown. Physicians treating patients with group A beta-hemolytic streptococcal infections should be aware of possible hepatic involvement

Kongenitale Langerhans-Zellen-Histiozytose unter dem klinischen Bild einer Varizelleninfektion

We report on a preterm infant (33rd gestational week) with a varicella-like congenital rash, which initially appeared to respond to therapy with acyclovir. At the age of 3 weeks, lesions were in different stages of evolution and still resembled a varicella zoster virus (VZV) infection. However, since proof of VZV infection was lacking and new lesions erupted at the age of 4 weeks, a skin biopsy was performed which revealed a diagnosis of Langerhans cells histiocytosis. Therapy with prednisone resulted in prompt healing of the lesions. DISCUSSION: Congenital Langerhans cell histiocytosis is rare and symptoms may vary substantially from case to case. Like in our observation it may be confused with congenital varicella. In case of congenital skin lesions of uncertain etiology a skin biopsy should be performe

Metalloprotease-mediated shedding of enzymatically active mouse ecto-ADP-ribosyltransferase ART2.2 upon T cell activation [In Process Citation]

T cells proteolytically shed the ectodomains of several cell surface proteins and, thereby, can alter their responsiveness and can release soluble intercellular regulators. ART2.2 is a GPI-anchored ecto-ADP-ribosyltransferase (ART) related to ADP-ribosylating bacterial toxins. ART2.2 is expressed exclusively by mature T cells. Here we show that ART2.2 is shed from the cell surface in enzymatically active form upon activation of T cells. Shedding of ART2.2 resembles that of L-selectin (CD62L) in dose response, kinetics of release, and sensitivity to the metalloprotease inhibitor Immunex Compound 3, suggesting that ART2.2, like CD62L, is cleaved by TNF-alpha-converting enzyme or by another metalloprotease. ART2.2 shed from activated T cells migrates slightly faster in SDS-PAGE analyses than does ART2.2 released upon cleavage of the GPI anchor. This indicates that shedding of ART2.2 is mediated by proteolytic cleavage close to its membrane anchor. Shed ART2.2 is enzymatically active and ADP-ribosylates several substrates in vitro. Thus, shedding of ART2.2 releases a potential intercellular regulator. Finally, using a new FACS assay for monitoring ADP-ribosylation of cell surface proteins, we demonstrate that shedding of ART2.2 correlates with a reduced sensitivity of T cell surface proteins to ADP-ribosylation. Our findings suggest that by shedding ART2.2 the activated T cell not only releases a potential intercellular regulator but also may alter its responsiveness to immune regulation by ART2.2-mediated ADP-ribosylation of cell surface proteins