Triangular gold nanoparticles modify shell characteristics and increase antioxidant enzyme activities in the clam Ruditapes decussatus.

CONTEXT: Nanoparticles may cause adverse environmental effects but there is limited information on their interactions with marine organisms. OBJECTIVE: Our aim was to examine the effects of triangular gold nanoparticles (Tr-Au NPs) on the clam, Ruditapes decussatus. MATERIALS AND METHODS: Clams were exposed to Tr-Au1 = 5 µg/L and Tr-Au2 = 10 µg/L for 2 and 7 days. Effects on shell structure were investigated. Superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GST) activities, protein carbonyl levels and malondialdehyde content were used to assess biochemical status. RESULTS: Transmission electron microscopy (TEM) and electron dispersive X-ray microanalysis (EDX) showed that Tr-Au NPs modified shell structure and morphology. Tr-Au NPs size increased forming aggregate particles. Tr-Au NPs increased SOD, CAT and GST activities in gill and digestive gland in a concentration- and time-dependent manner indicating defence against oxidative stress. Enhanced lipid peroxidation and protein carbonyl levels confirmed oxidative stress. CONCLUSION: Tr-Au NPs cause oxidative stress and affect shell structure of clams. These findings may have relevance to other marine species.

Imaging-guided Parenchymal Liver Biopsy: How We Do It.

Liver biopsies are performed for both focal and nonfocal lesions (parenchymal). In our center, majority of liver biopsies are performed for parenchymal liver disease. Parenchymal liver biopsy plays a key role in the diagnosis of various diffuse liver dysfunctions. Results of the biopsy help grade the disease, facilitating prognostication, which helps in planning specific treatment strategies. Imaging guidance is gaining wide acceptance as the standard procedure. Ultrasound (US) guidance is currently considered the most cost-effective and safe way to perform parenchymal liver biopsies. Radiologists worldwide and particularly in the United States are increasingly performing this procedure. Radiologists performing biopsies generally use the cutting needle. Different needle sizes, techniques and preference for biopsy of the right or left lobe have been described. We attribute these preferences to prior training and individual radiologist's comfort level. We describe the algorithm followed at our institution for performing percutaneous US-guided parenchymal liver biopsy. While clinical societies have recommended a minimum of 40 liver biopsies as a requirement for proficiency of clinicians, specific to radiology trainees/fellows interested in pursuing a career in intervention, we feel a total of 20 liver biopsies (includes assisted and independently performed biopsies under supervision) should be adequate training.

Assessment of a glutathione S-transferase and related proteins in the gill and digestive gland of Mytilus edulis (L.), as potential organic pollution biomarkers.

The response of the glutathione S-transferase (GST, EC 2.5.1.18) and related proteins of Mytilus edulis to environmental pollution load was assessed. Mussels were reciprocally transplanted between an industrial estuary (Douglas), a rural estuary (Youghal) and a m arine site (Bantry). In addition, m ussels were sam pled along a pollution gradient in an estuary receiving leather tannery effluent (Colligan). These latter m ussels were previously shown to be subject to oxidative stress resulting from the discharges. GST specific activity of cytosolic extracts from the gill and digestive gland tissues was determ ined for all anim als. Specific activity was shown to vary significantly in anim als from different sites, with highest specific activity always observed in sam ples (local and transplanted) taken from the industrial site. By com parison, the m ussels exposed to tannery discharges displayed no significant alteration in GST specific activity. Total intracellular glutathione (GSH) was also determ ined for sam ples taken from the Douglas and Youghal estuaries but no correlation with pollution load was observed. Using FPLC analysis, we observed no specific effect on the relative levels of the GST and the individual GST related proteins in gill or digestive gland sam ples from local or reciprocally transplanted anim als from Douglas or Youghal. The increase in GST specific activity observed in samples from the industrial estuary are indicative of a possible, specific inductive agent at this site. The results from the tannery site, by com parison, indicate that general oxidative stress does not result in elevated G ST specific activity in M. edulis.