Delineation of blacktip shark (Carcharhinus limbatus) nursery habitats in the north-western Gulf of Mexico

Coevolution with predators leads to the use of low-risk habitats by many prey species, which promotes survival during early developmental phases. These nurseries are valued by conservation and management agencies because of their contributions to adult populations. However, the physical and geographic characteristics, like shallow depths and isolation from other marine habitats, that restrict access to predators and thereby reduce risk to juvenile animals can also limit scientific research. Consequently, many nursery habitats are still unidentified and understudied. Here we used gillnet monitoring from 1982 to 2018 to delineate blacktip shark (Carcharhinus limbatus) nurseries in the north-western Gulf of Mexico and elucidated their physical, environmental and biological characteristics. Nursery habitats within estuaries (<2% of spatial area) were proximate to the Gulf of Mexico and exhibited significantly lower variability in salinity than non-nurseries. However, relative abundances of predators and prey were not significant delineators of nursery habitats. As such, food and risk may not influence juvenile blacktip habitat use as expected. Alternatively, reduced osmoregulatory stress attributed to predictable environments likely provides advantageous conditions for blacktips to develop foraging and antipredator tactics, which is vital prior to the winter migration of juvenile sharks into the Gulf of Mexico.

Cath lab nursing – it's a risky business

Background

The continuing evolution of transcatheter therapies and improvements in x-ray imaging technology has led to an exponential increase in the numbers and complexity of fluoroscopically guided cardiac procedures. There is also heightened concern regarding the associated increase in radiation exposure to the patients and staff. The effects of x-rays at high doses is well documented, but the effects of protracted exposure to low levels of radiation are less well understood (1) and may include malignancy (2), circulatory disease (3), and chromosomal aberrations (4). The link between the occupational exposure in the cath lab and the development of posterior cataracts has been well established (5).

Dose levels to the doctors performing the procedures has been a focus of previous research, but there is recent evidence that nurses may be exposed to similar, if not higher levels of occupational radiation. The lack of literature explicitly investigating nursing dose is concerning.

Purpose

This prospective single-centre observational study compared the occupational temple dose to staff during cardiac angiography.

Methods

Radiation levels were measured via dosimeter badges worn near the left temple of the cardiologist (n=14), scrub (n=28), and scout (n=29) nurse between Feb 2017 and August 2019. Procedures were categorised into coronary angiography (CA) and percutaneous coronary intervention (PCI). Cases that included any supplementary investigations such as left-ventriculogram, fractional flow reserve measurement, graft vessels, right heart study, rotablation, or aortograms were classified “CA+” or “PCI+”. Non-parametric statistical testing was performed.

Results

There is a correlation between higher dose to the scrub nurse during CA and CA+ when compared with the cardiologist (p=0.001). Interventional procedures were associated with a higher dose to the cardiologist when compared to the scrub nurse (p=0.000), and increased dose to the scout nurse (p&lt;0.000) when compared to scout dose during CA and CA+.

Conclusion

The previously held assumption that the doctor is exposed to higher levels of radiation during angiography may no longer be applicable in modern departments, possibly due to the increased awareness and appropriate use of ceiling-mounted lead shielding. Nurses are typically involved in a greater number of procedures and have a potentially extended career in the cath lab setting compared with doctors. Hence, workplaces must provide adequate training and protective equipment to nursing staff to facilitate all team members to minimise the potentially detrimental effects of occupational radiation exposure.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The first author would like to acknowledge the PhD study support provided via an Australian Government Research Training Program Scholarship Occupational dose during angiography

Multibiomarker assessment of cerium dioxide nanoparticle (nCeO2) sublethal effects on two freshwater invertebrates, Dreissena polymorpha and Gammarus roeseli

Cerium nanoparticles (nCeO2) are widely used in everyday products, as fuel and paint additives. Meanwhile, very few studies on nCeO2 sublethal effects on aquatic organisms are available. We tried to fill this knowledge gap by investigating short-term effects of nCeO2 at environmentally realistic concentrations on two freshwater invertebrates; the amphipod Gammarus roeseli and the bivalve Dreissena polymorpha, using an integrated multibiomarker approach to detect early adverse effects of nCeO2 on organism biology. Differences in the behaviour of the organisms and of nanoparticles in the water column led to differential nCeO2 bioaccumulations, G. roeseli accumulating more cerium than D. polymorpha. Exposure to nCeO2 led to decreases in the size of the lysosomal system, catalase activity and lipoperoxidation in mussel digestive glands that could result from nCeO2 antioxidant properties, but also negatively impacted haemolymph ion concentrations. At the same time, no strong adverse effects of nCeO2 could be observed on G. roeseli. Further experiments will be necessary to confirm the absence of severe nCeO2 adverse effects in long-term environmentally realistic conditions.

One-year monitoring of core biomarker and digestive enzyme responses in transplanted zebra mussels (Dreissena polymorpha)

A 12-month active biomonitoring study was performed in 2008-2009 on the Vesle river basin (Champagne-Ardenne, France) using the freshwater mussel Dreissena polymorpha as a sentinel species; allochthonous mussels originating from a reference site (Commercy) were exposed at four sites (Bouy, Sept-Saulx, Fismes, Ardre) within the Vesle river basin. Selected core biomarkers (acetylcholinesterase (AChE) activity, glutathione-S transferase (GST) activity, metallothionein concentration), along with digestive enzyme activities (amylase, endocellulase) and energy reserve concentrations (glycogen, lipids), were monitored throughout the study in exposed mussels. At the Fismes and Ardre sites (downstream basin), metallic and organic contamination levels were low but still high enough to elicit AChE and GST activity induction in exposed mussels (chemical stress); besides, chemical pollutants had no apparent deleterious effects on mussel condition. At the Bouy and Sept-Saulx sites (upstream basin), mussels obviously suffered from adverse food conditions which seriously impaired individual physiological state and survival (nutritional stress); food scarcity had however no apparent effects on core biomarker responses. Digestive enzyme activities responded to both chemical and nutritional stresses, the increase in energy outputs (general adaptation syndrome-downstream sites) or the decrease in energy inputs (food scarcity-upstream sites) leading to mid- or long-term induction of digestive carbohydrase activities in exposed mussels (energy optimizing strategy). Complex regulation patterns of these activities require nevertheless the use of a multi-marker approach to allow data interpretation. Besides, their sensitivity to natural confounding environmental factors remains to be precised.

Disseminated intravascular coagulopathy due to salmonellosis precipitated by blunt trauma

We have reported an unusual cause of disseminated intravascular coagulopathy (DIC) in a patient with multiple injuries from blunt trauma. The source of continued hemorrhage remained elusive despite laparotomy and thoracotomy. Bleeding appeared to resolve only after discovery and treatment of infection due to Salmonella enteritidis, which the patient had contracted during a recent trip to Mexico.

Cardiovascular evaluation in blunt thoracic trauma using transesophageal echocardiography (TEE)

Blunt chest trauma can result in significant cardiothoracic injury, which can include cardiac contusion, aortic injury, and myocardial valvular injury. Nineteen patients with no prior history of cardiac abnormalities who sustained severe blunt chest trauma and had widening of the mediastinum on chest radiographs were prospectively evaluated using transesophageal echocardiography (TEE). In each instance TEE was performed without difficulty, excellent images were obtained of the aorta and heart, and no complications were noted. Abnormalities were seen in 12 (63%) patients, with hypokinetic regional wall motion consistent with cardiac contusion demonstrated in five (26%) patients. Tricuspid regurgitation was found in three (16%) patients, and aortic and mitral regurgitation in one (5%) patient each. Aortic wall hematomas were seen in two patients, one of whom had an intimal tear on aortography, and a pericardial effusion was seen in one patient with an aortic intimal tear confirmed angiographically. Thus TEE can be performed safely in the acute setting of patients sustaining severe blunt chest trauma and yield useful information with respect to cardiovascular function and the aorta.