Underground Radiobiology: A Perspective at Gran Sasso National Laboratory.

Scientific community and institutions (e. g., ICRP) consider that the Linear No-Threshold (LNT) model, which extrapolates stochastic risk at low dose/low dose rate from the risk at moderate/high doses, provides a prudent basis for practical purposes of radiological protection. However, biological low dose/dose rate responses that challenge the LNT model have been highlighted and important dowels came from radiobiology studies conducted in Deep Underground Laboratories (DULs). These extreme ultra-low radiation environments are ideal locations to conduct below-background radiobiology experiments, interesting from basic and applied science. The INFN Gran Sasso National Laboratory (LNGS) (Italy) is the site where most of the underground radiobiological data has been collected so far and where the first in vivo underground experiment was carried out using Drosophila melanogaster as model organism. Presently, many DULs around the world have implemented dedicated programs, meetings and proposals. The general message coming from studies conducted in DULs using protozoan, bacteria, mammalian cells and organisms (flies, worms, fishes) is that environmental radiation may trigger biological mechanisms that can increase the capability to cope against stress. However, several issues are still open, among them: the role of the quality of the radiation spectrum in modulating the biological response, the dependence on the biological endpoint and on the model system considered, the overall effect at organism level (detrimental or beneficial). At LNGS, we recently launched the RENOIR experiment aimed at improving knowledge on the environmental radiation spectrum and to investigate the specific role of the gamma component on the biological response of Drosophila melanogaster.

Predictors and prognosis of delirium among older subjects in cardiac intensive care unit: focus on potentially preventable forms.

BACKGROUND: Delirium is a common and potentially preventable condition in older individuals admitted to acute and intensive care wards, associated with negative prognostic effects. Its clinical relevance is being increasingly recognised also in cardiology settings. The aim of the present study was to assess the prevalence, incidence, predictors and prognostic role of delirium in older individuals admitted to two cardiology intensive care units. METHODS: All patients aged over 65 years consecutively admitted to the two participating cardiology intensive care units were enrolled. Assessment on admission included acute physiological derangement (modified rapid emergency medicine score, REMS), chronic comorbidity, premorbid disability and dementia. The Confusion Assessment Method-Intensive Care Unit was applied daily for delirium detection. RESULTS: Of 497 patients (40% women, mean age 79 years), 18% had delirium over the entire cardiology intensive care unit course, half of whom more than 24 hours after admission (incident delirium). Advanced age, a main diagnosis of ST-segment elevation myocardial infarction or acute respiratory failure, modified REMS, comorbidity and dementia were independent predictors of delirium. Adjusting for patient's features on admission, incident delirium was predicted by invasive procedures (insertion of peripheral arterial catheter, urinary catheter, central venous catheter, naso-gastric tube and intra-aortic balloon pump). In a logistic regression model, delirium was an independent predictor of inhospital mortality (odds ratio 3.18, 95% confidence interval 1.02, 9.93). CONCLUSIONS: Eighteen per cent of older cardiology intensive care unit patients had delirium, with half of the cases being incident, thus potentially preventable. Invasive procedures were independently associated with incident delirium. Delirium was an independent predictor of inhospital mortality. Awareness of delirium should be increased in the cardiology intensive care unit setting and prevention studies are warranted.

Invasive strategy in non-ST-segment elevation acute coronary syndrome: What should be the benchmark target in the real world patients? Insights from BLITZ-4 Quality Campaign.

AIMS: To define a benchmark target for an invasive strategy (IS) rate appropriate for performance assessment in intermediate-to-high risk non-ST-segment elevation acute coronary syndromes (NSTE-ACS). METHODS AND RESULTS: During the BLITZ-4 campaign, which aimed at improving the quality of care in 163 Italian coronary care units, 4923/5786 (85.1%) of consecutive patients admitted with NSTE-ACS with troponin elevation and/or dynamic ST-T changes on the electrocardiogram were managed with IS. The reasons driving the choice (RDC) for a conservative strategy (CS) in the remaining 863 patients were prospectively recorded. In 33.8%, CS was mandatory because of patients refusal, known coronary anatomy or death before coronary angiography; in 52.8% it was clinically justified because of active stroke, bleeding, advanced frailty, severe comorbidities, contraindication to antiplatelet therapy or because they were considered to be at low risk; only in 13.4% the reasons, such as renal failure, advanced age or other, were less stringent. As compared to patients undergoing IS, those in the CS were 12years older and had significantly more severe comorbidities. The in-hospital and 6-month all-cause mortality were 9.0% vs 0.9% and 22.0% vs 3.9% in CS and IS groups respectively (p<0.0001 for both). CONCLUSION: As the RDC for CS were clinically correct in vast majority of cases the observed 85% invasive strategy rate may be considered as the desirable benchmark target in patients with NSTE-ACS. For the same reason, it remains questionable if the higher rate of IS could have improved the prognosis in CS patients, despite their highly unfavorable prognosis.