Nuclear weapons, a continuing threat to health

Radiation as a risk factor for cardiovascular disease

Abstract population are ubiquitous background radiation and medical exposure of patients. From the early 1980s to 2006, the average dose per individual in the United States for all sources of radiation increased by a factor of 1.7-6.2 mSv, with this increase due to the growth of medical imaging procedures. Radiation can place individuals at an increased risk of developing cardiovascular disease. Excess risk of cardiovascular disease occurs a long time after exposure to lower doses of radiation as demonstrated in Japanese atomic bomb survivors. This review examines sources of radiation (atomic bombs, radiation accidents, radiological terrorism, cancer treatment, space exploration, radiosurgery for cardiac arrhythmia, and computed tomography) and the risk for developing cardiovascular disease. The evidence presented suggests an association between cardiovascular disease and exposure to low-to-moderate levels of radiation, as well as the well-known association at high doses. Studies are needed to define the extent that diagnostic and therapeutic radiation results in increased risk factors for cardiovascular disease, to understand the mechanisms involved, and to develop strategies to mitigate or treat radiation-induced cardiovascular disease.

Hematopoietic radiation syndrome in the Gottingen minipig

Additional large animal models for the acute radiation syndrome (ARS) would facilitate countermeasure development. We demonstrate here that Gottingen minipigs develop hematopoietic ARS symptoms similar to those observed in canines, non-human primates (NHPs) and humans. Dosimetry for whole-body γ irradiation (0.6 Gy/min) was performed using electronic paramagnetic resonance (EPR) with alanine; National Institute of Standards and Technology (NIST)-calibrated alanine pellets and water-filled Plexiglas phantoms were used. After irradiations of 1.6-2.0 Gy, blood pancytopenia was observed for several weeks, accompanied by the characteristic ARS stages: prodromal symptoms, latent period, illness and recovery or morbidity. Morbidity occurred between days 14 and 27, with a preliminary LD(50/30) estimate between 1.7 and 1.9 Gy. The criterion of whether platelet counts were <200 × 10(3)/µl 7 days postirradiation predicted whether animals would survive in 18 out of 20 cases. The degree of granulocytosis 3 h postirradiation was inversely correlated with survival. Animals euthanized based on preset morbidity criteria displayed signs of multi-organ dysfunction, including widespread internal hemorrhage and alterations in organ function reflected in blood chemistry. Circulating C-reactive protein (CRP), a marker for inflammation, became elevated within hours after irradiation, subsided after several days, and increased again after 14 days. The results support further development of the Gottingen minipig as a model for ARS.

5-androstenediol improves survival in clinically unsupported rhesus monkeys with radiation-induced myelosuppression

We previously reported that five daily intramuscular doses of 5-androstenediol (AED), a naturally occurring adrenal steroid hormone, stimulated multilineage recovery of bone marrow in rhesus monkeys with radiation-induced myelosuppression after 4.0 Gy total body irradiation (TBI). Here we report the effect of AED on the survival of eighty rhesus macaques that received a 6.0 Gy dose of TBI in four sequential pilot studies. The drug was administered intramuscularly, based on body weight, 2-4 h after irradiation and continued once daily for a total of five injections. No clinical support in the form of antibiotics or transfusions was given to the animals at any time during the study. Five of the 40 (12.5%) treated animals died, compared to 13 of 40 (32.5%) of the animals in the control group (p=0.032). The combination of accumulated days of thrombocytopenia (<20,000 platelets/microL) up to day 14 (before the first death) together with treatment, accurately predicts mortality (p<0.001). The compound significantly reduced the duration of thrombocytopenia and neutropenia (p<0.01). The accumulation of days of neutropenia (ANC<500 cells/microL) up to day 14 plays no major role in predicting death. AED shows significant activity in irradiated primates with acute hematopoietic radiation syndrome.

Caring for victims of nuclear and radiological terrorism

As primary care providers, we must consider the manifestations of radiation sickness and syndromes when managing radiological injuries. Assessment and treatment regimens include unique sample handling requirements to avoid self-contamination and further contamination of the environment. Addressing psychological aspects and the needs of pediatric and geriatric populations is also important for effective treatment.