Single CT Scan Prolongs Survival by Extending Cancer Latency in Trp53 Heterozygous Mice.

There is growing concern over the effects of medical diagnostic procedures on cancer risk. Although numerous studies have demonstrated that low doses of ionizing radiation can have protective effects including reduced cancer risk and increasing lifespan, the hypothesis that any radiation exposure increases cancer risk still predominates. In this study, we investigated cancer development and longevity of cancer-prone Trp53 mice exposed at 7-8 weeks of age to a single 10 mGy dose from either a diagnostic CT scan or gamma radiation.

Multiple CT Scans Extend Lifespan by Delaying Cancer Progression in Cancer-Prone Mice.

Computed tomography (CT) scans are a routine diagnostic imaging technique that utilize low-energy X rays with an average absorbed dose of approximately 10 mGy per clinical whole-body CT scan. The growing use of CT scans in the clinic has raised concern of increased carcinogenic risk in patients exposed to ionizing radiation from diagnostic procedures. The goal of this study was to better understand cancer risk associated with low-dose exposures from CT scans.

The influence of Trp53 in the dose response of radiation-induced apoptosis, DNA repair and genomic stability in murine haematopoietic cells.

Apoptotic and DNA damage endpoints are frequently used as surrogate markers of cancer risk, and have been well-studied in the Trp53+/- mouse model. We report the effect of differing Trp53 gene status on the dose response of ionizing radiation exposures (0.01-2 Gy), with the unique perspective of determining if effects of gene status remain at extended time points.

Low-dose radiation from 18F-FDG PET does not increase cancer frequency or shorten latency but reduces kidney disease in cancer-prone Trp53+/- mice.

There is considerable interest in the health effects associated with low-level radiation exposure from medical imaging procedures. Concerns in the medical community that increased radiation exposure from imaging procedures may increase cancer risk among patients are confounded by research showing that low-dose radiation exposure can extend lifespan by increasing the latency period of some types of cancer. The most commonly used radiopharmaceutical for positron emission tomography (PET) scans is 2-[(18)F] fluoro-2-deoxy-d-glucose ((18)F-FDG), which exposes tissue to a low-dose, mixed radiation quality: 634 keV β+ and 511 keV γ-rays.

Biological effects and adaptive response from single and repeated computed tomography scans in reticulocytes and bone marrow of C57BL/6 mice.

This study investigated the biological effects and adaptive responses induced by single and repeated in vivo computed tomography (CT) scans. We postulated that, through the induction of low-level oxidative stress, repeated low-dose CT scans (20 mGy, 2 days/week, 10 weeks) could protect mice (C57BL/6) from acute effects of high-dose radiation (1 Gy, 2 Gy). The micronucleated reticulocyte (MN-RET) count increased linearly after exposure to single CT scans of doses ranging from 20 to 80 mGy (P = 0.

Exercise-induced protection of bone marrow cells following exposure to radiation.

The hormetic effects of exercise training have previously been shown to enhance cellular protection against oxidative stress. Therefore, adaptations to exercise training may attenuate the harmful effects of radiation induced by oxidative stress. Flow cytometric analysis of genotoxicity (γH2AX foci and micronucleated reticulocytes (MN-RET)) and cytotoxicity (apoptosis and percentage of reticulocytes) were conducted on bone marrow cells isolated from acutely exercised (Acute EX), exercise-trained (EX), and sedentary (SED) mice following 1 and 2 Gy radiation challenges in vitro.

Exercise training enhances the skeletal muscle response to radiation-induced oxidative stress.

Overproduction of reactive oxygen species (ROS) can damage cellular macromolecules and lead to cellular dysfunction or death. Exercise training induces beneficial adaptations in skeletal muscle that may reduce cellular damage from exposure to ROS. To determine the response of exercise-conditioned muscle to acute increases in ROS, four groups of mice were used: non-trained (NT, n = 12); NT + high-dose radiation (HDR, n = 3); exercise-trained (EX, n = 13, 3 days/week for 10 weeks, 10 m/min to 18 m/min); and EX + HDR (n = 3/group).

Pulmonary alveolar proteinosis in a 67-year-old woman with Wegener's granulomatosis.

Mycophenolate mofetil (MM) is commonly used in patients with autoimmune diseases or who have undergone transplantation. Common side effects of MM include anemia, leukopenia, mucositis and opportunistic infections. We report an unusual case of pulmonary alveolar proteinosis (PAP) in a 67-year-old woman on MM for Wegener's granulomatosis (WG).

Symptomatic persistent sciatic artery in a newborn.

Persistent sciatic artery is an unusual anatomical anomaly first noted in 1832. Approximately 60 to 70 cases have been documented in the literature, but none described symptomatic persistent sciatic artery presenting in the neonate. We report a case of a newborn infant who presented after birth with an atrophic right lower extremity and ischemia.