Non-Hodgkins lymphoma of the nasal cavity: A case report.

We present a rare case of an 81-year-old woman presenting with acute left nasal blockage caused by a large nasal mass of unknown origin. The mass was subsequently diagnosed as diffuse large B-cell non-Hodgkin lymphoma (NHL). Nasal/paranasal space involvement in NHL is uncommon, representing only 0.2%-2% of cases. In this case, the nasal NHL mass exhibited a favorable prognosis, in contrast to previously reported sinonasal lymphomas with poor outcomes. The patient underwent excisional biopsy and was treated with 3 cycles of R-CHOP chemotherapy, resulting in complete resolution of the mass confirmed by a follow-up CT scan and no signs of disease after 1 year. Differentiating sinonasal lymphomas from other neoplasms can be challenging due to their variable morphology and location. Diffuse presentations of sinonasal lymphoma can aid in distinguishing them from discrete lesions associated with other sinonasal neoplasms. However, differentiation from acute invasive sinonasal infection remains difficult. MRI can help identify lymphomas through the characteristic hypointense T2 signal and diffusion restriction, with the combined use of CT to aid in differentiating masses of unknown morphology. Nonetheless, squamous cell carcinoma, which mimics lymphoma features on MRI, poses additional challenges to accurate identification. This case highlights the rarity of nasal NHLs, their potential for excellent prognosis, and the importance of diverse imaging techniques in their diagnosis and differentiation from other sinonasal pathologies.

DOSIMETRIC CHARACTERISATION OF A SUB-NATURAL BACKGROUND RADIATION ENVIRONMENT FOR RADIOBIOLOGY INVESTIGATIONS.

Living systems have evolved in the presence of naturally occurring ionising radiation. REPAIR is a research project investigating the biological effects of sub-natural background radiation exposure in SNOLAB, a deep-underground laboratory. Biological systems are being cultured within a sub-background environment as well as two control locations (underground and surface). A comprehensive dosimetric analysis was performed. GEANT4 simulation was used to characterise the contribution from gamma, muons and neutrons. Additionally, dose rates from radon, 40K and 14C were calculated based on measured activity concentrations. The total absorbed dose rate in the sub-background environment was 27 times lower than the surface control, at 2.48 ± 0.20 nGy hr-1, including a >400-fold reduction in the high linear energy transfer components. This modelling quantitatively confirms that the environment within SNOLAB provides a substantially reduced background radiation dose rate, thereby setting the stage for future sub-background biological studies using a variety of model organisms.

Physical and chemical characterization of McIntyre Powder: An aluminum dust inhaled by miners to combat silicosis.

McIntyre Powder (MP) is a finely ground aluminum powder that was used between 1943 and 1979 as a prophylaxis for silicosis. Silicosis is a chronic lung disease caused by the inhalation of crystalline silica dust and was prevalent in the Canadian mining industry during this time period. The McIntyre Research Foundation developed, patented, and produced the MP and distributed it to licensees in Canada, the United States, Mexico, Chile, Belgian Congo, and Western Australia. In the province of Ontario, Canada it is estimated that at least 27,500 miners between 1943 and 1979 were exposed to MP. The present study was undertaken to examine the chemical and physical characteristics of two variations of MP (light grey and black). Chemical analyses (using X-ray Fluorescence and Inductively Coupled Plasma approaches) indicate that the black MP contains significantly higher concentrations of aluminum and metal impurities than the light grey MP (p < 0.001). X-ray diffractometry shows that while aluminum hydroxide dominates the aluminum speciation in both variations, the higher total aluminum content in the black MP is attributable to a greater proportion of elemental aluminum. Physical characterization (using electron microscopy, light microscopy, and dynamic light scattering) indicates that the light grey MP consists of particles ranging from 5 nm to 5 µm in diameter. Atomic Force Microscopy shows that the light grey MP particles in the nanoparticle range (<100 nm) have a mode between 5 and 10 nm. Consequently, it is possible that inhaled smaller MP nanoparticles may be transported via blood and lymph fluid circulation to many different organs including the brain. It is also possible for inhaled larger MP particles to deposit onto lung tissue and for potential health effects to arise from inflammatory responses through immune activation. This MP characterization will provide crucial data to help inform future toxicological, epidemiological, and biological studies of any long-term effects related to the inhalation of aluminum dust and nanomaterials.