Glenn I. Lykken

Perquisite spin-off from twenty-two years of measuring background in the whole body counter steel room.

G. I. LYKKEN,a,b H. S. ONG,b H. A. ALKHATIB,b T. R. HARRIS,c B. MOM ∨ CILOV ′ C,d AND J. G. PENLANDe aPhysics Department, University of North Dakota, Grand Forks, North Dakota 58202-7129, USA cMathematics Department, University of North Dakota, Grand Forks, North Dakota 58202-8376, USA dInstitute of Medical Research and Occupational Health, Zagreb, Croatia eUSDA, Agricultural Research Service GFHNRC, Grand Forks, North Dakota 58202-9034, USA

Seasonality of 214Bi activity in the human body and of 222Rn concentration in home ambient air

We studied the seasonal variation of the environmental radon progeny 214Bi activity in the whole bodies (WB) of women and men participating in community-based studies at the Grand Forks Human Nutrition Research Center (GFHNRC), the 214Bi background activity of the GFHNRC whole body counter (WBC) steel room, and ambient air 222Rn concentration in the homes of Grand Forks residents, over the 1988–2004 time period. In this cross-sectional epidemiological study, 214Bi activity in women and men, in the WBC steel room, and 222Rn concentration in resident homes fluctuated such that the highest values were observed in winter and the lowest in summer, respectively. 214Bi activity in the WB of human subjects was higher in women who have more 214Bi activity per unit mass than men. Apart from their common seasonal pattern, human WB 214Bi activity (lnBq) was comparatively higher than that for the ambient air 222Rn activity in a human-equivalent volume of 72 L.

Zinc availability from beef served with various carbohydrates or beverages.

Two sets of meals containing a beef patty labeled intrinsically with 65Zn and various carbohydrate foods or beverages were fed in random order to adult men and women. Twelve subjects participated in each study. Meals contained 210 g beef and either water, white bread, potatoes, rice, milk, orange juice, or coffee. Whole body zinc retention was monitored for 8 weeks after each meal. Mean Zn absorption in the first study was 28.8% from beef alone, 20.2% from beef and white bread, 17.6% from beef and potato, and 23.8% from beef and rice. Zinc absorption from beef alone was significantly greater than the average absorption from all beef/carbohydrate meals together (p<0.01), and was significantly greater than from beef with bread or potatoes, but zinc absorption from beef with rice did not differ significantly from absorption from beef alone. In the second group of meals, mean zinc absorption was 35.4% from beef alone, 28.0% from beef and milk, 29.2% from beef and orange juice, and 29.5% from beef and coffee. Zinc absorption from beef alone was significantly greater (p<0.01) than the average absorption from all beef/beverage meals together and was significantly different from beef plus milk; however, zinc absorption from beef with coffee or beef with orange juice did not differ significantly from zinc absorption from beef alone. These findings suggest that total amount of food in the meal may affect zinc absorption.

Natural distribution of environmental radon daughters in the different brain areas of an Alzheimer Disease victim

BackgroundRadon is a ubiquitous noble gas in the environment and a primary source of harmful radiation exposure for humans; it decays in a cascade of daughters (RAD) by releasing the cell damaging high energy alpha particles.ResultsWe studied natural distribution of RAD 210Po and 210Bi in the different parts of the postmortem brain of 86-year-old woman who had suffered from Alzheimers disease (AD). A distinct brain map emerged, since RAD distribution was different among the analyzed brain areas. The highest RAD irradiation (mSv·year-1) occurred in the decreasing order of magnitude: amygdale (Amy) >> hippocampus (Hip) > temporal lobe (Tem) ~ frontal lobe (Fro) > occipital lobe (Occ) ~ parietal lobe (Par) > substantia nigra (SN) >> locus ceruleus (LC) ~ nucleus basalis (NB); generally more RAD accumulated in the proteins than lipids of gray and white (gray > white) brain matter. Amy and Hip are particularly vulnerable brain structure targets to significant RAD internal radiation damage in AD (5.98 and 1.82 mSv·year-1, respectively). Next, naturally occurring RAD radiation for Tem and Fro, then Occ and Par, and SN was an order of magnitude higher than that in LC and NB; the later was within RAD we observed previously in the healthy control brains.ConclusionNaturally occurring environmental RAD exposure may dramatically enhance AD deterioration by selectively targeting brain areas of emotions (Amy) and memory (Hip).

Internal dosimetry of 210Pb in the human cranium: preliminary results from instrumentation needs for in vivo counting in a low-background underground counting facility

Internal dosimetry of (210)Pb in the cranium deals with the determination of the amount of energy deposited in tissue by (210)Pb radiations within the cranium. (210)Pb in the human cranium was monitored by in vivo counting in a low background facility 640 m (2100 ft) underground with a germanium (Ge) gamma-ray detector having a beryllium window. The minimum detectable activity (MDA) was established with this system to be 0.2 Bq (5 pCi) in 25-h counting time with a 15-mm diameter and 7-mm thick Ge detector, having a beryllium window of thickness of 0.08 mm, in contact with the cranium just above the ear adjacent to the temple region. To establish an MDA of 0.004 Bq (0.1 pCi) with this system, the limitation arising from the ambient radon level at 10 Bq m(-3) was investigated.

Comment on the Capstone Depleted Uranium (DU) Aerosol Characterization and Risk Assessment Study.

Dear Editors: WE NOTED that nowhere in the issue of Health Physics, March 2009, devoted to “The Capstone Depleted Uranium (DU) Aerosol Characterization and Risk Assessment Study” (Parkhurst and Guilmette 2009) were nanoparticles considered or even mentioned. The smallest particles considered were approximately 0.7 m in diameter (Holmes et al. 2009). Perhaps DU atoms may have entered the brain via olfactory pathways (Tjälve and Henriksson 1999) or carbon nanoparticles, i.e., buckyballs or fullerenes (Kroto et al. 1985), may have been produced when DU burned as the armor piercing shells struck a target (Krupka et al. 2009). Recent research has indicated the possibility of nanotoxicity to the lung and via lungs to other body compartments. (Oberdörster et al. 2005). One may ask, is it possible that the carbon fullerenes could also capture individual DU molecules that can be taken in the nasal mucosa and transported through the olfactory nerve further into the brain (Persson et al. 2003; Dorman et al. 2009)?