Measurement of potassium in rats using an In vivo neutron activation analysis system.

Abnormal levels of potassium are linked to several health conditions, including high blood pressure, cardiac dysfunction, kidney damage, and osteoporosis. Given the limited availability of in vivo measurement techniques, there is a need for novel methods to measure potassium to enhance the diagnosis and management of potassium metabolism related diseases. This study aimed to evaluate the feasibility of compact neutron generator based in vivo measurement system for quantification of potassium using rat carcasses. A cohort of thirty-nine rats (n = 20 males and 19 females, average weight 255 ± 15 and 163 ± 7 g) were sacrificed, and their carcasses were placed in polyethylene bottles. The rats were then positioned and irradiated in a carefully designed irradiation cave built alongside the neutron generator with an optimized thermal neutron flux and radiation dose ratio. The irradiation time was 10 min, followed by a 5-min decay and 2-h measurement using a high efficiency high purity germanium detector(HPGe). RESULTS: The average potassium concentration in male and female rats was found to be comparable (male 2874 ± 161 and female 2866 ± 144 µg/g). A marginally positive correlation between potassium concentration and weight was found in female rats only (male(20) = 0.07, P = 0.76 and female r(19) = 0.34, P = 0.15). We assessed the influence of manganese toxicity on potassium levels and observed no significant impact. These results were consistent with our previous study in mice. CONCLUSION: This study suggests that in vivo neutron activation analysis could serve as a promising method to quantify potassium and to investigate the storage and metabolism of potassium in human and in animals.

Whole body potassium as a biomarker for potassium uptake using a mouse model.

Potassium is known for its effect on modifiable chronic diseases like hypertension, cardiac disease, diabetes (type-2), and bone health. In this study, a new method, neutron generator based neutron activation analysis (NAA), was utilized to measure potassium (K) in mouse carcasses. A DD110 neutron generator based NAA assembly was used for irradiation.Thirty-two postmortem mice (n= 16 males and 16 females, average weight [Formula: see text] and [Formula: see text] g) were employed for this study. Soft-tissue equivalent mouse phantoms were prepared for the calibration. All mice were irradiated for 10 minutes, and the gamma spectrum with 42K was collected using a high efficiency, high purity germanium (HPGe) detector. A lead shielding assembly was designed and developed around the HPGe detector to obtain an improved detection limit. Each mouse sample was irradiated and measured twice to reduce uncertainty. The average potassium concentration was found to be significantly higher in males [Formula: see text] compared to females [Formula: see text]. We also observed a significant correlation between potassium concentration and the weight of the mice. The detection limit for potassium quantification with the NAA system was 46 ppm. The radiation dose to the mouse was approximately 56 [Formula: see text] mSv for 10-min irradiation. In conclusion, this method is suitable for estimating individual potassium concentration in small animals. The direct evaluation of total body potassium in small animals provides a new way to estimate potassium uptake in animal models. This method can be adapted later to quantify potassium in the human hand and small animals in vivo. When used in vivo, it is also expected to be a valuable tool for longitudinal assessment, kinetics, and health outcomes.

Rodent hair is a Poor biomarker for internal manganese exposure.

Hair is used as a biomarker of manganese (Mn) exposure, yet there is limited evidence to support its utility to quantify internal vs external Mn exposure. C57BL/6 J mice and Sprague-Dawley rats were exposed in two blocks of 3 subcutaneous injections every 3 days starting on day 0 or 20. The control group received two blocks of saline (vehicle); Treatment A received the first block as Mn (50 mg/kg MnCl2 tetrahydrate), with the second block as either methylmercury (MeHg at 2.6 or 1.3 mg/kg) for mice or vehicle for rats; and Treatment B received Mn for both blocks. Hair was collected on days 0 and 60 from all treatment groups and Mn quantified by inductively coupled plasma-mass spectrometry (ICP-MS) and total Hg by Direct Mercury Analyzer (DMA). No correlation between internal Mn dose and hair Mn was observed, whereas hair Hg was significantly elevated in MeHg exposed vs non-exposed mice. Whole body Mn content at day 60 was quantified postmortem by neutron activation analysis, which detected significantly elevated Mn for Treatment B in mice and rats. Overall, we find no evidence to support the use of hair as a valid biomarker for internal exposure to Mn at a neurotoxic level.

In vivoneutron activation assembly design for quantification of trace elements using MCNP.

Background: Trace and essential elements both play a crucial role in maintaining normal cellular and organ functions in human, while abnormal exposure to some of them is also potentially related to diseases, e.g.manganism. To study the association between elemental intake and health outcomes, accurate assessment of elemental uptake and storage in the human body is essential.Objective: Technology based on neutron activation analysis can be used forin vivomeasurement of the trace elements given that the measurement system guarantees a low detection limit with an acceptable dose. This study aims to design and optimize a customized and portable deuterium-deuterium neutron generator-based irradiation assembly for the NAA of trace elementsin vivo,using Monte Carlo simulations.Approach: The irradiation assembly includes a moderator, a fast neutron filter, a reflector, and shielding. The human hand phantoms doped with manganese (Mn) and potassium (K) are used to determine the respective elements' system sensitivity and detection limit.Main results: The calculated detection limit is 0.16µg Mn per gram dry bone (ppm) for Mn and 17 ppm for K, with an equivalent dose of 36 mSv to the hand for 10 min irradiation.Significance: This more sensitivein vivoneutron activation analysis system will detect trace elementsin vivo.