Comparative Analysis of Approaches to Regulation and Monitoring of Workers for Internal Radiation Exposure

Purpose: Harmonization and improvement of the system for regulating the internal radiation exposure of workers and the basic requirements for ensuring radiation safety with international requirements and recommendations. Material and methods: Issues related to the development of approaches to regulation and monitoring of workers for internal radiation exposure in the process of evolution of the ICRP recommendations and the national radiation safety standards, are considered. The subject of analysis is the standardized values: dose limits for workers and permissible levels as well as directly related methods of monitoring of workers for internal radiation exposure, whose purpose is to determine the degree of compliance with the principles of radiation safety and regulatory requirements, including non-exceeding the basic dose limits and permissible levels. The permissible levels of inhalation intake of insoluble compounds (dioxide) of plutonium-239 are considered as a numerical example. Results: Based on the analysis of approaches to the regulation and monitoring of workers for internal radiation exposure for the period from 1959 to 2019, it is shown that a qualitative change in the approach occurred in the 1990s. It was due to a decrease in the number of standardized values by introducing a single dose limit for all types of exposure: the effective dose E, which takes into account the different sensitivity of organs and tissues for stochastic radiation effects (WT), using the previously accepted concepts of the equivalent dose H and groups of critical organs. From the analysis it follows that the committed effective dose is a linear transformation of the intake, linking these two quantities by the dose coefficient, which does not depend on the time during which the intake occurred, and reflects certain exposure conditions of the radionuclide intake (intake routes, parameters of aerosols and type of radionuclide compounds). It was also shown that the reference value of the function z(t) linking the measured value of activity in an organ (tissue) or in excretion products with the committed effective dose for a reference person, which is introduced for the first time in the publications of the ICRP OIR 2015-2019, makes it possible to standardize the method of measuring the normalized value of the effective dose. Based on the comparison of the predicted values of the lung and daily urine excretion activities following constant chronic inhalation intake of insoluble plutonium compounds at a rate equal annual limit of intake (ALI) during the period of occupational activity 50 years it was shown that the modern biokinetic models give a slightly lower level (on average 2 times) of the lungs exposure compared to the models of the previous generation and a proportionally lower level (on average 1.4 times) of plutonium urine excretion for the standard type of insoluble plutonium compounds S. However, for the specially defined insoluble plutonium compound, PuO2, the level of plutonium urine excretion differs significantly downward (on average 11.5 times) compared to the models of the previous generation. Conclusion: With the practical implementation of new ICRP OIR models, in particular for PuO2 compounds, additional studies should be carried out on the behavior of insoluble industrial plutonium compounds in the human body. Besides, additional possibilities should be used to determine the intake of plutonium by measuring in the human body the radionuclide Am-241, which is the Pu-241 daughter. To determine the plutonium urine excretion, the most sensitive measurement techniques should be used, having a decision threshold about fractions of mBq in a daily urine for S-type compounds and an order of magnitude lower for PuO2 compounds. This may require the development and implementation in monitoring practice the plutonium-DTPA Biokinetic Model.

Calcium and bone metabolism

This chapter covers calcium and bone metabolism. It starts with the physiology of bone, investigation of the bones, imaging, mass measurements, and biopsy, then goes on to investigation of calcium, phosphate, and magnesium. Urine excretion and calcium-regulating hormones are explained. It goes on to hypercalcaemia, primary hyperparathyroidism and its treatment, vitamin D intoxication, sarcoidosis, and hypocalcaemia. Vitamin D deficiency, Paget’s disease, and inherited disorders of bone are all included. The pathology, epidemiology, presentation, investigation, and treatment of osteoporosis are covered in detail.

The increase in urinary serotonin and decrease in salivary cortisol concentrations following direct inhalations of concentrated essential oils is not induced by non-specific effects

Objectives. The effectiveness of exogenously triggered serotonin (e.g., dietary supplements, drugs) increase is varied. However, since urinary serotonin concentrations were found to correlate with those in the cerebrospinal fluid, the olfactory system might be an efficient and testable pathway to quickly elevate serotonin levels due to its fast-acting central neurophysiological and peripheral pathways. However, little research has been devoted to investigate this assumption. This paper extends previous findings of parasympathetic activation of a specially designed essential oil inhaler (AromaStick® Balance) by experimentally testing its impact on urine serotonin and saliva cortisol excretion. Method. Two experiments involving healthy individuals were conducted to test the efficacy of essential oil application to the nose by employing different inhalation protocols and control conditions. Results. In the pilot study (n=8), serotonin urine excretion was increased after six inhalations (effect size Cohen’s d=0.7). In the second experiment (n=80), inhalations proved superior to both the natural control condition and the pseudo placebo condition after three and six inhalation cycles (0.6<d<1.8). In addition, there was a large reduction of cortisol saliva levels after three inhalations (d=0.9). Conclusion. Short and deep inhalations of essential oil scents directly delivered to the olfac-tory system appear to result in an enhanced serotonin and a reduced cortisol release in healthy individuals of both sexes.

Losartan and Eprosartan Induce a Similar Effect on the Acute Rise in Serum Uric Acid Concentration after an Oral Fructose Load in Patients with Metabolic Syndrome

Introduction. Excessive intake of fructose increases serum uric acid concentration. Hyperuricemia induces a negative effect on atherosclerosis and inflammation. Hyperuricemia is common in patients with arterial hypertension. Several antihypertensive drugs including diuretics increase serum uric acid concentration. In contrast, the angiotensin II receptor antagonist (ARB) losartan was found to lower serum uric acid though it may increase renal excretion while other ARBs showed mostly a neutral effect. In this study, effects of two AT1 receptor antagonists losartan and eprosartan on serum uric acid changes induced by oral fructose load were directly compared. Methods. The randomized, crossover, head-to-head comparative study comprised 16 ambulatory patients (mean age 64.5 ± 9.8 years). The patients fulfilled AHA/NHLBI 2005 criteria of metabolic syndrome. A daily single morning dose of each study drug (50 mg of losartan or 600 mg of eprosartan) was given during two 3-month periods in a random order separated by 2-week washout time. The oral fructose tolerance test (OFTT) was performed at baseline and after each two 3-onth treatment periods. Before and during OFTT, urine excretion of uric acid and creatinine was assessed in the first morning portion of urine. Blood samples for the measurement of serum uric acid and lipids were taken at baseline and 30, 60, and 120 minutes after oral intake of 75 g of fructose. Results. After 3-month treatment with eprosartan and losartan, both systolic and diastolic blood pressure decreased significantly and to a similar extent. After the treatment, serum uric acid and its baseline and postfructose urine excretion were unchanged. No significant changes of plasma lipids before and after OFTT were observed throughout the study. Conclusions. The study showed that in patients with hypertension and metabolic syndrome, both losartan and eprosartan have a neutral effect on fasting and postfructose load serum uric acid concentration and its urinary excretion. This trial is registered with NCT04954560.

Stress Condition on a Restricted Sodium Diet Using Umami Substance (L-Glutamate) in a Pilot Randomized Cross-Over Study

Hypertensive patients who adopt a sodium-restricted diet have difficulty maintaining this change, and this could increase stress. On the other hand, soup rich in umami substances (dashi) was reported to reduce indexes of anxiety and stress. The objective of this study was to measure mood and physiological stress indexes during administration of a sodium-restricted diet with and without an umami substance (free L-glutamate) by a cross-over randomized, single-blind, placebo-controlled trial in Japanese female university students. The baseline was measured for 5 days followed by a sodium-restricted diet intervention phase that lasted for 10 days. The Profile of Mood States questionnaire was administered, a stress marker in saliva (chromogranin-A) was measured, and the amount of sodium intake was confirmed from 24 h urine collection samples. Results showed that the sodium reduction was verified by 24 h urine excretion. The percentage of change in the stress marker from the baseline showed that the stress level in group without the umami substance was significantly higher than that in the group with the umami substance (p = 0.013) after receiving a sodium-reduced diet for 6 or more days, indicating that stress was alleviated. This study suggested that umami substances might help to ameliorate stress during a sodium-reduced diet, especially in the initial phase.

Sodium intake assessed by 24-h urine excretion and its relationship with anthropometric measurements in Malaysian adults

Background Sodium intake is associated with anthropometric measurement including weight, waist circumference (WC), and body mass index (BMI). Higher intake of sodium is usually linked to higher risk of obesity among adults globally, especially in developing countries. This study aims to explore the probable relationship between sodium intake by 24-h urine excretion assessment and anthropometric measurement of adults in Malaysia. Methods A cross-sectional study was conducted from October 2017 to March 2018 using a multi-stage stratified sampling method among Malaysian adults aged 18 years old and above. Sodium intake was determined by 24-h urinary sodium excretion, estimated from the respondents’ 24-h urinary sample. Height was obtained based on standard protocol. Weight and WC were measured twice using validated anthropometric equipment and BMI was calculated according to World Health Organization (WHO) 1998 classification. Descriptive analysis was done to describe socio-demographic characteristics. A simple linear regression and multiple linear regression tests were done to assess the relationship of 24-h urinary excretion and anthropometric measurement. All statistical analysis was done using SPSS version 22.0. Results Of 1047 interviewed respondents, 798 respondents had done the 24-h urine collection (76.0% response rate). Majority was between 40 and 59 years old (43.5%) and married (77.7%). Simple linear regression showed a significant positive linear association between 24-h urinary excretion and household income, WC, and obese group. In the multivariate analysis, it was indicated that, an increase of 1 unit of BMI will significantly increase the sodium intake by 129.20 mg/dl and an increase of 1 cm of WC will significantly increase the sodium intake by 376.45 mg/dl. Conclusion Our study showed a positive significant relationship between sodium intake estimated by 24-h urinary sodium excretion and BMI of Malaysian adults. More research is suggested on how sodium control can potentially contribute to obesity prevention.

Study of urine steroid profiles by gas chromatography-mass spectrometry in patients with adrenocortical cancer in the course of treatment

Background: Adrenocortical carcinoma (ACC) is a rare and aggressive disease. There are only few studies evaluating the diagnostic value of gas chromatography-mass spectrometry (GC-MS) for detection of ACC recurrence after surgery. It is necessary to conduct an in-depth study to search for the most informative markers of the disease relapse.Aim: To study urine steroid metabolism by GC-MS during treatment to identify early signs of metastatic disease and relapse.Materials and methods: Thirty nine (39) ACC patients were examined before and after surgery, in the early postoperative period (< 1 year) and late postoperative period (at 2 to 5 years). Ten (10) patients were disease-free at less than 1 year after surgery. Twenty nine (29) patients had metastases in lungs and other organs: 14, within 1 year after surgery, and 15, at 2 to 5 years. The control group included 25 patients with nonfunctioning adrenocortical adenomas (NAA) without malignant characteristics at histological examination. Urine steroid profiles were assessed with a gas chromatograph-mass spectrometer Shimadzu GCMS-QP2020.Results: As assessed by GC-MS, 16 major ACC biomarkers were found before surgery, including etiocholanolone, dehydroepiandrosterone (DHEA) and its metabolites, pregnanediol, pregnanetriol, 5-ene-pregnenes, and tetrahydro-11-deoxycortisol (THS). Their urine excretion was increased compared to that in the patients with NAA (р < 0.002). A non-classic 5-ene-pregnene, 3β,16,20-pregnenetriol (3β,16,20-dP3), was identified, with its urine excretion of > 500 mcg/day that was typical for ACC patients. After surgery, decreased urinary excretion of THS (р < 0.0001) and 3β,16,20-dP3 (р < 0.0001), increased 3α,16,20-dP3/3β,16,20-dP3 ratio (р = 0.003), compared to those before surgery, were indicative of the absence of any metastases. No difference of urine THS excretion and 3α,16,20-dP3/3β,16,20-dP3 ratio from the corresponding values before surgery (p > 0.05) is a sign of metastatic diseases in the ACC patients at less than 1 year after the surgery, of the disease relapse at 2 to 5 years, and of the disease relapse after chemotherapy. In addition, in the ACC patients with metastatic disease within 1 year after surgery, increased progestogen urine excretion was found. Urine excretion of DHEA and its metabolites in the patients with the disease relapse after chemotherapy was not different from those in the ACC patients before surgery (p > 0.05).Conclusion: Determination of urine excretion of THS, DHEA and its metabolites, etiocholanolone, 5-ene-pregnenes, 3β,16,20-dP3, and 3α,16,20-dP3/3β,16,20-dP3 ratio by GC-MS is of utmost importance in the monitoring of treatment for ACC and early diagnosis of the disease progression.