Large-scale individual monitoring of internal contamination by gamma-emitting radionuclides in nuclear accident scenarios.

The results obtained in a measurement campaign concerning internal contamination by the gamma-emitting radionuclides of a large number of individuals are presented in this work. The aim is to assess the effectiveness of the spectrometric method in an emergency response following a nuclear power plant accident or a spread of radionuclides in the atmosphere due to an act of terrorism. An HPGe portable spectrometer, deployed in a collective protection apparatus, was used for both whole-body and thyroid measurements. An adult bottle mannequin absorption (BOMAB) and thyroid phantoms were used to evaluate the detector performance. The BOMAB phantom was provided by the Italian Institute of Ionizing Radiation Metrology (INMRI) for the ENEA intercomparison exercise. Thyroid phantoms were provided by the Belgian Nuclear Research Centre for the 'Child and Adult Thyroid Monitoring After Reactor Accident' European intercomparison exercise. The instrument performance was further evaluated by collecting spectral data from healthy volunteers, using acquisition times of 180 s and 100 s, respectively, for the whole-body and thyroid measurements. The detector showed good accuracy in quantifying radionuclide activities in the adult BOMAB and in the thyroids of persons of all ages. The proposed method allows us to detect in vivo activity leading to a committed effective dose E(50) and committed thyroid equivalent doses H T greater than 2 mSv due to all gamma-emitting fission products, if the scan is performed within five days after intake. Assuming, for instance, an acute inhalation of 137Cs and 131I, the obtained detection limit values for adults lead to a E(50) value equal to 0.08 mSv and an H T value of 0.27 mSv. The E(50) and H T values show that the proposed method can be successfully used when the dose assessment must be rapidly performed for a large number of individuals in the eventuality of the scenarios previously mentioned.

Large-scale individual thyroid monitoring following nuclear accidents by means of non-spectrometric devices.

In order to properly respond to an emergency caused by an accident in a nuclear power plant with a spread of radionuclides in the atmosphere, we propose a field procedure to perform a large-scale individual thyroid monitoring of internal contamination due to inhalation of 131I, by means of non-spectrometric equipment, in particular dose rate meters. Specific attention is paid to the individual monitoring of children, because of the very high radiosensitivity of the child's thyroid to the carcinogenic effects of ionising radiation. The device performance was evaluated by measuring mock iodine sources provided in the Child and Adult Thyroid Monitoring After Reactor Accident (CAThyMARA) intercomparison and, just for a scintillator dose rate meter, by means of 60 s acquisitions of healthy volunteers' thyroids. All the devices showed a remarkable accuracy in quantification of equivalent 131I activity in the thyroids of persons of all ages. The selected scintillator dose rate meter showed detection limit values resulting in a maximum committed equivalent dose to thyroid HT, assuming an acute 131I inhalation occurred five days before the measurement, equal to 10 mSv (related to five-year-old children). Considering the level of HT values associated with the calculated detection limit activities, the proposed procedure has a significant sensitivity to be used for fast internally thyroid monitoring in nuclear or radiological emergencies, allowing daily monitoring a large amount of individuals.

IN VIVO public monitoring in emergency exposure scenarios by means of spectrometric and non-spetrometric devices.

In a nuclear or radiological accident scenario, when potentially members of the public can undergo internal contamination by anthropogenic radionuclides released in the atmosphere, effective methods that can be used directly in the field to perform a fast scan for internal contamination on a large number of individuals can play a major role to undertake appropriate countermeasures. Specific attention should be paid to the individual monitoring of children since they constitute the sensitive population group with the highest risk of developing cancer. At the ENEA Casaccia Research Center in Rome (Italy), monitoring procedures based on a portable HPGe detector and ratemeters were tested in the field. A total of 170 acquisitions of uncontaminated volunteers for the blank measurements were collected, 105 acquisitions on adult and 65 acquisitions on 10-y/o children. The detection limit calculation, in terms of activity taken up (Bq), was carried out according to the Standard ISO's 11929 and 28218, whereas the corresponding 'minimum effective dose' (mSv) was calculated based on international commission on radiological protection (ICRP) Publications 134, 137 and 141. Results and evaluations of the measurement campaign are presented and discussed in respect to the aspects reported in the current literature.

Internal dosimetry: towards harmonisation and coordination of research.

The CONRAD Project is a Coordinated Network for Radiation Dosimetry funded by the European Commission 6th Framework Programme. The activities developed within CONRAD Work Package 5 ('Coordination of Research on Internal Dosimetry') have contributed to improve the harmonisation and reliability in the assessment of internal doses. The tasks carried out included a study of uncertainties and the refinement of the IDEAS Guidelines associated with the evaluation of doses after intakes of radionuclides. The implementation and quality assurance of new biokinetic models for dose assessment and the first attempt to develop a generic dosimetric model for DTPA therapy are important WP5 achievements. Applications of voxel phantoms and Monte Carlo simulations for the assessment of intakes from in vivo measurements were also considered. A Nuclear Emergency Monitoring Network (EUREMON) has been established for the interpretation of monitoring data after accidental or deliberate releases of radionuclides. Finally, WP5 group has worked on the update of the existing IDEAS bibliographic, internal contamination and case evaluation databases. A summary of CONRAD WP5 objectives and results is presented here.

Cushing's syndrome patient who exhibited congestive heart failure.

Cushing's Syndrome (CS) may sometimes lead to dilated cardiomyopathy, even though this condition can be partially or completely reversed after treatment. In this article we report the case of a 28-yr-old woman with CS secondary to adrenal adenoma who exhibited congestive heart failure as an initial symptom. Two weeks before being admitted to our hospital, the patient started complaining of shortness of breath, orthopnea, paroxysmal nocturnal dyspnea and generalized edema. A physical examination did not reveal signs of hypercortisolism. Chest auscultation revealed bilateral diffused crepitation; blood pressure was 180/120 mmHg with heart rate of 90 beats/min. A chest X-ray showed a cardiac shade enlargement due to congestive heart failure. Transthoracic echocardiography demonstrated a dilated left ventricle and an impaired left ventricular systolic function. The patient's urinary cortisol excretion was elevated and circadian rhythm of cortisol was absent. ACTH level was low. In addition, plasma cortisol failed to decrease after administration of dexamethasone. An abdominal magnetic resonance imaging scan showed a 7-cm right adrenal mass. The patient was administered oxygen, spironolactone, ACE-inhibitor and the signs and symptoms of heart failure gradually improved. A laparoscopic right adrenalectomy was performed and pathological examination of the gland showed a benign adrenocortical adenoma. After the adrenalectomy the patient was started on hydrocortisone therapy and 5 months later the wall thickness of the left ventricle was within normal range and the patient's blood pressure was 130/80 mmHg. In conclusion we report the case of heart failure as the main clinical symptom in CS secondary to adrenal adenoma.

Coordination of research on internal dosimetry in Europe: the CONRAD project.

The EUropean RAdiation DOSimetry Group (EURADOS) initiated in 2005 the CONRAD Project, a Coordinated Network for Radiation Dosimetry funded by the European Commission (EC), within the 6th Framework Programme (FP). The main purpose of CONRAD is to generate a European Network in the field of Radiation Dosimetry and to promote both research activities and dissemination of knowledge. The objective of CONRAD Work Package 5 (WP5) is the coordination of research on assessment and evaluation of internal exposures. Nineteen institutes from 14 countries participate in this action. Some of the activities to be developed are continuations of former European projects supported by the EC in the 5th FP (OMINEX and IDEAS). Other tasks are linked with ICRP activities, and there are new actions never considered before. A collaboration is established with CONRAD Work Package 4, dealing with Computational Dosimetry, to organise an intercomparison on Monte Carlo modelling for in vivo measurements of (241)Am deposited in a knee phantom. Preliminary results associated with CONRAD WP5 tasks are presented here.

Radiation dose to the testes after 131I therapy for ablation of postsurgical thyroid remnants in patients with differentiated thyroid cancer.

UNLABELLED: Radioiodine-131 is used in differentiated thyroid cancer (DTC) for ablation of postsurgical thyroid remnants and destruction of metastases. The question may be raised of whether 131I treatment of DTC in male patients may give an irradiation dose to the testes that could impair fertility. Few data in the literature concern the dose absorbed by the testes after 1311 therapy for DTC. Because 131I kinetics may be altered by the hypothyroid condition commonly present at the time of treatment and by the radioiodinated iodoproteins released by the damaged thyroid tissue, the dose values reported in the International Commission on Radiological Protection (ICRP) tables for euthyroid men may not be appropriate. To clarify this problem, three male subjects undergoing 131I therapy for ablation of thyroid remnants shortly after thyroidectomy for DTC were studied. METHODS: The mean administered activity was 1256 MBq, and the duration of the study was 2 wk. The gamma dose was measured by thermoluminescent dosimeters (TLDs) applied to the lower poles of the testes. Correction factors were calculated for the distance of the TLD from the center of the testes and for attenuation by the testes of the gamma rays reaching the TLD. After correction, the gamma dose to the testes ranged from 21 to 29 mGy. The gamma dose calculated by the Medical Internal Radiation Dose (MIRD) method from blood and urine samples was similar (18-20 mGy) to that measured by TLDs. The beta dose was estimated by the MIRD method from blood activity and testicular volume and ranged between 14 and 31 mGy. RESULTS: The total (beta and gamma) doses to testes were 30, 33 and 43 microGy/MBq in the three subjects. CONCLUSION: These values are close to those derived from the ICRP tables (26-37 microGy/MBq 131I) for euthyroid subjects. The present data indicate that significant irradiation is delivered to the testes after the administration of the 131I ablative dose to thyroidectomized patients. The relevance of the radiation absorbed by testes on fertility remains to be established.

Usefulness of twenty-four-hour blood pressure patterns and response to short-term sodium restriction in normotensive subjects in detecting a predisposition to systemic arterial hypertension.

Twenty clinically healthy subjects were studied to identify normotensive adults with a predisposition to arterial hypertension by monitoring blood pressure (BP) and restricting dietary sodium intake. Short-term restriction in sodium intake resulted in a decrease of the mean level for the circadian rhythm of BP. The phenomenon is visible in subjects without familial hypertension but not in individuals with a positive history for high BP. The response of the 24-hour BP patterns to abrupt sodium deprivation seems to be an indicator for discovering normotensive subjects at risk of developing arterial hypertension.

Blood pressure 24-hour pattern in two industrialized countries (Italy and Japan) with a different culture in salt intake.

This study investigates the blood pressure (BP) 24-hour pattern in representative samples of 2 industrialized countries, Italy and Japan, showing different cultures in salt intake. BP was monitored by means of a noninvasive ambulatory device whose readings were analyzed by means of chronobiometric procedures. The results show that the 24-hour BP pattern is not substantially different in Italian and Japanese subjects. In particular, the expected lower BP in the Italians was not detected despite their lower salt intake. Because the 24-hour mean BP value was seen not to be proportional to salt intake, the hypothesis is formulated that maintenance of the pressure regimen within a given range of variability is a principle of human physiology. To comply with this rule the Japanese people are supposed to have ethnically developed a certain resistance to dietary salt for which their cardiovascular apparatus is protected (phyletic escape to dietary sodium excess).

Twenty-four-hour pattern of hunger sensation in obesity complicated by type 2 diabetes mellitus: a pattern recognition by spectral analysis.

Hunger sensation (HS) in humans physiologically shows intraday (circadian) and within-day (ultradian) recursivity. This intrinsic periodicity was investigated by applying the cosinor method and spectral analysis to the 24-hour profile of HS (orexigram) derived by a self-rating score (from 1 to 10 hunger units [HU]) recorded every half-hour. The study of circadian and ultradian recursivity on the orexigram was performed in 30 diabetic obese patients ([DOPs], 14 men and 16 women aged 22 to 62 years; body weight, 77 to 130 kg; body mass index, 31-47). The control group consisted of 30 clinically healthy subjects ([CHS], 15 men and 15 women aged 21 to 60 years; body weight, 65 to 72 kg; body mass index, 23 to 25). DOPs showed two types of orexigrams in which hunger was felt with limitation to the diurnal part of the day or with extension to the night, respectively. The type 1 orexigram was characterized by a normal spectrum and circadian rhythm. The type 2 orexigram was characterized by subsidiary ultradian components associated with an abnormal elevation of the circadian mesor and a significant delay of the circadian phase, as the spectral analysis was indicative of a structural difference in the frequencies that sustain the intraday and within-day recursivity of the HS. Accordingly, DOPs can be recognized by their orexigram as "eurectic" or "hyperrectic" to indicate subjects with a normal or an exaggerated HS, respectively, during the 24-hour span.

Chronobiometric identification of disorders of hunger sensation in essential obesity: therapeutic effects of dexfenfluramine.

In human beings, hunger is a proprioceptive signal that shows intraday (circadian components) and within-day (ultradian components) recursivity. Both periodic components can be investigated by chronobiometric procedures by combining the Cosinor method with spectral analysis. A 24-hour profile of hunger sensation (HS) can be plotted on a 1-to-10 scale of intensity using self-rated scores performed every half-hour of the day. Circadian and ultradian components were studied in 60 patients affected by essential obesity (20 men and 40 women; mean age, 38.4 years; mean body weight, 101 kg) before and after treatment with dexfenfluramine (Isomeride; Servier, Orléans, France) 15 mg orally twice daily, for 30 days. The control group consisted of 30 clinically healthy subjects (15 men and 15 women; mean age, 37.5 years; mean body weight, 69 kg). Chronobiometric analysis shows three patterns in obese patients, which suggests that HS may be normal (eurectic obesity), exaggerated (hyperrectic obesity), or diminished (hyporectic obesity). After dexfenfluramine administration, HS was showed a substantial decrease in the daily mean level. The spectrum of resolution in circadian and ultradian components was found to be maintained in eurectic obesity and partially readjusted in hyperrectic and hyporectic obesities. This demonstrates that dexfenfluramine acts not only as an anorectic but also as a chronizer by interfering with the recursive components of HS. The anorectic and chronizing effects suggest that dexfenfluramine is a "chronoanorectic drug" that interacts with the chronobiologic properties of the serotoninergic system.

Vasoactive intestinal peptide fluctuates in human blood with a circadian rhythm.

The vasoactive intestinal peptide (VIP) may be radioimmunoassayed in systemic venous blood. The plasma concentrations of VIP were investigated in human blood according to a chronobiological design. The study documented a circadian rhythmicity in time-qualified concentrations of VIP. Accordingly, VIP may be ascribed to biological variables characterized by periodicity in their physiological attributes. The rhythmic physiology of VIP is, however, highly disturbed in its tonic and phasic properties during senescence.

Day-time changes for pituitary-thyroid hormones denote a rhythmic structure not detectable in elderly subjects.

The day-time concentrations of TSH, T3, T4, FT3 and FT4 were investigated in clinically healthy volunteers, 20 young individuals, aged from 20 to 27 years, and 12 elderly subjects, aged from 70 to 81 years. Nocturnal sampling was purposely avoided in order to eliminate the interindividual differences in sleep patterns. The day-time series were analysed by means of cosinor analysis to interpolate the best-fitting sinusoidal wave that covers the day-night period. The reconstruction of the circadian sinusoidal wave was validated for TSH, T3, T4, FT3 and FT4 in young subjects, and, with limitation, for T4 in elderly individuals. The findings suggest that the day time patterns of TSH, T3, FT4 and FT3 in elderly subjects are characterized by a dyschronism that is not detectable in young subjects. The investigation of the day-time concentrations is suggested as a cost-effective tool for exploring the circadian cycle of the pituitary-thyroid hormones in aged people.

Circadian rhythm of cardiac output, peripheral vascular resistance, and related variables by a beat-to-beat monitoring.

This study aimed to explore the 24-h patterns of stroke volume, cardiac output, and peripheral vascular resistance along with other correlated variables, such as left ventricular ejection time, ejection velocity index, thoracic fluid index, heart rate, and blood pressure. The study was performed on 12 clinically healthy subjects by means of a noninvasive beat-to-beat monitoring using the thoracic electric bioimpedance technique associated with the automated sphygmomanometric recording. Time data series were analyzed by means of chronobiological procedures. The results documented the occurrence of a circadian rhythm for all the variables investigated, giving relevance to the beat-to-beat bioperiodicity of cardiac output and peripheral vascular resistance. Temporal quantification of the investigated variables may be useful for a better insight of the chronophysiology of the cardiovascular apparatus.

A chronobiological approach to circulating levels of renin, angiotensin-converting enzyme, aldosterone, ACTH, and cortisol in Addison's disease.

This study deals with a chronobiological approach to the circadian rhythm of the renin-angiotensin-aldosterone system (RAAS) and the ACTH-cortisol axis (ACA) in patients with Addison's disease (PAD). The aim is to explore the mechanism(s) for which the circadian rhythmicity of the RAAS and ACA takes place. The study has shown that both the RAAS and ACA are devoid of a circadian rhythm in PAD. The lack of rhythmicity for renin and ACTH provides indirect evidence that their rhythmic secretion is in some way related to the circadian oscillation of aldosterone and cortisol. This implies a new concept: a positive feedback may be included among the mechanisms which chronoregulate the RAAS and ACA.

Development and characterisation of a head calibration phantom for in vivo measurements of actinides.

The investigation of actinides' internal contamination in human body makes use of a variety of techniques. In large scale screening the technique of "in vivo" evaluation of bone 241Am burden via the determination of the nuclide activity in the skull is often used. For this purpose, adequate calibration procedures and standard phantoms are needed. The present paper summarises the studies and technical procedures followed for the development of a calibration phantom based on a commercial Alderson angiographic head in which a set of 24 241Am point sources were embedded. A theoretical study was first carried out, at the ENEA Institute for Radiation Protection, using the MCNP4-B Monte Carlo code to determine the point source distribution that closely approximates a homogeneous bone contamination. The numerical models were also used to evaluate the resulting degree of approximation. The point sources were prepared at the ENEA National Metrology Institute for ionising radiation quantities and were traceable to the Italian national standard of radionuclide activity. The sources were prepared by quantitatively dispensing a liquid solution onto a plastic disc. The activity of each source was checked by gamma-ray spectrometry and the reproducibility of the activity values was determined. Each source was then placed in the optimum position in the skull, given by the Monte Carlo modelling, by a precision mechanical device. The phantom was finally used to calibrate a whole body counter operating at the ENEA Institute for Radiation Protection. The paper reports the main theoretical and experimental aspects of this work, and also discusses the results of the first calibrations.

Endocrine response to HIV infection. Involvement of thyroid gland.

Endocrine dysfunctions were associated at different stages of infection, including those early in the course of HIV infection. In fact adrenal insufficiency, hyporeninemic hypoaldosteronism, hyponatremia, reduced gonadotropins levels, gonadal abnormalities and changes in hormone-binding proteins were reported in HIV infection. Also a thyroid involvement with autoimmune phenomena was observed in HIV infection by several studies giving different explanations of altered thyroid conditions. These findings suggest an effect of HIV on endocrine system. Recognition of endocrine manifestations in these patients may contribute to better characterize different stages of the infection and improve the management of HIV patients.

[Congenital hypothyroidism: organization and coordination of neonatal screening in Italy]. / Ipotiroidismo congenito: organizzazione e coordinamento dello screening neonatale in Italia.

Congenital hypothyroidism (IC) is the most frequent endocrine disease of the infancy and it is caused by primary deficiency of thyroid hormones. The damages derived by protracted hormone deficiency are diffused to all organs and systems and particularly severe for the development of central nervous system. Mental retardation can be prevented by early diagnosis and therapy. Early diagnosis is assured by neonatal thyroid screening performed on all newborns in the first days of life. The progress report on the screening situation in Italy as well as the national coordination realized in this field are presented.

[Circadian rhythm of the renin-angiotensin-aldosterone system in subjects with kidney and heart transplants]. / Ritmo circadiano del sistema renina-angiotensina-aldosterone in soggetti con trapianto di rene e di cuore.

The present investigation evaluates the circadian rhythm of renin-angiotensin-aldosterone system (RAAS) in subjects with kidney (KTS) or heart (HTS) transplantation undergoing conventional therapy with prednisone and cyclosporine. RAAS circadian rhythmicity has been compared with the circadian cycle of cortisol as a marker rhythm. The chronobiological exploration has been performed by measuring the circulating levels of plasma renin activity (PRA), plasma aldosterone (PA), and serum angiotensin-converting-enzyme (SACE) and plasma cortisol (PC) in serial samplings collected six times over a 24-h span. Time-qualified levels of plasma cyclosporine (CYCL) have been established. The control group consisted of 10 normal subjects matching in age and sex. Individual data series were analysed by the Cosinor method. The chronobiometric estimates demonstrate the lack of a circadian rhythmicity for PRA, PA and SACE in KTS and HTS. The PC circadian rhythm is demonstrable in KTS, but not in HTS. The abolition of the RAAS circadian rhythm in both KTS and HTS seems to be attributable to the effects exerted by CYCL. The disappearance of the PC circadian rhythm may be due to the prednisone therapy that is administered twice a day in HTS but not in KTS. The asynchronous effects of this drug lead us to suggest that antirejection therapy may be optimized by administering prednisone and cyclosporine according to a chronomodulated scheme.

[24-hour blood pressure: effects of sports in aged subjects]. / La pressione arteriosa di 24-h: effetto dello sport in soggetti anziani.

The present study deals with the blood pressure (BP) and heart rate (HR) 24-h pattern in aged people of both sexes ranging in age from 66 to 75 years. 20 subjects were active in agonistic sports (running and swimming), 20 others had sedentary habits. BP and HR were studied by non-invasive monitoring along with chronobiometric analysis. The BP and HR 24-h pattern was seen to preserve its circadian rhythm in both aged athletes and sedentary elderly. The analysis reveals that the aged athletes show a higher mesor for systolic BP and a lower mesor for diastolic BP and HR. The daily pressure load, as the integral of the BP 24-h values multiplied by the HR mesor, is lower in aged people practising sport as compared to age-matched individuals with sedentary habits. The spectral analysis reveals that physical exercise acts to change the time structure of BP and HR 24-h patterns. The conclusion is drawn that active sport plays beneficial effects in aged people because of a lower pressure load.