Cardiovascular reflex tests detect autonomic dysfunction in symptomatic and pre-symptomatic subjects with hereditary transthyretin amyloidosis

PURPOSE

Autonomic dysfunction is a distinctive but undervalued feature of hereditary transthyretin amyloidosis (ATTRv). It may predate the onset of polyneuropathy and cardiomyopathy, thereby providing crucial prognostic and therapeutic information. The objective of this study was to assess autonomic function by means of the standardized cardiovascular autonomic reflex tests (CRTs) in a cohort of subjects with genetically proven ATTRv from non-endemic areas who were in the symptomatic and pre-symptomatic stages.

METHODS

All subjects enrolled in this cross-sectional study had genetically proven ATTRv. They underwent the head-up tilt test, Valsalva manoeuvre, deep breathing test, cold face test and handgrip test while under continuous blood pressure and heart rate monitoring. Based on the results of the nerve conduction study, the subjects were divided into two groups: those with polyneuropathy (ATTRv-wPN) and those without polyneuropathy (ATTRv-woPN). Age- and sex-matched healthy controls (HC) were used for comparison.

RESULTS

Thirty-seven ATTRv subjects (19 with ATTRv-wPN, 18 with ATTRv-woPN) and 41 HC performed the CRTs. Of these 37 subjects with ATTRv, four (11%) presented neurogenic orthostatic hypotension the during head-up tilt test. Based on the results of the CRTs, autonomic dysfunction characterized by either sympathetic or parasympathetic impairment was detected in 37% and 63% of ATTRv-wPN subjects, respectively. Subjects with ATTRv-woPN presented a significant impairment of autonomic responses to the Valsalva manoeuvre compared to the HC (overshoot p = 0.004; Valsalva ratio p = 0.001).

CONCLUSION

Autonomic dysfunctions are frequent in subjects with ATTRv when investigated by means of standardized CRTs, and are also relevant in the pre-symptomatic stage. Cardiovagal functions are the primary functions affected, among others. This may be crucial in defining the proper diagnostic workout for early diagnosis and improving the likelihood of providing the patient with prompt administration of disease-modifying treatments.

Occupational exposure to electromagnetic fields in magnetic resonance environment: an update on regulation, exposure assessment techniques, health risk evaluation, and surveillance

Magnetic resonance imaging (MRI) is one of the most-used diagnostic imaging methods worldwide. There are ∼50,000 MRI scanners worldwide each of which involves a minimum of five workers from different disciplines who spend their working days around MRI scanners. This review analyzes the state of the art of literature about the several aspects of the occupational exposure to electromagnetic fields (EMF) in MRI: regulations, literature studies on biological effects, and health surveillance are addressed here in detail, along with a summary of the main approaches for exposure assessment. The original research papers published from 2013 to 2021 in international peer-reviewed journals, in the English language, are analyzed, together with documents published by legislative bodies. The key points for each topic are identified and described together with useful tips for precise safeguarding of MRI operators, in terms of exposure assessment, studies on biological effects, and health surveillance.

A Standard Protocol Proposal for Reliable and Time-Saving Shielding Effectiveness Measurements for MRI Faraday Cages

Background:

An inadequate shielding of radio-frequency cabins for magnetic resonance imaging devices can affect clinical images with artifacts. For this reason, periodic measurements of shielding effectiveness are recommended. However, a wide gap exists between the international reference standard currently available for shielding effectiveness measurement (IEEE-Std 299/2006) and the practical approach, mainly because of the poor applicability of the standard to any situation.

Objective:

The aim of this work is to suggest a novel procedure for the measurement of the shielding effectiveness of radiofrequency cabins for clinical magnetic resonance imaging devices. The application of the cabin door measurements for shielding effectiveness assessment is proposed.

Methods:

Based on the only international standard currently available, some critical aspects of shielding effectiveness measurements are highlighted. Taking into account theoretical considerations, a novel approach is suggested in order to simplify the applicability of the standard. Frequency ranges and measurement points were reduced by considering the specific device inside the shield.

Results:

Results obtained by the application of the proposed protocol were compared with the results obtained by the application of the standard procedure IEEE-Std 299/2006. No significant discrepancies between measurements have been found. It was observed that the time to perform measurements reduced by almost three times.

Conclusion:

A time-saving method for measurement of shielding effectiveness in a narrow range of frequencies is proposed.

Intraoperative Gamma Probe Detection of Head and Neck Paragangliomas with 111In-Pentetreotide: A Pilot Study

Aims and background

The aim of this study was to assess whether intraoperative radiolocalization of head and neck paragangliomas with 111In-pentetreotide may increase surgical effectiveness, reducing the risk of recurrence.

Methods

Our study included eight patients with untreated, recently diagnosed paragangliomas (four unilateral and four bilateral tumors of the carotid body). After iv injection of −150 MBq 111In-pentetreotide, preoperative somatostatin receptor scintigraphy (SRS) was performed. SPECT of the neck was performed at four hours and planar Images of the head and neck were also obtained at four and 24 hours post injection. Scintigraphy was always compared with the results of conventional imaging methods (MRI, angiography and sonography). Intraoperative detection was performed on 11 lesions 24 hours after radiopharmaceutical administration using a handheld gamma probe.

Results

Preoperative SRS showed high radiotracer uptake in all patients. All the intraoperatively detected lesions were radically resected and histologically confirmed to be involved by tumor. No false positive results were recorded. Gamma probe detection revealed a small intracranial extension not detected by other imaging methods in a patient with a paraganglioma of the right carotid, and partial involvement of the carotid artery in another patient. During follow-up (median 3.5 years; range, 4 months-7 years) all patients remained disease free according to all parameters.

Conclusions

To our knowledge, this is the first experience of radioguided surgery in paraganglioma. Although our study included a relatively small number of patients, we suggest that intraoperative gamma probe detection may be a powerful tool to improve surgical effectiveness.

Radioguided Biopsy of Osteoid Osteoma: Usefulness of Imaging Probe

Aims and Background

When removal of osteoid osteoma is performed with open biopsy, the surgeon can be guided by radioactivity of 99mTc-MDP (methylene D- phosphonate) acquired by a probe.

Material and methods

We compared the performance of a commercially available ZnCdTe probe (Neoprobe 2000) and a one-square-inch-field-of-view imaging probe (IP) on two patients undergoing open biopsy for osteoid osteoma. Triphasic bone scintigraphy was performed before operation and Neoprobe as well as IP were used in the operating room by two nuclear physicians. When the surgeon asked for guidance, each nuclear physician had to indicate a precise direction.

Results

The surgeon asked for guidance once in the first operation, on a patient with osteoid osteoma of the femur, and four times in the second operation, for osteoid osteoma of the acetabulum. The indications provided by IP were correct 5/5 times, whereas the commercial probe was correct 3/5 times. Both devices were able to assess the surgical radicality. After biopsy, bone samples were divided into high-count and low-count samples. Pathological examination confirmed the presence of osteoid osteoma in high-count samples.

Conclusions

IP has already been used to guide biopsy, but only in breast disease. The present work confirms its good performance also in orthopedics as a portable mini gamma camera that can be used in the operating room.

Breast Cancer Takes up 99mTc Bombesin. A Preliminary Report

Background

Several tumors including lung, prostate, ovarian, colon, and exocrine pancreatic cancer show receptors for the amphibian neurotransmitter and growth factor bombesin (BN) and its mammalian counterparts gastrin-releasing peptide and neuromedin B. Also breast cancer has been reported to show such receptors: the presence of BN receptors in primary breast cancer has been demonstrated on cultured cells and by autoradiography on breast tissue samples. Authors who have studied BN receptors in breast cancer do not agree on their frequency in primary cancer, but indicate that 100% of metastatic breast cancers show such receptors.

Methods

We examined three primary breast cancer patients with 99mTc BN and 99mTc sestamibi one week before surgery. One of them showed axillary node invasion. The same acquisition technique was used for breast and chest imaging with both radiopharmaceuticals, whereas total body images were acquired only with 99mTc BN. Also the administered radioactivity was different: 20 mCi of 99mTc sestamibi and 5-8 mCi of 99mTc BN. Dynamic images were acquired for 20 mins after iv injection with the patient in ventral decubitus and the gamma camera positioned in lateral view, as is generally done in Khakhali's prone scintimammography. Anterior chest images were acquired for 30 mins. Prone scintimammography was performed one hour after administration of both tracers. ROIs were drawn on tumors and surrounding breast with the same technique in order to calculate the tumor to breast ratio (T/B). In addition, total body scan was performed one hour and three hours after 99mTc BN administration. All three patients underwent breast conserving surgery with lymphadenectomy. Postoperative pathologic assessment showed the following T and N stages in the three patients: T1bN0, T1cN0. and T1cN1.

Results

All three cancers were imaged with both tracers. The T/B of 99mTc BN was always higher than that of 99mTc sestamibi. Chest uptake was always much higher with 99mTc sestamibi than with 99mTc BN. Comparison between 99mTc BN and 99mTc sestamibi images gave other intriguing results: in the N1 patient both tracers clearly imaged the invaded node, but on the 99mTc BN image the primary tumor was larger than on the 99mTc sestamibi image and the node was smaller. It is known that 99mTc BN is not taken up by vessels and inflammatory tissue. The time activity curves of the two tracers were significantly different in all patients, with an increase in 99mTc BN uptake in the first three to five minutes, followed by a less sharp uprise of the curve, quite similar to a plateau.

Conclusions

Our first impression is that 99mTc BN is a useful breast cancer seeking agent and very promising for lymph node staging.

Exposure Assessment and Biomonitoring of Workers in Magnetic Resonance Environment: An Exploratory Study

Magnetic resonance imaging (MRI) has evolved rapidly over the past few decades as one of the most flexible tools in medical research and diagnostic imaging. MRI facilities are important sources of multiple exposure to electromagnetic fields for both patients and health-care staff, due to the presence of electromagnetic fields of multiple frequency ranges, different temporal variations, and field strengths. Due to the increasing use and technological advancements of MRI systems, clearer insights into exposure assessment and a better understanding of possible harmful effects due to long-term exposures are highly needed. In the present exploratory study, exposure assessment and biomonitoring of MRI workers at the Radio-diagnostics Unit of the National Cancer Institute of Naples "Pascale Foundation" (Naples, Italy) have been carried out. In particular, exposure to the MRI static magnetic field (SMF) has been evaluated by means of personal monitoring, while an application tool has been developed to provide an estimate of motion-induced, time-varying electric fields. Measurement results have highlighted a high day-to-day and worker-to-worker variability of the exposure to the SMF, which strongly depends on the characteristics of the environment and on personal behaviors, and the developed application tool can be adopted as an easy-to-use tool for rapid and qualitative evaluation of motion-induced, time-varying electric field exposure. Regarding biomonitoring, the 24 workers of the Radio-diagnostics Unit were enrolled to evaluate both spontaneous and mitomycin C-induced chromosomal fragility in human peripheral blood lymphocytes, by means of the cytokinesis-block micronucleus assay. The study subjects were 12 MRI workers, representative of different professional categories, as the exposed group, and 12 workers with no MRI exposure history, as the reference group. The results show a high worker-to-worker variability for both field exposure assessment and biomonitoring, as well as several critical issues and practicalities to be faced with in this type of investigations. The procedures for risk assessment and biomonitoring proposed here can be used to inform future research in this field, which will require a refinement of exposure assessment methods and an enlargement of the number of subjects enrolled in the biomonitoring study to gain robust statistics and reliable results.

MYH7-related myopathies: clinical, histopathological and imaging findings in a cohort of Italian patients

BACKGROUND

Myosin heavy chain 7 (MYH7)-related myopathies are emerging as an important group of muscle diseases of childhood and adulthood, with variable clinical and histopathological expression depending on the type and location of the mutation. Mutations in the head and neck domains are a well-established cause of hypertrophic cardiomyopathy whereas mutation in the distal regions have been associated with a range of skeletal myopathies with or without cardiac involvement, including Laing distal myopathy and Myosin storage myopathy. Recently the spectrum of clinical phenotypes associated with mutations in MYH7 has increased, blurring this scheme and adding further phenotypes to the list. A broader disease spectrum could lead to misdiagnosis of different congenital myopathies, neurogenic atrophy and other neuromuscular conditions.

RESULTS

As a result of a multicenter Italian study we collected clinical, histopathological and imaging data from a population of 21 cases from 15 families, carrying reported or novel mutations in MYH7. Patients displayed a variable phenotype including atypical pictures, as dropped head and bent spine, which cannot be classified in previously described groups. Half of the patients showed congenital or early infantile weakness with predominant distal weakness. Conversely, patients with later onset present prevalent proximal weakness. Seven patients were also affected by cardiomyopathy mostly in the form of non-compacted left ventricle. Muscle biopsy was consistent with minicores myopathy in numerous cases. Muscle MRI was meaningful in delineating a shared pattern of selective involvement of tibialis anterior muscles, with relative sparing of quadriceps.

CONCLUSION

This work adds to the genotype-phenotype correlation of MYH7-relatedmyopathies confirming the complexity of the disorder.

Lack of effects on key cellular parameters of MRC-5 human lung fibroblasts exposed to 370 mT static magnetic field

The last decades have seen increased interest toward possible adverse effects arising from exposure to intense static magnetic fields. This concern is mainly due to the wider and wider applications of such fields in industry and clinical practice; among them, Magnetic Resonance Imaging (MRI) facilities are the main sources of exposure to static magnetic fields for both general public (patients) and workers. In recent investigations, exposures to static magnetic fields have been demonstrated to elicit, in different cell models, both permanent and transient modifications in cellular endpoints critical for the carcinogenesis process. The World Health Organization has therefore recommended in vitro investigations as important research need, to be carried out under strictly controlled exposure conditions. Here we report on the absence of effects on cell viability, reactive oxygen species levels and DNA integrity in MRC-5 human foetal lung fibroblasts exposed to 370 mT magnetic induction level, under different exposure regimens. Exposures have been performed by using an experimental apparatus designed and realized for operating with the static magnetic field generated by permanent magnets, and confined in a magnetic circuit, to allow cell cultures exposure in absence of confounding factors like heating or electric field components.

LOPED study: looking for an early diagnosis in a late-onset Pompe disease high-risk population

OBJECTIVE

A multicentre observational study was aimed to assess the prevalence of late-onset Pompe disease (LOPD) in a large high-risk population, using the dried blood spot (DBS) as a main screening tool.

DESIGN/METHODS

17 Italian neuromuscular centres were involved in the late-onset Pompe early diagnosis (LOPED) study. Inclusion criteria were: (1) age ≥5 years, (2) persistent hyperCKaemia and (3) muscle weakness at upper and/or lower limbs (limb-girdle muscle weakness, LGMW). Acid α-glucosidase (GAA) activity was measured separately on DBS by fluorometric as well as tandem mass spectrometry methods. A DBS retest was performed in patients resulted positive at first assay. For the final diagnosis, GAA deficiency was confirmed by a biochemical assay in skeletal muscle, whereas genotype was assessed by GAA molecular analysis.

RESULTS

In a 14-month period, we studied 1051 cases: 30 positive samples (2.9%) were detected by first DBS screening, whereas, after retesting, 21 samples were still positive. Biochemical and molecular genetic studies finally confirmed LOPD diagnosis in 17 cases (1.6%). The median time from the onset of symptoms/signs to diagnosis was 5 years. Among those patients, 35% showed presymptomatic hyperCKaemia and 59% showed hyperCKaemia+LGMW, whereas 6% manifested with LGMW.

CONCLUSIONS

LOPED study suggests that GAA activity should be accurately screened by DBS in all patients referring for isolated hyperCKaemia and/or LGMW. A timely diagnosis was performed in five patients with presymptomatic hyperCKaemia, but two had already manifested with relevant changes on muscle morphology and MRI. Consequently, enzyme replacement therapy was started in 14/17 patients, including the 2 patients still clinically presymptomatic but with a laboratory evidence of disease progression.

Influence of treatments in multiple sclerosis disability: A cohort study

Background and objective:

A critical aspect of multiple sclerosis (MS) treatments is understanding the effect of disease-modifying drugs (DMDs) on the long-term risk of disability and whether the effect is related to disability at start of treatment.

Methods:

We performed an observational study on 3060 MS patients. The effect of therapy on progression to Expanded Disability Status Scale (EDSS) 3.0 and 6.0 from onset was analysed in treated vs untreated (UTP) patients using Cox regression analysis adjusted for propensity score and immortal time bias.

Results:

Compared to UTP, the risks of EDSS 3.0 were 94% and 73% lower in immunomodulant (IMTP-) and immunosuppressant (ISTP-) treated patients, respectively, while the risk of EDSS 6.0 was 86% lower in IMTP. The risk of EDSS 6.0 was, respectively, 91% and 75% lower in 1275 IMTP before and 114 after EDSS 3.0 than in 539 UTP; the risk was higher in IMTP starting therapy after EDSS 3.0 than before (HR = 4.42).

Conclusions:

DMDs delayed long-term disability in MS patients treated either in the early or, to a lesser extent, in the later phase of the disease. Thus, the window of therapeutic opportunity is relatively extended, assuming that early is better than late treatment, but late is better than never.

Effect of millimetre waves on phosphatidylcholine membrane models: a non-thermal mechanism of interaction

The nonthermal biological effects of millimeter waves have been mainly attributed to the interaction with biological membranes. Several data on biomimetic membrane systems seem to support this conclusion. In this paper a mechanistic hypothesis is evaluated to explain such an interaction taking into account experimental NMR data on deuterium-labeled phospholipid vesicles. These data showed that millimeter waves induce a time and a hydration-dependent reduction of the water ordering around the phosphocholine headgroups. This effect is here interpreted as a change in membrane water partitioning, due to the coupling of the radiation with the fast rotational dynamics of bound water molecules, that results in a measurable relocation of water molecules from the inner to the outer binding regions of the membrane interface. When millimeter wave exposure is performed in the vicinity of the transition point, this effect can lead to an upward shift of the membrane phase transition temperature from the fluid to the gel phase. At a macroscopic level, this unique sensitivity may be explained by the universal dynamic behaviour of the membranes in the vicinity of the transition point, where a pretransitional increase of membrane area fluctuations, i.e., of the mean area per phospholipid headgroup, is observed. Exposure to millimeter waves increases the above fluctuations and enhances the second order character of the transition.

Induced movements of giant vesicles by millimeter wave radiation

Our previous study of interaction between low intensity radiation at 53.37GHz and cell-size system - such as giant vesicles - indicated that a vectorial movement of vesicles was induced. This effect among others, i.e. elongation, induced diffusion of fluorescent dye di-8-ANEPPS, and increased attractions between vesicles was attributed to the action of the field on charged and dipolar residues located at the membrane-water interface. In an attempt to improve the understanding on how millimeter wave radiation (MMW) can induce this movement we report here a real time evaluation of changes induced on the movement of giant vesicles. Direct optical observations of vesicles subjected to irradiation enabled the monitoring in real time of the response of vesicles. Changes of the direction of vesicle movement are demonstrated, which occur only during irradiation with a "switch on" of the effect. This MMW-induced effect was observed at a larger extent on giant vesicles prepared with negatively charged phospholipids. The monitoring of induced-by-irradiation temperature variation and numerical dosimetry indicate that the observed effects in vesicle movement cannot be attributed to local heating.

Adaptive response in human blood lymphocytes exposed to non-ionizing radiofrequency fields: resistance to ionizing radiation-induced damage

The aim of this preliminary investigation was to assess whether human peripheral blood lymphocytes which have been pre-exposed to non-ionizing radiofrequency fields exhibit an adaptive response (AR) by resisting the induction of genetic damage from subsequent exposure to ionizing radiation. Peripheral blood lymphocytes from four healthy donors were stimulated with phytohemagglutinin for 24 h and then exposed for 20 h to 1950 MHz radiofrequency fields (RF, adaptive dose, AD) at an average specific absorption rate of 0.3 W/kg. At 48 h, the cells were subjected to a challenge dose (CD) of 1.0 or 1.5 Gy X-irradiation (XR, challenge dose, CD). After a 72 h total culture period, cells were collected to examine the incidence of micronuclei (MN). There was a significant decrease in the number of MN in lymphocytes exposed to RF + XR (AD + CD) as compared with those subjected to XR alone (CD). These observations thus suggested a RF-induced AR and induction of resistance to subsequent damage from XR. There was variability between the donors in RF-induced AR. The data reported in our earlier investigations also indicated a similar induction of AR in human blood lymphocytes that had been pre-exposed to RF (AD) and subsequently treated with a chemical mutagen, mitomycin C (CD). Since XR and mitomycin-C induce different kinds of lesions in cellular DNA, further studies are required to understand the mechanism(s) involved in the RF-induced adaptive response.