Magnetocardiography measurements with 4He vector optically pumped magnetometers at room temperature

In this paper, we present a proof of concept study which demonstrates for the first time the possibility of recording magnetocardiography (MCG) signals with ⁴He vector optically pumped magnetometers (OPM) operated in a gradiometer mode. Resulting from a compromise between sensitivity, size and operability in a clinical environment, the developed magnetometers are based on the parametric resonance of helium in a zero magnetic field. Sensors are operated at room temperature and provide a tri-axis vector measurement of the magnetic field. Measured sensitivity is around 210 f T (√Hz)^-1 in the bandwidth (2 Hz; 300 Hz). MCG signals from a phantom and two healthy subjects are successfully recorded. Human MCG data obtained with the OPMs are compared to reference electrocardiogram recordings: similar heart rates, shapes of the main patterns of the cardiac cycle (P/T waves, QRS complex) and QRS widths are obtained with both techniques.

Monolayer protected gold nanoparticles with metal-ion binding sites: functional systems for chemosensing applications

Au NPs containing binding sites for metal ions in the monolayer are attractive components of sensing assays.

Health economic evaluation of a vaccine for the prevention of herpes zoster (shingles) and post-herpetic neuralgia in adults in Belgium

OBJECTIVE

To determine the cost-effectiveness of vaccination against herpes zoster (HZ) and post-herpetic neuralgia (PHN) in individuals aged 60 years and older in Belgium.

METHODS

A Markov model was developed to compare the cost-effectiveness of vaccination with that of a policy of no vaccination. The model estimated the lifetime incidence and consequences of HZ and PHN using inputs derived from Belgian data, literature sources, and expert opinion. Cost-effectiveness was measured by the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life-year (QALY) gained.

RESULTS

Vaccination in individuals aged 60 years and older resulted in ICERs of €6,799 (third party payer perspective), €7,168 (healthcare perspective), and €7,137 (societal perspective). The number needed to vaccinate to prevent one case was 12 for HZ, and 35 or 36 for PHN depending on the definition used. Univariate sensitivity analyses produced ICERs of €4,959-19,052/QALY; duration of vaccine efficacy had the greatest impact on cost-effectiveness. Probabilistic sensitivity analysis showed at least a 94% probability of ICERs remaining below the unofficial €30,000 threshold.

DISCUSSION

Key strengths of the model are the combination of efficacy data from a pivotal clinical trial with country-specific epidemiological data and complete sensitivity analysis performed. Main limitations are the use of non country-specific PHN proportion and non Belgian disease-specific utilities. Results are comparable with those recently published.

CONCLUSIONS

HZ vaccination in individuals aged 60 years and older would represent a cost-effective strategy in Belgium.

Frontotemporal dementia: impact of P301L tau mutation on a healthy carrier

Frontotemporal dementia (FTD) is the second commonest form of dementia after Alzheimer's disease, but its clinical and biological features are less well known. To uncover its earliest signs, we studied the main clinical, neuroimaging, and biochemical findings in an asymptomatic carrier from a three generation FTD family, bearing the P301L pathogenic mutation in the tau gene. Except for selective impairment on the Verbal Fluency Test for letters, all cognitive tests were normal. The brain computed tomography scan was normal, but the brain single photon emission computed tomography and statistical parametric mapping (SPECT-SPM) scan revealed bilateral frontal lobe hypoperfusion. Levels of total tau, 181P-tau, and Abeta1-42 in the cerebrospinal fluid were increased compared with control values. We conclude that detection of these distinctive abnormalities should improve early diagnostic accuracy for FTD and help distinguish it from Alzheimer's disease.

Executive dysfunction and avoidant personality trait in myotonic dystrophy type 1 (DM-1) and in proximal myotonic myopathy (PROMM/DM-2)

A previous study in proximal myotonic myopathy (PROMM/DM-2) and myotonic dystrophy type 1 (DM-1) using brain positron emission tomography demonstrated a reduced cerebral blood flow in the frontal and temporal regions associated with cognitive impairment. The objective was to investigate further cognitive and behavioural aspects in a new series of patients with DM-1 and PROMM/DM-2. Nineteen patients with genetically determined PROMM/DM-2 and 21 patients with moderately severe DM-1 underwent neuropsychological testing and neuropsychiatric interviews. DM-1 and PROMM/DM-2 patients had significantly lower scores on tests of frontal lobe function compared to controls. Neuropsychiatric interviews demonstrated an avoidant trait personality disorder in both patient groups. Brain single photon emission computed tomography showed frontal and parieto-occipital hypoperfusion. The results suggest that there is a specific cognitive and behavioural profile in PROMM/DM-2 and in DM-1, and that this profile is associated with hypoperfusion in frontal and parieto-occipital regions of the brain.

In vivo serotonin 5HT(2A) receptor binding and personality traits in healthy subjects: a positron emission tomography study

Using positron emission tomography (PET) and [(11)C]raclopride, an association between striatal D(2) dopamine receptors and emotional detachment has been recently reported. Several laboratory findings indicate a link between the serotoninergic system and harm avoidance. In this study we investigated, in a group of healthy volunteers, the relationship between the in vivo binding of 3-(2'-[(18)F]fluoroethyl)spiperone ([(18)F]FESP) to cortical 5HT(2) and striatal D(2) receptors and three personality dimensions, i.e., "novelty seeking," "reward dependence," and "harm avoidance." Eleven healthy volunteers were evaluated by means of the Tridimensional personality Questionnaire (C. R., Arch. Gen. Psychiatry 44: 573-588.) and underwent a PET scan with [(18)F]FESP. Harm avoidance showed a significant inverse correlation with [(18)F]FESP binding in the cerebral cortex, particularly in the frontal cortex (R(2) = -0.709, P = 0.0145) and left parietal cortex (R = -0.629, P = 0.038) but not in the basal ganglia (r = -0.176, P = 0.651). Similar results were obtained using SPM at a P threshold of 0.05. No significant correlation was observed with novelty seeking or reward dependence. In the cerebral cortex, high values of [(18)F]FESP binding values are associated with a high tendency to avoid danger, indicating involvement of the serotoninergic system and, in particular, 5HT(2A) receptors, in this trait of personality. The results of this as well as of previous studies on personality dimensions indicate the existence of a relationship between behavioral and neurobiological factors. In addition these results support the concept that the variability of PET data may be explained by neurochemical differences related to the prevalence of specific personality traits.

The feasibility of statistical parametric mapping for the analysis of positron emission tomography studies using 11C-2-beta-carbomethoxy-3-beta-(4-fluorophenyl)-tropane in patients with movement disorders

Movement disorders, including Parkinson's disease and parkinsonian syndromes, e.g. progressive supranuclear palsy, multiple system atrophy, and Lewy body dementia, may be difficult to differentiate among each other at an early stage, since they may share similar clinical features and response to dopaminergic drugs. As new tracers for imaging the dopamine transporters become available, the use of positron emission tomography (PET) for the differential diagnosis of movement disorders is gaining clinical relevance. Visual interpretation is generally used for PET image analysis. However, the use of some form of less subjective analysis is desirable in order to detect subtle changes that may be difficult to identify by visual interpretation and to achieve an operator independent analysis. To this end this study was aimed at assessing the feasibility of using statistical parametric mapping (SPM) for the clinical evaluation of single PET scans performed with 2-beta-carbomethoxy-3-beta-(4-fluorophenyl)-tropane ( C-beta-CIT-FE). Eleven healthy volunteers and five patients with movement disorders (Parkinson's disease, essential tremor, PSP and Lewy body dementia) were included in this study. Each subject underwent a PET study after i.v. injection of C-beta-CIT-FE. The PET images of C-beta-CIT-FE distribution acquired between 60 and 90 min were spatially fitted into the Talairach and Tournoux space. A template of normal C-beta-CIT-FE distribution was derived from studies in the 11 normal control subjects. Different patterns of reduction of the uptake of the tracer were detected in the basal ganglia of the five patients, in relation to each pathological condition. The patterns of distribution were all consistent with the severity and type of disease. The results of this study demonstrate the feasibility of differentiating among different states of dopaminergic impairment, due to Parkinson's disease and parkinsonian syndromes, by using PET scans with C-beta-CIT-FE and by using the SPM procedure for analysis of the data.

New perspectives on neurochemical effects of amantadine in the brain of parkinsonian patients: a PET - [(11)C]raclopride study

Amantadine, is a non competitive NMDA receptors antagonist that has been proved beneficial in Parkinson's disease. However its mechanism of action at therapeutic doses is still under discussion. Aim of this study was to evaluate the effect of repeated administration of amantadine on striatal dopaminergic system by measuring [(11)C]raclopride binding to striatal D(2) dopamine receptors, in patients with moderate idiopathic Parkinson's disease. Eight patients completed the study undergoing a PET scan, before and after 10-14 days treatment with Amantadine (200 mg/day). Patients were on treatment with L-DOPA, which was suspended 1 night before each PET scans, and free from dopaminergic agonists, anticholinergic and antidepressants. Amantadine treatment significantly increased [(11)C-]Raclopride binding (caudate: 10% p = 0.04; putamen 11% p = 0.01). A slight reduction (-7.3%, p = 0.062) of UPDRS total scores was also observed. The increased availability of striatal D(2) receptors, is likely to be caused by drug induced modification of receptors expression. This hypothesis is consistent with previous experiments, indicating an increase in striatal D(2) receptors in rats treated with amantadine or other non competitive NMDA antagonists and suggests that the neo-synthesis of D(2) receptors may represent a reinforcing mechanism of drug efficacy.

Striatal dopaminergic denervation in early and late onset Parkinson's disease assessed by PET and the tracer [11C]FECIT: preliminary findings in one patient with autosomal recessive parkinsonism (Park2)

Neuroimaging studies of striatal dopamine transporters (DAT) have shown that this measurement is a specific marker of dopaminergic degeneration in patients with Parkinson's disease. However, little data is available in subjects with early disease onset, particularly in those with autosomal recessive parkinsonism. We measured striatal DAT binding in 10 patients with early onset PD (onset <40 years) and in 10 with late onset PD (onset >50 years) using PET and the tracer [(11)C]FECIT. One early onset subject presented a mutation in the parkin gene consistent with autosomal recessive parkinsonism. Data were compared with those of 15 control subjects. We found a comparable decrement of striatal DAT binding in early and late onset PD. Loss was widespread and bilateral in the patient carrying the Park2 mutation, suggesting a different pattern of denervation in these individuals.

Acute effect of 3-(4-acetamido)-butyrril-lorazepam (DDS2700) on brain function assessed by PET at rest and during attentive tasks

The aim of this study was to assess, by positron emission tomography (PET), the effect on cerebral functional activity of a new lorazepam-gamma-aminobutyric acid (GABA) conjugate [3-(4-acetamido)-butyrril lorazepam (DDS2700)]. Ten healthy volunteers were studied by PET and [18F]fluoro-deoxy-D-glucose ([18F]FDG) under baseline conditions and following the administration of DDS2700. Regional cerebral blood flow (rCBF) was measured by PET and 15O-water in three additional participants while they performed attentive tasks, before and after drug administration. DDS2700 induced a decrease in the regional cerebral metabolic rate of glucose (rCMRglu) in the thalamus (-17%), cerebellum (-11%) and caudate nucleus (-8%). The observed effects on glucose metabolism were probably related to the subjective sedation and tiredness reported by the participants. During the attentive tasks, rCBF increased in frontal and temporal regions associated with attentional processing of auditory material. These circuits were no longer active after DDS2700 administration, while rCBF increased in cingulate cortex, occipitoparietal regions, pons and cerebellum. These drug-induced activations might be directly related to intervening sleepiness and to the consequent effort in keeping attention focused on the tasks. The effects of DDS2700 on glucose metabolism at rest, and on rCBF during activation conditions, indicate a drug action on cerebral networks involved in alertness, vigilance and attention maintenance. PET assessment by [18F]FDG and water may provide complementary information in pharmacodynamic studies.

The status of dopamine nerve terminals in Parkinson's disease and essential tremor: a PET study with the tracer [11-C]FE-CIT

Neuroimaging studies of the striatal dopamine transporter (DAT) are useful in the assessment of the dopaminergic system in Parkinson's disease (PD). We used positron emisson tomography (PET) and the tracer [11C]FE-CIT to measure DAT binding in the caudate nucleus and putamen of 31 patients with PD, 5 with essential tremor and 8 healthy control subjects. Of the patients with PD, 17 were drug naive, while the others were either on levodopa or dopamine agonist monotherapy. DAT binding was significantly reduced in the caudate nucleus and to a greater extent in the putamen of PD patients compared to both healthy controls and essential tremor individuals. No overlap was observed between putamen values in PD and normals. No differences were found between controls and essential tremor subjects. These data confirm that measurements of DAT binding can provide an accurate and highly sensitive measure of degeneration in the dopamine system in PD.

A PET study with [11-C]raclopride in Parkinson's disease: preliminary results on the effect of amantadine on the dopaminergic system

Amantadine has been proved to be beneficial in Parkinson's disease. Although it is still uncertain which neurochemical events are modified at therapeutic doses, an increase in dopaminergic tone secondary to NMDA receptor blockade and a direct inhibition of the glutamatergic overactivity have been suggested to be involved in its clinical effects. The aim of this study was to evaluate the effects of amantadine on the dopaminergic system by measuring the in vivo binding of [11-C]raclopride to D2 dopamine receptors in the basal ganglia of 6 patients with idiopathic Parkinson's disease. Each patient underwent a PET study, before and after 14 days of treatment with amantadine (200 mg/day). Repeated treatment with therapeutic doses of amantadine induced a moderate increase in the in vivo binding of [11C]raclopride in the putamen of PD patients. This observation indicates that in PD patients, 200 mg/day amantadine does not produce an increase in extracellular levels of dopamine sufficiently to inhibit raclopride binding or that, if present, is it masked by a concurrent increase in receptor availability, as recently reported in rat striatum.

Increased 5-hydroxytryptamine-2 receptor binding in the frontal cortex of depressed patients responding to paroxetine treatment: a positron emission tomography scan study

The changes in aminergic receptors elicited by antidepressant treatments have been extensively examined in the brain of experimental animals using radioligand and molecular techniques. However, there is a very limited direct information regarding the changes effected by such treatments in the human brain, as well as its relationship to clinical improvement. Using positron emission tomography (PET) scanning, the authors examined the cortical 5-Hydroxytryptamine-2A (5-HT2A) receptor binding of [18F]fluoro-ethyl-spiperone after a 4-week treatment with the selective serotonin reuptake inhibitor paroxetine. [18F]fluoro-ethyl-spiperone labels 5-HT2A receptors in the cortex and dopamine D2 receptors in the basal ganglia. A binding index (BI) was calculated in the frontal cortex and the basal ganglia (mostly caudate-putamen) by reference to cerebellum. Thirty-seven inpatients with major depression with a mean +/- SD score on the 21-item Hamilton Rating Scale for Depression (HAM-D-21) of 26.3 +/- 4.3 at admission were treated with paroxetine 40 mg/day. After 4 weeks of treatment, the BI in the frontal cortex of remitted patients (HAM-D-21 score = 4.7 +/- 4.0; N = 20) was significantly greater than the score in nonresponder patients (HAM-D-21 score = 21.2 +/- 4.0; N = 17) (BI = 0.54 +/- 0.15 and 0.41 +/- 0.17, respectively; p < 0.02). No such difference was observed in the basal ganglia (5.45 +/- 1.11 and 5.39 +/- 0.82, respectively; p = 0.85). The significant difference in cortical BI persisted when age was used as covariate (p < 0.016). These data suggest that clinical improvement in patients treated with paroxetine is associated with an increase in the density of 5-HT2A receptors in the frontal cortex.

Effects of fluvoxamine treatment on the in vivo binding of [F-18]FESP in drug naive depressed patients: a PET study

This study investigates the effect of chronic treatment with Fluvoxamine, a potent and specific serotonin reuptake sites inhibitor (SSRI), on 5HT(2) serotonin and D(2) dopamine receptors in the brain of drug naive unipolar depressed patients. Drug effect was evaluated in different cortical areas and in the basal ganglia by positron emission tomography (PET) and fluoro-ethyl-spiperone ([(18)F]FESP), an high affinity 5HT(2) serotonin and D(2) dopamine receptors antagonist. Patients underwent a PET study at recruitment and after clinical response to Fluvoxamine treatment. Nine of the 15 patients recruited completed the study. Fluvoxamine treatment significantly improved clinical symptoms and modified [(18)F]FESP binding in the frontal and occipital cortex of all of the nine patients who completed the study; in these regions a mean 31% increase in the in vivo [(18)F]FESP binding was found (P < 0.01). On the contrary, no significant changes in the in vivo [(18)F]FESP binding were found in the basal ganglia where [(18)F]FESP binds mainly to D(2) dopamine receptors. Chronic treatment with Fluvoxamine significantly increases the in vivo binding of [(18)F]FESP in the frontal and occipital cortex of drug naive unipolar depressed patients. The increase of the in vivo binding of [(18)F]FESP may reflect a modification in 5HT(2) binding capacity secondary to changes in cortical serotonin activity.

Synthesis and in vivo evaluation of [11C]ICI 118551 as a putative subtype selective beta2-adrenergic radioligand

Erytro-(+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[ iso-propylamino]-2-butanol (ICI 118551) a potent clinically used beta2 adrenergic antagonist, was labelled with carbon-11 (t1/2 = 20.4 min) as a potential radioligand for the non-invasive assessment of beta2 adrenergic receptors in the lung with positron emission tomography (PET). The radiolabelled compound was prepared by reductive N-alkylation of its des-isopropyl precursor with [2-11C]acetone. (+/-)-[11C]ICI 118551 was obtained in greater than 98% radiochemical purity in 30 min with a radiochemical yield of 15 + 5% (non-decay corrected) and a specific radioactivity 2.5 +/- 0.5 Ci/micromol. The biological evaluation of racemic erythro (+/-)-[11C]ICI 118551 in rats and Macaca Nemestrina shows a high radioactivity uptake in lung and heart. However, in both animal models no detectable displacement of lung radioactivity concentration was observed after pre-treatment with propranolol or ICI 118551, which indicates that in this organ, radioligand uptake is mostly due to non-specific binding. The biological data suggest that erythro (+/-)-[11C]ICI 118551 is not adequate to be further developed as a tracer for beta2 adrenergic receptor imaging in vivo.

Diagnostic pitfalls of echography in a case of hepatic cavernous hemangioma

An ecographic study of the liver in a 55-year-old female, with a history of mastectomy for a breast ductal cancer, showed multiple focal lesions. On computer tomography, we interpreted these lesions as metastatic disease. 99m Tc-labeled RBC showed non-homogeneous flow distribution in the right lobe of the liver. Fine needle aspiration biopsy under ecographic guidance showed no metastatic disease, and suggested a vascular lesion. The presence of spindle-shaped cells, reactive for CD 34 and for factor VIII, enabled definitive diagnosis of angiomatous lesion. Cytological confirmation of each hepatic mass is a mandatory prerequisite for any therapy.

Children's comprehension of Italian comparative forms and the three-term problem solution

Children aged 7; 6 to 10; 0 were required to solve 2-term relational problems in order to explore developmental changes in the comprehension of Italian positive and negative comparatives. The results indicate that at first children spatially represent the two terms of the positive comparatives in a contrastive-positional way, while in the second phase children represent the terms relationally. Comprehension of negative comparatives is characterized by three phases: a contrastive-positional phase, a presuppositional phase and a relational representation. The older subjects were subsequently divided into two groups based on their previous performance, and required to solve 3-term series problems in order (a) to confirm and extend the result of the first experiment; (b) to examine whether the linguistic comprehension of the comparative was a sufficient and necessary prerequisite for solution of 3-term problems. The developmental sequence of comprehension of comparatives was confirmed. Furthermore, the results suggested how cognitive load in making transitive inferences is influenced by linguistic encoding. The data are discussed in the light of a linguistic model versus a spatial representation model. A developmental version of a spatial representation model is proposed to account for the results.