Andrea Ciarmiello

In vivo detection of multidrug-resistant (MDR1) phenotype by technetium-99m sestamibi scan in untreated breast cancer patients

Technetium-99m sestamibi is a transport substrate recognised by the multidrug-resistant P-glycoprotein (Pgp). To test whether99mTc-sestamibi efflux is enhanced in breast carcinomas overexpressing Pgp, we determined the efflux rates of99mTc-sestamibi and Pgp levels in tumours from 30 patients with untreated breast carcinoma. Patients were intravenously injected with 740 MBq of99mTc-sestamibi and underwent a 15-min dynamic study followed by the acquisition of static planar images at 0.5, 1, 2 and 4 h. Tumour specimens were obtained from each patient 24 h after99mTc-sestamibi scan and Pgp levels were determined using125I-MRK16 monoclonal antibody and in vitro quantitative autoradiography. All breast carcinomas showed high uptake of99mTc-sestamibi and data from region of interest analysis on sequential images were fitted with a monoexponential function. The efflux rates of99mTc-sestamibi, calculated from decay-corrected time-activity curves, ranged between 0.00121 and 0.01690 min−1 and were directly correlated with Pgp levels measured in the same tumours (r=0.62;P<0.001). Ten out of 30 breast carcinomas (33%) contained 5 times more Pgp than benign breast lesions and showed a mean concentration of 5.73±1.63 pmol/g of tumour (group A). The remaining 20 breast carcinomas had a mean Pgp concentration of 1.29±0.64 pmol/g (group B), equivalent to that found in benign breast lesions.99mTc-sestamibi efflux from tumours of group A was 2.7 times higher than that observed in tumours of group B (0.00686±0.00390 min−1 vs 0.00250±0.00090 min−1,P<0.001). The in vivo functional test with99mTc-sestamibi showed a sensitivity and a specificity of 80% and 95%, respectively. In conclusion, the efflux rate of99mTc-sestamibi may be used for the in vivo identification of the multidrug resistant (MDR1) phenotype in untreated breast cancer patients.

Effects of induced asynchrony on left ventricular diastolic function in patients with coronary artery disease

OBJECTIVES This study was designed to increase asynchrony with sequential atrioventricular (AV) pacing and to study its effects on left ventricular isovolumetric relaxation, rapid filling and stiffness. BACKGROUND Left ventricular nonuniformity is a major determinant of diastolic function. METHODS Thirteen patients with coronary artery disease were studied by simultaneous equilibrium radionuclide angiography and cardiac catheterization during atrial and AV pacing. Ejection fraction and peak filling rate were measured by radionuclide angiography. Regional analysis was obtained by analyzing time-activity curves of four left ventricular sectors; systolic and diastolic asynchrony were evaluated as the coefficient of variation of time to end-systole and, respectively, time to peak filling rate in the four sectors. Cardiac index and left ventricular pressure were measured with high fidelity catheters at cardiac catheterization. The time constant of isovolumetric relaxation was derived from left ventricular pressure. Pressure-volume loops were assembled and constants of chamber stiffness were computed. RESULTS Atrioventricular pacing led to a decrease in cardiac index (3.7 +/- 0.9 to 3.3 +/- 0.8 liters/min per m2, p = 0.01) and peak filling rate (352 +/- 125 to 287 +/- 141 ml/s, p = 0.03; 2.4 +/- 0.8 to 2.0 +/- 0.8 end-diastolic counts/s, p = 0.02; 4 +/- 1.3 to 3.2 +/- 1.0 stroke counts/s, p = 0.008). The time constant of isovolumetric relaxation increased (57 +/- 10 to 64 +/- 12 ms, p = 0.04) and the global diastolic pressure-volume relation shifted upward. CONCLUSIONS Atrioventricular pacing induces left ventricular asynchrony, which is associated with a slower rate of isovolumetric relaxation. The isovolumetric relaxation lasts after the filling phase has begun, thereby reducing the rate of rapid filling.

Distinct brain volume changes correlating with clinical stage, disease progression rate, mutation size, and age at onset prediction as early biomarkers of brain atrophy in Huntington's disease.

Searching brain and peripheral biomarkers is a requisite to cure Huntingtons disease (HD). To search for markers indicating the rate of brain neurodegenerative changes in the various disease stages, we quantified changes in brain atrophy in subjects with HD. We analyzed the cross‐sectional and longitudinal rate of brain atrophy, quantitatively measured by fully‐automated multiparametric magnetic resonance imaging, as fractional gray matter (GM, determining brain cortex volume), white matter (WM, measuring the volume of axonal fibers), and corresponding cerebral spinal fluid (CSF, a measure of global brain atrophy), in 94 gene‐positive subjects with presymptomatic to advanced HD, and age‐matched healthy controls. Each of the three brain compartments we studied (WM, GM, and CSF) had a diverse role and their time courses differed in the development of HD. GM volume decreased early in life. Its decrease was associated with decreased serum brain‐derived‐neurotrophic‐factor and started even many years before onset symptoms, then decreased slowly in a nonlinear manner during the various symptomatic HD stages. WM volume loss also began in the presymptomatic stage of HD a few years before manifest symptoms appear, rapidly decreasing near to the zone‐of‐onset. Finally, the CSF volume increase began many years before age at onset. Its volume measured in presymptomatic subjects contributed to improve the CAG‐based model of age at onset prediction. The progressive CSF increase depended on CAG mutation size and continued linearly until the last stages of HD, perhaps representing the best marker of progression rate and severity in HD (R2= 0.25, P < 0.0001).

Stereotaxy-Based Regional Brain Volumetry Applied to Segmented MRI: Validation and Results in Deficit and Nondeficit Schizophrenia

A method for postprocessing of segmented routine brain MRI studies providing automated definition of major structures (frontal, parietal, occipital, and temporal lobes; cerebellar hemispheres; and lateral ventricles) according to the Talairach atlas is presented. The method was applied to MRI studies from 25 normal subjects (NV), 14 patients with deficit schizophrenia (DS), and 14 with nondeficit schizophrenia (NDS), to evaluate their gray matter and CSF regional volumes. The two patient groups did not differ in mean age at illness onset, duration of illness, severity of psychotic symptoms, or disorganization; DS had more severe avolition and worse social functioning than NDS. For validation purposes, brain structures were manually outlined on original MR images in 10 studies, thus obtaining reference measures. Manual and automated measures were repeated 1 month apart to measure reproducibilities of both methods. The automated method required less than 1 min/operator per study vs more than 30 min for manual assessment. Mean absolute difference per structure between the two techniques was 4.8 ml. Overall reproducibility did not significantly differ between the two methods. In subjects with schizophrenia, a significant decrease in GM and increase in CSF were found. GM loss was confined to frontal and temporal lobes. Lateral ventricles were significantly larger bilaterally in NDS compared to NV and only on the right in NDS compared to DS. The finding of greater structural brain abnormalities in NDS adds to the evidence that deficit schizophrenia does not represent just the more severe end of the schizophrenia continuum.

Juvenile Huntington's disease: does a dosage-effect pathogenic mechanism differ from the classical adult disease?

Huntingtons disease (HD) is caused by a CAG repeat mutation translating as a polyglutamine (poly(Q)) expansion in the huntingtin protein, whose main pathogenic mechanism is a gain of toxic function. In the case of large expansions beyond 60 repeats onset may result in juvenile HD (JHD, onset before 20 years of age). However, the triplet number does not represent the only onset modifier even in case of large expansions, mechanisms other than the size of the mutation contribute to the phenotype. In this review we discuss the possibility that some of the pathogenic mechanisms contributing to age at onset and progression may differ in the early onset HD compared with the classical adult pathology.

Riluzole protects Huntington disease patients from brain glucose hypometabolism and grey matter volume loss and increases production of neurotrophins

PurposeHuntington disease (HD) mutation increases gain-of-toxic functions contributing to glutamate-mediated excitotoxicity. Riluzole interferes with glutamatergic neurotransmission, thereby reducing excitotoxicity, enhancing neurite formation in damaged motoneurons and increasing serum concentrations of BDNF, a brain cortex neurotrophin protecting striatal neurons from degeneration.MethodsWe investigated metabolic and volumetric differences in distinct brain areas between 11 riluzole-treated and 12 placebo-treated patients by MRI and 18F-fluoro-2-deoxy-d-glucose (FDG) PET scanning, according to fully automated protocols. We also investigated the influence of riluzole on peripheral growth factor blood levels.ResultsPlacebo-treated patients showed significantly greater proportional volume loss of grey matter and decrease in metabolic FDG uptake than patients treated with riluzole in all cortical areas (p<0.05). The decreased rate of metabolic FDG uptake correlated with worsening clinical scores in placebo-treated patients, compared to those who were treated with riluzole. The progressive decrease in metabolic FDG uptake observed in the frontal, parietal and occipital cortex correlated linearly with the severity of motor scores calculated by Unified Huntington Disease Rating Scale (UHDRS-I) in placebo-treated patients. Similarly, the rate of metabolic changes in the frontal and temporal areas of the brain cortex correlated linearly with worsening behavioural scores calculated by UHDRS-III in the placebo-treated patients. Finally, BDNF and transforming growth factor beta-1 serum levels were significantly higher in patients treated with riluzole.ConclusionThe linear correlation between decreased metabolic FDG uptake and worsening clinical scores in the placebo-treated patients suggests that FDG-PET may be a valuable procedure to assess brain markers of HD.

Early defect of transforming growth factor β1 formation in Huntington's disease.

A defective expression or activity of neurotrophic factors, such as brain‐ and glial‐derived neurotrophic factors, contributes to neuronal damage in Huntington’s disease (HD). Here, we focused on transforming growth factor‐β (TGF‐β1), a pleiotropic cytokine with an established role in mechanisms of neuroprotection. Asymptomatic HD patients showed a reduction in TGF‐β1 levels in the peripheral blood, which was related to trinucleotide mutation length and glucose hypometabolism in the caudate nucleus. Immunohistochemical analysis in post‐mortem brain tissues showed that TGF‐β1 was reduced in cortical neurons of asymptomatic and symptomatic HD patients. Both YAC128 and R6/2 HD mutant mice showed a reduced expression of TGF‐β1 in the cerebral cortex, localized in neurons, but not in astrocytes. We examined the pharmacological regulation of TGF‐β1 formation in asymptomatic R6/2 mice, where blood TGF‐β1 levels were also reduced. In these R6/2 mice, both the mGlu2/3 metabotropic glutamate receptor agonist, LY379268, and riluzole failed to increase TGF‐β1 formation in the cerebral cortex and corpus striatum, suggesting that a defect in the regulation of TGF‐β1 production is associated with HD. Accordingly, reduced TGF‐β1 mRNA and protein levels were found in cultured astrocytes transfected with mutated exon 1 of the human huntingtin gene, and in striatal knock‐in cell lines expressing full‐length huntingtin with an expanded glutamine repeat. Taken together, our data suggest that serum TGF‐β1 levels are potential biomarkers of HD development during the asymptomatic phase of the disease, and raise the possibility that strategies aimed at rescuing TGF‐β1 levels in the brain may influence the progression of HD.

Aripiprazole in the treatment of Huntington’s disease: a case series

Objectives: The aim of the study was to describe the effects of aripiprazole, a new atypical antipsychotic drug that acts as a partial dopamine agonist on motor, behavioral and cognitive functions in patients with genetically confirmed Huntington’s disease (HD). Methods and results: Three HD patients were evaluated for Unified Huntington Disease Rating Scale part I and II and Beck Depression Inventory at baseline, after two months and one-year treatment. Aripiprazole effectively controlled involuntary movements and psychiatric symptoms, with effects on cognitive functions. Conclusions: Our case reports suggest that aripiprazole is well tolerated, remarkably improving some of the motor and behavioral symptoms in patients affected by HD. Randomized, controlled, long-term studies are warranted.

Measurement of global brain atrophy in Alzheimer's disease with unsupervised segmentation of spin-echo MRI studies.

In 16 patients with probable Alzheimers disease (AD; NINDS criteria, age range 56–78 years), gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) absolute and fractional volumes were measured with an unsupervised multiparametric post‐processing segmentation method based on estimates of relaxation rates R1, R2 (R1 = 1/T1; R2 = 1/T2) and proton density [N(H)] from conventional spin‐echo studies (Alfano et al. Magn. Reson. Med. 1997;37:84–93). Global brain atrophy, and GM and WM fractions significantly correlated with Mini‐Mental Status Examination and Blessed Dementia Scale scores. Compared with normals, brain compartments in AD patients showed decreased GM (−6.84 ± 1.58%) and WM fractions (−9.79 ± 2.47%) and increased CSF fractions (+58.80 ± 10.37%). Changes were more evident in early‐onset AD patients. In AD, measurement of global brain atrophy obtained by a computerized procedure based on routine magnetic resonance studies could complement the information provided by neuropsychological tests for the assessment of disease severity. J. Magn. Reson. Imaging 2000;11:260–266.

PET/MRI and the revolution of the third eye.

The 20th century diagnostic imaging scenario almost for the whole of its existence was divided into two well-separated universes: (1) the morphostructural, in which information on anatomy and structures are acquired, with pathology as the gold standard, and (2) the functional, in which normal and altered functions are analysed, with pathophysiology as the reference. Morphostructural techniques show differences in density, as observed in a picture taken in a steady state as a freezeframe effectively not allowing distinction between a living and a dead body. Functional techniques, which can only be applied in a living being, show dynamic changes as in a movie where “time” is a major element, taking information from parameters such as differences in concentration and movement. This category includes techniques such as urography and cardio-CT, in which increasing doses in dynamic scans and the number of acquisitions are important considerations [1]. To avoid a high radiation dose, the lowest number of frames are acquired, and this is a major disadvantage with respect to nuclear medicine and MRI, which are queens in “clinical” functional imaging because of their superiority in studying pathophysiology. Nuclear medicine as molecular imaging