Corradina Caracò

Voxel-based comparison of rCBF SPET images in frontotemporal dementia and Alzheimer's disease highlights the involvement of different cortical networks.

Abstract. Characteristic patterns of regional cerebral blood flow (rCBF) reduction, as detected by technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) single-photon emission tomography (SPET), may help clinicians in differentiating patients with frontotemporal dementia (FTD) from those with Alzheimers disease (AD). However, in some cases these patients may share common rCBF abnormalities and the visual analysis and/or the region of interest (ROI) approach may not sensitively detect more localised focal changes that could be more specific for each pathology. Recently, automated voxel-by-voxel statistical analysis of perfusion brain maps has been applied to SPET images. This method has the advantage of including the rCBF information for the whole brain for statistical analysis without any a priori hypothesis regarding the regions possibly involved. This could result in a better characterisation of rCBF differences in brain regions while also reducing the operators subjectivity and the time required for data analysis. The purpose of this study was to apply such a technique to highlight the specific brain areas showing a relative functional involvement in FTD and AD. Thus, we compared the relative rCBF patterns obtained in eight FTD patients with those obtained in 21 AD patients using 99mTc-HMPAO SPET and statistical parametric mapping (SPM). When FTD patients were compared with AD patients, relatively lower rCBF was observed in right medial frontal cortex (BA 8, 9, 10), right anterior cingulate cortex (BA 32), right temporal cortex (BA 21/22), right orbitofrontal cortex (BA 11) and ventrolateral prefrontal cortex (BA 47); in BA 47 the reduction was evident bilaterally but was more marked on the right side. On the other hand, when AD patients were compared with FTD patients, a significant relative rCBF decrease was found in the bilateral superior parietal cortex (BA 7); this decrease was more extensive on the left side, where it also included the inferior parietal (BA 40), superior occipital (BA 19) and temporo-occipital regions (BA 39, 19). The results of this study confirm the preferential involvement of the frontotemporal regions in FTD patients and of the temporoparietal regions in AD patients. Furthermore, they highlight the networks that are more specifically impaired in these disorders and that could be implicated in the emotional-behavioural and cognitive disturbances that characterise FTD and AD respectively.

Acute administration of antipsychotics modulates Homer striatal gene expression differentially

Typical and atypical antipsychotics, the mainstay of schizophrenia pharmacotherapy, have been demonstrated to affect differently neuronal gene expression in several preclinical paradigms. Here we report the differential gene expression of the glutamatergic post-synaptic density proteins Homer and PSD-95 in rat forebrain following acute haloperidol or olanzapine treatment. Moreover, considering the extensive interactions between dopaminergic and opioidergic systems we also measured striatal preproenkephalin mRNA. Male Sprague-Dawley rats were treated with haloperidol 1 mg/kg or olanzapine 0.5 mg/kg or vehicle, i.p. and sacrificed 3 h after the injection. Homer gene expression was significantly increased in caudate putamen and nucleus accumbens of rats treated with haloperidol and in the core of accumbens of rats treated with olanzapine. No changes were detected for Homer in prefrontal and parietal cortex in any of the experimental groups. PSD-95 gene expression was not modulated in our paradigm by administration of either typical or atypical antipsychotics. These results (1) suggest a differential modulation of Homer by typical and atypical antipsychotics; (2) confirm that Homer can be induced as an early gene with putative direct effect on neuronal plasticity and (3) demonstrate different response to antipsychotics by different classes of postsynaptic density proteins at glutamatergic synapses.

Early PET/CT scan is more effective than RECIST in predicting outcome of patients with liver metastases from colorectal cancer treated with preoperative chemotherapy plus bevacizumab.

Markers predictive of treatment effect might be useful to improve the treatment of patients with metastatic solid tumors. Particularly, early changes in tumor metabolism measured by PET/CT with 18F-FDG could predict the efficacy of treatment better than standard dimensional Response Evaluation Criteria In Solid Tumors (RECIST) response. Methods: We performed PET/CT evaluation before and after 1 cycle of treatment in patients with resectable liver metastases from colorectal cancer, within a phase 2 trial of preoperative FOLFIRI plus bevacizumab. For each lesion, the maximum standardized uptake value (SUV) and the total lesion glycolysis (TLG) were determined. On the basis of previous studies, a ≤ −50% change from baseline was used as a threshold for significant metabolic response for maximum SUV and, exploratively, for TLG. Standard RECIST response was assessed with CT after 3 mo of treatment. Pathologic response was assessed in patients undergoing resection. The association between metabolic and CT/RECIST and pathologic response was tested with the McNemar test; the ability to predict progression-free survival (PFS) and overall survival (OS) was tested with the Log-rank test and a multivariable Cox model. Results: Thirty-three patients were analyzed. After treatment, there was a notable decrease of all the parameters measured by PET/CT. Early metabolic PET/CT response (either SUV- or TLG-based) had a stronger, independent and statistically significant predictive value for PFS and OS than both CT/RECIST and pathologic response at multivariate analysis, although with different degrees of statistical significance. The predictive value of CT/RECIST response was not significant at multivariate analysis. Conclusion: PET/CT response was significantly predictive of long-term outcomes during preoperative treatment of patients with liver metastases from colorectal cancer, and its predictive ability was higher than that of CT/RECIST response after 3 mo of treatment. Such findings need to be confirmed by larger prospective trials.

The role of radiolabeled somatostatin analogs in adrenal imaging.

We investigated the role of radiolabeled somatostatin analogs (SAs) in adrenal imaging. We evaluated 15 patients (6 men and 9 women, mean age 47 +/- 17 years) with imaging-detected adrenal tumors. Patient population was divided into two groups on the basis of the nature of adrenal lesions. Group 1 consisted of patients with benign adrenal lesions (n = 10). Group 2 consisted of patients with malignant adrenal lesions (n = 5). Pathology examinations were obtained in 13 cases: 7 pheochromocytomas, 2 adenomas, 2 cysts, 1 carcinoma, and 1 fibro-histiocytoma. One patient had a proven diagnosis of non-small-cell lung cancer associated with the presence of a right adrenal mass. The last patient had a clinical diagnosis of Werner syndrome associated with the presence of a large left adrenal mass. All patients underwent scientigraphic studies using radiolabeled SAs, of which indium-111 (In-111) pentetreotide was used in 11 cases and technetium-99m (Tc-99m)-labeled peptides (P-587 or P-829) were used in the remaining four cases. No significant labeled SAs uptake was observed in the majority (8 of 10, 80%) of the benign adrenal lesions (Group 1); however, increased uptake was found in two benign pheochromocytomas. Conversely, significant labeled SAs uptake was observed in the majority (4 of 5, 80%) of the malignant adrenal lesions (Group 2); however, the last lesion (carcinoma) did not show abnormal uptake. Results of this study show that the majority of benign adrenal tumors do not concentrate radiolabeled SAs; conversely, the majority of malignant adrenal lesions show significant SAs uptake, suggesting the presence of somatostatin receptors. This finding may allow the use of somatostatin as a treatment agent in malignant adrenal tumors. Thus, the main role of labeled SAs in adrenal imaging consists of lesion characterization rather than tumor detection and localization.

Secretive and proliferative tumor profile helps to select the best imaging technique to identify postoperative persistent or relapsing medullary thyroid cancer

In patients with postoperative persistent medullary thyroid cancer (MTC), the tumor detection rate is generally low for most of the imaging techniques now available. The aim of this study was to investigate if the clinico-biological profile of the tumor may indicate which imaging technique to perform in order to identify postoperative persistent or relapsing MTC foci. Thirty-five consecutive MTC patients with detectable and progressively increasing postoperative serum concentrations of calcitonin were enrolled in the study. The detection rates of 18F-deoxy-d-glucose (FDG)-positron emission tomography (PET), somatostatin receptor scintigraphy (SRS), and 131I-metaiodobenzylguanidine scintigraphy (MIBG) were compared in relation with calcitonin and carcinoembryonic antigen serum concentrations, Ki-67 score and results of conventional imaging techniques (CIT). FDG-PET positivity was significantly associated with calcitonin serum concentrations >400 pg/ml and Ki-67 score >2.0% (P<0.05), while SRS positivity was associated with calcitonin serum concentrations >800 pg/ml (P<0.05). SRS positivity significantly correlated with tumor appearance at CIT (P<0.01), while FDG-PET was positive in nine CIT-negative patients. The secretive and proliferative tumor profile may guide the choice of the imaging technique to use in the follow-up of patients with MTC. A Ki-67 score >2.0% suggests to perform a FDG-PET in addition to conventional imaging. Calcitonin secretion predicts both FDG-PET and SRS uptake but SRS positivity is generally found only in patients with well defined MTC lesions that are also detectable at the conventional imaging examination. MIBG outcome is not predicted by any clinico-biological factors here investigated.

Neoadjuvant FOLFIRI+bevacizumab in patients with resectable liver metastases from colorectal cancer: a phase 2 trial

Background:Preoperative treatment of resectable liver metastases from colorectal cancer (CRC) is a matter of debate. The aim of this study was to assess the feasibility and activity of bevacizumab plus FOLFIRI in this setting.Methods:Patients aged 18–75 years, PS 0–1, with resectable liver-confined metastases from CRC were eligible. They received bevacizumab 5 mg kg−1 followed by irinotecan 180 mg m−2, leucovorin 200 mg m−2, 5-fluorouracil 400 mg m−2 bolus and 5-fluorouracil 2400 mg m−2 46-h infusion, biweekly, for 7 cycles. Bevacizumab was stopped at cycle 6. A single-stage, single-arm phase 2 study design was applied with 1-year progression-free rate as the primary end point, and 39 patients required.Results:From October 2007 to December 2009, 39 patients were enrolled in a single institution. Objective response rate was 66.7% (95% exact CI: 49.8–80.9). Of these, 37 patients (94.9%) underwent surgery, with a R0 rate of 84.6%. Five patients had a pathological complete remission (14%). Out of 37 patients, 16 (43.2%) had at least one surgical complication (most frequently biloma). At 1 year of follow-up, 24 patients were alive and free from disease progression (61.6%, 95% CI: 44.6–76.6). Median PFS and OS were 14 (95% CI: 11–24) and 38 (95% CI: 28–NA) months, respectively.Conclusion:Preoperative treatment of patients with resectable liver metastases from CRC with bevacizumab plus FOLFIRI is feasible, but further studies are needed to define its clinical relevance.

Use of neoadjuvant electrochemotherapy to treat a large metastatic lesion of the cheek in a patient with melanoma

BackgroundApproximately 200,000 new cases of melanoma are diagnosed worldwide each year. Skin metastases are a frequent event, occurring in 18.2% of cases. This can be distressing for the patient, as the number and size of cutaneous lesions increases, often worsened by ulceration, bleeding and pain. Electrochemotherapy (ECT) is a local modality for the treatment of cutaneous or subcutaneous tumors that allows delivery of low- and non-permeant drugs into cells. ECT has been used in palliative management of metastatic melanoma to improve patients’ quality of life. This is, to our knowledge, the first application of ECT as neoadjuvant treatment of metastatic subcutaneous melanoma.Methods and resultsA 44-year-old Caucasian woman underwent extensive surgical resection of a melanoma, with a Breslow thickness of 1.5 mm, located on the right side of her scalp. No further treatment was given and the woman remained well until she came to our attention with a large nodule in her right cheek. Whole-body fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) was performed for staging and treatment monitoring. Baseline FDG PET/CT showed the lesion in the cheek to have a maximal standardized uptake value (SUVmax) of 19.5 with no evidence of further disease spread. Fine needle aspiration cytology confirmed the presence of metastatic melanoma. The patient underwent two sessions of ECT with intravenous injections of bleomycin using a CliniporatorTM as neoadjuvant treatment permitting conservative surgery three months later.Follow-up PET/CT three months after the first ECT treatment showed a marked decrease in SUVmax to 5. Further monitoring was performed through monthly PET/CT studies. Multiple cytology examinations showed necrotic tissue. Conservative surgery was carried out three months after the second ECT. Reconstruction was easily achieved through a rotation flap. Pathological examination of the specimen showed necrotic tissue without residual melanoma. One year after the last ECT treatment, the patient was disease-free as determined by contrast-enhanced CT and PET/-CT scans with a good functional and aesthetic result.ConclusionsECT represents a safe and effective therapeutic approach that is associated with clear benefits in terms of quality of life (minimal discomfort, mild post-treatment pain and short duration of hospital stay) and may, in the neoadjuvant setting as reported here, offer the option of more conservative surgery and an improved cosmetic effect with complete local tumor control.

Comparison of an 18F labeled derivative of vasoactive intestinal peptide and 2-deoxy-2-[18F]fluoro-D-glucose in nude mice bearing breast cancer xenografts.

PURPOSE A 18fluorine-labeled derivative of vasoactive intestinal peptide [18F- Arg,Arg VIP(18F-dVIP)] was evaluated as a potential imaging agent for breast cancer by comparison with 2-deoxy-2-[18F]fluoro-D-glucose (FDG) using standard ex vivo determinations and small animal position emission tomography (PET) imaging. PROCEDURES Human breast carcinomas, T-47D and MDA-MB231, tumor-bearing nude mice were injected intravenously with 18F-dVIP or FDG for imaging and/or biodistribution (ex vivo) determined by gamma counting. RESULTS FDG had two- to three-fold greater tumor accumulation and target-to-non target contrast relative to 18F-dVIP. VIP receptors were detected in both tumor types but in low concentrations (<15,000 receptors/cell) consistent with lower uptakes. FDG was cleared rapidly from non-target tissues while 18F-dVIP cleared into the kidneys. CONCLUSIONS 18F-dVIP uptake in mice T-47D tumors and kidneys determined by imaging correlated with values determined by ex vivo counting suggesting that tumor and other tissue uptakes can be quantified by in vivo positron projection imaging.

The gallium–deferoxamine complex: stability with different deferoxamine concentrations and incubation conditions

Previous studies report that deferoxamine (DFO) binds metallic ions such as Fe3+, In3+ and Ga3+ with very high affinity. This property of DFO has been utilized to label DFO-coupled compounds with radiometals such as 67Ga and 111In. We have studied the effect of low DFO concentrations and of different incubation conditions on the stability of the 67Ga-DFO complex. In our experience high (> 5 microM) DFO concentration appears to be critical in obtaining high radiochemical purity of such complexes.

In vivo and in vitro characterization of CCK8 bearing a histidine-based chelator labeled with 99mTc-tricarbonyl

The development of receptor targeting radiolabeled ligands has gained much interest in recent years for diagnostic and therapeutic applications in nuclear medicine. Cholecystokinin (CCK) receptors have been shown to be overexpressed in a subset of neuroendocrine and other tumors. We are evaluating binding and biodistribution properties of a CCK8 peptide derivative labeled with 99mTc(I)‐tricarbonyl. The CCK8 peptide was modified at its N‐terminus by adding to its N‐terminus two lysine–histidine modules (KH), where histidine is coupled to the side chain of the lysine ((KH)2‐CCK8). 99mTc(I)‐tricarbonyl was generated with the IsoLink™ kit. A431 cells stably transfected with a cDNA encoding for the human CCK2 receptor were utilized to determine binding affinity, internalization, and retention of the labeled peptide, in comparison with wild‐type A431 cells. A nude mouse tumor model was obtained by generating A431‐CCK2R and A431‐control tumors in opposite flanks of the animals. High specific activity labeling with 99mTc was achieved. In A431‐CCK2R cells, specific saturable binding was observed as well as evident internalization of the radiolabeled peptide after binding. Biodistribution experiments showed rapid, specific localization of (KH)2‐CCK8 on A431‐CCK2R xenografts compared with control tumors, although absolute uptake values were not markedly higher compared with background activity. Clearance of unbound radioactivity was both urinary and hepatobiliary. In imaging experiments, while targeting to CCK2R positive tumors could be appreciated, there was poor contrast between target and nontarget areas. (KH)2‐CCK8 shows adequate in vitro and in vivo properties for CCK2R targeting although improvement of biodistribution warrant further development.