No abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. Beta-amyloid (Aβ) deposition and neurofibrillary tangles (NFTs) of abnormal hyperphosphorylated tau protein are the pathological hallmarks of the disease, accompanied by other pathological processes such as microglia activation. Functional and molecular nuclear medicine imaging with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) techniques provides valuable information about the underlying pathological processes, many years before the appearance of clinical symptoms. Nuclear neuroimaging in AD has made great progress in the past two decades and has extended beyond the traditional role of brain perfusion and glucose metabolism evaluation. Intense efforts in radiopharmaceuticals research have led to the development of various probes able to detect Aβ deposits, tau protein accumulation, microglia activation and neuroinflammation. As a result, SPECT and PET have proposed to serve as biomarkers in recently revised diagnostic clinical criteria for the early diagnosis of AD and the prediction of progression to AD in mild cognitive impairment (MCI) subjects.

Nanomedicine applications have recently gathered great attention in terms of their revolutionary properties and multivalency. Nanoparticles (NPs) have proven useful owing to their size, surface and kinetics advantages, as well as their ability to be functionalized with targeting, imaging and therapeutic moieties. Nuclear medicine is actively involved in nano-research innovative breakthrough efforts in multiple applications, through the radiolabeling of NP structures. There are several ways that NP-radiolabeling can be approached depending on the radionuclide that is used and the NP type. The radiolabeling of NPs with the most widely and easily available radiometal, which is (99m) Tc, is the focus of this review.

Ghrelin is a novel GH-releasing peptide, which has been identified as an endogenous ligand for GH-secretagogue receptor. Ghrelin is mainly secreted by the stomach and plays a critical role in a variety of physiological processes including endocrine, metabolic, cardiovascular, immunological, and other actions. Ghrelin stimulates food intake via hypothalamic neurons and causes a positive energy balance and body weight gain by decreasing fat utilization and promoting adiposity. Given the multiple effects of ghrelin, its potential clinical applications have been evaluated in various conditions. Preliminary trials have shown that it may prove valuable in the management of disease-induced cachexia. Ghrelin may improve the wasting syndrome through GH-dependent or GH-independent effects. Moreover, ghrelin may play a role in the management of disorders of gut motility and obesity. Finally, other potential clinical applications of ghrelin include the treatment of patients with diabetes mellitus, infections, rheumatological diseases or GH deficiency and the diagnosis of this hormonal disorder.

BackgroundS100A12, a calcium-binding proinflammatory protein secreted by granulocytes, has been associated with different diseases of inflammatory origin, including inflammatory bowel disease (IBD). In this study, the utility of serum S100A12, in discriminating IBD from irritable bowel syndrome (IBS), was tested.MethodsS100A12 serum levels were determined in 64 patients with ulcerative colitis (UC), 64 with Crohn's disease (CD) and 73 with IBS, by means of an enzyme-linked immunosorbent assay. S100A12 serum levels were evaluated with respect to the levels of known inflammatory markers and patients' characteristics.ResultsThe median values of serum S100A12 levels were 68.2 ng/mL (range: 43.4-147.4) in UC, 70 ng/mL (41.4-169.8) in CD and 43.4 ng/mL (34.4-74.4) in IBS patients. UC and CD patients had significantly higher serum S100A12 levels compared to IBS patients (P = 0.001 for both comparisons). Moreover, a cut-off for serum S100A12 levels of 54.4 ng/mL could predict both UC and CD with a 66.7% sensitivity and a 64.4% specificity. The area under curve was estimated at 0.67 with a 95% confidence interval of 0.60-0.75 (P < 0.001). Considering standard activity indices, higher serum S100A12 levels in active compared to inactive IBD were observed, although the recorded difference did not reach statistical significance. C-reactive protein (CRP) and serum amyloid A (SAA) levels, showed a statistically significant positive correlation with S100A12 (r = 0.39, P = 0.001 and r = 0.23, P = 0.02 respectively).ConclusionsIncreased levels of circulating S100A12 are found in IBD, compared to IBS. When used to distinguish IBD from IBS adult patients, serum S100A12 levels exhibit moderate performance. On the other hand, serum S100A12 may serve as an inflammatory marker in IBD, since it is well correlated with CRP and SAA.

Adiponectin, the most abundant adipose-released cytokine, has an important role in metabolism, primarily through reducing insulin resistance. Reproductive functions are known to be influenced by energy balance and adiponectin may be involved in the underlying mechanisms connecting reproduction and metabolism. Interestingly, adiponectin has been shown to exert actions in the female reproductive system, including the hypothalamic-pituitary-ovarian axis and the endometrium. The peripheral effects of this adipocytokine are mediated mainly via 2 receptors, AdipoR1 and AdipoR2. The expression of these receptors has been reported in the brain, ovaries, endometrium, and the placenta. Thus, adiponectin may influence fertility and pregnancy. Furthermore, adiponectin concentrations and effects have been assessed in some pregnancy-associated disorders and gynecological conditions. The findings may lead to the use of adiponectin or its receptors as therapeutic targets in novel treatment strategies of these disorders.

Despite the known validity of clinical diagnostic criteria, significant overlap of clinical symptoms between Frontotemporal dementia (FTD) subtypes exists in several cases, resulting in great uncertainty of the diagnostic boundaries. We evaluated the perfusion between FTD subtypes using brain perfusion (99m)Tc-HMPAO SPECT with Brodmann areas (BA) mapping. NeuroGam software was applied on single photon emission computed tomographic (SPECT) studies for the semi-quantitative evaluation of perfusion in BA and the comparison with the software's normal database. We studied 91 consecutive FTD patients: 21 with behavioural variants (bvFTD), 39 with language variants (lvFTD) [12 with progressive non-fluent aphasia (PNFA), 27 with semantic dementia (SD)], and 31 patients with progressive supranuclear palsy (PSP)/corticobasal degeneration (CBD). Stepwise logistic regression analyses showed that the BA 28L and 32R could independently differentiate bvFTD from lvFTD, while the BA 8R and 25R could discriminate bvFTD from SD and PNFA, respectively. Additionally, BA 7R and 32R were found to discriminate bvFTD from CBD/PSP. The only BA that could differentiate SD from PNFA was 6L. BA 6R and 20L were found to independently differentiate CBD/PSP from lvFTD. Moreover, BA 20L and 22R could discriminate CBD/PSP from PNFA, while BA 6R, 20L and 45R were found to independently discriminate CBD/PSP from SD. Brain perfusion SPECT with BA mapping can be a useful additional tool in differentiating FTD variants by improving the definition of brain areas that are specifically implicated, resulting in a more accurate differential diagnosis in atypical or uncertain forms of FTD.

Meningiomas arise from the meningothelial cells of the arachnoid membranes. They are the most common primary intracranial neoplasms and represent about 20% of all intracranial tumors. They are usually diagnosed after the third decade of life and they are more frequent in women than in men. According to the World Health Organization (WHO) criteria, meningiomas can be classified into grade I meningiomas, which are benign, grade II (atypical) and grade III (anaplastic) meningiomas, which have a much more aggressive clinical behaviour. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are routinely used in the diagnostic workup of patients with meningiomas. Molecular Nuclear Medicine Imaging with Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) could provide complementary information to CT and MRI. Various SPECT and PET tracers may provide information about cellular processes and biological characteristics of meningiomas. Therefore, SPECT and PET imaging could be used for the preoperative noninvasive diagnosis and differential diagnosis of meningiomas, prediction of tumor grade and tumor recurrence, response to treatment, target volume delineation for radiation therapy planning, and distinction between residual or recurrent tumour from scar tissue.