The role of PET-CT in detecting unknown primary tumour in patients with cervical lymph node metastases

PET-CT examination was conducted with 440 patients treated at the Department of Head and Neck Surgery, National Institute of Oncology, Budapest, between January 1, 2006 and December 31, 2010. Out of them 77 patients were selected with whom no examination of any sort (physical, pan-endoscopy, or any of the conventional imaging techniques) succeeded in identifying the primary tumour. In each case the primary examination (aspiration cytology and histology) verified cervical metastases, most of them being squamous cell carcinoma. The significance of PET-CT was retrospectively evaluated in cases of unknown primary tumour with verified cervical metastases. We tested the sensitivity of PET-CT in detection of the primary malignant tumour, and possible distant metastases or a second primary in order to plan an optimal treatment schedule for the patient. Patients with whom the examinations specified in the treatment protocol (physical examination, pan-endoscopy, conventional imaging, biopsy) had failed to diagnose the primary tumour were referred to PET-CT. In each case 18F-FDG tracer was used. In 21/77 patients (27%), the PET-CT yielded unequivocal evidence for the primary tumour confirmed by histology, as well. With 10 others (13%), the precarious diagnoses by various imaging techniques were confirmed by the PET-CT. False positive findings with PET-CT that were not verified either by histology or control examination tests occurred but in 10 patients (13%). Concerning the primary tumour, false negative result was obtained only with 3 patients (4%). It should be noted that their retrospective evaluation proved diagnostic errors, the primary tumours were visible in all the scans. With 33 patients (43%) PET-CT furnished no additional information compared to the previous examinations. In 10 patients, asymptomatic distant metastases and in 3 patients synchronous tumours were diagnosed. We also acknowledge that the significance of PET-CT using 18F-FDG is unquestionable in the detection of unknown primary tumours. It is strongly recommended to re-include the detection of unknown primaries in the approved national indication list of PET-CT. (Note, until January 1, 2008 it had been included!) PET-CT is capable of detecting a primary tumour, after all unsuccessful diagnostic examinations till then, in 25-40% of the cases. One cannot disregard the role and significance of PET-CT in the detection of asymptomatic synchronous tumours, or distant metastases. These benefits make PET-CT a suitable tool for the refinement of individually tailored treatment strategies leading to better therapeutic results and more favourable cost-benefit ratio.     

Model requirements for Biobank Software Systems

Biobanks are essential tools in diagnostics and therapeutics research and development related to personalized medicine. Several international recommendations, standards and guidelines exist that discuss the legal, ethical, technological, and management requirements of biobanks. Today's biobanks are much more than just collections of biospecimens. They also store a huge amount of data related to biological samples which can be either clinical data or data coming from biochemical experiments. A well-designed biobank software system also provides the possibility of finding associations between stored elements. Modern research biobanks are able to manage multicenter sample collections while fulfilling all requirements of data protection and security. While developing several biobanks and analyzing the data stored in them, our research group recognized the need for a well-organized, easy-to-check requirements guideline that can be used to develop biobank software systems. International best practices along with relevant ICT standards were integrated into a comprehensive guideline: The Model Requirements for the Management of Biological Repositories (BioReq), which covers the full range of activities related to biobank development. The guideline is freely available on the Internet for the research community. AVAILABILITY: The database is available for free at http://bioreq.astridbio.com/bioreq_v2.0.pdf.     

Phospho-dependent functional modulation of GABA(B) receptors by the metabolic sensor AMP-dependent protein kinase

GABA(B) receptors are heterodimeric G protein-coupled receptors composed of R1 and R2 subunits that mediate slow synaptic inhibition in the brain by activating inwardly rectifying K(+) channels (GIRKs) and inhibiting Ca(2+) channels. We demonstrate here that GABA(B) receptors are intimately associated with 5'AMP-dependent protein kinase (AMPK). AMPK acts as a metabolic sensor that is potently activated by increases in 5'AMP concentration that are caused by enhanced metabolic activity, anoxia, or ischemia. AMPK binds the R1 subunit and directly phosphorylates S783 in the R2 subunit to enhance GABA(B) receptor activation of GIRKs. Phosphorylation of S783 is evident in many brain regions, and is increased dramatically after ischemic injury. Finally, we also reveal that S783 plays a critical role in enhancing neuronal survival after ischemia. Together our results provide evidence of a neuroprotective mechanism, which, under conditions of metabolic stress or after ischemia, increases GABA(B) receptor function to reduce excitotoxicity and thereby promotes neuronal survival.     

Genetic Addiction Risk Score (GARS): Molecular Neurogenetic Evidence for Predisposition to Reward Deficiency Syndrome (RDS)

We have published extensively on the neurogenetics of brain reward systems with reference to the genes related to dopaminergic function in particular. In 1996, we coined “Reward Deficiency Syndrome” (RDS), to portray behaviors found to have gene-based association with hypodopaminergic function. RDS as a useful concept has been embraced in many subsequent studies, to increase our understanding of Substance Use Disorder (SUD), addictions, and other obsessive, compulsive, and impulsive behaviors. Interestingly, albeit others, in one published study, we were able to describe lifetime RDS behaviors in a recovering addict (17 years sober) blindly by assessing resultant Genetic Addiction Risk Score (GARS?) data only. We hypothesize that genetic testing at an early age may be an effective preventive strategy to reduce or eliminate pathological substance and behavioral seeking activity. Here, we consider a select number of genes, their polymorphisms, and associated risks for RDS whereby, utilizing GWAS, there is evidence for convergence to reward candidate genes. The evidence presented serves as a plausible brain-print providing relevant genetic information that will reinforce targeted therapies, to improve recovery and prevent relapse on an individualized basis. The primary driver of RDS is a hypodopaminergic trait (genes) as well as epigenetic states (methylation and deacetylation on chromatin structure). We now have entered a new era in addiction medicine that embraces the neuroscience of addiction and RDS as a pathological condition in brain reward circuitry that calls for appropriate evidence-based therapy and early genetic diagnosis and that requires further intensive investigation.     

Unusual Temperature‐Induced Retention Behavior of Constrained β‐Amino Acid Enantiomers on the Zwitterionic Chiral Stationary Phases ZWIX(+) and ZWIX(–)

The effects of temperature on the chiral recognition of cyclic β‐amino acid enantiomers on zwitterionic [Chiralpak ZWIX(+) and ZWIX(–)] chiral stationary phases were investigated. Experiments were performed at different mobile phase compositions and under 10°C column temperature increments in the temperature range 10–50°C. Apparent thermodynamic parameters and T_iso values were calculated from plots of ln k and ln α versus 1/T, respectively. Unusual temperature behavior was observed, especially on the ZWIX(–) column, where the application of MeOH/MeCN (50/50 v/v) containing 25 mM triethylamine and 50 mM formic acid as mobile phase led to nonlinear van't Hoff plots and increasing retention time with increasing temperature. On both columns, both enthalpically and entropically driven separations were observed. Chirality 26:385–393, 2014. © 2014 Wiley Periodicals, Inc.     

Atg17/FIP200 localizes to perilysosomal Ref(2)P aggregates and promotes autophagy by activation of Atg1 in Drosophila

Phagophore-derived autophagosomes deliver cytoplasmic material to lysosomes for degradation and reuse. Autophagy mediated by the incompletely characterized actions of Atg proteins is involved in numerous physiological and pathological settings including stress resistance, immunity, aging, cancer, and neurodegenerative diseases. Here we characterized Atg17/FIP200, the Drosophila ortholog of mammalian RB1CC1/FIP200, a proposed functional equivalent of yeast Atg17. Atg17 disruption inhibits basal, starvation-induced and developmental autophagy, and interferes with the programmed elimination of larval salivary glands and midgut during metamorphosis. Upon starvation, Atg17-positive structures appear at aggregates of the selective cargo Ref(2)P/p62 near lysosomes. This location may be similar to the perivacuolar PAS (phagophore assembly site) described in yeast. Drosophila Atg17 is a member of the Atg1 kinase complex as in mammals, and we showed that it binds to the other subunits including Atg1, Atg13, and Atg101 (C12orf44 in humans, 9430023L20Rik in mice and RGD1359310 in rats). Atg17 is required for the kinase activity of endogenous Atg1 in vivo, as loss of Atg17 prevents the Atg1-dependent shift of endogenous Atg13 to hyperphosphorylated forms, and also blocks punctate Atg1 localization during starvation. Finally, we found that Atg1 overexpression induces autophagy and reduces cell size in Atg17-null mutant fat body cells, and that overexpression of Atg17 promotes endogenous Atg13 phosphorylation and enhances autophagy in an Atg1-dependent manner in the fat body. We propose a model according to which the relative activity of Atg1, estimated by the ratio of hyper- to hypophosphorylated Atg13, contributes to setting low (basal) vs. high (starvation-induced) autophagy levels in Drosophila.     

Temporal Features of Spike Trains in the Moth Antennal Lobe Revealed by a Comparative Time-Frequency Analysis

The discrimination of complex sensory stimuli in a noisy environment is an immense computational task. Sensory systems often encode stimulus features in a spatiotemporal fashion through the complex firing patterns of individual neurons. To identify these temporal features, we have developed an analysis that allows the comparison of statistically significant features of spike trains localized over multiple scales of time-frequency resolution. Our approach provides an original way to utilize the discrete wavelet transform to process instantaneous rate functions derived from spike trains, and select relevant wavelet coefficients through statistical analysis. Our method uncovered localized features within olfactory projection neuron (PN) responses in the moth antennal lobe coding for the presence of an odor mixture and the concentration of single component odorants, but not for compound identities. We found that odor mixtures evoked earlier responses in biphasic response type PNs compared to single components, which led to differences in the instantaneous firing rate functions with their signal power spread across multiple frequency bands (ranging from 0 to 45.71 Hz) during a time window immediately preceding behavioral response latencies observed in insects. Odor concentrations were coded in excited response type PNs both in low frequency band differences (2.86 to 5.71 Hz) during the stimulus and in the odor trace after stimulus offset in low (0 to 2.86 Hz) and high (22.86 to 45.71 Hz) frequency bands. These high frequency differences in both types of PNs could have particular relevance for recruiting cellular activity in higher brain centers such as mushroom body Kenyon cells. In contrast, neurons in the specialized pheromone-responsive area of the moth antennal lobe exhibited few stimulus-dependent differences in temporal response features. These results provide interesting insights on early insect olfactory processing and introduce a novel comparative approach for spike train analysis applicable to a variety of neuronal data sets.     

Individual Globular Domains and Domain Unfolding Visualized in Overstretched Titin Molecules with Atomic Force Microscopy

Titin is a giant elastomeric protein responsible for the generation of passive muscle force. Mechanical force unfolds titin’s globular domains, but the exact structure of the overstretched titin molecule is not known. Here we analyzed, by using high-resolution atomic force microscopy, the structure of titin molecules overstretched with receding meniscus. The axial contour of the molecules was interrupted by topographical gaps with a mean width of 27.7 nm that corresponds well to the length of an unfolded globular (immunoglobulin and fibronectin) domain. The wide gap-width distribution suggests, however, that additional mechanisms such as partial domain unfolding and the unfolding of neighboring domain multimers may also be present. In the folded regions we resolved globules with an average spacing of 5.9 nm, which is consistent with a titin chain composed globular domains with extended interdomain linker regions. Topographical analysis allowed us to allocate the most distal unfolded titin region to the kinase domain, suggesting that this domain systematically unfolds when the molecule is exposed to overstretching forces. The observations support the prediction that upon the action of stretching forces the N-terminal ß-sheet of the titin kinase unfolds, thus exposing the enzyme’s ATP-binding site and hence contributing to the molecule’s mechanosensory function.