The alternative lengthening of telomeres pathway may operate in non-neoplastic human cells.

The alternative lengthening of telomeres (ALT) mechanism represents an alternative to the enzyme telomerase in the maintenance of mammalian telomeres in 25-60% of sarcomas and a minority of carcinomas (about 5-15%). ALT-positive cells are distinguished by long and heterogeneous telomere length distributions by terminal restriction fragment (TRF) Southern blotting. Another diagnostic marker of ALT is discrete nuclear co-localized signals of telomeric DNA and the promyelocytic leukaemia protein (PML), referred to as ALT-associated PML bodies (APBs). Recently, we detected smaller sized co-localized PML and telomere DNA (APB-like) bodies in endothelial cells adjacent to astrocytoma tumour cells in situ. In this study, we examined a wide variety of non-neoplastic tissues, and report that co-localized signals of PML and telomere DNA are present in endothelial, stromal, and some epithelial cells. Co-localized signals of PML and telomere DNA showed an increased frequency in non-neoplastic cells with DNA damage. These results suggest that a mechanism similar to that in ALT-positive tumours also operates in non-neoplastic cells, which may be activated by DNA damage.

Modulation of GABAA receptors in cerebellar granule neurons by ethanol: a review of genetic and electrophysiological studies.

Cerebellar granule neurons (CGNs) receive inhibitory input from Golgi cells in the form of phasic and tonic currents that are mediated by postsynaptic and extrasynaptic gamma-aminobutyric acid type A (GABAA) receptors, respectively. Extrasynaptic receptors are thought to contain alpha6betaxdelta subunits. Here, we review studies on ethanol (EtOH) modulation of these receptors, which have yielded contradictory results. Although studies with recombinant receptors expressed in Xenopus oocytes indicate that alpha6beta3delta receptors are potently enhanced by acute exposure to low (>or=3 mM) EtOH concentrations, this effect was not observed when these receptors were expressed in Chinese hamster ovary cells. Slice recordings of CGNs have consistently shown that EtOH increases the frequency of phasic spontaneous inhibitory postsynaptic currents (sIPSCs), as well as the tonic current amplitude and noise. However, there is a lack of consensus as to whether EtOH directly acts on extrasynaptic receptors or modulates them indirectly; that is, via an increase in spillover of synaptically released GABA. It was recently demonstrated that an R to Q mutation of amino acid 100 of the alpha6 subunit increases the effect of EtOH on both sIPSCs and tonic current. These electrophysiological findings have not been reproducible in our hands. Moreover, it was shown the alpha6-R100Q mutation enhances sensitivity to the motor-impairing effects of EtOH in outbred Sprague-Dawley rats, but this was not observed in a line of rats selectively bred for high sensitivity to EtOH-induced motor alterations (Alcohol Non-Tolerant rats). We conclude that currently there is insufficient evidence conclusively supporting a direct potentiation of extrasynaptic GABAA receptors following acute EtOH exposure in CGNs.

Robust dimensions of anxiety sensitivity: development and initial validation of the Anxiety Sensitivity Index-3.

Accumulating evidence suggests that anxiety sensitivity (fear of arousal-related sensations) plays an important role in many clinical conditions, particularly anxiety disorders. Research has increasingly focused on how the basic dimensions of anxiety sensitivity are related to various forms of psychopathology. Such work has been hampered because the original measure--the Anxiety Sensitivity Index (ASI)--was not designed to be multidimensional. Subsequently developed multidimensional measures have unstable factor structures or measure only a subset of the most widely replicated factors. Therefore, the authors developed, via factor analysis of responses from U.S. and Canadian nonclinical participants (n=2,361), an 18-item measure, the ASI-3, which assesses the 3 factors best replicated in previous research: Physical, Cognitive, and Social Concerns. Factorial validity of the ASI-3 was supported by confirmatory factor analyses of 6 replication samples, including nonclinical samples from the United States and Canada, France, Mexico, the Netherlands, and Spain (n=4,494) and a clinical sample from the United States and Canada (n=390). The ASI-3 displayed generally good performance on other indices of reliability and validity, along with evidence of improved psychometric properties over the original ASI.

FT-IR spectroscopy and density functional theory calculations of 13C isotopologues of the helical peptide Z-Aib6-OtBu.

Isotope-edited FT-IR spectroscopy is a combined synthetic and spectroscopic method used to characterize local (e.g., residue-level) vibrational environments of biomolecules. We have prepared the 3(10) helical peptide Z-Aib6-OtBu and seven (13)C-enriched analogues that vary only in the number and position(s) of (13)C═O isotopic enrichment. FT-IR spectra of these eight peptides solvated in the nonpolar aprotic solvent dichloromethane have been collected and compared to frequency, intensity, and normal mode results of DFT calculations. Single (13)C enrichment of amide functional groups tends to localize amide I vibrational eigenmodes, providing residue-specific information regarding the local environment (e.g., hydrogen bonding or solvent exposure) of the peptide bond. Double (13)C enrichment of Z-Aib6-OtBu allows for examination of interamide coupling between two labeled amide functional groups, providing experimental evidence of interamide coupling in the context of 3(10) helical structure. Although the calculated and observed interamide couplings of Z-Aib6-OtBu are a few cm(-1) and less, the eight peptides exhibit distinct infrared spectra, revealing details of interamide coupling and residue level vibrational environments.

Predictors of posttraumatic stress disorder and other psychological symptoms in trauma-exposed firefighters.

Firefighters are exposed to a range of potentially traumatic stressors, yet studies examining the impact of this exposure are equivocal. Although some studies suggest increased risk for mental health problems, others suggest unusual resilience. Type of assessment methodology may contribute to the lack of consistent findings. We assessed 142 trauma-exposed, professional firefighters utilizing a standardized clinical interview and self-report measures and found low rates of posttraumatic stress disorder (PTSD) diagnoses (4.2%), and depressive, anxiety, and alcohol-abuse symptoms. Frequency of trauma exposure did not predict psychological symptoms. Perceived social support, occupational stress, coping, as well as the interaction between perceived social support and self-blame were significant predictors of symptoms. Firefighters reporting low-perceived social support and high self-blame demonstrated the highest levels of clinically significant symptoms. These findings may inform education, treatment, and resilience training for emergency personnel.

Disaster mental health workers responding to Ground Zero: one year later.

The current study examined anniversary reactions in mental health disaster relief workers following traumatic exposure at the site of the World Trade Center terrorist attacks. Despite relatively low levels of symptom reporting, workers endorsed an increase in both negative mood symptoms and functional impairment at the one-year anniversary of their traumatic exposure (compared to 6 months postexposure). For those individuals who met at least partial criteria for PTSD immediately following exposure, overall self-reported PTSD symptoms tended to increase from 6 to 12 months. This tendency resulted specifically from an increase in hyperarousal symptoms. Although few endorsed symptoms at clinical levels, our results demonstrate that disaster relief workers may experience an increase in symptomatology at the anniversary of their traumatic exposure.

19F NMR chemical shifts induced by a helical peptide.

(19)F NMR spectra of two neutral, organic-soluble helical peptide octamers, each labeled at its N terminus with either 4-fluorobenzamide or 4-trifluoromethylbenzamide, in solvents with widely varying dielectric constants have been observed. The peptides are oligomers of alpha-aminoisobutyric acid (Aib), which is a residue known to form stable 3(10) helices in organic solution. In relation to the (19)F NMR spectra of a control molecule, the peptide terminating in 4-fluorobenzamide shows a solvent-dependent downfield chemical shift of between approximately 1.5 and approximately 4 ppm, whilst the peptide terminating in 4-trifluoromethylbenzamide shows only an approximately 0.2 ppm chemical shift dependence on the solvent dielectric constant. The experimental observations were compared to calculated values of the electric field generated by the correlation of dipolar amide units through the peptide's helical conformation. We find the chemical-shift response of the 4-fluorobenzamide group to the peptide's calculated electric field is consistent with the magnitude of (19)F chemical shift dispersion observed in proteins.