Autonomic reactivity to induced emotion as potential predictor of response to antidepressant treatment.

Distinct factors have been identified as potential predictors of antidepressant treatment response. Although autonomic function changes have been described in depressive subjects, their value as predictors of antidepressant response has not been systematically evaluated. Eight un-medicated patients with major depressive order (MDD) have their skin conductance (SC) and heart rate variability (HRV) measured at basal condition and during four induced emotional states: happy, angry, sad and neutral.

Spatial first-passage statistics of Al/Si(111)-(square root 3 x square root 3) step fluctuations.

Spatial step edge fluctuations on a multicomponent surface of Al/Si(111)-(square root 3 x square root 3) were measured via scanning tunneling microscopy over a temperature range of 720-1070 K, for step lengths of L=65-160 nm. Even though the time scale of fluctuations of steps on this surface varies by orders of magnitude over the indicated temperature range, measured first-passage spatial persistence and survival probabilities are temperature independent. The power law functional form for spatial persistence probabilities is confirmed and the symmetric spatial persistence exponent is measured to be theta=0.

Consensus report on impulsive aggression as a symptom across diagnostic categories in child psychiatry: implications for medication studies.

Objective: To determine whether impulsive aggression (IA) is a meaningful clinical construct and to ascertain whether it is sufficiently similar across diagnostic categories, such that parallel studies across disorders might constitute appropriate evidence for pursuing indications. If so, how should IA be assessed, pharmacological studies designed, and ethical issues addressed?

Method: Experts from key stakeholder communities, including academic clinicians, researchers, practicing clinicians, U.S.

Major depressive disorder with anger attacks and subcortical MRI white matter hyperintensities.

Previous reports of increased rates of cardiovascular risk factors in major depressive disorder (MDD) with anger attacks led the authors to hypothesize that MDD with anger attacks may be associated with brain vascular changes (magnetic resonance imaging white matter hyperintensities [WMHs]). Sixty-five subjects meeting DSM-III-R criteria for major depressive disorder were administered brain magnetic resonance imaging scans at 1.5T to detect T2 WMH.

Local spectroscopy of image-potential-derived states: from single molecules to monolayers of benzene on Cu(111).

Stark-shifted image-potential states were measured with an STM tip for benzene adsorbed on a Cu(111) surface. A single benzene molecule locally shifts the position of the first image state toward the Fermi level by 0.2 eV relative to its position on the clean surface.

Unnatural amino acid mutagenesis of the GABA(A) receptor binding site residues reveals a novel cation-pi interaction between GABA and beta 2Tyr97.

The binding pockets of Cys-loop receptors are dominated by aromatic amino acids. In the GABA(A) receptor alpha1Phe65, beta2Tyr97, beta2Tyr157, and beta2Tyr205 are present at the beta2/alpha1 interface and have been implicated in forming an important part of the GABA binding site. Here, we have probed interactions of these residues using subtle chemical changes: unnatural amino acid mutagenesis was used to introduce a range of Phe analogs, and mutant receptors expressed in oocytes were studied using voltage-clamp electrophysiology.

A cation-pi interaction discriminates among sodium channels that are either sensitive or resistant to tetrodotoxin block.

Voltage-gated sodium channels control the upstroke of the action potential in excitable cells of nerve and muscle tissue, making them ideal targets for exogenous toxins that aim to squelch electrical excitability. One such toxin, tetrodotoxin (TTX), blocks sodium channels with nanomolar affinity only when an aromatic Phe or Tyr residue is present at a specific location in the external vestibule of the ion-conducting pore. To test whether TTX is attracted to Tyr401 of NaV1.

Chemical-scale studies on the role of a conserved aspartate in preorganizing the agonist binding site of the nicotinic acetylcholine receptor.

The nicotinic acetylcholine receptor and related Cys-loop receptors are ligand-gated ion channels that mediate fast synaptic transmission throughout the central and peripheral nervous system. A highly conserved aspartate residue (D89) that is near the agonist binding site but does not directly contact the ligand plays a critical part in receptor function. Here we probe the role of D89 using unnatural amino acid mutagenesis coupled with electrophysiology.

Probing the Mg2+ blockade site of an N-methyl-D-aspartate (NMDA) receptor with unnatural amino acid mutagenesis.

The N -methyl-D-aspartate (NMDA) receptor plays a central role in learning and memory in the mammalian CNS. At normal neuronal resting membrane potentials, the pore of this glutamate-gated ion channel is blocked by a Mg(2+) ion. Previous work suggests that the Mg(2+) binding site is quite novel, involving several asparagine residues and a cation-pi interaction between Mg(2+) and a conserved tryptophan in the pore.

A cation-pi interaction between extracellular TEA and an aromatic residue in potassium channels.

Open-channel blockers such as tetraethylammonium (TEA) have a long history as probes of the permeation pathway of ion channels. High affinity blockade by extracellular TEA requires the presence of an aromatic amino acid at a position that sits at the external entrance of the permeation pathway (residue 449 in the eukaryotic voltage-gated potassium channel Shaker). We investigated whether a cation-pi interaction between TEA and such an aromatic residue contributes to TEA block using the in vivo nonsense suppression method to incorporate a series of increasingly fluorinated Phe side chains at position 449.

Reconstitution of ion channels in agarose-supported silicon orifices.

A silicon wafer with eight individually addressable microfabricated orifices was used for ion channel reconstitution and single-channel recording. A spin-on fluoropolymer created an insulating, hydrophobic interface that was more stable than silane. Total capacitance of the membranes was <10 pF, making it easy to evaluate bilayer formation by capacitance change.

Assembly of linear clusters of iodobenzene dimers on Cu(110).

Low-temperature STM observations of the low-coverage chemisorption behavior of iodobenzene on Cu(110) are presented at two annealing temperatures. When a random distribution of isolated iodobenzene molecules deposited at T < 100 K is annealed to approximately 170 K, the undissociated molecules assemble into chainlike clusters composed of identical subunits. An STM tip-induced dissociation reaction is used to determine that the individual units in the chains are composed of pairs of iodobenzene molecules.

Health care for children and youth in the United States: annual report on patterns of coverage, utilization, quality, and expenditures by a county level of urban influence.

Objective: To examine child and hospital demographics and children's health care coverage, use, expenditures, and quality by a county-level measure of urban influence.

Methods: Two national health care databases serve as the sources of data for this report: the 2002 Medical Expenditure Panel Survey (MEPS) and the 2002 Nationwide Inpatient Sample (NIS) and State Inpatient Databases (SID) from the Healthcare Cost and Utilization Project (HCUP). In both data sets, county urbanicity is defined by use of a collapsed version of the 2003 Urban Influence Codes, to distinguish among children residing in and hospitals located in large metropolitan (metro) counties, small metro counties, micropolitan counties, and noncore counties.

Edge-on bonding of benzene molecules in the second adsorbed layer on Cu(110).

The bilayer of benzene on Cu(110) was studied with temperature-programmed desorption (TPD), time-of-flight electron stimulated desorption ion angular distribution (TOF-ESDIAD), and scanning tunneling microscopy (STM). TPD spectra show that three well-defined adsorption states exist. The alpha layer corresponds to the first layer containing flat-lying benzene molecules.

Current posttraumatic stress disorder and history of trauma in trichotillomania.

Though some researchers and clinicians postulate that trauma and posttraumatic stress disorder (PTSD) may be implicated in the etiologic underpinnings of trichotillomania (TTM), very little research to date has examined such postulations. To address this gap in the literature, the current study assessed the prevalence of trauma and PTSD in 42 individuals seeking treatment for TTM. Relations between symptoms of PTSD and TTM also were examined, as were differences in TTM symptoms between those with and without PTSD.

Impulsivity and BOLD fMRI activation in MDMA users and healthy control subjects.

The correlation between scores on the Barratt Impulsiveness Scale (BIS) and activation measured by functional magnetic resonance imaging in a dorsolateral prefrontal cortical (DLPFC) activating task was examined in 15 MDMA-using subjects and 19 controls. A significant correlation between BIS scores and DLPFC activation was found, supporting a role for the DLPFC in BIS-measured impulsivity.

Single modality versus dual modality treatment for trichotillomania: sertraline, behavioral therapy, or both?

Background: Trichotillomania is a psychiatric condition characterized by chronic hair pulling. Both cognitive behavioral therapy (CBT) and the selective serotonin reuptake inhibitors (SSRIs) have shown promise in the treatment of trichotillomania, with comparison studies favoring CBT over pharmacotherapy. However, no randomized, controlled studies to date have compared the efficacy of individual SSRI or CBT treatment to the combination of both treatment modalities.

Semi-mechanistic partial buffer approach to modeling pH, the buffer properties, and the distribution of ionic species in complex solutions.

In many biological science and food processing applications, it is very important to control or modify pH. However, the complex, unknown composition of biological media and foods often limits the utility of purely theoretical approaches to modeling pH and calculating the distributions of ionizable species. This paper provides general formulas and efficient algorithms for predicting the pH, titration, ionic species concentrations, buffer capacity, and ionic strength of buffer solutions containing both defined and undefined components.

Surface bonding and dynamical behavior of the CH3SH molecule on Au(111).

The chemisorption of the undissociated CH3SH molecule on the Au(111) surface has been studied at 5 K using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. The molecule was found to adsorb on atop Au sites on the defect-free surface. CH3SH undergoes hindered rotation about the Au-S bond on the defect-free surface which is seen in STM as a time-averaged 6-fold pattern.

Role of conformation in the electronic properties of chemisorbed pyridine on Cu(110): an STM/STS study.

Pyridine was chemisorbed on Cu(110) at 10 K and observed using STM at 5 K as dosed and after annealing to temperatures between 20 and 300 K. At very low coverage, two molecular species with different apparent heights are observed to coexist. The higher species is assigned to a pyridine molecule bonded with its symmetry axis perpendicular to the surface plane, while the lower species is assigned to a pyridine molecule that is tilted down toward the surface plane.

In vivo incorporation of multiple unnatural amino acids through nonsense and frameshift suppression.

Site-specific incorporation of unnatural amino acids (UAAs) into proteins is a valuable tool for studying structure-function relationships, incorporating biophysical probes, and elucidating protein-protein interactions. In higher eukaryotic cells, the methodology is currently limited to incorporation of a single UAA in response to a stop codon, which is known as nonsense suppression. Frameshift suppression is a unique methodology for incorporating UAAs in response to quadruplet codons, but currently, it is mostly limited to in vitro protein translation systems.

Phenyl species formation and preferential hydrogen abstraction in the decomposition of chemisorbed benzoate on Cu(110).

The adsorption and decomposition of benzoic acid on the Cu(110) surface has been investigated using temperature-programmed reaction (TPR) spectroscopy and scanning tunneling microscopy (STM). The benzoate species is found to exist in two conformations--a phase containing upright species at monolayer saturation and a phase containing many lying-down species at lower coverages. Thermal decomposition begins to occur near 500 K, yielding benzene and CO(2).

Chemisorbed benzoate-to-benzene conversion via phenyl radicals on Cu(110): kinetic observation of conformational effects.

The adsorption and decomposition of benzoic acid on the Cu(110) surface has been investigated using temperature-programmed reaction (TPR) spectroscopy and scanning tunneling microscopy (STM). The benzoate species is found to exist in two conformations: a phase containing upright species at monolayer saturation and a phase containing many tilted species at lower coverages. Thermal decomposition begins to occur near 500 K, yielding benzene and CO2.