The influence of semantic encoding on recognition memory in Alzheimer's disease

Within the framework of the distinction between episodic and semantic memory, it has been argued that these two memory systems are organised in a hierarchical way. The hierarchical hypothesis assumes that episodic memory is a specific subsystem of semantic memory and therefore implies that episodic memory cannot exist without semantic memory. If this hypothesis is correct, it should be expected that patients with impaired semantic memory also have impaired episodic memory. In the present study, two experiments investigated the influence of semantic encoding on recognition memory performance in a population of 20 patients with Alzheimer's disease and 18 normal controls. Both experiments assessed recognition memory for semantically-related items. In Experiment 2, but not in Experiment 1, subjects were explicitly instructed to make a semantic association between the items. Alzheimer's disease patients were impaired, compared to the normal controls, on the recognition memory performance of both experiments. The ability to make a semantic association between two items was significantly and positively correlated with the subjects' performance on the recognition tasks. A further analysis showed that patients who were impaired on the semantic association task did significantly worse on the recognition task of Experiment 2 than normal controls and patients who were unimpaired on the semantic association task. These findings are discussed in the context of memory deficits in Alzheimer's disease, and are interpreted as supporting the view that episodic memory for an item is affected by the level of semantic awareness of that same item.     

Efficient Incorporation of Clickable Unnatural Amino Acids Enables Rapid and Biocompatible Labeling of Proteins in Vitro and in Bacteria

Site-specific incorporation of unnatural amino acids (uAAs) bearing a bioorthogonal group has enabled the attachment – typically at a single site or at a few sites per protein – of chemical groups at precise locations for protein and biomaterial labeling, conjugation, and functionalization. Herein, we report the evolution of chromosomal Methanocaldococcus jannaschii tyrosyl-tRNA synthetase (aaRS) for the alkyne-bearing uAA, 4-propargyloxy-l -phenylalanine (pPR), with ∼30-fold increased production of green fluorescent protein containing three instances of pPR compared with a previously described M. jannaschii-derived aaRS for pPR, when expressed from a single chromosomal copy. We show that when expressed from multicopy plasmids, the evolved aaRSs enable the production – using a genomically recoded Escherichia coli and the non-recoded BL21 E. coli strain – of elastin-like polypeptides (ELPs) containing multiple pPR residues in high yields. We further show that the multisite incorporation of pPR in ELPs facilitates the rapid, robust, and nontoxic fluorescent labeling of these proteins in bacteria. The evolved variants described in this work can be used to produce a variety of protein and biomaterial conjugates and to create efficient minimal tags for protein labeling.     

Overload, autonomy, and burnout as predictors of physicians' quality of care.

A model in which perceived overload and burnout mediated the relations of workload and autonomy with physicians' quality of care to their patients was examined. The study was based on data from 890 specialists representing six medical specialties. Including global burnout as well as its three first-order facets of physical fatigue, cognitive weariness, and emotional exhaustion improved the fit between the structural model and the data relative to an alternative model that included only global burnout. Workload (number of work hours) indirectly predicted quality of care through perceived overload. Additionally, the authors found that the paths from the first order factors of emotional exhaustion, physical fatigue, and cognitive weariness predicted quality of care negatively, positively, and nonsignificantly, respectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Planar and Nonplanar Unsaturation. Preparation,Properties and Molecular-Orbital Characterization of Some Fluoro-Derivatives of Anthracene and Anthraquinone

Several fluoroanthracenes (I-III) and fluoroanthraquinones (IV-VII) were prepared, and their PMR and UV spectra, as well as dipole moments, recorded. These are discussed in terms of molecular-orbital data, both of the pi-electronic type (including nonbonding 2p-orbitals) and of the all-valence-electron type. PMR signals can be assigned on the basis of such calculations. The interpretation of UV spectra is straightforward in the case of fluoroanthracenes, but other techniques are required for fluoroanthraquinones. Measured dipole moments are close to the theoretical, except in the case of 1, 4, 5, 8-tetrafluoroanthraquinone. A distorted structure is proposed for this molecule.     

Exploring the conformational space of cyclic peptides by a stochastic search method

A stochastic search algorithm is applied in order to probe the conformations of cyclic peptides. The search is conducted in two stages. In the first stage, random conformations are generated and evaluated by a penalty function for ring closure ability, following a stepwise construction of each amino acid into the peptide by a random choice of one of its allowed conformations. The allowed conformational ranges of backbone dihedral angles for each amino acid have been extracted from a Data Bank of diverse proteins. Values of dihedral angles that do not contribute favorably to the scoring of ring closure are retained or discarded by a statistical test. Values are discarded up to a point from which all remaining combinations of angles are constructed, scored, sorted, and clustered. In the second stage, side chains have been added and fast optimization was applied to the set of diverse conformations in a "united atoms" approach, with the "Kollman forcefield" of Sybyl 6.8. This iterative stochastic elimination algorithm finds the global minimum and most of the best results, when compared to a full exhaustive search in appropriately sized problems. In larger problems, we compare the results to experimental structures. The root mean square deviation (RMSD) of our best results compared to crystal structures of cyclic peptides with sizes from 4 to 15 amino acids are mostly below 1.0 A up to 8 mers and under 2.0 A for larger cyclic peptides.     

Determinants of perceived social support: Interpersonal transactions, personal outlook, and transient affective states.

During the last decade, the study of social support has relied heavily on recipients' reports of perceived support. However, such reports of support may reflect not only actual supportive interpersonal transactions but also the recipients' own personal and perceptual dispositions and comparatively transient mood states. This study examines these factors' independent effects on perceived support. Interpersonal transactions of social support were assessed in a longitudinal panel design using reports from 486 adult male respondents and their significant others (mostly wives). Using structural modeling techniques ({lisrel vi}), an unfolding series of statistical analyses were performed. The results provide strong support for a model in which recipients' perception of support is determined significantly and strongly by actual interpersonal transactions as reported by significant others, moderately by the recipients' negative outlook bias, and weakly by their anxiety and depression as indicators of their poor mental health. The implications of the results for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Radio psychology and psychotherapy: Comparison of client attitudes and expectations.

We compared the expectations and attitudes of two groups of subjects who sought psychological help. One group (n?=?47) comprised callers to a radio counseling program broadcast in Israel that offers psychological help to parents and children; the second group (n?=?34) consisted of individuals who had received counseling in a child guidance clinic located in an urban center in Israel. We primarily compared the subjects' attitudes toward receiving psychological help. The results indicate that the attitudes of those who received help in the clinic were more positive than those who called the radio program. In addition, we investigated the satisfaction levels of callers to the radio counseling program and of those who received help in clinics. Last, we examined the callers' expectations of the radio counseling program and found them to be in keeping with the goals of primary prevention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Epithelioid smooth-muscle tumors of the uterus: a clinicopathologic study of 18 patients

Epithelioid smooth-muscle tumors of the uterus are uncommon neoplasms for which prognostic factors have not been well established. A retrospective follow-up study of 18 uterine epithelioid smooth-muscle tumors was performed. Patients ranged in age from 27 to 83 years (mean, 45 years) and were separated into three groups based on the nuclear grade of the epithelioid tumor cells. Two tumors had grade 1 nuclei; both were examples of intravenous leiomyomatosis. They had highest mitosis counts of 1 and 3 mitotic figures (MF)/10 high-power fields (HPF), no tumor cell necrosis was found, and both patients were alive with no evidence of disease at 64 and 5 months' follow-up. Ten tumors had grade 2 nuclei. All had highest mitosis counts of 0 to 3 MF/10 HPF, except one (5 MF/10 HPF). Tumor cell necrosis was absent in nine and only one had an infiltrative border. Tumor size ranged from 1.5 to 14 cm. Two tumors contained pleomorphic ("symplastic") multinucleated giant cells similar to those seen in bizarre leiomyomas. All nine patients with follow-up were alive with no evidence of disease 5 to 203 months postoperatively (median, 74 months). One patient had also received adjuvant radiation therapy. Six tumors had grade 3 nuclei. Highest mitosis counts of 4 to 9 MF/10 HPF were found in five; one had 1 MF/10 HPF. Maximum tumor size ranged from 4.5 to 13 cm. Two had tumor cell necrosis, and two had an infiltrative border. Two of these patients died of tumor 11 and 132 months postoperatively. The former had widespread metastases at initial surgery (stage IVb); the latter patient (stage I) developed the first of seven tumor recurrences 3 years postoperatively. Both patients had also received adjuvant chemotherapy. Of the remaining four patients, two were alive with no evidence of disease at 48 and 83 months, one was alive (tumor status unknown) at 28 months, and one was lost to follow-up. Based on our findings and those in the literature, we conclude that uterine smooth-muscle tumors with a predominance of epithelioid cells are extremely uncommon and metastasize infrequently. No single histologic feature is predictive of metastatic potential. Clinically malignant tumors (i.e., epithelioid leiomyosarcomas) typically have the combination of significant nuclear atypia (either grade 2 or grade 3 nuclei) and some mitotic activity (usually at least 3 to 4 MF/10 HPF); most also have tumor cell necrosis.