Absolute quantification of the G protein-coupled receptor rhodopsin by LC/MS/MS using proteolysis product peptides and synthetic peptide standards

Methods for the absolute quantification of a membrane protein are described using isotopically labeled or unlabeled synthetic peptides as standards. Synthetic peptides are designed to mimic peptides that are cleaved from target analyte proteins by proteolytic or chemical digestion, and the peptides selected serve as standards for quantification by LC/MS/MS on a triple quadrupole mass spectrometer. The technique is complementary to relative quantification techniques in widespread use by providing absolute quantitation of selected targets with greater sensitivity, dynamic range, and precision. Proteins that are found to be of interest by global proteome searches can be selected as targets for quantitation by the present method. This method has a much shorter analytical cycle time (minutes versus hours for the global proteome experiments), making it well suited for high-throughput environments. The present approach using synthetic peptides as standards, in conjunction with proteolytic or chemical cleavage of target proteins, allows mass spectrometry to be used as a highly selective detector for providing absolute quantification of proteins for which no standards are available. We demonstrate that quantification is simple and reliable for the integral membrane protein rhodopsin with reasonable recoveries for replicate experiments using low-micromolar solutions of rhodopsin from rod outer segments.     

Hydromorphone-naloxone combinations in opioid-dependent humans under naloxone novel-response discrimination procedure.

Naloxone-hydromorphone combinations were tested in participants trained to discriminate naloxone from placebo under a novel-response drug discrimination procedure while maintained on methadone. Naloxone alone produced dose-related increases in naloxone appropriate responding, little or no "novel"-appropriate responding, and increases in opioid antagonist adjective ratings (n?=?5). Hydromorphone alone produced dose-related increases in novel-appropriate responding, little or no naloxone-appropriate responding, and increases in opioid agonist adjective ratings (n?=?6). When combined with naloxone, hydromorphone produced dose-related decreases in naloxone-appropriate responding and antagonist adjective ratings (n?=?6). These findings are consistent with nonhuman data and suggest that this procedure may be useful as a human laboratory model of opioid withdrawal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in learned helplessness: IV. An experimental and naturalistic study of failure generalization and its mediators.

Tested the hypothesis that attributions for failure can mediate the generalization of failure effects across situations: When perceived causal factors remain present in otherwise novel situations, failure effects should transfer; when perceived causal factors are removed, failure effects should be attenuated. Specifically, it was predicted that sex differences in attributions would result in differential transfer to novel situations, with boys showing greater recovery of success expectancies when the evaluator changes, but girls showing greater recovery of success when the ability areas change. Two studies are reported: one a field study (40 female and 40 male 5th graders) examining changes in expectancy of academic success over the school year, and the other a laboratory analog (171 female and 143 male 4th–6th graders) examining directly the effects of evaluator and task change. Results provide strong support for the hypothesis and suggest an explanation for sex differences in long-term academic achievement. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trypsin inhibitors from Pisum sativum L exhibit identical epitopes

Pea (Pisum sativum L) trypsin inhibitor, known to be a mixture of at least eight different peptides exhibiting different charges as shown by electrophoresis, was subjected to an immunochemical analysis. By PAGE-SDS analysis, only one large diffuse band was detected showing that pea trypsin inhibitor peptides have a molecular weight between 12000 and 15000 amu. After preparative non-denaturing electrophoresis, four major bands, as judged by Coomassie blue staining, were purified and each of them was used to raise specific antibodies in rabbits. By ELISA test, immunoelectrophoresis and absorption on an immunoaffinity column, it was shown that each antiserum directed against any one of the four bands completely cross-reacted against each other. Thus, it can be concluded that each component of the pea trypsin inhibitor should exhibit a very strong sequence homology.     

Awareness of the response after feedback training for changes in heart rate and sudomotor laterality.

Examined the relation between (a) the ability to control visceral responding on a biofeedback (BFB) task and (b) the ability to report behaviors actually contributing to this performance in 4 experiments with 97 male Ss. Ss received BFB training for unidentified visceral responses and then gave written reports about what they had done to control BFB displays. Independent judges were given these reports and, on the basis of knowledge about activities known to contribute to visceral activity, were asked to determine the visceral responses for which Ss had been trained. The reports of Ss who succeeded at bidirectional control of heart rate (Exp I) or sudomotor laterality (Exp II) showed awareness of behaviors related to BFB as assessed by this procedure, whereas the reports of Ss who failed at bidirectional control did not. Subsequent experiments indicated that these results did not depend on a learning strategy that might have been specific to the initial studies. Findings question the view that people are unaware of what they have done to produce the response after training on BFB tasks. (81 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adrenalectomy reduces peripheral neural responses to gustatory stimuli in the rat.

The adrenalectomized rat, because of excessive body sodium loss, has been an important animal model for studying the physiological mechanisms underlying salt ingestion. To investigate the mediation by peripheral taste responsivity of changes in salt intake, multiunit responses of the chorda tympani nerve to various concentrations of NaCl, KCl, and LiCl, hydrochloric acid, and quinine hydrochloride were recorded from 18 adrenalectomized or intact male Sprague-Dawley rats. To control for a generalized decrease in sensory sensitivity, recordings from this auriculotemporal nerve to tactile stimulation of the pinna were also performed. There were no group differences in amplitude of the integrated neural responses to tactile stimulation. The largest decrease in gustatory responsivity occurred for suprathreshold concentrations of NaCl and LiCl. Data are discussed with reference to possible mechanisms underlying this neural alteration and the role that reductions in salt taste responsivity play in mediating increases in salt intake. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strain differences in maintenance of cocaine self-administration and their relationship to novelty activity responses.

The authors previously demonstrated that Fischer 344 (F344) and Lewis inbred rats differ in acquisition of cocaine self-administration. Other studies show that acquisition and maintenance of drug self-administration are predicted by locomotor activity in a novel environment among outbred Sprague-Dawley rats. The present study was designed to determine whether this relationship extended to F344 and Lewis rats. In Experiment 1, F344, Lewis, and Sprague-Dawley rats were trained to self-administer cocaine and tested with several doses under fixed- and progressive-ratio schedules of reinforcement. Self-administered infusions and ineffective active lever presses--those emitted during infusion and time-out periods--were assessed. In Experiment 2, separate sets of rats of each strain were examined for locomotor responses (distance traveled and center time) under novelty conditions. Results show that F344 rats self-administer more cocaine than Lewis or Sprague-Dawley rats under both schedules and emit more ineffective lever presses--a possible measure of craving. Strain comparisons of locomotor responses suggest that center time, not activity, relates to self-administration behavior. Maintenance studies of cocaine self-administration rather than acquisition may better reflect vulnerability to addiction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential Response in Foliar Chemistry of Three Ash Species to Emerald Ash Borer Adult Feeding

The emerald ash borer (EAB; Agrilus planipennis Fairmaire; Coleoptera: Buprestidae), is an exotic wood-boring beetle that has been threatening North American ash (Fraxinus spp.) resources since its discovery in Michigan and Ontario in 2002. In this study, we investigated the phytochemical responses of the three most common North American ash species (black, green, and white ash) in northeastern USA to EAB adult feeding. Black ash was the least responsive to EAB adult feeding in terms of the induction of volatile compounds, and levels of only two (indole and benzyl cyanide) of the 11 compounds studied increased. In green ash, levels of two [(E)-β-ocimene and indole] of the 11 volatile compounds studied were elevated, while the levels of two green leaf volatiles [hexanal and (E)-2-hexenal] decreased. White ash showed the greatest response with an increase in levels of seven of the 11 compounds studied. Qualitative differences among ash species were detected. Among the phenolic compounds detected, ligustroside was the only one detected in all three species. Oleuropein aglycone and 2 unidentified compounds were found only in black ash; coumaroylquinic acid and feruloylquinic acid were detected only in green ash; and verbascoside hexoside was detected only in white ash. EAB adult feeding did not elicit or decrease concentrations of any selected individual phenolic compounds. However, although levels of total phenolics from black and green ash foliage were not affected by EAB adult feeding, they decreased significantly in white ash. EAB adult feeding elevated chymotrypsin inhibitors in black ash. The possible ecological implications of these findings are discussed.     

Factorization-based active contour segmentation and pelican optimization-based modified bidirectional long short-term memory for ovarian tumor detection

This paper proposes a novel three-dimensional convolution neural network-based modified bidirectional long short-term memory with pelican optimization (3D CNN based MBiLSTM with PO) algorithm for multiclass ovarian tumor detection. Initially, the International Collaboration on Cancer Reporting endometrial cancer dataset images are provided in pre-processing phase, which uses a pre-emphasis filter to process the input image. In the segmentation phase, pre-processed data is then partitioned into diverse subgroups (i.e., pixels), which minimizes the complexity of images. In this paper, a factorization-based active contour technique is employed in the effective segmentation of images. The segmented features are then extracted and classified using the 3D CNN-MBiLSTM with PO algorithm. Finally, the experimental results are conducted and compared with various other approaches for various performance metrics. Each metric is evaluated with respect to the different number of iterations. The accuracy, sensitivity, and specificity have reached a higher value of 98.5%, 96%, and 98.25%, respectively.