Levels of selection and capacity limits.

Examined the effects of word relevancy (word in relevant or irrelevant location) and display load (1–4 words) on physical, semantic, and controlled processing of nontargets in visual target-detection tasks administered to 300 undergraduates in 8 experiments. Interwoven with the detection task was a test-word identification task that was used to measure priming potency of nontargets. Physical and semantic levels of processing were measured in terms of identity and semantic priming, respectively. Nontarget primes were repeated as test words in identity priming. Nontarget primes were semantic associates of test words in semantic priming. Controlled processing of nontargets was measured in terms of recognition memory on a subsequent test. All measures increased with word relevancy and decreased with display load. The priming effects remained intact even when word presentation was speeded up and controlled processing was sharply curtailed. Data indicate that all levels of processing are selective and capacity limited. (60 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential assembly of coexpressed glutamate receptor subunits in neurons of rat cerebral cortex

In the rat, subunits of the glutamate receptor family fall into three pharmacologically distinct groups: alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid preferring receptors (Glu R1-4), kainate preferring receptors (Glu R5-7, KA 1, KA 2), and N-methyl-D-aspartate preferring receptors (NMDA R1, NMDA R2A-2D). In the present study, we demonstrate immunocytochemically that the majority of neurons in rat cerebral cortex coexpress members of all three groups of glutamate receptor subunits, Glu R2/3, Glu R5/6/7, and NMDA R1. Using immunoaffinity purified or immunoprecipitated alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid, kainate and N-methyl-D-aspartate receptors, we show that alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors containing Glu R1-4, kainate receptors containing Glu R6, Glu R7, and KA 2 and N-methyl-D-aspartate receptors containing NMDA R1 each form distinct protein complexes that do not share subunits. Our data indicate that a mechanism exists which allows for the specific assembly of selected glutamate receptor subunits into functionally and structurally distinct heteromeric receptors.     

Differential subcellular regulation of NMDAR1 protein and mRNA in dendrites of dentate gyrus granule cells after perforant path transection

Unilateral transection of the excitatory perforant path results in the acute deafferentation of a segregated zone on the distal dendrites of hippocampal dentate gyrus granule cells (i.e., outer molecular layer), followed by sprouting, reactive synaptogenesis, and a return of physiological and behavioral function. To investigate cellular mechanisms underlying NMDA receptor plasticity in response to such extensive synaptic reorganization, we quantitatively evaluated changes in intensity levels of NMDAR1 immunofluorescence and NMDAR1 mRNA hybridization within subcellular compartments of dentate gyrus granule cells 2, 5, and 9 d after perforant path lesions. There were no significant changes in either measure at 2 d postlesion. However, at 5 and 9 d postlesion, during the period of axonal sprouting and synaptogenesis, there was an increase in NMDAR1 immunolabeling that was restricted to the dendritic segments of the denervated outer molecular layer and the granule cell somata. In contrast, NMDAR1 mRNA levels at 5 and 9 d postlesion increased throughout the full extent of the molecular layer, including both denervated and nondenervated segments of granule cell dendrites. These findings reveal that NMDAR1 mRNA is one of a limited population of mRNAs that is transported into dendrites and further suggest that in response to terminal proliferation and sprouting, increased mRNA transport occurs throughout the full dendritic extent, whereas increased local protein synthesis is restricted to denervated regions of the dendrites whose afferent activity is perturbed. These results begin to elucidate the dynamic postsynaptic subcellular regulation of receptor subunits associated with synaptic plasticity after denervation.     

Sambar deer (Cervus unicolor) x red deer (C. elaphus) interspecies hybrids

The artificial insemination of 400 red deer hinds with sambar deer semen resulted in 31 pregnancies at day 40 (24 at day 100) and the birth of four calves. Only one female calf was born alive. The artificial insemination of 10 sambar deer hinds with red deer semen resulted in five pregnancies at day 40, of which none went to term. Gel electrophoresis of three blood proteins confirmed the live calf as the first documented sambar deer x red deer hydrid. G-banded karyotypes were consistent with the calf (2n = 62; six unpaired and one paired metacentric autosomes) being the offspring of a red deer dam (2n = 68; single pair of metacentric autosomes) and a sambar deer sire (2n = 56; seven pairs of metacentric autosomes).     

Inhaled nitric oxide improves exercise capacity in patients with severe heart failure and right ventricular dysfunction

Fourteen cardiac transplant candidates were studied with cardiopulmonary exercise testing at baseline and while breathing nitric oxide (40 ppm). Oxygen consumption at the anaerobic threshold was improved by breathing nitric oxide in patients with pulmonary hypertension and in patients with an elevated left ventricular end-diastolic volume index.