Verbal working memory and language production: Common approaches to the serial ordering of verbal information.

[Correction Notice: An erratum for this article was reported in Vol 136(3) of Psychological Bulletin (see record 2010-07936-010). In the article “Verbal Working Memory and Language Production: Common Approaches to the Serial Ordering of Verbal Information” by Daniel J. Acheson and Maryellen C. MacDonald (Psychological Bulletin, 2009, Vol. 135, No. 1, pp. 50–68), the initial sentence of the text of the article (p. 50) contains an error. The first name of the researcher Andrew W. Ellis was listed incorrectly. The sentence should read as follows: Nearly 30 years ago, Andrew W. Ellis (1980) observed that errors on tests of verbal working memory (WM) paralleled those that occur naturally in speech production.] Verbal working memory (WM) tasks typically involve the language production architecture for recall; however, language production processes have had a minimal role in theorizing about WM. A framework for understanding verbal WM results is presented here. In this framework, domain-specific mechanisms for serial ordering in verbal WM are provided by the language production architecture, in which positional, lexical, and phonological similarity constraints are highly similar to those identified in the WM literature. These behavioral similarities are paralleled in computational modeling of serial ordering in both fields. The role of long-term learning in serial ordering performance is emphasized, in contrast to some models of verbal WM. Classic WM findings are discussed in terms of the language production architecture. The integration of principles from both fields illuminates the maintenance and ordering mechanisms for verbal information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

BDNF attenuates functional and structural disorders in nerves of galactose-fed rats

Galactose intoxication of rats was used to disrupt metabolism of Schwann cells and skeletal muscle, two sites that contain the polyol-forming enzyme aldose reductase (AR). Galactose-fed rats develop a neuropathy characterized by nerve conduction deficits and axonal atrophy. To investigate the possibility that galactose metabolism by AR influences axonal function and structure by altering production of neurotrophic factors, the impact of galactose intoxication on nerve and muscle BDNF levels and the effects of exogenous BDNF treatment on galactose neuropathy were examined using biochemical, electrophysiologic and morphometric techniques. Galactose feeding increased BDNF protein in peripheral nerve and muscle. Exogenous BDNF treatment attenuated motor nerve conduction velocity deficits in the sciatic nerve of galactose-fed animals and myelin splitting of motor axons in the ventral root. In contrast, sensory nerve conduction velocity (SNCV) deficits in the sciatic nerve and myelin splitting in the central projections of sensory neurons were not prevented by BDNF treatment. BDNF treatment did not attenuate reduced axonal caliber in the sciatic nerve, but did ameliorate the diminution of the caliber of central sensory projections in the dorsal root. These findings point to the potential use of BDNF in the treatment of peripheral neuropathies.     

Energy expenditure of Chinese infants in Guangdong Province, south China, determined with use of the doubly labeled water method

The doubly labeled water method was used to measure the energy expenditure of a group of 41, 4- or 6-mo-old infants with a cross-sectional design. The infants were divided into two groups according to whether they were breast-fed (11 at 4 mo, 9 at 6 mo) or formula fed (11 at 4 mo, 10 at 6 mo). Anthropometric measurements were recorded at birth and at the beginning and end of the 8-d study. Anthropometric data, which were supported by the food intake and energy expenditure results, indicated that the infants were within the norms for European and American infants of the same age. Mean energy intakes of 352 kJ (84 kcal) kg(-1) x d(-1) at 4 and 6 mo were lower than the FAO/WHO/UNU recommended value of 452 kJ (108 kcal) x kg(-1) x d(-1)) and Chinese recommendations of 502 kJ (120 kcal) kg(-1) x d(-1). However, some authors believe that values of 398 kJ (95 kcal) kg(-1) x d(-1) at 4 mo and 356 kJ (85 kcal) kg(-1) x d(-1) at 6 mo are more appropriate. At 6 mo the infants' length-for-age and weight-for-age were at the National Center for Health Statistics 55th and 47th percentiles, respectively, whereas 58% were below the 50th percentile for weight-for-length. We conclude that at 4 mo infants receive sufficient energy for their requirements. However, at 6 mo energy requirements might well be greater than the revised recommendations, when infants are being weaned to alternative foods and are more prone to the influence of diet on their growth and development.     

Preparation of ceramic fibre TEM cross-sections using ultramicrotomy and ion beam thinning methods

The preparation of specimens for detailed TEM microanalysis of micrometre-diameter, ceramic fibre cross-sections is described. The starter material is ceramic fibre in powder form and both ultramicrotomy-based and ion beam thinning-based methods are described. Requirements for specimens of uniform and adequate thinness, for easy selection of representative fibre cross-sections within the same specimen and for a reliable and time-efficient preparation method, resulted in choice of the ultramicrotomy-based method and the associated development of a novel extrusion and sedimentation technique of embedding the fibres to provide necessary pre-alignment and packing.     

Evaluation of the premier EHEC assay for detection of Shiga toxin-producing Escherichia coli

An enzyme-linked immunosorbent assay for the detection of Shiga toxins (Premier EHEC assay; Meridian Diagnostics, Inc.) was compared to conventional sorbitol-MacConkey culture for the recovery of enterohemorrhagic Escherichia coli. A total of 74 enteric pathogens, including 8 E. coli O157:H7 isolates, were recovered from 974 stool specimens. Two of these specimens were not tested by Premier assaying due to insufficient sample and are not considered in the data analysis. The Premier EHEC assay detected the 6 evaluable specimens which were culture positive for E. coli O157:H7 and identified an additional 10 specimens as containing Shiga toxin. Seven isolates were recovered from these 10 specimens by an immunoblot assay and were confirmed as toxin producers by a cytotoxin assay. Of these seven, four isolates were serotype O157:H7, one was O26:NM, one was O6:H-, and one was O untypeable:H untypeable. Three specimens contained Shiga toxin by both EHEC immunoassaying and cytotoxin testing; however, no cytotoxin-producing E. coli could be recovered. The sorbitol-MacConkey method had a sensitivity and a specificity of 60 and 100%, respectively, while the Premier EHEC assay had a sensitivity and a specificity of 100 and 99.7%, respectively, for E. coli O157:H7 only. The Premier EHEC assay also detected an additional 20% Shiga toxin-producing E. coli (STEC) that were non-O157:H7. Thus, the Premier EHEC assay is a sensitive and specific method for the detection of all STEC isolates. Routine use would improve the detection of E. coli O157:H7 and allow for determination of the true incidence of STEC other than O157:H7. The presence of blood in the stool and/or the ages of the patients were poor predictors of the presence of STEC. Criteria need to be determined which would allow for the cost-effective incorporation of this assay into the routine screen for enteric pathogens in high-risk individuals, especially children.     

The interaction of concreteness and phonological similarity in verbal working memory.

Although phonological representations have been a primary focus of verbal working memory research, lexical-semantic manipulations also influence performance. In the present study, the authors investigated whether a classic phenomenon in verbal working memory, the phonological similarity effect (PSE), is modulated by a lexical-semantic variable, word concreteness. Phonological overlap and concreteness were factorially manipulated in each of four experiments across which presentation modality (Experiments 1 and 2: visual presentation; Experiments 3 and 4: auditory presentation) and concurrent articulation (present in Experiments 2 and 4) were manipulated. In addition to main effects of each variable, results show a Phonological Overlap × Concreteness interaction whereby the magnitude of the PSE is greater for concrete word lists relative to abstract word lists. This effect is driven by superior item memory for nonoverlapping, concrete lists and is robust to the modality of presentation and concurrent articulation. These results demonstrate that in verbal working memory tasks, there are multiple routes to the phonological form of a word and that maintenance and retrieval occur over more than just a phonological level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How does Escherichia coli O157:H7 testing in meat compare with what we are seeing clinically?

Escherichia coli O157:H7 is but one of a group of Shiga toxin-producing E. coli (STEC) that cause both intestinal disease such as bloody and nonbloody diarrhea and serious complications like hemolytic uremic syndrome (HUS). While E. coli O157: H7 is the most renowned STEC, over 200 different types of STEC have been documented in meat and animals, at least 60 of which have been linked with human disease. A number of studies have suggested that non-O157 STEC are associated with clinical disease, and non-O157 STEC are present in the food supply. Non-O157 STEC, such as O111 have caused large outbreaks and HUS in the United States and other countries. The current policy in the United States is to examine ground beef for O157:H7 only, but restricting the focus to O157 will miss other important human STEC pathogens.