Learning disabilities: Policy issues and promising approaches.

The current status of knowledge concerning learning disabilities is reviewed with respect to areas of consensus and areas of disagreement about this phenomenon. The adequacy of the knowledge base is evaluated, and implications for social policies regarding the definition, diagnosis, treatment, and education of learning disabled children are drawn. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cutting edge: novel RNA ligands able to bind CD4 antigen and inhibit CD4+ T lymphocyte function

The value of high affinity-specific reagents in immunology is exemplified by the use of mAbs. Recent in vitro selection methods suggested that oligonucleotides may provide a useful alternative, especially where Abs have been insufficient thus far. We used a systematic evolution of ligands by exponential enrichment (SELEX) procedure to derive high affinity oligonucleotide ligands (aptamers) recognizing CD4. These RNase-resistant aptamers bound with high affinity and specificity as demonstrated using BIAcore (Stevenage, U.K.) technology. They also bound native CD4 on rat lymphocytes and specifically interfered with labeling by high affinity mAbs. All aptamers recognized the same binding site in the CDR2-like region in domain 1 of CD4. The applicability of these aptamers for immunologic studies was clearly demonstrated by their ability to block a fully allogeneic MLR in a CD4-specific manner. The high affinity and stability of aptamers point to their value in the analysis and functional manipulation of the immune system.     

Life span changes in visual enumeration: The number discrimination task.

Participants from 5 groups with mean ages of 6, 8, 10, 22, and 72 yrs were tested on a series of speeded number discriminations: 1 vs 2, 3 vs 4, 6 vs 7, and 8 vs 9. The primary measure of interest (response time slope as a function of number size) decreased with age for numbers in the 1–4 range. However, a U-shaped age function emerged in the 6–9 range, with larger slopes for children and senior adults, and the smallest slopes for young adults. These data suggest that different processes are involved in enumerating small and large numbers of items. It is argued that subitizing, the process for small numbers, makes only minimal demands on spatial attention and thus shows developmental improvements without any decline in old age. In contrast, counting, the process for large numbers, requires sophisticated coordination of spatial attention, which has previously been shown first to improve and then decline over the life span. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of Aging on the Physical-Mechanical Properties of Acrylic Resin Films Cast from Aqueous Dispersions and Organic Solutions

The physical-mechanical properties of the enteric copolymers, poly(methacrylic acid, ethyl acrylate) Eudragit® L100-55, and Eudragit® L30D have been investigated. Free films of the copolymer containing varying levels of glyceryl triacetate (triacetin) and citrate ester (Citroflex®) plasticizers were prepared by both aqueous and solvent casting techniques. Conditioned films were stored at different humidities and temperatures for predetermined time periods prior to testing. Free films with plasticizer concentration ranging from 0 to 30% by weight of the polymer demonstrated that physical aging at room temperature resulted in physical-mechanical changes as the stress-strain curves indicated a decrease in the percent elongation with increases in the tensile strength. Films prepared from the aqueous latex approached a constant state of equilibrium at a faster rate than films prepared from isopropyl alcohol, where the mechanical properties approach a relatively constant value. Free films containing varying amounts of the plasticizer, triethyl citrate, were stored under different humidity and temperature conditions. In addition, a headspace-gas chromatography (HSGC) method was developed to correlate solvent residues with mechanical properties. The results indicated that an increase in temperature and humidity accelerated the rate of solvent evaporation as a function of time. High vacuum and low humidity conditions were demonstrated to be ineffective conditions for solvent removal. Solvent residues were found in all films after 48 hours of exposure to temperatures up to 60°C and/or exposure to relatively high humidity conditions. A direct relationship between plasticizer content and rate of solvent evaporation from the film was established. Higher concentrations of the plasticizer were found to augment the evaporation of the solvents. This enhanced evaporation was due to the stronger molecular interaction forces between the polymer and the plasticizer than between the polymer and the solvent.     

A theory of humor elicitation.

Presents a general theory of humor elicitation that specifies the conditions in which humor is experienced in both social and nonsocial situations. The theory takes into account the interpretation of a stimulus event that is necessary to elicit humor, the difficulty of identifying the humor-eliciting features of this interpretation, and the cognitive elaboration of implications of the event. The influence of these factors is postulated to depend on Ss' information-processing objectives at the time a stimulus event occurs. The theory is used to conceptualize the humor elicited by jokes, witticisms, and social events that are neither intended nor expected to be humorous. Particular attention is given to the cognitive underpinnings of responses to ethnic humor and to the humor that is elicited by one's own behavior in social situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Foundations of psychological assessment: Implications for cognitive assessment in clinical science.

We examine psychological assessment within the broader framework of psychology's efforts to build and test useful scientific theories. In the first section, we consider in detail a number of fundamental epistemological, conceptual, and methodological issues that tend either to inhibit or to foster theoretical progress in psychology. In light of these issues, we then recommend that psychology adopt an information-based, quantitative approach to theory building and testing. This approach should help us model the dynamic, stochastic processes underlying human behavior. In the second section, we explore the implications of the issues and strategies that we outlined in the first section for the future of clinical assessment, with a particular focus on the clinical assessment of cognitive processes. We conclude by advocating a conceptual and methodological integration of clinical and cognitive neuroscience in psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Glucose transporter (GLUT-4) is targeted to secretory granules in rat atrial cardiomyocytes

The insulin-responsive glucose transporter GLUT-4 is found in muscle and fat cells in the trans-Golgi reticulum (TGR) and in an intracellular tubulovesicular compartment, from where it undergoes insulin-dependent movement to the cell surface. To examine the relationship between these GLUT-4-containing compartments and the regulated secretory pathway we have localized GLUT-4 in atrial cardiomyocytes. This cell type secretes an antihypertensive hormone, referred to as the atrial natriuretic factor (ANF), in response to elevated blood pressure. We show that GLUT-4 is targeted in the atrial cell to the TGR and a tubulo-vesicular compartment, which is morphologically and functionally indistinguishable from the intracellular GLUT-4 compartment found in other types of myocytes and in fat cells, and in addition to the ANF secretory granules. Forming ANF granules are present throughout all Golgi cisternae but only become GLUT4 positive in the TGR. The inability of cyclohexamide treatment to effect the TGR localization of GLUT-4 indicates that GLUT-4 enters the ANF secretory granules at the TGR via the recycling pathway and not via the biosynthetic pathway. These data suggest that a large proportion of GLUT-4 must recycle via the TGR in insulin-sensitive cells. It will be important to determine if this is the pathway by which the insulin-regulatable tubulo-vesicular compartment is formed.     

Further evidence for an imprinted gene for neonatal diabetes localised to chromosome 6q22-q23

Transient neonatal diabetes mellitus (TNDM) is a rare form of childhood diabetes which usually resolves in the first 6 months of life but which predisposes to type 2 diabetes of adult onset. We recently reported paternal uniparental isodisomy of chromosome 6 (UPD6) in two children with TNDM and proposed that there may be an imprinted gene important in the aetiology of diabetes on chromosome 6. We now describe two unrelated families which independently suggest that the gene is imprinted, is paternally expressed and maps to 6q22-q23. One family has a duplication while the other, with familial TNDM, shows linkage to a marker in this region.     

Criteria for good adjustment to chronic hemodialysis: Nurse-patient differences.

Examined nurse–patient agreement on behaviors and attitudes associated with patient adjustment to chronic hemodialysis treatment. 164 hemodialysis nurses and 79 chronic hemodialysis outpatients completed a patient adjustment to dialysis inventory consisting of 43 behaviors and attitudes reported by nurses in earlier research to be important for adjustment to chronic hemodialysis. Results show that over 60% of nurses and patients showed sufficient agreement on the importance of 33 of 43 behaviors and attitudes for patient adjustment in the areas of compliance with the medical regimen, involvement in treatment, patient–staff interactions, and psychological and social functioning. Nurses and patients disagreed as to whether 9 behaviors and attitudes were at least important, while agreeing that only 1 item was irrelevant. Results also show that significantly more patients than nurses rated 25 out of 43 behaviors and attitudes as crucial. Approximately 50% of these related to interacting with staff, family, and friends. It is suggested that social and psychological criteria for adjustment to hemodialysis treatment should be defined by nurses and patients together. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)