Beyond verbal fluency: Investigating the long-term effects of bilateral subthalamic (STN) deep brain stimulation (DBS) on language in two cases

Cognitive functioning has been described as largely impervious to chronic STN-DBS administered over 12-month periods. In relation to the domain of language, however, the effects of STN-DBS are yet to be thoroughly delineated. Verbal fluency tasks represent an almost exclusively applied index of linguistic proficiency relative to neuropsychological research within this population. Comprehensive investigations of the impact of STN-DBS on language function, however, have never been undertaken. The more precise elucidation of the role of the STN in the mediation of language processes, by way of assessments which probe language comprehension and production mechanisms, served as the primary focus of this research. Longitudinal analysis also afforded consideration of the way in which cognitive-linguistic circuits respond to STN-DBS over time. Bilateral STN-DBS primarily effected clinically reliable fluctuations (i.e., both improvements and declines) in performance in both subjects on tasks demanding cognitive-linguistic flexibility in the formulation and comprehension of complex language. Of particular note, both subjects demonstrated a cumulative increase in the proportion of reliable post-operative improvements achieved over time. The findings of this research lend support to models of subcortical participation in language which endorse a role for the STN, and suggest that bilateral STN-DBS may serve to enhance the proficiency of basal ganglia-thalamocortical linguistic circuits over time.

Probing expert anticipation with the temporal occlusion paradigm: Experimental investigations of some methodological issues

Two experiments were conducted to examine whether the conclusions drawn regarding the timing of anticipatory information pick-up from temporal occlusion studies are influenced by whether (a) the viewing period is of variable or fixed duration and (b) the task is a laboratory-based one with simple responses or a natural one requiring a coupled, interceptive movement response. Skilled and novice tennis players either made pencil-and-paper predictions of service direction (Experiment 1) or attempted to hit return strokes (Experiment 2) to tennis serves while their vision was temporally occluded in either a traditional progressive mode (where more information was revealed in each subsequent occlusion condition) or a moving window mode (where the visual display was only available for a fixed duration with this window shifted to different phases of the service action). Conclusions regarding the timing of information pick-up were generally consistent across display mode and across task setting lending support to the veracity and generalisability of findings regarding perceptual expertise in existing laboratory-based progressive temporal occlusion studies.

Effects of visual occlusion and fatigue on motor performance in water

The purpose of this study was to test the effects of visual occlusion and fatigue on the motor performance of vertical skills in synchronized swimming. Experienced synchronized swimmers (n = 12) were randomly assigned to either an exercise or nonexercise (control) activity group. Subjective ratings of fatigue were obtained from the swimmers who then each performed four vertical skills under alternating conditions of vision and visual occlusion before and after either a swimming (designed to induce fatigue) or nonphysical activity. A main effect of activity (p < .03) was found for two measures of performance accuracy (lateral and anterior total distance traveled) but not for lateral and anterior maximum deviation from vertical, indicating that fatigue played a role in executing the skills. The data also indicate that the maintenance of a stationary position is a skill of greater difficulty than maintaining a true vertical. In contrast with previous research findings on synchronized swimmers, a significant effect of vision in all conditions was found, with performance decrements in the conditions of visual occlusion showing that vision provided important sensory input for the swimmers.

Existence of complementary pairs of proportionally balanced designs

Proportionally balanced designs (pi BDs) were introduced by Gray and Matters in response to a need for the allocation of markers of the Queensland Core Skills Test to have a certain property. Subsequent papers extended the theoretical results relating to such designs and provided further instances and general constructions. This work focused on designs comprising blocks of precisely two sizes, and when each variety occurs with one of precisely two possible frequencies. Two designs based on the set V of varieties are complementary if, whenever B is a block of one, then its complement with regard to the set V is a block of the other. Here we present necessary conditions for the existence of complementary pairs of such pi BDs and provide lists of some restricted parameter sets satisfying these necessary conditions. The lists are arranged according to the number of blocks. We demonstrate that not all of these parameter sets give rise to designs. However we establish by construction of the sets of blocks that, for every feasible number of blocks less than or equal to 100, with the possible exception of 63, there exists at least one pair of complementary pi BDs. We also investigate the conditions under which the complementary design can be isomorphic to the original design, and again provide a list of feasible parameters for pairs of such designs with at most 400 blocks.

Neural pathways mediating bilateral interactions between the upper limbs

The ease with which we perform tasks such as opening the lid of a jar, in which the two hands execute quite different actions, belies the fact that there is a strong tendency for the movements of the upper limbs to be drawn systematically towards one another. Mirror movements, involuntary contractions during intended unilateral engagement of the opposite limb, are considered pathological, as they occur in association with specific disorders of the CNS. Yet they are also observed frequently in normally developing children, and motor irradiation, an increase in the excitability of the (opposite) homologous motor pathways when unimanual movements are performed, is a robust feature of the mature motor system. The systematic nature of the interactions that occur between the upper limbs has also given rise to the expectation that functional improvements in the control of a paretic limb may occur when movements are performed in a bimanual context. In spite of the ubiquitous nature of these phenomena, there is remarkably little consensus concerning the neural basis of their mediation. In the present review, consideration is given to the putative roles of uncrossed corticofugal fibers, branched bilateral corticomotoroneuronal projections, and segmental networks. The potential for bilateral interactions to occur in various brain regions including the primary motor cortex, the supplementary motor area, non-primary motor areas, the basal ganglia, and the cerebellum is also explored. This information may provide principled bases upon which to evaluate and develop task and deficit-specific programs of movement rehabilitation and therapy. (c) 2005 Elsevier B.V. All rights reserved.

Review of Beginning Reading: A balanced approach to teaching literacy during the first three years at school by Yola Centre

Beginning Reading: A Balanced Approach to Literacy Instruction during the First Three Years at School by Yola Center is intended for those involved in teaching and supporting literacy practices in regular classrooms and addresses literacy practices for learners with disabilities and those experiencing difficulties in literacy learning.

Renal endothelial dysfunction and impaired autoregulation after ischemia-reperfusion injury result from excess nitric oxide

Endothelial dysfunction in ischemic acute renal failure (IARF) has been attributed to both direct endothelial injury and to altered endothelial nitric oxide synthase ( eNOS) activity, with either maximal upregulation of eNOS or inhibition of eNOS by excess nitric oxide ( NO) derived from iNOS. We investigated renal endothelial dysfunction in kidneys from Sprague-Dawley rats by assessing autoregulation and endothelium-dependent vasorelaxation 24 h after unilateral ( U) or bilateral ( B) renal artery occlusion for 30 (U30, B30) or 60 min (U60, B60) and in sham-operated controls. Although renal failure was induced in all degrees of ischemia, neither endothelial dysfunction nor altered facilitation of autoregulation by 75 pM angiotensin II was detected in U30, U60, or B30 kidneys. Baseline and angiotensin II-facilitated autoregulation were impaired, methacholine EC50 was increased, and endothelium-derived hyperpolarizing factor ( EDHF) activity was preserved in B60 kidneys. Increasing angiotensin II concentration restored autoregulation and increased renal vascular resistance ( RVR) in B60 kidneys; this facilitated autoregulation, and the increase in RVR was abolished by 100 mu M furosemide. Autoregulation was enhanced by N-omega-nitro-L-arginine methyl ester. Peri-ischemic inhibition of inducible NOS ameliorated renal failure but did not prevent endothelial dysfunction or impaired autoregulation. There was no significant structural injury to the afferent arterioles with ischemia. These results suggest that tubuloglomerular feedback is preserved in IARF but that excess NO and probably EDHF produce endothelial dysfunction and antagonize autoregulation. The threshold for injury-producing, detectable endothelial dysfunction was higher than for the loss of glomerular filtration rate. Arteriolar endothelial dysfunction after prolonged IARF is predominantly functional rather than structural.

A note on the Balanced method

Recently the Balanced method was introduced as a class of quasi-implicit methods for solving stiff stochastic differential equations. We examine asymptotic and mean-square stability for several implementations of the Balanced method and give a generalized result for the mean-square stability region of any Balanced method. We also investigate the optimal implementation of the Balanced method with respect to strong convergence.

Degenerate dentition of the dugong (Dugong dugon), or why a grazer does not need teeth: morphology, occlusion and wear of mouthparts

The morphology and functional occlusion of the cheekteeth of 57 dugongs Dugong dugon of both sexes were examined using reflected light and scanning electron microscopy, radiography, hardness testing and skull manipulation. The functional morphology of the horny oral pads was also described. Mouthparts and body size allometry was examined for ontogenetic and gender-related trends. We found that the worn erupted cheekteeth of the dugong are simple flat pegs composed of soft degenerative dentine. During occlusion, the mandible moves in a mainly antero-lingual direction, with the possibility of mandibular retraction in some individuals. Anterior parts of the cheektooth row may become non-functional as a dugong ages. As a function of body size, dugong cheekteeth are extremely small compared with those of other mammalian herbivores, and with other hindgut fermenters in particular. The morphology, small size and occlusal variability of the cheekteeth suggest that there has not been strong selective pressure acting to maintain an effective dentition. In contrast, great development of the horny pads and associated skull parameters and their lower size variability suggest that the horny pads may have assumed the major role in food comminution.

Rehabilitation approaches to promote successful unilateral and bilateral fittings and avoid inappropriate prescription

Successful hearing aid fitting occurs when the person fitted wears the aid/s on a regular basis and reports benefit when the aid/s is used. A significant number of people fitted with unilateral or bilateral hearing aids for the first time do not continue to use one or both aids in the long term. In this paper, factors consistently found in previous research to be associated with unsuccessful fitting are explored; in particular, the negative attitudes of some clients towards hearing aids, their lack of motivation for seeking help, inability to identify goals for rehabilitation, and problems with the management of the devices. It is argued here that success in hearing aid fitting involves the same dynamics as found with other assistive technologies (e.g., wheelchairs, walking frames), and is dependent on a match between the characteristics of a prospective user, the technology itself, and the environments of use (Scherer, 2002). It is recommended that for clients who identify concerns about hearing aids, or who are unsure about when they would use them, and/or are likely to have problems with aid management, only one aid be fitted in the first instance, if hearing aid fitting is to proceed at all. Rehabilitation approaches to promote successful fitting are discussed in light of results obtained from a survey of clients who experienced both successful and unsuccessful aid fitting.

The discriminative bilateral filter: An enhanced denoising filter for electron microscopy data

Advances in three-dimensional (313) electron microscopy (EM) and image processing are providing considerable improvements in the resolution of subcellular volumes, macromolecular assemblies and individual proteins. However, the recovery of high-frequency information from biological samples is hindered by specimen sensitivity to beam damage. Low dose electron cryo-microscopy conditions afford reduced beam damage but typically yield images with reduced contrast and low signal-to-noise ratios (SNRs). Here, we describe the properties of a new discriminative bilateral (DBL) filter that is based upon the bilateral filter implementation of Jiang et al. (Jiang, W., Baker, M.L., Wu, Q., Bajaj, C., Chin, W., 2003. Applications of a bilateral denoising filter in biological electron microscopy. J. Struc. Biol. 128, 82-97.). In contrast to the latter, the DBL filter can distinguish between object edges and high-frequency noise pixels through the use of an additional photometric exclusion function. As a result, high frequency noise pixels are smoothed, yet object edge detail is preserved. In the present study, we show that the DBL filter effectively reduces noise in low SNR single particle data as well as cellular tomograms of stained plastic sections. The properties of the DBL filter are discussed in terms of its usefulness for single particle analysis and for pre-processing cellular tomograms ahead of image segmentation. (c) 2006 Elsevier Inc. All rights reserved.

Delayed administration of darbepoetin or erythropoietin protects against ischemic acute renal injury and failure

Administration of human recombinant erythropoietin ( EPO) at time of acute ischemic renal injury ( IRI) inhibits apoptosis, enhances tubular epithelial regeneration, and promotes renal functional recovery. The present study aimed to determine whether darbepoetin-alfa ( DPO) exhibits comparable renoprotection to that afforded by EPO, whether pro or antiapoptotic Bcl-2 proteins are involved, and whether delayed administration of EPO or DPO 6 h following IRI ameliorates renal dysfunction. The model of IRI involved bilateral renal artery occlusion for 45 min in rats ( N = 4 per group), followed by reperfusion for 1-7 days. Controls were sham-operated. Rats were treated at time of ischemia or sham operation ( T0), or post-treated ( 6 h after the onset of reperfusion, T6) with EPO ( 5000 IU/kg), DPO ( 25 mu g/kg), or appropriate vehicle by intraperitoneal injection. Renal function, structure, and immunohistochemistry for Bcl-2, Bcl-XL, and Bax were analyzed. DPO or EPO at T0 significantly abrogated renal dysfunction in IRI animals ( serum creatinine for IRI 0.17 +/- 0.05mmol/l vs DPO-IRI 0.08 +/- 0.03mmol/l vs EPO-IRI 0.04 +/- 0.01mmol/l, P = 0.01). Delayed administration of DPO or EPO ( T6) also significantly abrogated subsequent renal dysfunction ( serum creatinine for IRI 0.17 +/- 0.05mmol/l vs DPO-IRI 0.06 +/- 0.01mmol/l vs EPO-IRI 0.03 +/- 0.03mmol/l, P = 0.01). There was also significantly decreased tissue injury ( apoptosis, P < 0.05), decreased proapoptotic Bax, and increased regenerative capacity, especially in the outer stripe of the outer medulla, with DPO or EPO at T0 or T6. These results reaffirm the potential clinical application of DPO and EPO as novel renoprotective agents for patients at risk of ischemic acute renal failure or after having sustained an ischemic renal insult.

Evidence for microsatellite instability in bilateral breast carcinomas

The molecular pathogenesis of various categories of breast cancer (BC) has been well described, but surprisingly few reports have appeared on analysis of somatic mutations in bilateral BC. We have performed a polymerase chain reaction (PCR)-driven investigation of chromosomal regions showing common loss of heterozygosity (LOH) in 23 cases (46 rumors) from patients diagnosed with bilateral BC, LOH was observed in 15/46 (33%) informative tumors for chromosome 1p, 5/32 (16%) for 5q, 12/44 (27%) for 11q, 15/40 (38%) for 13q and 4/24 (17%) for 17p. These values are within the range of interlaboratory variations reported fur unilateral BC, There was no strong evidence for concordance of LOH within the same patient for any of the chromosomal loci tested. Atypical for breast carcinomas, 7/46 (15%) turners accumulated a high frequency (ranging from 11 to 29%) of shortened dinucleotide CA repeats, implying microsatellite instability (MI). Further analysis with the highly informative BAT-26 marker allowed for the classification of two of these tumors as having a replication error positive (RER+/MSI-H) phenotype, whereas the remaining five carcinomas harbored so-called borderline MI. Thus an involvement of both RER+ and borderline MI appears to be a distinct feature of bilateral breast carcinomas compared to unilateral lesions. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.