Does stroke impair academic achievement in children? The role of metacognition in math and spelling outcomes following pediatric stroke

Introduction: Current research suggests that pediatric stroke is associated with a reduction in intellectual functioning. However, less is known about academic achievement and the contribution of specific executive functions to math and literacy in this population. The current study investigates behavioral ratings of executive functioning and their relationship to math and spelling performance in children with a history of unilateral arterial ischemic stroke.

Method: Thirty-two pediatric patients with stroke (M_age = 9.5 ± 2.7 years) and 32 demographically equivalent, healthy controls were tested on standardized measures of arithmetic, spelling, and intelligence. Executive functioning data were collected via standardized parent questionnaire.

Results: Relative to controls, stroke participants demonstrated significantly poorer functioning in math, spelling, metacognition, and behavioral-regulation. Pencil and paper arithmetic was particularly challenging for the stroke group, with 40% of patients reaching levels of clinical impairment. Hierarchical regression in stroke participants further revealed that metacognition was a robust predictor of academic deficits. Stroke occurring in later childhood and affecting cortical and subcortical brain regions also presented as potential clinical risk factors.

Conclusions: Children with stroke were especially vulnerable to math achievement deficits. Metacognition made a substantial contribution to academic achievement abilities among stroke patients, and results underscore the importance of early metacognitive skills in the completion of schoolwork. Results also emphasize that pediatric stroke patients are a heterogeneous group with regard to functioning and that there is value in examining standard score distributions of clinical participant samples.     

Management of psychopharmacologic agents in children and adolescents

This article summarizes the ways in which a clinician should think about medication use in children and describes practical usage of the most frequently used child psychopharmacologic agents.Leena Ranade, M.D., and Aftab Qadir, M.D., were Fellows in Child Psychiatry, State University of New York at Stony Brook at the time of writing this article.     

Double-crowned valved stents for off-pump mitral valve replacement.

OBJECTIVE: An animal model has been designed to assess the feasibility of off-pump mitral valve replacement using valved stents. METHODS: Glutaraldehyde-preserved homograft was sutured inside a prosthetic tube (Dacron). Then, two self-expandable nitinol Z-stents were sutured on the external surface of the prosthesis in such a way to create two self-expanding crowns for fixation. In adult pigs and under general anesthesia, the left atrium was exposed through a left thoracotomy and atrio-ventricular roadmapping was performed with intravascular ultrasound (IVUS) and fluoroscopy. The double-crowned valved stents were loaded into a delivery sheath. The sheath was then introduced into the left atrium and the valved stents was deployed in mitral position in such a way that the part in between the two stents was at the level of the mitral annulus. Intracardiac Unltrasound (ICUS) was used to assess the valve function. Hemodynamic parameters were gathered as well. Animal survived for no more than 3h after the valve deployment and gross anatomy examination of the left heart was carried out. RESULTS: The mean height of the valved stents was 29.4+/-0.2 mm, with an internal diameter of 20.4+/-1.0mm, and an external diameter of 25.5+/-0.8 mm. The procedure was successfully carried out in eight animals. In vivo evaluation showed a native mitral annulus diameter of 24.9+/-0.6 mm, and a mean mitral valve area of 421.4+/-17.5 mm2. ICUS showed a mild mitral regurgitation in three out of eight animals. Mean pressure gradient across the valved stents was 2.6+/-3.1 mmHg. Mean pressure gradient across the left ventricular outflow tract (LVOT) was 6.6+/-5.2 mmHg. The mean survival time was 97.5+/-56.3 min (survival time range was 40-180 min). One animal died due to the occlusion of the LVOT because of valved stents displacement. Postmortem evaluation confirmed correct positioning of the valved stent in the mitral position in seven out of eight animals. No atrial or ventricular lesions due to the valved stents were found. CONCLUSIONS: Off-pump implantation of a self-expandable valved stent in the mitral position is technically feasible. Further studies will assess if this procedure is also feasible in humans.     

Primary cerebral neuroblastoma (neurocytoma) in adults

Summary We report a case of a third ventricular neuroblastoma (neurocytoma) in a 66 year old man. A stereotactic needly biopsy was performed to obtain a tissue diagnosis and was followed by total resection. We elected not to give radiation or chemotherapy and to follow the patient closely with serial CT scans. Presently, 48 months postoperatively, the patient is free of tumor by head CT scan and able to live independently. We reviewed the literature of primary cerebral neuroblastomas/neurocytomas occurring in adults (15 years of age) and found 32 cases. Our patient is the oldest of this group with a mean age of 32 ± 14 years (S.D.). The location of the 33 neoplasms was intraventricular in 17 cases (52%) and intraparenchymal in 16 cases. The male to female ratio was 2: 1. Of the 17 patients having a minimal follow-up period of 5 months (mean 51 months), five developed recurrences after 5 to 144 months (mean 50 months) compared to 12 patients without recurrence after a 6- to 72-month follow-up period (mean 52 months). Recurrences occurred statistically significantly more often in parenchymal neuroblastomas/neurocytomas than in intraventricular tumor locations.     

Effects of muscle conditioning on position sense at the human forearm during loading or fatigue of elbow flexors and the role of the sense of effort

In a forearm position-matching task in the horizontal plane, when one (reference) arm is conditioned by contraction and length changes, subjects make systematic errors in the placement of their other, indicator arm. Here we describe experiments that demonstrate the importance not just of conditioning the reference arm, but of the indicator arm as well. Total errors from muscle conditioning represented up to a quarter of the angular range available to subjects. The sizes of the observed effects have led us to repeat other, previously reported experiments. In a matching task in the vertical plane, when muscles of both arms were conditioned identically, if the subject supported their arms themselves, or when the arms were loaded by the addition of weights, the loading did not introduce new position errors. To test the effect of exercise, subjects' elbow flexors were exercised eccentrically or concentrically by asking them to lower or raise a set of weights using forearm muscles. The exercise produced 25–30% decreases in maximum voluntary contraction strength of elbow flexors and this led to significant position-matching errors. The directions and magnitudes of the errors were similar after the two forms of exercise and indicated that subjects perceived their exercised muscles to be longer than they actually were. To conclude, the new data from loading the arm are not consistent with the idea that the sense of effort accompanying support of a load, provides positional information in any simple way. Our current working hypothesis is that when muscles are active, position-sense involves operation of a forward internal model. Loading the arm produces predictable changes in motor output and afferent feedback whereas changes after exercise are unpredictable. This difference leads to exercise-dependent errors.     

Suggestions for the assessment of the allergenic potential of genetically modified organisms

The prevalence of allergic diseases has been increasing continuously and, accordingly, there is a great desire to evaluate the allergenic potential of components in our daily environment (e.g., food). Although there is almost no scientific evidence that genetically modified organisms (GMOs) exhibit increased allergenicity compared with the corresponding wild type significant concerns have been raised regarding this matter. In principle, it is possible that the allergenic potential of GMOs may be increased due to the introduction of potential foreign allergens, to potentially upregulated expression of allergenic components caused by the modification of the wild type organism or to different means of exposure. According to the current practice, the proteins to be introduced into a GMO are evaluated for their physiochemical properties, sequence homology with known allergens and occasionally regarding their allergenic activity. We discuss why these current rules and procedures cannot predict or exclude the allergenicity of a given GMO with certainty. As an alternative we suggest to improve the current evaluation by an experimental comparison of the wild-type organism with the whole GMO regarding their potential to elicit reactions in allergic individuals and to induce de novo sensitizations. We also recommend that the suggested assessment procedures be equally applied to GMOs as well as to natural cultivars in order to establish effective measures for allergy prevention.     

Acquisition of vimentin in astrocytes cultured from postnatal rat brain

Summary Vimentin and glial fibrillary acidic protein (GFAP) represent the principal constituents of intermediate filaments found in astrocytes. In contrast to vimentin—GFAP transition which occurs during glial developmentin situ, vimentin coexists with GFAP in cortical astrocytes allowed to differentiate in culture. To examine whether culture conditions or proliferative activity of the cells is responsible for the expression of vimentin, we generated cultures of GFAP-positive, vimentin-negative astrocytes isolated from 26-day postnatal rat brain cortices. Isolated astrocytes are characterized by a very thin rim of perinuclear cytoplasm and by numerous processes. Antiserum to GFAP labelled major processes and cell somata of some astrocytes, especially those with relatively short and large processes. Within 3 days in culture, all astrocytes accumulated GFAP in hypertrophic cell bodies and many began to express vimentin. Vimentin appeared primarily close to nuclei, and filaments of vimentin extended into proximal segments of the cell processes. In some astrocytes, however, vimentin was always absent. Combined double immunolabelling and histoautoradiography experiments demonstrated that the acquisition of vimentin was independent of the ability of astrocytes to incorporate tritiated thymidine. The results indicate that astrocytes isolated from 26-day postnatal rat brain are heterogeneous with respect to their ability to express vimentin and that vimentin synthesis is not correlated with the growth state of the cells as had been previously suspected.     

Chimaeric anti-CD4 monoclonal antibody cross-linked by monocyte Fcγ receptor mediates apoptosis of human CD4 lymphocytes

Previous studies have shown that murine anti-CD4 monoclonal antibody, cross-linked by rabbit anti-mouse immunoglobulin, could mediate apoptosis of murine CD4⁺ lymphocytes when they were stimulated by T cell receptor antibody. In this study, we have shown that the murine anti-CD4 monoclonal antibody, OKT4, can induce apoptosis in human CD4⁺ T cells stimulated by the recall antigen tuberculin purified protein derivative (PPD) only when cross-linked by rabbit anti-mouse immunoglobulin. The chimeric anti-CD4 monoclonal antibody, cM-T412 whose Fc fragment is human, was able to cause apoptosis without cross-linking by a second antibody. Similarly, abolition of PPD-induced proliferation of peripheral blood mononuclear cells by cM-T412 did not require cross-linking with rabbit anti-human immunoglobulin. Inhibition of proliferation by cM-T412 could be reduced by pre-treating monocytes with heat-aggregated human IgG. This suggested that monocyte Fcγ receptors might be cross-linking the human Fc of cM-T412. Propidium iodide staining together with immunofluorescence showed that the apoptotic cells were indeed CD4⁺ lymphocytes. It is proposed that during treatment with cM-T412 in autoimmune disease such as rheumatoid arthritis, cM-T412-coated CD4 T cells, when they are subsequently stimulated by the unknown arthritogenic antigen, may undergo apoptotic cell death through cross-linking of cM-T412 on Fey receptor-positive cells within the joint.