Motor and non-motor sequence learning in children and adolescents with cerebellar damage.

Cerebellar involvement in motor and non-motor sequence learning was examined with serial reaction time tasks (SRT). Our sample consisted of 8 children and adolescents who had undergone surgical removal of a benign posterior fossa tumor (PFT) during childhood. None of them had undergone chemotherapy or cranial radiation therapy (CRT). Ages ranged from 1-11 years at surgery and 9-17 years at testing. The children were tested not earlier than 2.5 years after surgery (M = 5.9 years), enabling brain plasticity and recovery of functions. Their performance was compared with a matched control sample. The PFT group was not impaired in the implicit learning of sequences, as reflected in their performance in blocks with a repeated sequence, both before and after a random block. However, in the perceptual task, their performance deteriorated more than that of the control group when a random block was introduced, suggesting that it was more difficult for the patients to respond flexibly or change their response set when encountering changing task demands. These results are in line with another study by our group on task switching with the same patients.     

Familial Sneddon's syndrome

We report the familial occurrence and apparent autosomal dominant inheritance of Sneddon's syndrome with variable clinical expression. The proband, a 40-year-old woman, presented with livedo reticularis and progressive neurological deterioration following a stroke. The diagnosis was confirmed by cerebral angiogram and skin biopsy, both showing the characteristic findings. Two of the patient's sisters were reported to have been similarly affected in the past. Her mother, two additional siblings and five of her seven children exhibited various vasospastic skin phenomena. Familial aggregation of this disorder may be common and a genetic basis may be involved in its pathogenesis.     

Normothemic Continuous Blood Cardioplegia Improves Electrophysiologic Recovery after Open Heart Surgery

Background: Myocardial protection during open heart surgery is based on administration of oxygenated blood cardioplegia, the preferred temperature of which is still under debate. The current randomized study was designed to prospectively evaluate the quality of myocardial protection and the functional recovery of the heart with either normothermic (group N) or hypothermic (group H) oxygenated blood cardioplegia.

Methods: Under continuous electrocardiographic Holter monitoring, 42 patients were randomly scheduled to receive either normothermic (33.5 degrees C) or hypothermic (10 degrees C) cardioplegia solutions during coronary bypass grafting surgery. Blood samples for creatinine phosphokinase, creatinine phosphokinase-MB, lactate, epinephrine, and norepinephrine were withdrawn during cardiopulmonary bypass via a coronary sinus cannula.

Results: Active cooling in group H on initiation of cardio-pulmonary bypass was characterized by transition through ventricular fibrillation in 75% of patients, whereas in group N atrial fibrillation occurred in 65% of patients. On myocardial reperfusion, sinus rhythm spontaneously resumed in 95% of group N patients compared to 25% in group H (P = 0.0003). In the latter, 75% of patients developed ventricular fibrillation often followed by complete atrioventricular block, which necessitated temporary pacing for a mean duration of 168+/-32 min. Both groups showed a similar incidence of intraventricular block and ST segment changes. However, the incidence of ventricular premature beats in the first 16 h after cardiopulmonary bypass was significantly greater in group H (P < 0.05), 20 +/-26/h, compared to 3+/-5/h in group N. Blood concentrations of lactate, creatinine phosphokinase, epinephrine, and norepinephrine increased gradually during the operation, but the differences between the groups were not significant.     

Singularities explained: Response to Klein.

Klein [Klein, A. S. (2006). Separating transducer nonlinearities and multiplicative noise in contrast discrimination. Vision Research, 46, 4279-4293] questions the existence of intrinsic singularities in two-alternative force-choice (2AFC) Signal Detection Theory (SDT) models, suggesting that the singularities found in Katkov et al. [Katkov, M., Tsodyks, M., & Sagi, D. (2006a). Singularities in the inverse modeling of 2AFC contrast discrimination data. Vision Research, 46, 259-266; Katkov, M., Tsodyks, M., & Sagi, D. (2006b). Analysis of two-alternative force-choice Signal Detection Theory model. Journal of Mathematical Psychology, 50, 411-420] are due to discarding higher order terms in the Taylor expansion of d' and/or limited to steep psychometric functions. Here we provide some simple intuitive examples that illustrate the results described in Katkov et al. (2006a, 2006b). We show, for the constant noise model, that singularities exist when exact values of d' are computed and that the singularities are not limited to steep psychometric functions. In these cases the disambiguation of the different models requires millions of trials.     

Progressive multifocal leukoencephalopathy in a lung transplant recipient.

Progressive multifocal leukoencephalopathy (PML) is a sub-acute, demyelinating disease of the brain caused by a human polyomavirus. We describe a patient with the onset of PML 7 months after lung transplantation. The patient was treated with immunosuppressive modulation and cidofovir, a new anti-viral therapy for PML, with stabilization of the symptoms. We also review the 4 additional reports in the literature of PML after heart and lung transplantation. Progressive multifocal leukoencephalopathy may become more prevalent as the population of heart and lung transplantation recipients increases.     

Burkitt''s Lymphoma in an Old Patient with Diarrhea: Ileoscopic Diagnosis

A 61-yr-old man with Burkitt's lymphoma who presented with 6 months of diarrhea was found, at ileoscopy, to have inflammation of the mucosal narrow lumen, deep linear ulcerations, and a "cobblestone" appearance of the terminal ileum. Endoscopic biopsies were diagnostic of Burkitt's lymphoma, and no laparotomy was necessary. Presentation with diarrhea and the age of the patient were unusual, and the endoscopic features and diagnosis of the disease in the terminal ileum made by ileoscopy have not been previously reported.     

Spontaneous increase of DNA turnover in murine systemic lupus erythematosus

DNA synthesis and release was studied in unstimulated splenocytes of strains of mice known to develop spontaneous systemic lupus erythematosus (SLE)-like disease and in non-SLE age- and sex-matched strains as well. Newly synthesized DNA was measured as total acid-insoluble radioactive material present in cell pellet plus supernatant of unstimulated 0–72 h cell cultures [³H]thymidine-pulsed, whereas DNA release was measured as amount of acid-precipitable radioactivity found in supernatant of those cultures. In all strains known to develop spontaneous murine SLE the amount of newly synthesized DNA was 1.3–2.1-fold increased when compared to normal strains studied concomitantly. Furthermore, a significant increase in DNA release into medium, unrelated to cell viability, was observed in those strains as well. These observations clearly demonstrate different metabolic rates of synthesis and release of DNA in murine SLE. This difference suggests the existance of an underlying mechanism responsible for extracellular DNA abundancy, which may be important for the formation of circulating DNA-anti-DNA immune complexes.     

Anti-beta(2)-glycoprotein I antibodies in children with atopic dermatitis

beta(2)-Glycoprotein I (beta(2)GPI) appears to be the major antigen for antiphospholipid antibodies (aPL) in patients with antiphospholipid syndrome (APS). In early infancy, virtually all children initiate transient immune response to non-pathogenic nutritional antigens, which fails to terminate in children with atopic diseases. To examine the possibility that a prolonged immune response to beta(2)GPI could also spread to the human protein, antibodies against human beta(2)GPI (anti-beta(2)GPI) were determined in 93 randomly selected children with different allergic diseases. A high frequency (42%) of IgG anti-beta(2)GPI was found in children with atopic dermatitis (AD), but not in those with other allergic diseases. Anti-beta(2)GPI in children with AD were exclusively of the IgG1 subclass and bound to bovine beta(2)GPI as well, but not to either beta(2)GPI combined with the phospholipid cardiolipin. The epitopes were identified in domain V of beta(2)GPI and the antibody binding was abolished upon the specific proteolytic cleavage of the phospholipid-binding C-terminal loop in domain V of beta(2)GPI. These results indicated that the epitopes for anti-beta(2)GPI in children with AD most likely resided in close vicinity of the phospholipid-binding site of beta(2)GPI. The epitopic difference from anti-beta(2)GPI in APS may explain presumed non-thrombogenicity of anti-beta(2)GPI in children with AD.     

Expression of matrix metalloproteinases and their inhibitors during the resorption of schistosome egg-induced fibrosis in praziquantel-treated mice

Schistosomiasis mansoni is a tropical helminthic disease characterized by parasite egg-induced granulomatous inflammation and cumulative fibrosis. Because fibrosis is influenced by the imbalance between degradative matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), we analysed the resorption of fibrous tissue and MMP/TIMP expression in the livers of S. mansoni-infected and praziquantel-cured mice. Worm elimination significantly enhanced survival rate, ameliorated the granulomatous pathology and reduced collagen I, III and IV gene expression at 6 and 12 months post-treatment. Compared to 6 months infected, untreated controls, liver fibrous tissue was resorbed by 71.4% at 12 months after treatment. At 3 months post-treatment, expression of the MMP-2, -3, -8, -10, -13, -14 and -16 genes decreased compared with untreated controls. By 6 months, a highly significant increase in MMP-10 gene expression was manifest. At 12 months, messages for all MMP genes decreased in relation to untreated controls. TIMP-1, -2 and -3 gene expression drastically decreased between 3 and 6 months. At 1 year, only TIMP-1 expression was significantly diminished. Overall, profibrogenic tumour necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta and inducible nitric oxide synthase (iNOS) gene expression decreased. Antigen-stimulated splenocytes secreted significantly higher levels of interleukin (IL)-4, IL-5, IL-10 and IL-13 cytokines between 3 and 12 months after treatment. Production of interferon (IFN)-gamma was higher than in untreated controls 3 and 6 months after treatment. In conclusion, praziquantel-treated mice showed a slow resorption of liver fibrous tissue. Resorption is attributed to the precipitous drop in TIMP-1 gene expression level, which shifted the balance in favour of MMP message expression and presumed enhanced collagenase activity.     

Estimation of hand preshaping during human grasping

A new method for evaluating hand preshaping during reaching-to-grasp movement is proposed. The method makes use of all five fingers in estimation of prehension. The investigation was performed on six healthy subjects grasping three different objects at various positions and orientations. The objects were presented to the subjects by means of a robot, which also induced perturbations in both object position and orientation. Positions of markers attached to the finger-tips and dorsum of the hand were recorded by means of a 3D optical tracking system. In the data analysis, the adjacent fingertips were interconnected, thus obtaining a planar pentagon whose various characteristics were investigated and discussed. New parameters for the evaluation of finger preshaping, such as pentagon surface area, angle between the pentagon and hand normal vectors, and the angle between the pentagon and object normal vectors were introduced. The proposed pentagon approach is expected to be useful in future work when examining grasping abilities of subjects with neuromuscular disorders.