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.     

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.     

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.     

Ectodermal dysplasia,ectrodactyly and macular dystrophy (EEM syndrome) in siblings

We report a brother and sister with ectodermal dysplasia, ectrodactyly, and macular dystrophy (the EEM syndrome). Both children had abnormalities of the hands and the hair, and bilateral macular degeneration. The clinical picture in both is similar to, but less severe than, that described in the previously reported cases of this rare syndrome. Even though the parents are not related, they are both of Jewish Yemenite origin, and the possibility of a common ancestor cannot be ruled out. This would suggest autosomal recessive inheritance. The clinical picture in these patients suggests either variable expression or genetic heterogeneity in the EEM syndrome and further delineates the clinical and genetic spectrum of this condition. © 2001 Wiley‐Liss, Inc.     

Traumatic rupture of hydatid cysts

Objective

To stress the relation between rupture of hydatid cysts and trauma.

Design

A case series.

Setting

A university-affiliated hospital for emergency medicine.

Patients

Four college students who suffered traumatic rupture of hydatid cysts. All injuries were sustained during sporting activities.

Interventions

Resection or unroofing of the cysts with careful removal of all hydatid elements, and suture-plication of the residual liver cavities.

Results

The ruptured cysts were located in the liver, spleen and splenic flexure of the colon. At exploration, additional hydatid cysts were found, usually in the liver. Treatment resulted in complete recovery in all patients.

Conclusions

Traumatic rupture of hydatid cysts related to sporting activities may be commoner than indicated by the rarity of reports. Increased awareness of this possibility in areas where hydatid disease is endemic is encouraged.     

Mast cell activity in experimental allergic encephalomyelitis

The number and functional reactivity of peritoneal mast cells (MCs) were evaluated in rats with experimental allergic encephalomyelitis (EAE). Cells were counted following staining with toluidine blue and activation was measured by B-hexosaminidase (B-hex) release. The number of detectable MCs and their capacity to release B-hex decreased significantly by 40 and 65%, respectively, as compared with normal controls just prior to the onset of clinical signs. These values returned to normal on clinical recovery. Preliminary data on MC counts performed on histological sections of rat brains with EAE suggested a similar pattern of response, i.e., an early decrease prior to disease onset with subsequent normalization on recovery. In an attempt to modify the course of EAE, rats were treated with the MC stabilizing agent nedocromil or with the MC activating agent, compound 48/80. Nedocromil induced a slight delay in the onset of EAE, but only when administered at the time of EAE induction. Compound 48/80 did not seem to affect the clinical course of the disease. Our results suggest that MCs are involved in the pathogenesis of EAE and may contribute to the induction of the disease rather than to the effector phase and its clinical expression.