INTRAMYELINIC EDEMA: AN ELEMENTARY PATHOLOGICAL LESION IN CIDP

Pathological abnormalities of sural nerve biopsies from patients affected by chronic inflammatory demyelinating polyneuropathy (CIDP) include segmental demyelination, inflammatory infiltrates, axonal degeneration, subperineurial edema and Schwann cell proliferation. There are few reports in the literature (Waddy '89, Sabatelli '96) describing edema of the myelin sheath as an additional pathological feature of CIDP. This peculiar abnormality is a prominent finding in several experimental toxic and compression neuropathies. In 1993 Tatum described Intramyelinic Edema in experimental allergic neuritis induced by systemic passive transfer of human IgM anti‐myelin‐associated glycoprotein, and suggested that this change may play a role in the pathogenesis of demyelination. In order to establish whether intramyelinic edema may represent an elementary pathological lesion in human peripheral neuropathies, we reviewed morphological data of sural nerve biopsies from 46 CIDP patients admitted to our Institute from 1988 to 2001 and we compared them with findings from patients affected by other neuropathies. IE was observed in 6 patients with CIDP, but in none of the 500 patients affected by neuropathies of different etiology. In two out of the six patients the neuropathy was associated with IgM‐paraprotein, without anti‐MAG activity. IE was a prominent feature in only one patient while in the remaining patients it was confined to sporadic fibers. In one patient with a mild form of CIDP, IE was the only pathological finding. In the remaining patients it was associated with segmental demyelination and axonal loss. Our findings show that although IE is observed in only a minority of CIDP patients (13% of our series), this pathological finding may be considered a specific abnormality of inflammatory demyelinating neuropathies. We suggest that axonal shrinkage, which is invariably associated with IE, may represent a mechanism of loss of function in CIDP, in addition to segmental demyelination and axonal loss.     

Magnetic resonance image findings of primary intradural Ewing sarcoma of the cauda equina: case report and review of the literature

Background contextInvolvement of the cauda equina in Ewing sarcoma (ES) is extremely rare, and only few cases are reported in literature. However, ES of cauda equina shares some neuroradiological features with other neoplasms that can involve the intradural space. Therefore, differential diagnosis with other tumors of cauda equina should be considered by neuroradiologists and neurosurgeons to provide appropriate treatment.PurposeTo present a rare case of intradural extramedullary primary ES.Study designCase report.MethodsWe report a case of a 44-year-old woman presenting with the rapid onset of cauda equina syndrome. Radiological analysis showed multiple intradural masses, extending from L1 to S3 level. After radical surgery, lesions were histologically defined as ES. We present a literature review, analyzing magnetic resonance image (MRI) features of primary intradural ES of the cauda equina.ResultsFour cases of primitive ES arising from the cauda equina have been reported in the literature.ConclusionsBecause of the low number of reported cases, it is not possible to describe pathognomonic MRI findings for intradural ES of the cauda equina. However, few tumors show similar MRI features. Therefore, despite its rarity, intradural ES should be taken into account in the differential diagnosis of spinal tumors involving cauda equina.     

D11Y SOD1 mutation and benign ALS: a consistent genotype-phenotype correlation

We describe three sporadic ALS patients in which a D11Y SOD1 mutation was detected. All three patients disclosed a prolonged survival and a stereotypical distal limbs involvement in the initial stages of the disease. By this report we demonstrate that D11Y SOD1 mutation is associated with a peculiar phenotype and we confirm its probable pathogenetic role.     

Growth hormone receptor deficiency is associated with a major reduction in pro-aging signaling, cancer, and diabetes in humans

Mutations in growth signaling pathways extend life span, as well as protect against age-dependent DNA damage in yeast and decrease insulin resistance and cancer in mice. To test their effect in humans, we monitored for 22 years Ecuadorian individuals who carry mutations in the growth hormone receptor (GHR) gene that lead to severe GHR and IGF-1 (insulin-like growth factor-1) deficiencies. We combined this information with surveys to identify the cause and age of death for individuals in this community who died before this period. The individuals with GHR deficiency exhibited only one nonlethal malignancy and no cases of diabetes, in contrast to a prevalence of 17% for cancer and 5% for diabetes in control subjects. A possible explanation for the very low incidence of cancer was suggested by in vitro studies: Serum from subjects with GHR deficiency reduced DNA breaks but increased apoptosis in human mammary epithelial cells treated with hydrogen peroxide. Serum from GHR-deficient subjects also caused reduced expression of RAS, PKA (protein kinase A), and TOR (target of rapamycin) and up-regulation of SOD2 (superoxide dismutase 2) in treated cells, changes that promote cellular protection and life-span extension in model organisms. We also observed reduced insulin concentrations (1.4 μU/ml versus 4.4 μU/ml in unaffected relatives) and a very low HOMA-IR (homeostatic model assessment-insulin resistance) index (0.34 versus 0.96 in unaffected relatives) in individuals with GHR deficiency, indicating higher insulin sensitivity, which could explain the absence of diabetes in these subjects. These results provide evidence for a role of evolutionarily conserved pathways in the control of aging and disease burden in humans.     

High-functioning autism spectrum disorder with fluent speech and late-onset epilepsy: an unusual presentation of Inv-Dup (15) syndrome

Many neuropsychiatric phenotypes have been reported in association with rearrangements in the 15q11-q13 region. Clinical presentations can include hypotonia, developmental delay, severe/moderate intellectual disabilities, poor expressive language, difficult to treat epilepsy, and autism spectrum disorders. Here we report an additional case of a girl with inversion duplication on chromosome 15 (Inv-Dup 15) showing a peculiar and milder clinical phenotype, including atypical high-functioning autism disorder, late onset and drug-responsive epilepsy, and a relatively good language development . This report suggests that a diagnosis of Inv-Dup (15) can be suspected during more benign atypical condition with a better outcome than usually reported.     

Peroxynitrite detoxification and its biologic implications

Peroxynitrite is a cytotoxic oxidant formed in vivo from the diffusional-controlled reaction between nitric oxide and superoxide radicals. Increased peroxynitrite formation has been related to the pathogenesis of multiple diseases, thus underlining the importance of understanding the mechanisms of its detoxification. In nature, different enzymatic routes for peroxynitrite decomposition have evolved. Among them, peroxiredoxins catalytically reduce peroxynitrite in vitro; modulation of their expression affects peroxynitrite-mediated cytotoxicity, and their content changes in pathologic conditions associated with increased peroxynitrite formation in vivo, thus indicating a physiologic role of these enzymes in peroxynitrite reduction. Selenium-containing glutathione peroxidase also catalyzes peroxynitrite reduction, but its role in vivo is still a matter of debate. In selected cellular systems, heme proteins also play a role in peroxynitrite detoxification, such as its isomerization by oxyhemoglobin in red blood cells. Moreover, different pharmacologic approaches have been used to decrease the toxicity related to peroxynitrite formation. Manganese or iron porphyrins catalyze peroxynitrite decomposition, and their protective role in vivo has been confirmed in biologic systems. Glutathione peroxidase mimetics also rapidly reduce peroxynitrite, but their biologic role is less well established. Flavonoids, nitroxides, and tyrosine-containing peptides decreased peroxynitrite-mediated toxicity under different conditions, but their mechanism of action is indirect.     

Pleiotropic function of ezrin in human metastatic melanomas

The membrane cytoskeleton cross‐linker, ezrin, has recently been depicted as a key regulator in the progression and metastasis of several pediatric tumors. Less defined appears the role of ezrin in human adult tumors, especially melanoma. We therefore addressed ezrin involvement in the metastatic phenotype of human adult metastatic melanoma cells. Our results show that cells resected from melanoma metastatic lesions of patients, display marked metastatic spreading capacity in SCID mice organs. Stable transfection of human melanoma cells with an ezrin deletion mutant comprising only 146 N‐terminal aminoacids led to the abolishment of metastatic dissemination. In vitro experiments revealed ezrin direct molecular interactions with molecules related to metastatic functions such as CD44, merlin and Lamp‐1, consistent with its participation to the formation of phagocitic vacuoles, vesicular sorting and migration capacities of melanoma cells. Moreover, the ezrin fragment capable of binding to CD44 was shorter than that previously reported, and transfection with the ezrin deletion mutant abrogated plasma membrane Lamp‐1 recruitment. This study highlights key involvement of ezrin in a complex machinery, which allows metastatic cancer cells to migrate, invade and survive in very unfavorable conditions. Our in vivo and in vitro data reveal that ezrin is the hub of the metastatic behavior also in human adult tumors. © 2009 UICC