Neuropathology of pyridoxine toxicity

Pyridoxine can cause sensory neuropathy in man. Previous experimental studies have demonstrated selective neurofilament accumulation in dorsal root ganglion cells which, in most cases, was associated with axonal damage without causing cell death, but in others produced death of cells. From these observations the following hypotheses were formulated and tested in this thesis. 1. Pyridoxine interferes with axonal transport of neurofilaments and organelles and would thus cause a dying back neuropathy. 2. As the dorsal root ganglion cells, in many cases, do not die, regeneration should take place. 3. The major action of pyridoxine in causing a dying back neuropathy is due to interference with dorsal root ganglion cell metabolism rather than a local effect on the axon. A total of 100 rats was used in these experiments. In the first group of animals, rats were dosed daily with pyridoxine for periods of 7-90 days. Following perfusion with fixative, fifth cranial nerve, dorsal root and autonomic ganglia, the saphenous nerve (a purely sensory nerve) were removed and examined by light and electron microscopy. Immunocyto-chemistry was performed using the RT97 antibody against phosphorylated neurofilaments. Axonal degeneration, axonal regeneration, neurofilament and microtubule numbers and distribution were quantified. In the second group of animals the sciatic nerve was crushed immediately followed by the intraneural injection of pyridoxine and the degree of axon degeneration and regeneration were quantified. Damage to dorsal root ganglion cells (used as a measure of toxicity) was very variable so that the effects were only approximately dose-related. The hypotheses set out above were all proved in that: 1. There was distal degeneration of axons tending to affect the largest myelinated nerve fibres but also affecting the unmyelinated fibres. Posterior column axons in the spinal cord showed severe damage. 2. Affected dorsal root ganglion cells showed dispersion and degranulation of rough endoplasmic reticulum (RER), active Golgi bodies and increased neurofilaments. Immunocytochemistry showed increased staining for phosphorylated neurofilaments within small dorsal root ganglion cells compatible with interference with axonal transport. 3. Neurofilaments within axons were reduced and there was clustering of microtubules which probably preceded: 4. Axonal atrophy. 5. Axonal regeneration occurred while dosing continued. 6. Intraneural injection of pyridoxine caused axonal degeneration but paradoxically appeared to stimulate axonal regeneration. The results of this study suggests that pyridoxine has a direct toxic effect upon dorsal root ganglion cells which interferes with axoplasmic transport and thus results in a "dying back" neuropathy. The biochemical actions involved remain to be elucidated

Clinico-Pathological Correlations of the Most Common Neurodegenerative Dementias

Neurodegenerative dementias are a group of neurological disorders characterized by deterioration in several cognitive domains in which there is selective and progressive loss of specific populations of neurons. The precise neurobiological basis for the different neurodegenerative dementias remains unknown. It is expected that different pathologies reflect different mechanisms, at least early in the neurodegeneration process. The next decades promise treatments directed to causes and mechanisms, bringing an outstanding challenge to clinicians due to heterogeneous clinical presentations with the same molecular pathology. The purpose of this brief review is to describe the key neuropathological features of the most common neurodegenerative dementias (Alzheimer disease, dementia with Lewy bodies and Parkinson’s disease dementia, and frontotemporal lobar degeneration) and the relationship with the clinical syndromes described in clinico-pathological studies. We expect this overview contributes for the understanding of this broad topic integrating the two ends of the spectrum: clinical and pathological

Does the Interplay Between Aging and Neuroinflammation Modulate Alzheimer's Disease Clinical Phenotypes? A Clinico-Pathological Perspective.

Uncorrected Author ProofAlzheimer's disease (AD) is a chronic neurodegenerative disorder and is the most common cause of dementia worldwide. Cumulative data suggests that neuroinflammation plays a prominent and early role in AD, and there is compelling data from different research groups of age-associated dysregulation of the neuroimmune system. From the clinical point of view, despite clinical resemblance and neuropathological findings, there are important differences between the group of patients with sporadic early-onset (65 years old). Thus, it seems important to understand the age-dependent relationship between neuroinflammation and the underlying biology of AD in order to identify potential explanations for clinical heterogeneity, interpret biomarkers, and promote the best treatment to different clinical AD phenotypes. The study of the delicate balance between pro-inflammatory or anti-inflammatory sides of immune players in the different ages of onset of AD would be important to understand treatment efficacy in clinical trials and eventually, not only direct treatment to early disease stages, but also the possibility of establishing different treatment approaches depending on the age of the patient. In this review, we would like to summarize what is currently known about the interplay between "normal" age associated inflammatory changes and AD pathological mechanisms, and also the potential differences between early-onset and late-onset AD taking into account the age-related neuroimmune background at disease onset.This work was funded by "Bolsa para Investigacao" of Centro Hospitalar do Porto.info:eu-repo/semantics/publishedVersio

Apoio emocional às crianças profissionais de saúde: intervenção virtual durante a pandemia de COVID-19.

The SARS-CoV2 pandemic context and sanitary confinement measures have exposed the population to anxiety and depressive symptoms and became a permanent mark in children’s psychosocial and affective development. This effect was certainly evident in healthcare professional’s children that saw their parents being called to the battlefield front line against an invisible enemy and at the same time facing the media avalanche propelling fear and insecurity. Material and Methods: This state of restlessness and vulnerability promoted the development of therapeutic mindfulness groups for children or children and parents (healthcare professional related), from a Hospital Reference Center, over a period of eight weeks. Results: Throughout the sessions, high adherence to conscious attention techniques was observed, allowing the children to overcome physical distance obstacles in a virtual context used as a gateway to the living circumstances and the difficulties experienced at the time of the intervention. Discussion: In the end, improvements were reported in anxious and depressive symptoms with greater capacity for emotional regulation, interpersonal communication and impulse management. Conclusion: These results instigated an intervention protocol elaboration and a research project ongoing at the date of this publication.El contexto pandémico del SARS-CoV2 y las medidas de confinamiento sanitario han expuesto a la población a síntomas de ansiedad y depresión y se han convertido en una marca permanente en el desarrollo psicosocial y afectivo de los niños. Este efecto fue ciertamente evidente en los hijos de los profesionales de la salud que vieron a sus padres ser llamados al frente del campo de batalla contra un enemigo invisible y al mismo tiempo enfrentarse a la avalancha mediática que impulsaba el miedo y la inseguridad. Material y Métodos: Este estado de inquietud y vulnerabilidad propició el desarrollo de grupos de mindfulness terapéuticos para niños o niños y padres (relacionados con el profesional de la salud), desde un Centro de Referencia Hospitalario, durante un período de ocho semanas. Resultados: A lo largo de las sesiones se observó una alta adherencia a las técnicas de atención consciente, lo que permitió a los niños superar los obstáculos de la distancia física en un contexto virtual utilizado como puerta de entrada a las circunstancias de la vida y las dificultades vividas en el momento de la intervención. Discusión: Al final, se reportaron mejoras en los síntomas ansiosos y depresivos con mayor capacidad de regulación emocional, comunicación interpersonal y manejo de impulsos. Conclusión: Estos resultados impulsaron la elaboración de un protocolo de intervención y un proyecto de investigación en curso a la fecha de esta publicación.Introdução: O contexto pandémico SARS-CoV2 e as medidas de confinamento tornaram a população vulnerável a sintomas ansiosos e depressivos e são um marco indelével no desenvolvimento psicossocial e afetivo das crianças. Tal foi notório nos filhos de profissionais de saúde, que perante a avalanche mediática propulsora de medo e insegurança, viram os seus progenitores ser chamados para a linha da frente de um campo de batalha contra um inimigo invisível. Material e Métodos: Este estado de inquietação e vulnerabilidade promoveu a elaboração de grupos terapêutico baseados no mindfulness para grupos de crianças (filhas de profissionais de saúde) de um Centro Hospitalar de referência, durante um período de oito semanas. Resultados: Participaram um total de quinze crianças e uma adolescente, sendo as crianças divididas em três grupos (dois grupos multifamiliares e um com crianças com idades entre oito e onze anos) e mantendo-se a adolescente em sessões individuais. Apenas uma criança não concluiu as oito sessões da terapia. Objetivou-se uma elevada adesão às técnicas de atenção plena e consciente, tendo sido transpostas as dificuldades impostas pelo distanciamento físico. A plataforma virtual foi usada como uma porta de acesso ao contexto vivencial e às dificuldades experienciadas no momento da intervenção. Discussão: No final foram reportadas melhorias na sintomatologia ansiosa e depressiva, com maior capacidade de regulação emocional, de comunicação interpessoal e gestão dos impulsos. Conclusão: Estes resultados promoveram a elaboração de um protocolo de intervenção e a realização de um projeto de investigação, em curso à data desta publicação

Peri-implant peripheral giant cell lesions : report of 13 new cases and comparative histological and immunohistochemical analysis with peripheral and central giant cell lesions

Few cases or peri-implant peripheral giant cell lesions (PGCL) have been reported in the literature. The aim of this study was to report 13 new cases of peri-implant PGCL and compare the expression of smooth muscle actin, Bcl-2 protein, GLUT-1, CD68, osteoprotegerin, receptor activator of nuclear factor kappa-B, Ki-67 and CD34 in these cases with PGCL and central giant cell lesions (CGCL). Clinical data were retrieved from the laboratory records and histological analysis was performed using HE-stained slides. Immunohistochemical reactions for the above mentioned antibodies were performed and digitally scored. Peri-implant PGCL mostly affected the posterior mandible of adult females. CD68 and Bcl-2 expressions were higher in conventional PGCL and CGCL than in peri-implant PGCL (p=0.033 for CD68 and p<.0001 for Bcl-2). Microvessel density was higher in conventional peripheral than in central and peri-implant PGCL (p=0.002). Proliferative index of the mononuclear cells showed no statistically significant differences comparing the three groups but it was higher in peri-implant PGCL. The current study demonstrated that peri-implant PGCL is more common in the posterior mandible of adult females. There were some differences in microvessel density, proliferative activity and expression of CD68 and Bcl-2 among conventional PGCL, peri-implant and CGCL. Further studies are encouraged to better understand these early findings

WNT6 is a novel oncogenic prognostic biomarker in human glioblastoma

Glioblastoma (GBM) is a universally fatal brain cancer, for which novel therapies targeting specific underlying oncogenic events are urgently needed. While the WNT pathway has been shown to be frequently activated in GBM, constituting a potential therapeutic target, the relevance of WNT6, an activator of this pathway, remains unknown. Methods: WNT6 protein and mRNA levels were evaluated in GBM. WNT6 levels were silenced or overexpressed in GBM cells to assess functional effects in vitro and in vivo. Phospho-kinase arrays and TCF/LEF reporter assays were used to identify WNT6-signaling pathways, and significant associations with stem cell features and cancer-related pathways were validated in patients. Survival analyses were performed with Cox regression and Log-rank tests. Meta-analyses were used to calculate the estimated pooled effect. Results: We show that WNT6 is significantly overexpressed in GBMs, as compared to lower-grade gliomas and normal brain, at mRNA and protein levels. Functionally, WNT6 increases typical oncogenic activities in GBM cells, including viability, proliferation, glioma stem cell capacity, invasion, migration, and resistance to temozolomide chemotherapy. Concordantly, in in vivo orthotopic GBM mice models, using both overexpressing and silencing models, WNT6 expression was associated with shorter overall survival, and increased features of tumor aggressiveness. Mechanistically, WNT6 contributes to activate typical oncogenic pathways, including Src and STAT, which intertwined with the WNT pathway may be critical effectors of WNT6-associated aggressiveness in GBM. Clinically, we establish WNT6 as an independent prognostic biomarker of shorter survival in GBM patients from several independent cohorts. Conclusion: Our findings establish WNT6 as a novel oncogene in GBM, opening opportunities to develop more rational therapies to treat this highly aggressive tumor.FCT - Foundation for Science and Technology (PTDC/SAU-GMG/113795/2009 and IF/00601/2012 to B.M.C.; SFRH/BD/92786/2013 to C.S.G.; SFRH/BD/88121/2012 to J.V.C.; SFRH/BD/81042/2011 to M.P.; SFRH/BD/93443/2013 to S.Q.) and Fundação Calouste Gulbenkian (B.M.C.), by FEDER funds through the Operational Programme Competitiveness Factors - COMPETE and National Funds through FCT under the project POCI-01-0145-FEDER-007038; by the project NORTE-01-0145-FEDER-000013 and NORTE-01-0246-FEDER-000012, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); and by the project NORTE-01-0145-FEDER-000023, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER)info:eu-repo/semantics/publishedVersio

Impact of EGFR genetic variants on glioma risk and patient outcome

B.M. Costa and M. Viana-Pereira contributed equally to this work; The authors thank the Immunochemotherapy Department of Hospital S. Marcos, and Clinica Laboratorial Dr. Edgar Botelho Moniz, S. Tirso, Portugal, for their helpful assistance in the management of controlsBACKGROUND: The epidermal growth factor receptor (EGFR) regulates important cellular processes and is frequently implicated in human tumors. Three EGFR polymorphisms have been described as having a transcriptional regulatory function: two single-nucleotide polymorphisms in the essential promoter region, -216G/T and -191C/A, and a polymorphic (CA)(n) microsatellite sequence in intron 1. We aimed to elucidate the roles of these EGFR polymorphisms in glioma susceptibility and prognosis. METHODS: We conducted a case-control study with 196 patients with glioma and 168 cancer-free controls. Unconditional multivariate logistic regression models were used to calculate ORs and 95% confidence intervals. A Cox regression model was used to evaluate associations with patient survival. False-positive report probabilities were also assessed. RESULTS: None of the EGFR -216G/T variants was significantly associated with glioma risk. The -191C/A genotype was associated with higher risk for glioma when the (CA)(n) alleles were classified as short for ≤16 or ≤17 repeats. Independently of the (CA)(n) repeat cutoff point used, shorter (CA)(n) repeat variants were significantly associated with increased risk for glioma, particularly glioblastoma and oligodendroglioma. In all tested models with different (CA)(n) cutoff points, only -191C/A genotype was consistently associated with improved survival of patients with glioblastoma. CONCLUSIONS: Our findings implicate EGFR -191C/A and the (CA)(n) repeat polymorphisms as risk factors for gliomas, and suggest -191C/A as a prognostic marker in glioblastoma. Impact: Our data support a role of these EGFR polymorphisms in determining glioma susceptibility, with potential relevance for molecularly based stratification of patients with glioblastoma for individualized therapies.Schering-Plough Farma, PortugalFundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/33612/2009; SFRH/BD/29145/200

Improving the serodiagnosis of canine Leishmania infantum infection in geographical areas of Brazil with different disease prevalence

Serodiagnosis of Leishmania infantum infection in dogs relies on the detection of antibodies against leishmanial crude extracts or parasitic defined antigens. The expansion of canine leishmaniasis from geographical areas of Brazil in which the infection is endemic to regions in which the disease is emerging is occurring. This fact makes necessary the analysis of the serodiagnostic capabilities of different leishmanial preparations in distinct geographical locations. In this article sera from dogs infected with Leishmania and showing the clinical form of the disease, were collected in three distinct Brazilian States and were tested against soluble leishmanial antigens or seven parasite individual antigens produced as recombinant proteins. We show that the recognition of soluble leishmanial antigens by sera from these animals was influenced by the geographical location of the infected dogs. Efficacy of the diagnosis based on this crude parasite preparation was higher in newly endemic regions when compared with areas of high disease endemicity. We also show that the use of three of the recombinant proteins, namely parasite surface kinetoplastid membrane protein of 11 kDa (KMP-11), and two members of the P protein family (P2a and P0), can improve the degree of sensitivity without adversely affecting the specificity of the diagnostic assays for canine leishmaniasis, independently of the geographical area of residence. In addition, sera from dogs clinically healthy but infected were also assayed with some of the antigen preparations. We demonstrate that the use of these proteins can help to the serodiagnosis of Leishmania infected animals with subclinical infections. Finally, we propose a diagnostic protocol using a combination of KMP-11, P2a y P0, together with total leishmanial extractsThis work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brazil) within the call“CNPq/MS/SCTIE/DECIT N° 32/2014 - Pesquisas sobre Leishmanioses”grant number reference 467389/2014-4. Institutional grants from the Fundación Ramón Areces and Banco de Santander to the CBMSO are also acknowledged. TC received scholarship from Fundação de Amparo a Pesquisa do Estado de Santa Catarina–FAPES