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1.
Br J Dermatol ; 186(1): 106-116, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34227096

RESUMEN

BACKGROUND: The microbiome is emerging as a crucial player of the immune checkpoint in cancer. Melanoma is a highly immunogenic tumour, and the composition of the gut microbiome has been correlated to prognosis and evolution of advanced melanoma and proposed as a biomarker for immune checkpoint therapy. OBJECTIVES: We investigated the gut fungal and bacterial compositions in early-stage melanoma and correlated microbial profiles with histopathological features. METHODS: Sequencing of bacterial 16S rRNA and the fungal internal transcribed spacer region was performed on faecal samples of patients with stage I and II melanoma, and healthy controls. A meta-analysis with gut microbiota data from patients with metastatic melanoma was also carried out. RESULTS: We found a combination of gut fungal and bacterial profiles significantly discriminating patients with melanoma from controls. In patients with melanoma, we observed an abundance of Prevotella copri and yeasts belonging to the order Saccharomycetales. We found that the bacterial and fungal community correlated to melanoma invasiveness, whereas the specific fungal profile correlated to melanoma regression. Bacteroides was identified as general marker of immunogenicity, being shared by regressive and invasive melanoma. In addition, the bacterial communities in patients with stage I and II melanoma were different in structure and richer than those from patients with metastatic melanoma. CONCLUSIONS: The composition of the gut microbiota in early-stage melanoma changes along the gradient from in situ to invasive (and metastatic) melanoma. Changes in the microbiota and mycobiota are correlated to the histological features of early-stage melanoma, and to the clinical course and response to immune therapies of advanced-stage melanoma, through direct or indirect immunomodulation.


Asunto(s)
Microbioma Gastrointestinal , Melanoma , Micobioma , Heces/microbiología , Hongos , Microbioma Gastrointestinal/genética , Humanos , ARN Ribosómico 16S/genética
3.
Philos Trans A Math Phys Eng Sci ; 378(2172): 20190296, 2020 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-32389079

RESUMEN

This paper addresses nonlinear viscoelastic behaviour of fractional systems with variable time-dependent fractional order. In this case, the main challenge is that the Boltzmann linear superposition principle, i.e. the theoretical basis on which linear viscoelastic fractional operators are formulated, does not apply in standard form because the fractional order is not constant with time. Moving from this consideration, the paper proposes a novel approach where the system response is derived by a consistent application of the Boltzmann principle to an equivalent system, built at every time instant based on the fractional order at that instant and the response at all the previous ones. The approach is readily implementable in numerical form, to calculate either stress or strain responses of any fractional system where fractional order may change with time. This article is part of the theme issue 'Advanced materials modelling via fractional calculus: challenges and perspectives'.

4.
Philos Trans A Math Phys Eng Sci ; 378(2172): 20190294, 2020 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-32389091

RESUMEN

In this paper the authors introduce a nonlinear model of fractional-order hereditariness used to capture experimental data obtained on human tendons of the knee. Creep and relaxation data on fibrous tissues have been obtained and fitted with logarithmic relations that correspond to power-laws with nonlinear dependence of the coefficients. The use of a proper nonlinear transform allows one to use Boltzmann superposition in the transformed variables yielding a fractional-order model for the nonlinear material hereditariness. The fundamental relations among the nonlinear creep and relaxation functions have been established, and the results from the equivalence relations have been contrasted with measures obtained from the experimental data. Numerical experiments introducing polynomial and harmonic stress and strain histories have been reported to assess the provided equivalence relations. This article is part of the theme issue 'Advanced materials modelling via fractional calculus: challenges and perspectives'.


Asunto(s)
Rodilla , Ligamentos , Fenómenos Mecánicos , Dinámicas no Lineales , Tendones , Fenómenos Biomecánicos , Humanos , Ligamentos/citología , Tendones/citología
5.
Ultrasound Obstet Gynecol ; 56(4): 597-602, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-31909525

RESUMEN

OBJECTIVE: To evaluate the performance of a new ultrasound technique for the automatic assessment of the change in head-perineum distance (delta-HPD) and angle of progression (delta-AoP) during the active phase of the second stage of labor. METHODS: This was a prospective observational cohort study including singleton term pregnancies with fetuses in cephalic presentation during the active phase of the second stage of labor. In each patient, two videoclips of 10 s each were acquired transperineally, one in the axial and one in the sagittal plane, between rest and the acme of an expulsive effort, in order to measure HPD and AoP, respectively. The videoclips were processed offline and the difference between the acme of the pushing effort and rest in HPD (delta-HPD) and AoP (delta-AoP) was calculated, first manually by an experienced sonographer and then using a new automatic technique. The reliability of the automatic algorithm was evaluated by comparing the automatic measurements with those obtained manually, which was considered as the reference gold standard. RESULTS: Overall, 27 women were included. A significant correlation was observed between the measurements obtained by the automatic and the manual methods for both delta-HPD (intraclass correlation coefficient (ICC) = 0.97) and delta-AoP (ICC = 0.99). The high accuracy provided by the automatic algorithm was confirmed by the high values of the coefficient of determination (r2 = 0.98 for both delta-HPD and delta-AoP) and the low residual errors (root mean square error = 1.2 mm for delta-HPD and 1.5° for delta-AoP). A Bland-Altman analysis showed a mean difference of 0.52 mm (limits of agreement, -1.58 to 2.62 mm) for delta-HPD (P = 0.034) and 0.35° (limits of agreement, -2.54 to 3.09°) for delta-AoP (P = 0.39) between the manual and automatic measurements. CONCLUSIONS: The automatic assessment of delta-AoP and delta-HPD during maternal pushing efforts is feasible. The automatic measurement of delta-AoP appears to be reliable when compared with the gold standard manual measurement by an experienced operator. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.


Asunto(s)
Algoritmos , Feto/diagnóstico por imagen , Cabeza/diagnóstico por imagen , Segundo Periodo del Trabajo de Parto/fisiología , Perineo/diagnóstico por imagen , Ultrasonografía Prenatal/métodos , Adulto , Femenino , Feto/embriología , Feto/fisiología , Cabeza/embriología , Humanos , Presentación en Trabajo de Parto , Perineo/embriología , Embarazo , Estudios Prospectivos , Reproducibilidad de los Resultados
6.
Osteoporos Int ; 30(2): 391-402, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30178159

RESUMEN

An innovative, non-ionizing technique to diagnose osteoporosis on lumbar spine and femoral neck was evaluated through a multicenter study involving 1914 women. The proposed method showed significant agreement with reference gold standard method and, therefore, a potential for early osteoporosis diagnoses and possibly improved patient management. INTRODUCTION: To assess precision (i.e., short term intra-operator precision) and diagnostic accuracy of an innovative non-ionizing technique, REMS (Radiofrequency Echographic Multi Spectrometry), in comparison with the clinical gold standard reference DXA (dual X-ray absorptiometry), through an observational multicenter clinical study. METHODS: In a multicenter cross-sectional observational study, a total of 1914 postmenopausal women (51-70 years) underwent spinal (n = 1553) and/or femoral (n = 1637) DXA, according to their medical prescription, and echographic scan of the same anatomical sites performed with the REMS approach. All the medical reports (DXA and REMS) were carefully checked to identify possible errors that could have caused inaccurate measurements: erroneous REMS reports were excluded, whereas erroneous DXA reports were re-analyzed where possible and otherwise excluded before assessing REMS accuracy. REMS precision was independently assessed. RESULTS: In the spinal group, quality assessment on medical reports produced the exclusion of 280 patients because of REMS errors and 78 patients because of DXA errors, whereas 296 DXA reports were re-analyzed and corrected. Analogously, in the femoral group there were 205 exclusions for REMS errors, 59 exclusions for DXA errors, and 217 re-analyzed DXA reports. In the resulting dataset (n = 1195 for spine, n = 1373 for femur) REMS outcome showed a good agreement with DXA: the average difference in bone mineral density (BMD, bias ± 2SD) was -0.004 ± 0.088 g/cm2 for spine and - 0.006 ± 0.076 g/cm2 for femur. Linear regression showed also that the two methods were well correlated: standard error of the estimate (SEE) was 5.3% for spine and 5.8% for femur. REMS precision, expressed as RMS-CV, was 0.38% for spine and 0.32% for femur. CONCLUSIONS: The REMS approach can be used for non-ionizing osteoporosis diagnosis directly on lumbar spine and femoral neck with a good level of accuracy and precision. However, a more rigorous operator training is needed to limit the erroneous acquisitions and to ensure the full clinical practicability.


Asunto(s)
Cuello Femoral/diagnóstico por imagen , Vértebras Lumbares/diagnóstico por imagen , Osteoporosis Posmenopáusica/diagnóstico por imagen , Absorciometría de Fotón/métodos , Anciano , Densidad Ósea/fisiología , Estudios Transversales , Femenino , Cuello Femoral/fisiopatología , Humanos , Vértebras Lumbares/fisiopatología , Persona de Mediana Edad , Osteoporosis Posmenopáusica/fisiopatología , Reproducibilidad de los Resultados , Ultrasonografía/métodos
7.
Sci Rep ; 8(1): 14241, 2018 09 24.
Artículo en Inglés | MEDLINE | ID: mdl-30250234

RESUMEN

Nucleotide-binding Oligomerization Domain-2 (NOD2) mutations are associated with an increased risk to develop Crohn's Disease. In previous studies, we have shown that Nod2-/- mice manifest increased proportion of Lamina Propria (LP) CD4+ LAP+ Foxp3- regulatory cells, when compared with Nod2+/+ mice, while CD4+ Foxp3 + regulatory cells were not affected. Here, we investigated the Nod2 gut microbiota, by 16S rRNA pyrosequencing, at steady state and after TNBS-colitis induction in mice reared separately or in cohousing, correlating the microbial profiles with LP regulatory T cells proportion and tissue cytokines content. We found that enrichment of Rikenella and Alistipes (Rikenellaceae) in Nod2-/- mice at 8 weeks of age reared separately was associated with increased proportion of CD4+ LAP+ Foxp3- cells and less severe TNBS-colitis. In co-housed mice the acquisition of Rickenellaceae by Nod2+/+ mice was associated with increased CD4+ LAP+ Foxp3- proportion and less severe colitis. Severe colitis was associated with enrichment of gram-negative pathobionts (Escherichia and Enterococcus), while less severe colitis with protective bacteria (Barnesiella, Odoribacter and Clostridium IV). Environmental factors acting on genetic background with different outcomes according to their impact on microbiota, predispose in different ways to inflammation. These results open a new scenario for therapeutic attempt to re-establish eubiosis in Inflammatory Bowel Disease patients with NOD2 polymorphisms.


Asunto(s)
Colitis/microbiología , Enfermedad de Crohn/microbiología , Inflamación/microbiología , Proteína Adaptadora de Señalización NOD2/genética , Animales , Linfocitos T CD4-Positivos/microbiología , Clostridium/genética , Clostridium/patogenicidad , Colitis/genética , Colitis/patología , Enfermedad de Crohn/genética , Enfermedad de Crohn/patología , Citocinas/genética , Modelos Animales de Enfermedad , Enterococcus/genética , Enterococcus/patogenicidad , Escherichia/genética , Escherichia/patogenicidad , Factores de Transcripción Forkhead/genética , Microbioma Gastrointestinal/genética , Humanos , Inflamación/genética , Inflamación/patología , Mucosa Intestinal/microbiología , Mucosa Intestinal/patología , Ratones , ARN Ribosómico 16S/genética , Linfocitos T Reguladores/metabolismo , Linfocitos T Reguladores/patología
8.
Ultrasound Obstet Gynecol ; 50(6): 766-775, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28233418

RESUMEN

OBJECTIVE: To evaluate the accuracy and reliability of an automatic ultrasound technique for assessment of the angle of progression (AoP) during labor. METHODS: Thirty-nine pregnant women in the second stage of labor, with fetus in cephalic presentation, underwent conventional labor management with additional translabial sonographic examination. AoP was measured in a total of 95 acquisition sessions, both automatically by an innovative algorithm and manually by an experienced sonographer, who was blinded to the algorithm outcome. The results obtained from the manual measurement were used as the reference against which the performance of the algorithm was assessed. In order to overcome the common difficulties encountered when visualizing by sonography the pubic symphysis, the AoP was measured by considering as the symphysis landmark its centroid rather than its distal point, thereby assuring high measurement reliability and reproducibility, while maintaining objectivity and accuracy in the evaluation of progression of labor. RESULTS: There was a strong and statistically significant correlation between AoP values measured by the algorithm and the reference values (r = 0.99, P < 0.001). The high accuracy provided by the automatic method was also highlighted by the corresponding high values of the coefficient of determination (r2 = 0.98) and the low residual errors (root mean square error = 2°27' (2.1%)). The global agreement between the two methods, assessed through Bland-Altman analysis, resulted in a negligible mean difference of 1°1' (limits of agreement, 4°29'). CONCLUSIONS: The proposed automatic algorithm is a reliable technique for measurement of the AoP. Its (relative) operator-independence has the potential to reduce human errors and speed up ultrasound acquisition time, which should facilitate management of women during labor. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.


Asunto(s)
Feto/diagnóstico por imagen , Presentación en Trabajo de Parto , Segundo Periodo del Trabajo de Parto/fisiología , Trabajo de Parto/fisiología , Ultrasonografía Prenatal , Adulto , Algoritmos , Estudios de Factibilidad , Femenino , Monitoreo Fetal , Humanos , Embarazo , Sínfisis Pubiana/anatomía & histología , Reproducibilidad de los Resultados
9.
Cereb Cortex ; 25(9): 2670-82, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24706734

RESUMEN

Huntington's disease (HD) is characterized by progressive motor impairment. Therefore, the connectivity of the corticospinal tract (CST), which is the main white matter (WM) pathway that conducts motor impulses from the primary motor cortex to the spinal cord, merits particular attention. WM abnormalities have already been shown in presymptomatic (Pre-HD) and symptomatic HD subjects using magnetic resonance imaging (MRI). In the present study, we examined CST microstructure using diffusion tensor imaging (DTI)-based tractography in 30-direction DTI data collected from 100 subjects: Pre-HD subjects (n = 25), HD patients (n = 25) and control subjects (n = 50), and T2*-weighted (iron sensitive) imaging. Results show decreased fractional anisotropy (FA) and increased axial (AD), and radial diffusivity (RD) in the bilateral CST of HD patients. Pre-HD subjects had elevated iron in the left CST, regionally localized between the brainstem and thalamus. CAG repeat length in conjunction with age, as well as motor (UHDRS) assessment were correlated with CST FA, AD, and RD both in Pre-HD and HD. In the presymptomatic phase, increased iron in the inferior portion supports the "dying back" hypothesis that axonal damage advances in a retrograde fashion. Furthermore, early iron alteration may cause a high level of toxicity, which may contribute to further damage.


Asunto(s)
Enfermedad de Huntington/patología , Corteza Motora/patología , Tractos Piramidales/patología , Médula Espinal/patología , Adulto , Análisis de Varianza , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Estadística como Asunto
10.
Hum Brain Mapp ; 35(7): 3143-51, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24895252

RESUMEN

Increased iron in subcortical gray matter (GM) structures of patients with Huntington's disease (HD) has been suggested as a causal factor in neuronal degeneration. But how iron content is related to white matter (WM) changes in HD is still unknown. For example, it is not clear whether WM changes share the same physiopathology (i.e. iron accumulation) with GM or whether there is a different mechanism. The present study used MRI to examine iron content in premanifest gene carriers (PreHD, n = 25) and in early HD patients (n = 25) compared with healthy controls (n = 50). 3T MRI acquisitions included high resolution 3D T1, EPI sequences for diffusion tensor imaging (DTI) as an indirect measure of tissue integrity, and T2*-weighted gradient echo-planar imaging for MR-based relaxometry (R2*), which provides an indirect measure of ferritin/iron deposition in the brain. Myelin breakdown starts in the PreHD stage, but there is no difference in iron content values. Iron content reduction manifests later, in the early HD stage, in which we found a lower R2* parameter value in the isthmus. The WM iron reduction in HD is temporally well-defined (no iron differences in PreHD subjects and iron differences only in early HD patients). Iron level in callosal WM may be regarded as a marker of disease state, as iron does not differentiate PreHD subjects from controls but distinguishes between PreHD and HD.


Asunto(s)
Cuerpo Calloso/metabolismo , Enfermedad de Huntington/patología , Hierro/metabolismo , Vaina de Mielina/patología , Adulto , Femenino , Humanos , Enfermedad de Huntington/metabolismo , Imagenología Tridimensional , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica
11.
Eur Psychiatry ; 28(8): 499-506, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23078960

RESUMEN

Abnormal brain connectivity has recently been reported in obsessive compulsive disorder (OCD). However, structural differences in the corpus callosum (CC), the primary structure connecting the two hemispheres, have not been extensively studied. In this case-control study, we recruited 30 patients with OCD and 30 healthy control subjects carefully matched for age, sex and handedness. Combining surface-based mesh-modeling and voxel-based morphometry (VBM), we compared callosal thickness and white matter (WM) density in patients and controls. We investigated associations between callosal structure and cortical gray matter (GM) density, and we related CC measures to neuropsychological performance in OCD. OCD patients showed small anterior and posterior callosal regions compared to healthy control subjects. In the OCD group, anterior callosal thickness was positively correlated with GM density of the right mid-dorso-lateral prefrontal (BA 9/46) area, while posterior callosal thickness was positively correlated with GM density in the left supramarginal gyrus (BA 40). Moreover, posterior callosal WM density was positively correlated with verbal memory, visuo-spatial memory, verbal fluency, and visuo-spatial reasoning performances. Callosal attributes were related to GM density in cortical areas innervated by the CC, and were also related to performance in cognitive domains impaired in the disorder. The CC may therefore be integrally involved in OCD.


Asunto(s)
Cuerpo Calloso/patología , Fibras Nerviosas Mielínicas/patología , Trastorno Obsesivo Compulsivo/patología , Adulto , Estudios de Casos y Controles , Imagen de Difusión Tensora , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Fibras Nerviosas Amielínicas/patología , Pruebas Neuropsicológicas , Trastorno Obsesivo Compulsivo/psicología , Tamaño de los Órganos
12.
Eur Psychiatry ; 2012 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-22705034

RESUMEN

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

13.
Cereb Cortex ; 22(12): 2858-66, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22223853

RESUMEN

Recent magnetic resonance imaging (MRI) studies suggest that abnormalities in Huntington's disease (HD) extend to white matter (WM) tracts in early HD and even in presymptomatic stages. Thus, changes of the corpus callosum (CC) may reflect various aspects of HD pathogenesis. We recruited 17 HD patients, 17 pre-HD subjects, and 34 healthy age-matched controls. Three-dimensional anatomical MRI and diffusion tensor images of the brain were acquired on a 3T scanner. Combining region-of-interest analyses, voxel-based morphometry, and tract-based spatial statistics, we investigated callosal thickness, WM density, fractional anisotropy, and radial and axial diffusivities. Compared with controls, pre-HD subjects showed reductions of the isthmus, likely due to myelin damage. Compared with pre-HD subjects, HD patients showed reductions of isthmus and body, with axonal damage confined to the body. Compared with controls, HD patients had significantly decreased callosal measures in extended regions across almost the entire CC. At this disease stage, both myelin and axonal damage are detectable. Supplementary multiple regression analyses revealed that WM reduction density in the isthmus as well as Disease Burden scores allowed to predict the "HD development" index. While callosal changes seem to proceed in a posterior-to-anterior direction as the diseases progresses, this observation requires validation in future longitudinal investigations.


Asunto(s)
Cuerpo Calloso/patología , Enfermedad de Huntington/patología , Imagen por Resonancia Magnética/métodos , Fibras Nerviosas Mielínicas/patología , Técnica de Sustracción , Adulto , Diagnóstico Precoz , Femenino , Humanos , Masculino , Persona de Mediana Edad
14.
Artículo en Inglés | MEDLINE | ID: mdl-21698537

RESUMEN

An increasing number of advanced therapy medicinal products (ATMPs) are under development and in clinical trials. Patients are central to this progress. In research, patients have funded, catalysed, coordinated and led projects. In regulation, patient groups have contributed to the creation of the political momentum for regulation of ATMPs, contributed to the debate and now participate in the regulatory process. Once licensed, patients will have a role in the pharmacovigilance, health technology assessment and reimbursement arrangements for these products. Patient groups contribute valuably as equal stakeholders at every step of the development of an ATMP.


Asunto(s)
Participación del Paciente , Terapias en Investigación , Ensayos Clínicos como Asunto , Organizaciones del Consumidor , Europa (Continente) , Terapia Genética , Humanos , Política , Trasplante de Células Madre , Trasplante de Tejidos
15.
Neurocase ; 17(1): 46-56, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20981620

RESUMEN

A deficit of declarative memory is a common sequela after a hypoxic episode. While the role of gray matter changes (i.e., atrophy of hippocampal formation) as mainly responsible for memory loss has been emphasized, the role of the white matter damage has so far been neglected. The present study was aimed at evaluating whether white matter damage, within the neural circuitry responsible for declarative memory functioning, is present in anoxic patients. We assessed, by means of voxel-based morphometry, the integrity of white matter regions in five patients with hypoxic amnesia. When anoxic patients were compared to healthy controls, significantly less white matter density was detected in the fornix, anterior portion of the cingulum bundle and uncinate fasciculus bilaterally. We conclude that cerebral hypoxia may alter, together with the hippocampi, the integrity of white matter fibers throughout the memory-limbic system.


Asunto(s)
Amnesia/patología , Encéfalo/patología , Fibras Nerviosas Mielínicas/patología , Adulto , Amnesia/etiología , Función Ejecutiva , Humanos , Hipoxia/complicaciones , Procesamiento de Imagen Asistido por Computador/métodos , Inteligencia , Imagen por Resonancia Magnética/métodos , Masculino , Memoria/fisiología , Persona de Mediana Edad , Pruebas Neuropsicológicas
16.
Neurology ; 74(14): 1136-42, 2010 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-20368633

RESUMEN

BACKGROUND: The corpus callosum (CC) has been shown to be susceptible to atrophy in Alzheimer disease (AD) as a correlate of wallerian degeneration or retrogenesis. However, when and where these 2 mechanisms intervene is still unclear. METHODS: In 3 memory clinics, we recruited 38 patients with amnestic mild cognitive impairment (MCI), 38 patients with mild AD, and 40 healthy controls (HC). Combining voxel-based morphometry and diffusion tensor imaging, we investigated CC white matter (WM) density and fractional anisotropy (FA), radial diffusivity (DR), and axial diffusivity (DA). RESULTS: Compared with HC, patients with amnestic MCI showed reduced WM density in the anterior CC subregion; however, FA, DR, and DA did not differ between the 2 groups. Significant changes were found in patients with mild AD compared with HC in the anterior and posterior CC regions. These differences were evident in both voxel-based morphometry and diffusion tensor imaging analyses. Specifically, we found reduced callosal WM density in the genu, posterior body, and splenium; decreased FA and increased DR in the anterior CC subregion; and increased DA, with no difference in the FA, in the posterior CC subregion. CONCLUSIONS: Callosal changes are already present in patients with amnestic mild cognitive impairment (MCI) and mild Alzheimer disease (AD). The precocious involvement of the anterior callosal subregion in amnestic MCI extends to posterior regions in mild AD. Two different mechanisms might contribute to the white matter changes in mild AD: wallerian degeneration in posterior subregions of the corpus callosum (suggested by increased axial diffusivity without fractional anisotropy modifications) and a retrogenesis process in the anterior callosal subregions (suggested by increased radial diffusivity without axial diffusivity modifications).


Asunto(s)
Enfermedad de Alzheimer/patología , Corteza Cerebral/patología , Trastornos del Conocimiento/patología , Cuerpo Calloso/patología , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/fisiopatología , Anisotropía , Biomarcadores/análisis , Mapeo Encefálico/métodos , Corteza Cerebral/fisiopatología , Trastornos del Conocimiento/fisiopatología , Cuerpo Calloso/fisiopatología , Difusión , Imagen de Difusión Tensora , Progresión de la Enfermedad , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Fibras Nerviosas Mielínicas/patología , Degeneración Walleriana/patología , Degeneración Walleriana/fisiopatología
17.
Pediatr Surg Int ; 26(5): 465-71, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20306059

RESUMEN

INTRODUCTION: The most invalidating and life-threatening complication in Hirschsprung's disease patients (HSCR) is Hirschsprung's disease-associated enterocolitis (HAEC). The mechanisms underlying enterocolitis have not been identified. The limited knowledge of the role of intestinal microflora is in part due to the complexity of the intestinal microbiome and to the limitation of cultivation-based technologies, given that less than 25% of the intestinal bacterial species can be cultured. MATERIALS AND METHODS: We used amplified ribosomal DNA restriction analysis (ARDRA) with four different restriction enzymes to study variations of microflora composition of the stools of a selected HSCR patient in different clinical conditions (acute phase vs. remission). RESULTS: We assessed a total of 15 stool specimens belonging to the same 3-year-old male patient suffering from HSCR, which were harvested during 4 HAEC episodes and remission phases. Restriction analysis showed that HAEC episodes seem to cluster together at ARDRA analysis, thus suggesting a sort of predisposing bacterial community for HAEC development and the need for a microflora equilibrium to maintain wellness. CONCLUSIONS: This approach proved to be effective, useful and powerful in assessing microflora dynamics and indicated that the differences in microflora associated with acute HAEC or remission are likely to result from a combination of disease activity and different antibiotic therapies. ARDRA proved to be useful in discriminating disease versus remission. Our findings indicated that HAEC results from a change in the equilibrium between bacterial species or from altered discrimination of harmless from harmful microorganisms, challenging the definition of pathogenic and non-pathogenic species. Based on these results, we propose ARDRA as a rapid inexpensive tool to assess microflora dynamics during HAEC episodes.


Asunto(s)
Bacterias/clasificación , Enterocolitis/microbiología , Enfermedad de Hirschsprung/complicaciones , Alelos , Antiinfecciosos/uso terapéutico , Bacterias/genética , Preescolar , ADN/análisis , Enterocolitis/tratamiento farmacológico , Enterocolitis/genética , Heces/microbiología , Genómica , Enfermedad de Hirschsprung/genética , Humanos , Masculino , Proyectos Piloto , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple , Proteínas Proto-Oncogénicas c-ret/genética
18.
Neuroscience ; 162(3): 827-35, 2009 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-19409211

RESUMEN

There is growing evidence based on behavioral and functional imaging studies about the cerebellar involvement in the modulation of cognitive functions. However, it still remains to be clarified how the cerebellum interacts with brain regions sub-serving different cognitive domains. In this study we used magnetic resonance imaging (MRI) and voxel based morphometry (VBM) to investigate changes of cerebral gray matter (GM) density in 15 patients with a focal cerebellar damage (CD) compared to 15 healthy controls. T2-weighted scans and T1-weighted volumes were collected from each subject. With the exception of the cerebellar lesion, none of the patients showed any additional brain MRI abnormality. T1-volumes were analyzed by voxel-based morphometry. Consistent with their neuropsychological abnormalities, patients with right-CD compared to controls showed a reduction of GM density mainly involving the left frontal, parietal and temporal lobes. Conversely, patients with left-CD did not show any significant neuropsychological or cerebral GM abnormality. The present study indicates that specific GM changes may be detected in patients with isolated CD and cognitive dysfunction. We discuss the findings in terms of cerebellar influence on the neuronal networks involved in higher level functions of the association cortex.


Asunto(s)
Corteza Cerebelosa/patología , Enfermedades Cerebelosas/patología , Adulto , Anciano , Mapeo Encefálico , Enfermedades Cerebelosas/complicaciones , Femenino , Lateralidad Funcional , Humanos , Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética/métodos , Masculino , Trastornos de la Memoria/etiología , Trastornos de la Memoria/patología , Persona de Mediana Edad , Actividad Motora/fisiología , Pruebas Neuropsicológicas , Desempeño Psicomotor
19.
Eur J Neurol ; 15(10): 1050-7, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18717724

RESUMEN

BACKGROUND AND PURPOSE: At high altitudes barometric pressure is reduced and, thus, less oxygen is inhaled. Reduced oxygen concentration in brain tissue can lead to cerebral damage and neurological and cognitive deficits. The present study was designed to explore the effects of high-altitude exposure using a quantitative MRI technique, voxel-based morphometry. METHODS: We studied nine world-class mountain climbers before (baseline) and after (follow-up) an extremely high-altitude ascent of Everest and K2. We investigated the effects of repeated extremely high-altitude exposures by comparing mountain climbers' scans at baseline with scans of 19 controls. In addition, we measured the effects of a single extremely high-altitude expedition by comparing mountain climbers' scans at baseline and follow-up. RESULTS: A region of reduced white matter density/volume was found in the left pyramidal tract near the primary (BA 4) and supplementary (BA 6) motor cortex when mountain climbers at baseline were compared with controls. Further, when mountain climbers' scans before and after the expedition were compared, a region of reduced grey matter density/volume was found in the left angular gyrus (BA 39). CONCLUSION: These findings suggest that extremely high-altitude exposures may cause subtle white and grey matter changes that mainly affect brain regions involved in motor activity.


Asunto(s)
Mal de Altura/patología , Encéfalo/patología , Hipoxia Encefálica/patología , Hipoxia/patología , Imagen por Resonancia Magnética/métodos , Montañismo/fisiología , Adulto , Atrofia , Humanos , Hipoxia/etiología , Hipoxia Encefálica/etiología , Masculino , Trastornos de la Memoria/etiología , Persona de Mediana Edad , Pruebas Neuropsicológicas , Lóbulo Parietal/patología , Tractos Piramidales/patología
20.
Hippocampus ; 18(7): 719-28, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18446831

RESUMEN

Anoxia is considered a good model for studying amnesia. However, not all individuals who experience anoxic events develop memory problems. Moreover, the question still remains about whether, after anoxia, damage is limited to the hippocampus in patients with amnesia and without other significant cognitive deficits. Here we investigated brain damage in a selected sample of adults affected exclusively by an amnesic syndrome after an anoxic episode. The cerebral MR images of these patients were submitted to visual inspection, volumetric measurements of the mesial temporal structures following manual segmentation, and to Voxel-Based Morphometry of the whole brain. We studied five anoxic patients and thirty-three well-matched healthy subjects. Our aim was to: (a) quantify regional atrophic changes associated with chronic anoxic damage compared to control subjects (Group Comparison Analysis); (b) identify regions of common abnormality across all patients (Conjunction Analysis in the VBM); (c) investigate whether measures of regional volume reduction correlated with neuropsychological memory scores; (d) compare the results obtained with visual inspection and ROI analyses with those obtained with VBM. We found that anoxic patients presented a significant reduction of gray matter volume in the hippocampus bilaterally compared to healthy subjects. The only common atrophic region across all patients was the hippocampus bilaterally. Correlation analysis showed only a trend between the Prose immediate free recall test and the left hippocampus. Our findings confirm that the hippocampus is very sensitive to damage stemming from anoxia. Patients with hypoxic amnesia may present damage in other brain regions, but only hippocampal atrophy is common in all of them.


Asunto(s)
Amnesia/patología , Hipocampo/patología , Hipoxia Encefálica/patología , Imagen por Resonancia Magnética , Adulto , Atrofia , Corteza Entorrinal/patología , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Giro Parahipocampal/patología
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