RESUMO
Testis specific protein, Y-encoded-like 2 (TSPYL2) regulates the expression of genes encoding glutamate receptors. Glutamate pathology is implicated in neurodevelopmental conditions such as autism spectrum disorder, attention deficit hyperactivity disorder (ADHD) and schizophrenia. In line with this, a microduplication incorporating the TSPYL2 locus has been reported in people with ADHD. However, the role of Tspyl2 remains unclear. Therefore here we used a Tspyl2 loss-of-function mouse model to directly examine how this gene impacts upon behavior and brain anatomy. We hypothesized that Tspyl2 knockout (KO) would precipitate a phenotype relevant to neurodevelopmental conditions. In line with this prediction, we found that Tspyl2 KO mice were marginally more active, had significantly impaired prepulse inhibition, and were significantly more 'sensitive' to the dopamine agonist amphetamine. In addition, the lateral ventricles were significantly smaller in KO mice. These findings suggest that disrupting Tspyl2 gene expression leads to behavioral and brain morphological alterations that mirror a number of neurodevelopmental psychiatric traits.
Assuntos
Encéfalo/anormalidades , Encéfalo/crescimento & desenvolvimento , Proteínas Nucleares/metabolismo , Anfetamina/administração & dosagem , Anfetamina/farmacologia , Animais , Comportamento Animal , Proteínas de Ciclo Celular , Ventrículos Cerebrais/efeitos dos fármacos , Ventrículos Cerebrais/patologia , Relações Interpessoais , Imageamento por Ressonância Magnética , Masculino , Camundongos Knockout , Atividade Motora , Proteínas Nucleares/deficiência , Inibição Pré-Pulso , Cloreto de Sódio/administração & dosagem , Cloreto de Sódio/farmacologiaRESUMO
The intense interest in spin-based quantum information processing has caused an increasing overlap between the two traditionally distinct disciplines of magnetic resonance and nanotechnology. In this work we discuss rigorous design guidelines to integrate microwave circuits with charge-sensitive nanostructures, and describe how to simulate such structures accurately and efficiently. We present a new design for an on-chip, broadband, nanoscale microwave line that optimizes the magnetic field used to drive a spin-based quantum bit (or qubit) while minimizing the disturbance to a nearby charge sensor. This new structure was successfully employed in a single-spin qubit experiment, and shows that the simulations accurately predict the magnetic field values even at frequencies as high as 30 GHz.
RESUMO
BACKGROUND: The question of whether Asperger syndrome can be distinguished from autism has attracted much debate and may even incur delay in diagnosis and intervention. Accordingly, there has been a proposal for Asperger syndrome to be subsumed under autism in the forthcoming Diagnostic and Statistical Manual of Mental Disorders, fifth edition, in 2013. One approach to resolve this question has been to adopt the criterion of absence of clinically significant language or cognitive delay--essentially, the "absence of language delay." To our knowledge, this is the first meta-analysis of magnetic resonance imaging (MRI) studies of people with autism to compare absence with presence of language delay. It capitalizes on the voxel-based morphometry (VBM) approach to systematically explore the whole brain for anatomic correlates of delay and no delay in language acquisition in people with autism spectrum disorders. METHODS: We conducted a systematic search for VBM MRI studies of grey matter volume in people with autism. Studies with a majority (at least 70%) of participants with autism diagnoses and a history of language delay were assigned to the autism group (n = 151, control n = 190). Those with a majority (at least 70%) of individuals with autism diagnoses and no language delay were assigned to the Asperger syndrome group (n = 149, control n = 214). We entered study coordinates into anatomic likelihood estimation meta-analysis software with sampling size weighting to compare grey matter summary maps driven by Asperger syndrome or autism. RESULTS: The summary autism grey matter map showed lower volumes in the cerebellum, right uncus, dorsal hippocampus and middle temporal gyrus compared with controls; grey matter volumes were greater in the bilateral caudate, prefrontal lobe and ventral temporal lobe. The summary Asperger syndrome map indicated lower grey matter volumes in the bilateral amygdala/hippocampal gyrus and prefrontal lobe, left occipital gyrus, right cerebellum, putamen and precuneus compared with controls; grey matter volumes were greater in more limited regions, including the bilateral inferior parietal lobule and the left fusiform gyrus. Both Asperger syndrome and autism studies reported volume increase in clusters in the ventral temporal lobe of the left hemisphere. LIMITATIONS: We assigned studies to autism and Asperger syndrome groups for separate analyses of the data and did not carry out a direct statistical group comparison. In addition, studies available for analysis did not capture the entire spectrum, therefore we cannot be certain that our findings apply to a wider population than that sampled. CONCLUSION: Whereas grey matter differences in people with Asperger syndrome compared with controls are sparser than those reported in studies of people with autism, the distribution and direction of differences in each category are distinctive.
Assuntos
Síndrome de Asperger/diagnóstico , Transtorno Autístico/diagnóstico , Transtornos do Desenvolvimento da Linguagem/patologia , Imageamento por Ressonância Magnética/psicologia , Fibras Nervosas Amielínicas/patologia , Neuroimagem/psicologia , Síndrome de Asperger/patologia , Síndrome de Asperger/psicologia , Transtorno Autístico/patologia , Transtorno Autístico/psicologia , Encéfalo/patologia , Diagnóstico Diferencial , Humanos , Imageamento por Ressonância Magnética/métodos , Neuroimagem/métodosRESUMO
Maternal infection during prenatal life is a risk factor for neurodevelopmental disorders, including schizophrenia and autism, in the offspring. We and others have reported white mater microstructure abnormalities in prefrontal-striato-temporal networks in these disorders. In addition we have shown that early rather than late maternal immune challenge in the mouse model precipitates ventricular volume change and impairs sensorimotor gating similar to that found in schizophrenia. However, it is not known whether the timing of maternal infection has a differential impact upon white matter microstructural indices. Therefore this study directly tested the effect of early or late gestation maternal immune activation on post-natal white matter microstructure in the mouse. The viral mimic PolyI:C was administered on day 9 or day 17 of gestation. In-vivo diffusion tensor imaging (DTI) was carried out when the offspring reached adulthood. We describe a novel application of voxel-based analysis to evaluate fractional anisotrophy (FA). In addition we conducted a preliminary immunohistochemical exploration of the oligodendrocyte marker, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), to determine whether differences in myelination might contribute to any changes in FA observed. Our results provide experimental evidence that prenatal exposure to inflammation elicits widespread differences in FA throughout fronto-striatal-limbic circuits compared to control saline exposure. Moreover, FA changes were more extensive in the group exposed earliest in gestation.
Assuntos
Encéfalo/patologia , Imagem de Tensor de Difusão/métodos , Processamento de Imagem Assistida por Computador/métodos , Complicações Infecciosas na Gravidez/imunologia , Efeitos Tardios da Exposição Pré-Natal , 2',3'-Nucleotídeo Cíclico Fosfodiesterases/metabolismo , Animais , Anisotropia , Encéfalo/enzimologia , Feminino , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fibras Nervosas Mielinizadas/enzimologia , Fibras Nervosas Mielinizadas/patologia , Vias Neurais/enzimologia , Vias Neurais/patologia , Oligodendroglia/enzimologia , Oligodendroglia/patologia , Gravidez , Fatores de TempoRESUMO
BACKGROUND: Children with attention-deficit hyperactivity disorder (ADHD) have difficulties with executive function and impulse control which may improve with age. AIMS: To map the brain correlates of executive function in ADHD and determine age-related changes in reaction times and brain volumes. METHOD: Attention-deficit hyperactivity disorder and control groups were compared on the change task measures of response inhibition (stop signal reaction time, SSRT) and shifting (change response reaction time, CRRT). Voxel-wise magnetic resonance imaging (MRI) correlations of reaction times and grey matter volume were determined, along with bivariate correlations of reaction times, brain volumes and age. RESULTS: Individuals in the ADHD group had longer SSRTs and CRRTs. Anterior cingulate, striatal and medial temporal volumes highly correlated with SSRT. Striatal and cerebellar volumes strongly correlated with CRRT. Older children had faster reaction times and larger regional brain volumes. In controls, orbitofrontal, medial temporal and cerebellar volumes correlated with CRRT but not SSRT. Neither reaction times nor regional brain volumes were strongly age-dependent. CONCLUSIONS: Our evidence supports delayed brain maturation in ADHD and implies that some features of ADHD improve with age.
Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/patologia , Cérebro/patologia , Tempo de Reação , Fatores Etários , Estudos de Casos e Controles , Cerebelo/patologia , Cérebro/crescimento & desenvolvimento , Criança , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Testes Neuropsicológicos/estatística & dados numéricosRESUMO
Previous studies of face processing in autism suggest abnormalities in anatomical development, functioning and connectivity/coordination of distributed brain systems involved in social cognition, but the spatial sequence and time course of rapid (sub-second) neural responses to emotional facial expressions have not been examined in detail. Source analysis of high-density event-related potentials (ERPs) is an optimal means to examine both the precise temporal profile and spatial location of early electrical brain activity in response to emotionally salient stimuli. Therefore, we recorded 128-channel ERPs from high-functioning males with autism (aged 6-10 years), and age-, sex- and IQ-matched typically developing controls during explicit and implicit processing of emotion from pictures showing happy, angry, fearful, sad and neutral facial expressions. Children with autism showed normal patterns of behavioural and ERP (P1, N170 and P2) responses. However, dipole source analysis revealed that ERP responses relating to face detection (visual cortex) and configural processing of faces (fusiform gyrus), as well as mental state decoding (medial prefrontal lobe), were significantly weaker and/or slower in autism compared with controls during both explicit and implicit emotion-processing tasks. Slower- and larger-amplitude ERP source activity in the parietal somatosensory cortices possibly reflected more effortful compensatory analytical strategies used by the autism group to process facial gender and emotion. Such aberrant neurophysiological processing of facial emotion observed in children with autism within the first 300 ms of stimulus presentation suggests abnormal cortical specialization within social brain networks, which would likely disrupt the development of normal social-cognitive skills.
Assuntos
Transtorno Autístico/fisiopatologia , Transtorno Autístico/psicologia , Encéfalo/fisiopatologia , Emoções , Potenciais Evocados , Expressão Facial , Transtorno Autístico/diagnóstico , Criança , Comportamento Infantil , Eletroencefalografia , Humanos , Masculino , Córtex Pré-Frontal/fisiopatologia , Tempo de Reação , Couro Cabeludo/fisiopatologia , Córtex Somatossensorial/fisiopatologia , Fatores de Tempo , Córtex Visual/fisiopatologiaRESUMO
BACKGROUND: Autism exists across a wide spectrum and there is considerable debate as to whether children with Asperger's syndrome, who have normal language milestones, should be considered to comprise a subgroup distinct other from high-functioning children with autism (HFA), who have a history of delayed language development. Magnetic resonance imaging (MRI) studies of autism are in disagreement. One possible reason is that the diagnosis of autism takes precedence over Asperger's syndrome and a distinction in language acquisition is rarely made. We therefore planned to examine a whole brain hypothesis that the patterns of grey matter differences in Asperger's syndrome and HFA can be distinguished. METHODS: We used voxel-based computational morphometry to map grey matter volume differences in 33 children with either Asperger's syndrome or high-functioning autism compared to 55 typical developing control children balanced for age, IQ, gender, maternal language and ethnicity. RESULTS: Children with HFA had significantly smaller grey matter volumes in subcortical, posterior cingulate and precuneus regions than the Asperger's group. Compared to controls, children with HFA had smaller grey matter volumes in predominantly fronto-pallidal regions, while children with Asperger's had less grey matter in mainly bilateral caudate and left thalamus. In addition we found a significant negative correlation between the size of a grey matter cluster around BA44 language area and the age of acquisition of phrase speech in the children with HFA. When the groups were combined we confirmed a mixed picture of smaller grey matter volumes in frontal, basal ganglia, temporal and parietal regions. CONCLUSIONS: Our study suggests that the underlying neurobiology in HFA and Asperger's syndrome is at least partly discrete. Future studies should therefore consider the history of language acquisition as a valuable tool to refine investigation of aetiological factors and management options in pervasive developmental disorders.
Assuntos
Síndrome de Asperger/fisiopatologia , Transtorno Autístico/fisiopatologia , Mapeamento Encefálico/métodos , Encéfalo/fisiopatologia , Síndrome de Asperger/psicologia , Transtorno Autístico/psicologia , Criança , China , Feminino , Humanos , Relações Interpessoais , Desenvolvimento da Linguagem , Imageamento por Ressonância Magnética/métodos , Masculino , Comportamento SocialRESUMO
Dichotic listening (DL) has been used as a tool to investigate possible left cerebral dysfunction in schizophrenia. However, the wide range of DL tests (e.g., words, emotions, sentences) as well as patient groups ("heterogeneity") has introduced several confounders. Assessing relatives of patients with schizophrenia may overcome some of these problems, and may be more useful in determining if loss of functional cerebral laterality in schizophrenia is a state or a trait phenomenon. The fused consonant-vowel DL test was administered to 114 subjects: 20 individuals with familial schizophrenia, 42 of their healthy relatives, and 52 healthy volunteers. We did this to investigate whether the normal language processing asymmetry-a right ear advantage (REA)-is present, and whether it could serve as a marker for genetic liability. General performance accuracy level was lower in schizophrenia patients and their relatives but the expected REA was present in all groups. Adjusting for age, accuracy, and obligate status made no difference. In conclusion, familial schizophrenic patients and their relatives have normal REA and hearing laterality on the fused DL test.
Assuntos
Lateralidade Funcional , Audição , Esquizofrenia/diagnóstico , Adulto , Testes com Listas de Dissílabos , Família , Feminino , Audição/genética , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Proibitinas , Esquizofrenia/genética , Esquizofrenia/patologia , Percepção da FalaRESUMO
We report the first voxel-based morphometric (VBM) study to examine cerebral grey and white matter and cerebrospinal fluid (CSF) using computational morphometry in never-medicated, first-episode psychosis (FEP). Region-of-interest (ROI) analysis was also performed blind to group membership. 26 never-medicated individuals with FEP (23 with DSM-IV schizophrenia) and 38 healthy controls had MRI brain scans. Groups were balanced for age, sex, handedness, ethnicity, paternal socio-economic status, and height. Healthy controls were recruited from the local community by advertisement. Grey matter, white matter, and CSF: global brain volume ratios were significantly smaller in patients. Patients had significantly less grey matter volume in L and R caudate nuclei, cingulate gyri, parahippocampal gyri, superior temporal gyri, cerebellum and R thalamus, prefrontal cortex. They also had significantly less white matter volume in the R anterior limb of the internal capsule fronto-occipital fasciculus and L and R fornices, and significantly greater CSF volume especially in the R lateral ventricle. Excluding the 3 subjects with brief psychotic disorder did not alter our results. Our data suggest that fronto-temporal and subcortical-limbic circuits are morphologically abnormal in never-medicated, schizophrenia. ROI analysis comparing the schizophrenia group (n=23) with the healthy controls (n=38) confirmed caudate volumes were significantly smaller bilaterally by 11%, and lateral ventricular volume was significantly larger on the right by 26% in the patients. Caudate nuclei and lateral ventricular volume measurements were uncorrelated (Pearson correlation coefficient 0.30, p=0.10), ruling out the possibility of segmentation artefact. Ratio of lateral ventricle to caudate volume was bilaterally significantly increased (p<0.005, 2-tailed), which could represent an early biomarker in first-episode, never-medicated schizophrenia.
Assuntos
Encéfalo/patologia , Líquido Cefalorraquidiano/fisiologia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Fibras Nervosas Mielinizadas/patologia , Fibras Nervosas/patologia , Esquizofrenia/diagnóstico , Adolescente , Adulto , Núcleo Caudado/patologia , Córtex Cerebral/patologia , Ventrículos Cerebrais/patologia , Dominância Cerebral/fisiologia , Feminino , Humanos , Ventrículos Laterais/patologia , Sistema Límbico/patologia , Masculino , Pessoa de Meia-Idade , Rede Nervosa/patologia , Escalas de Graduação Psiquiátrica , Valores de ReferênciaRESUMO
The neuroanatomical basis of attention deficit-hyperactivity disorder (ADHD) is postulated to involve brain circuitry responsible for attention and executive function. Relatively new automated methods of MRI analysis allow rapid examination of each volume element (voxel) of whole brain, therefore we planned a comprehensive quantitative examination of brain anatomy in children with ADHD using voxel-based methods. We aimed to quantify whole brain, global tissue class and regional grey and white matter volume differences in 28 male children with ADHD and 31 closely matched controls. Since ADHD is often complicated by comorbid oppositional defiant disorder (ODD) and conduct disorder (CD), we also conducted post-hoc analyses of subgroups of children with ADHD with and without these comorbidities. Significant regional deficits in ADHD were observed within a predominantly right-sided frontal-pallidal-parietal grey matter network and bilateral white matter tracts. Post-hoc comparisons suggested that comorbid ODD or CD did not greatly alter the extent of regional pathology in ADHD. The exceptions being cerebellar and striatal volume deficits which were significantly greater in children with ADHD plus comorbidities, but not those with ADHD alone, compared to controls. Overall, restricted structural brain abnormalities caused by ADHD were localized to brain systems known to be necessary for attention and executive function.
Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Encéfalo/anormalidades , Imageamento por Ressonância Magnética , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Transtornos de Deficit da Atenção e do Comportamento Disruptivo/diagnóstico , Transtornos de Deficit da Atenção e do Comportamento Disruptivo/epidemiologia , Criança , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/epidemiologia , Manual Diagnóstico e Estatístico de Transtornos Mentais , Lobo Frontal/patologia , Globo Pálido/patologia , Humanos , Masculino , Lobo Parietal/patologia , Índice de Gravidade de DoençaRESUMO
Autism is a disorder of neurodevelopment resulting in pervasive abnormalities in social interaction and communication, repetitive behaviours and restricted interests. There is evidence for functional abnormalities and metabolic dysconnectivity in 'social brain' circuitry in this condition, but its structural basis has proved difficult to establish reliably. Explanations for this include replication difficulties inherent in 'region of interest' approaches usually adopted, and variable inclusion criteria for subjects across the autism spectrum. Moreover, despite a consensus that autism probably affects widely distributed brain regions, the issue of anatomical connectivity has received little attention. Therefore, we planned a fully automated voxel-based whole brain volumetric analysis in children with autism and normal IQ. We predicted that brain structural changes would be similar to those previously shown in adults with autism spectrum disorder and that a correlation analysis would suggest structural dysconnectivity. We included 17 stringently diagnosed children with autism and 17 age-matched controls. All children had IQ >80. Using Brain Activation and Morphological Mapping (BAMM) software, we measured global brain and tissue class volumes and mapped regional grey and white matter differences across the whole brain. With the expectation that volumes of interconnected regions correlate positively, we carried out a preliminary exploration of 'connectivity' in autism by comparing the nature of inter-regional grey matter volume correlations with control. Children with autism had a significant reduction in total grey matter volume and significant increase in CSF volume. They had significant localized grey matter reductions within fronto-striatal and parietal networks similar to findings in our previous study, and additional decreases in ventral and superior temporal grey matter. White matter was reduced in the cerebellum, left internal capsule and fornices. Correlation analysis revealed significantly more numerous and more positive grey matter volumetric correlations in controls compared with children with autism. Thus, using similar diagnostic criteria and image analysis methods in otherwise healthy populations with an autistic spectrum disorder from different countries, cultures and age groups, we report a number of consistent findings. Taken together, our data suggest abnormalities in the anatomy and connectivity of limbic-striatal 'social' brain systems which may contribute to the brain metabolic differences and behavioural phenotype in autism.
Assuntos
Transtorno Autístico/patologia , Mapeamento Encefálico/métodos , Encéfalo/patologia , Adolescente , Transtorno Autístico/fisiopatologia , Encéfalo/fisiopatologia , Criança , Feminino , Lobo Frontal/patologia , Lobo Frontal/fisiopatologia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Lobo Parietal/patologia , Lobo Parietal/fisiopatologia , Lobo Temporal/patologia , Lobo Temporal/fisiopatologiaRESUMO
OBJECTIVE: Haem oxygenase-1 (HO-1) plays important roles in cytoprotection and tumour growth. Cholangiocarcinoma (CCA) is a deadly malignancy with very poor prognosis. The role of HO-1 in tumour progression in CCA up to now has been relatively unexplored, thus, its possible therapeutic implications in CCA have been investigated here. MATERIALS AND METHODS: HO-1 expression in tumour tissues from 50 CCA patients was determined by immunohistochemical analysis and its association with survival time was evaluated using the Kaplan-Meier method. Its role in CCA cells in vitro was evaluated by transwell and wound healing assays and suppression of HO-1 expression by siRNA. Effects of HO-1 inhibition on gemicitabine (GEM)-mediated tumour suppression was evaluated in nude mice xenografted with CCA cells. RESULTS: HO-1 expression was inversely associated with median overall survival time. Hazard ratio of patients with high HO-1 expression was 2.42 (95% CI: 1.16-5.08) with reference to low expression and HO-1 knock-down expression inhibited transwell cell migration. Suppression of HO-1 by Zn-protoporphyrin (ZnPP) enhanced cytotoxicity to GEM in CCA cells, validated in CCA xenografts. Treatment with GEM and ZnPP almost completely arrested tumour growth, whereas treatment with only a single reagent, retarded it. Tumour inhibition was associated with reduction in expression of Ki-67 and microvascular density, and enhanced p53 and p21 immunohistochemical staining. CONCLUSION: High HO-1 expression was associated with poor prognosis of CCA. Synergistic role of HO-1 inhibition in chemotherapy of CCA is a promising insight for treatment of this tumour and warrants further investigation.
Assuntos
Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/enzimologia , Desoxicitidina/análogos & derivados , Heme Oxigenase-1/metabolismo , Adulto , Idoso , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Colangiocarcinoma/patologia , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Desoxicitidina/farmacologia , Desoxicitidina/uso terapêutico , Feminino , Humanos , Imuno-Histoquímica , Antígeno Ki-67/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , Análise Multivariada , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Prognóstico , Modelos de Riscos Proporcionais , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Protoporfirinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Análise de Sobrevida , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , GencitabinaRESUMO
Gross correlation coefficient between light-scattering intensity and the optical parameters obtained for 48 sections of eight lenses with nuclear cataracts were evaluated. On the basis of these and other data in the literature, the structural elements, within the lens fiber are identified. These give rise to the optical parameters. It is proposed that three processes contribute to nuclear cataractogenesis: (1) syneretic process, (2) increase in the concentration but not in the size of protein aggregates, and (3) association (entanglement) between aggregates and optically anisotropic cytoskeleton or membrane components that leads to a decrease in structural bire-fringence.
Assuntos
Catarata/classificação , Cristalino/análise , Catarata/etiologia , Catarata/patologia , Núcleo Celular , Humanos , Luz , Nefelometria e Turbidimetria , Proteínas/análise , Espalhamento de RadiaçãoRESUMO
To ascertain a direct relationship between the light scattering intensity and the particle scattering the light, thin (6-20 micrometers) sections were cut from frozen human cataracts. Freezing for 15 min (-10 C) and then thawing had no effect on the clarity or light scattering properties of nuclear cataracts. Cortical cataracts treated in the same manner appeared to be much clearer than they were prior to freeze-thawing. Light scattering measurements were obtained as a function of scattering angle, both in the I parallel and I perpendicular mode; a He-Ne laser was used. Results showed a reduction in the light scattering intensity in the I parallel and I perpendicular modes with repeated cyclical freezing and thawing and that this decrease was most pronounced at higher scattering angles. Morphologic data showed that much of the anatomical heterogeneity present in the human cortical and rat lens osmotic cataract disappeared upon freeze-thawing. However, even though the anatomical heterogeneity was less, there was persistence of serious cellular anatomical disorganization in grossly transparent parts of the cortex. This suggests that transparency is not dependent upon the presence of intact fiber cells. The importance of these findings to studies of light scattering, cataract classification and analysis of cryoextracted human lenses is discussed.
Assuntos
Catarata/patologia , Congelamento , Espalhamento de Radiação , Animais , Humanos , Luz , RatosRESUMO
Eight lenses with nuclear cataracts have been classified. The light-scattering properties of the eight lenses were obtained with thin sections cut perpendicularly to the posterior-anterior axis. Analysis of the light scattering envelop in the I and I+ models yielded eight structural parameters that describe the density and orientation fluctuations. The variation of these parameters within each less corresponded well to the clinical description obtained from the stereoscopic photos.
Assuntos
Catarata/classificação , Espalhamento de Radiação , Humanos , Luz , Fotogrametria , RefratometriaRESUMO
For esthetic reasons, pigments and opacifiers are added to porcelains used in restorative dentistry. The purpose of this study was to use Kubelka-Munk theory (Kubelka and Munk, 1931) to predict and analyse the colors of porcelains modified by the addition of two pigments and an opacifying agent. The base porcelain was composed of 88% potassium feldspar, 6% quartz and 6% kaolin. The porcelain was modified by the addition of a yellow (Pr-Zr-Si) or a brown (Fe-Cr-Zn) stain and an opacifier (10% SnO in base porcelain). After firing at 1200 degrees C for 30 min, reflectance spectra of the various combinations were obtained with a spectrophotometer. Reflectance spectra, except at low wavelengths, were influenced by increased scattering due to the addition of the opacifier. Calculated values from Kubelka-Munk theory for absorption coefficients and scattering coefficients with appropriate correction factors were compared with the values from the reflectance spectra of the combinations. In general, good agreement was obtained if the scattering coefficient of the opacifier is set equal to 1.0. Using the L*a*b* transform of the CIE color space, it was found that this transform provided uniform color intervals for equal changes in pigment concentration.
Assuntos
Porcelana Dentária/química , Pigmentação em Prótese/normas , Análise de Variância , Análise dos Mínimos Quadrados , Pigmentação em Prótese/métodos , EspectrofotometriaRESUMO
The efficacy of MK-801, an N-methyl-D-aspartate receptor antagonist, was evaluated in a rat model of retinal ischemia induced by elevated intraocular pressure. Intraperitoneal injection of MK-801 at 0, 1, 3 and 10 mg/kg was given immediately after reperfusion. At 7 days after reperfusion, the inner retinal thickness, as measured from histologic sections of the retinas, of the 10 mg/kg treated group showed significant beneficial effect, while the other doses had no significant effect. Retinal ganglion cell counts on flat preparations of the retinas showed a beneficial dose dependent effect of MK-801 with the lowest dose showing no effect, 3 mg/kg showing marginal effects and 10 mg/kg showing significant effects. Intravitreal infusion of MK-801 during the ischemic period suppressed ischemia/reperfusion-induced internucleosomal DNA fragmentation measured at 18 hours after the insult as well as retinal tissue responses measured at 7 days. These findings suggested that the NMDA receptors may have an important role in ischemia-reperfusion insult as well as in mediating ischemia-induced apoptosis of retinal neurons. In addition, we demonstrated that pharmacological modulation of apoptotic cell death may affect the final tissue responses in vivo.
Assuntos
Maleato de Dizocilpina/uso terapêutico , Isquemia/tratamento farmacológico , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Vasos Retinianos/fisiopatologia , Animais , Contagem de Células , Fragmentação do DNA/efeitos dos fármacos , Maleato de Dizocilpina/administração & dosagem , Maleato de Dizocilpina/farmacologia , Pressão Intraocular/efeitos dos fármacos , Isquemia/fisiopatologia , Masculino , Ratos , Ratos Endogâmicos Lew , Retina/patologia , Células Ganglionares da Retina/patologia , Vasos Retinianos/efeitos dos fármacosRESUMO
This case report hopes to bring to attention the possibility of malposition and ligation of a long central venous catheter in a central venous tributary in the course of major neck surgery. A 49-year-old gentleman underwent total laryngectomy and right radical neck dissection for laryngeal carcinoma. A long central venous catheter was inserted via the right basilic vein. This was subsequently found to have malpositioned into the right inferior thyroid vein and ligated. It required an exploration of the neck wound to remove the ligated catheter.
Assuntos
Cateterismo Venoso Central/efeitos adversos , Veias Jugulares/lesões , Neoplasias Laríngeas/cirurgia , Erros Médicos , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
INTRODUCTION: Benign intrascrotal tumours are rare. CLINICAL PICTURE: Three patients with bilateral paratesticular leiomyomas, an adenomatoid tumour of the testis and a left paratesticular dermoid cyst coexisting with a synchronous left paratesticular epidermal cyst are presented. These tumours were discrete, hard and smooth lesions, in which the diagnosis of malignancy could not be safely excluded preoperatively even with ultrasonography. TREATMENT AND OUTCOME: The first patient had orchiectomy with contralateral testicular preserving surgery, the second patient underwent orchiectomy and the third had conservative testicular surgery. CONCLUSION: Awareness of these benign tumours may allow for testicular preservation.