RESUMO
Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection associated with impaired cerebral blood flow. Visualization of the eye vasculature, which is embryologically derived from that of the brain, is used clinically to diagnose the syndrome. Here, we introduce camera-phone laser speckle imaging as a new tool for in vivo, noncontact two-dimensional mapping of blood flow dynamics in the experimental cerebral malaria (ECM) murine model of Plasmodium berghei ANKA. In a longitudinal study, we show that the camera-phone imager can detect an overall decrease in the retinal blood-flow-speed (BFS) as ECM develops in P. berghei ANKA infected mice, with no similar change observed in uninfected control mice or mice infected with a non-ECM inducing strain (P. berghei NK65). Furthermore, by analyzing relative alterations in the BFS of individual retinal vessels during the progression of ECM, we illustrate the strength of our imager in identifying different BFS-change heterogeneities in the retinas of ECM and uninfected mice. The technique creates new possibilities for objective investigations into the diagnosis and pathogenesis of CM noninvasively through the eye. The camera-phone laser speckle imager along with measured spatial blood perfusion maps of the retina of a mouse infected with P. berghei ANKA-a fatal ECM model-on different days during the progression of the infection (top, day 3 after infection; middle, day 5 after infection; and bottom, day 7 after infection).
Assuntos
Lasers , Malária Cerebral/diagnóstico por imagem , Malária Cerebral/fisiopatologia , Imagem Molecular/instrumentação , Fluxo Sanguíneo Regional , Retina/diagnóstico por imagem , Retina/fisiopatologia , Animais , Matriz Extracelular/metabolismo , CamundongosRESUMO
The central aortic blood pressure (cBP) waveform, which is different to that of peripheral locations, is a clinically important parameter for assessing cardiovascular function, however the gold standard for measuring cBP involves invasive catheter-based techniques. The difficulties associated with invasive measurements have given rise to the development of a variety of noninvasive methods. An increasingly applied method for the noninvasive derivation of cBP involves the application of transfer function (TF) techniques to a non-invasively measured radial blood pressure (BP) waveform. The purpose of the current study was to investigate the development of a general parametric model for determination of cBP from tonometrically transduced radial BP waveforms. The study utilized simultaneously measured invasive central aortic and noninvasive radial BP waveform measurements. Data sets were available from 92 subjects, a large cohort for a study of this nature. The output error (OE) model was empirically identified as the most appropriate model structure. A generalized model was developed using a pre-specified derivation cohort and then applied to a validation data set to estimate the recognized features of the cBP waveform. While our results showed that many relevant BP parameters could be derived within acceptable limits, the estimated augmentation index (AI) displayed only a weak correlation compared to the invasively measured value, indicating that any clinical diagnosis or interpretation based on estimated AI should be undertaken with caution.
Assuntos
Aorta/fisiologia , Determinação da Pressão Arterial/métodos , Pressão Sanguínea/fisiologia , Processamento de Sinais Assistido por Computador , Feminino , Humanos , Masculino , Modelos EstatísticosRESUMO
Mass Spectrometry (MS) is a widely used technique in molecular biology for high throughput identification and sequencing of peptides (and proteins). Tandem mass spectrometry (MS/MS) is a specialised mass spectrometry technique whereby the sequence of peptides can be determined. Preprocessing of the MS/MS data is indispensable before performing any statistical analysis on the data. In this work, preprocessing of MS/MS data is proposed based on the Dual Tree Complex Wavelet Transform (DTCWT) using almost symmetric Hilbert pair of wavelets. After the preprocessing step, the identification of peptides is done using the database search approach. The performance of the proposed preprocessing technique is evaluated by comparing its performance against Discrete Wavelet Transform (DWT) and Stationary Wavelet Transform (SWT). The preprocessing performed using DTCWT identified more peptides compared to DWT and SWT.
Assuntos
Bases de Dados de Proteínas , Espectrometria de Massas/métodos , Modelos Químicos , Proteínas de Neoplasias , Neoplasias , Peptídeos , Humanos , Proteínas de Neoplasias/análise , Proteínas de Neoplasias/metabolismo , Neoplasias/química , Neoplasias/metabolismo , Peptídeos/análise , Peptídeos/metabolismoRESUMO
Neurovascular niches serve as the hosts for adult neural stem cells in both the hippocampus and subventricular zone. The rostral migratory stream (RMS) vasculature has been found to be important for neuroblast migration, while its roles in hosting putative neural stem cells have not been investigated. Here we investigated the organization of RMS vasculature and its contribution to the production of new neurons. A single pulse of bromodeoxyuridine (BrdU) administration revealed locally formed new neurons within RMS were located adjacent to blood vessels. In addition, BrdU label-retaining cells that are putative neural stem cells were also found close to the vasculature. Sodium fluorescein perfusion assay demonstrated that the blood-brain barrier (BBB) organization was especially "leaky" in the neurogenic niches. Immunohistochemical visualization of some BBB component molecules indicated a thinner BBB in the RMS region, compared to that in the frontal cortex of adult rats. Finally, the expression of vascular endothelial growth factor was strong and specialized in the RMS region, implying that the region was active in cell proliferation and migration. Here we show that the RMS vasculature associated with surrounding astrocytes provides a highly organized neurovascular niche for adult neural stem cell proliferation, in addition to the function of neuroblast migration support. This result points to a new vasculature supporting neurogenic region in the brain.
Assuntos
Astrócitos/fisiologia , Vasos Sanguíneos/citologia , Células-Tronco Neurais/citologia , Neurônios/fisiologia , Animais , Vasos Sanguíneos/efeitos dos fármacos , Vasos Sanguíneos/metabolismo , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Bromodesoxiuridina/farmacologia , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Conexinas/metabolismo , Feminino , Gelatina/química , Imuno-Histoquímica , Masculino , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/metabolismo , Óxido Nítrico Sintase Tipo I/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Ratos , Ratos Sprague-Dawley , Nicho de Células-Tronco , Fator A de Crescimento do Endotélio Vascular/farmacologiaRESUMO
There is no effective treatment for intracerebral hemorrhage (ICH). Intracerebral delivery of nanomaterials into the hemorrhagic lesion may be a new therapeutic strategy. In a rat model of ICH plus ultra-early hematoma aspiration, we found that locally delivered self-assembling peptide nanofiber scaffold (SAPNS) replaced the hematoma, reduced acute brain injury and brain cavity formation, and improved sensorimotor functional recovery. SAPNS serves as biocompatible material in the hemorrhagic brain cavity. Local delivery of this nanomaterial may facilitate the repair of ICH related brain injury and functional recovery. From the clinical editor: In a rat model of intracranial hemorrhage, these authors demonstrate that following ultra-early hematoma aspiration, local delivery of a self-assembling peptide nanofiber scaffold replaces the hematoma, reduces brain cavity formation, and improves sensorimotor functional recovery. Similar approaches would be welcome additions to the clinical treatment of this often devastating condition.
Assuntos
Lesões Encefálicas/tratamento farmacológico , Hemorragias Intracranianas/tratamento farmacológico , Nanofibras/química , Peptídeos , Recuperação de Função Fisiológica/efeitos dos fármacos , Doença Aguda , Animais , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Modelos Animais de Doenças , Hemorragias Intracranianas/patologia , Hemorragias Intracranianas/fisiopatologia , Masculino , Peptídeos/química , Peptídeos/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
Andean potatoes are gaining popularity not only for their appealing colors and culinary uses but also for their potential higher content of polyphenolic compounds. The objective of this study was to identify potato varieties with increased phenolic content. This was achieved through characterization and quantitation of the phenolic composition in 20 varieties of native Andean potatoes from 4 different Solanum species with different colors. Major quantitative and qualitative differences among evaluated samples were more dependent on the coloration of the extracted sample rather than on the species. The most predominant anthocyanidins were petunidin-3-coumaroylrutinoside-5-glucoside and pelargonidin-3-coumaroylrutinoside-5-glucoside in purple and red potato extracts, respectively, while chlorogenic acid and its isomers were the main phenolic compund (43% of the total phenolic content). Our study suggested that the appropriate selection of native potatoes could provide new sources of polyphenolics with health promoting properties and natural pigments with increased stability for food applications.
Assuntos
Antocianinas/química , Fenóis/química , Extratos Vegetais/química , Tubérculos/química , Solanum tuberosum/química , Antioxidantes/química , Cor , Peru , Tubérculos/classificação , Solanum tuberosum/classificaçãoRESUMO
Sweet potato (Ipomoea batatas (L.) Lam., Convolvulaceae) counts among the most widely cultivated staple crops worldwide, yet the origins of its domestication remain unclear. This hexaploid species could have had either an autopolyploid origin, from the diploid I. trifida, or an allopolyploid origin, involving genomes of I. trifida and I. triloba. We generated molecular genetic data for a broad sample of cultivated sweet potatoes and its diploid and polyploid wild relatives, for noncoding chloroplast and nuclear ITS sequences, and nuclear SSRs. Our data did not support an allopolyploid origin for I. batatas, nor any contribution of I. triloba in the genome of domesticated sweet potato. I. trifida and I. batatas are closely related although they do not share haplotypes. Our data support an autopolyploid origin of sweet potato from the ancestor it shares with I. trifida, which might be similar to currently observed tetraploid wild Ipomoea accessions. Two I. batatas chloroplast lineages were identified. They show more divergence with each other than either does with I. trifida. We thus propose that cultivated I. batatas have multiple origins, and evolved from at least two distinct autopolyploidization events in polymorphic wild populations of a single progenitor species. Secondary contact between sweet potatoes domesticated in Central America and in South America, from differentiated wild I. batatas populations, would have led to the introgression of chloroplast haplotypes of each lineage into nuclear backgrounds of the other, and to a reduced divergence between nuclear gene pools as compared with chloroplast haplotypes.
Assuntos
Genes de Plantas , Ipomoea batatas/genética , Sequência de Bases , Cloroplastos/genética , Colômbia , Produtos Agrícolas/genética , DNA de Plantas/genética , DNA Espaçador Ribossômico/genética , Equador , Evolução Molecular , Especiação Genética , Variação Genética , Genoma de Planta , Guatemala , Haplótipos , México , Repetições de Microssatélites , Tipagem de Sequências Multilocus , Filogenia , Filogeografia , Folhas de Planta/genética , PoliploidiaRESUMO
It is a well-known fact that (compact-support) dyadic wavelets [based on the two channel filter banks (FBs)] cannot be simultaneously orthogonal and symmetric. Although orthogonal wavelets have the energy preservation property, biorthogonal wavelets are preferred in image processing applications because of their symmetric property. In this paper, a novel method is presented for the design of almost symmetric orthogonal wavelet FB. Orthogonality is structurally imposed by using the unnormalized lattice structure, and this leads to an objective function, which is relatively simple to optimize. The designed filters have good frequency response, flat group delay, almost symmetric filter coefficients, and symmetric wavelet function.
Assuntos
Algoritmos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Processamento de Sinais Assistido por Computador , Análise de Ondaletas , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The different morphological stages of microglial activation have not yet been described in detail. We transected the olfactory bulb of rats and examined the activation of the microglial system histologically. Six stages of bidirectional microglial activation (A) and deactivation (R) were observed: from stage 1A to 6A, the cell body size increased, the cell process number decreased, and the cell processes retracted and thickened, orienting toward the direction of the injury site; until stage 6A, when all processes disappeared. In contrast, in deactivation stages 6R to 1R, the microglia returned to the original site exhibiting a stepwise retransformation to the original morphology. Thin highly branched processes re-formed in stage 1R, similar to those in stage 1A. This reverse transformation mirrored the forward transformation except in stages 6R to 1R: cells showed multiple nuclei which were slowly absorbed. Our findings support a morphologically defined stepwise activation and deactivation of microglia cells.
Assuntos
Polaridade Celular , Forma Celular , Microglia/citologia , Modelos Biológicos , Animais , Contagem de Células , Imuno-Histoquímica , Bulbo Olfatório/citologia , Ratos , Ratos Sprague-DawleyRESUMO
Morchella esculenta Pers. (Morchellaceae) was investigated for its antioxidant activity by measuring the intracellular reactive oxygen species in HT-29 colon cancer cells. The methylene chloride extract, which showed the highest antioxidant activity, led to the isolation of four fungal sterols, 1-4, and trilinolein (5), in addition to methyl myristate (6), 1-linoleoylglycerol (7), and ceramide (8). The isolated compounds were identified through the analysis of various spectroscopic methods. In the hydroxyl radical assay, 5-dihydroergosterol exhibited significant antioxidant activity. All compounds isolated were also tested using an enzyme-based Elisa NF-κB assay. Fungal sterols and trilinolein showed significant inhibition of NF-κB activation in the NF-κB assay.
Assuntos
Antioxidantes/farmacologia , Ascomicetos/química , NF-kappa B/antagonistas & inibidores , Cromatografia em Camada Fina , Ensaio de Imunoadsorção Enzimática , Células HT29 , Humanos , Espectroscopia de Ressonância Magnética , NF-kappa B/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Espectrofotometria UltravioletaRESUMO
The isolation of cells with stem-like properties from prostate tumors suggests the presence of a cancer stem cell (CSC) population, which may account for the initiation, progression, and metastasis as well as drug resistance of the disease. We hypothesized that containing, or at least immobilizing, the CSCs in a nano-self-assembling material might help prevent prostate tumor progression or metastasis. CSCs were plated in three conditions: 1) placed in 1% concentration self-assembled peptide (SAP) preequilibrate with culture medium; 2) placed in 3% concentration SAP preequilibrate with culture medium; and 3) in nonadherent culture. All were grown for 14 days, after which the cells in both 1% and 3% concentrations were washed out of the SAP and grown for an additional 14 days. Here we report that CSCs from prostate cancer cell lines remained quiescent for more than 28 days when embedded in SAP. When the prostate CSCs were embedded in 1% and 3% SAP, most of the CSCs remained single cells 14 days after plating in a nonadherent plate; no prostaspheres could be detected 14 days after plating, suggesting that self-renewal was significantly suppressed. In the controls, prostate CSCs began to divide 1 day after plating in a nonadherent plate and prostaspheres were visible at day 10, indicating the active self-renewal property of the prostate CSCs. Our findings suggest that SAP can completely inhibit a prostate CSC from self-renewal while preserving its viability and CSC property. Therefore, SAP may be an effective nanomaterial for inhibiting cancer progression and metastasis to stop the progression during treatment and removal.
Assuntos
Nanoestruturas/toxicidade , Células-Tronco Neoplásicas/efeitos dos fármacos , Peptídeos/toxicidade , Neoplasias da Próstata/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Masculino , Nanoestruturas/química , Metástase Neoplásica , Células-Tronco Neoplásicas/citologia , Neoplasias da Próstata/terapiaRESUMO
To speed up the process of central nervous system (CNS) recovery after injury, the need for real-time measurement of axon regeneration in vivo is essential to assess the extent of injury, as well as the optimal timing and delivery of therapeutics and rehabilitation. It was necessary to develop a chronic animal model with an in vivo measurement technique to provide a real-time monitoring and feedback system. Using the framework of the 4 P's of CNS regeneration (Preserve, Permit, Promote and Plasticity) as a guide, combined with noninvasive manganese-enhanced magnetic resonance imaging (MEMRI), we show a successful chronic injury model to measure CNS regeneration, combined with an in vivo measurement system to provide real-time feedback during every stage of the regeneration process. We also show that a chronic optic tract (OT) lesion is able to heal, and axons are able to regenerate, when treated with a self-assembling nanofiber peptide scaffold (SAPNS). FROM THE CLINICAL EDITOR: The authors of this study demonstrate the development of a chronic injury model to measure CNS regeneration, combined with an in vivo measurement system to provide real-time feedback during every stage of the regeneration process. In addition, they determined that chronic optic tract lesions are able to heal with axonal regeneration when treated with a self-assembling nanofiber peptide scaffold (SAPNS).
Assuntos
Sistema Nervoso Central/lesões , Sistema Nervoso Central/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Manganês , Nanofibras , Regeneração Nervosa/fisiologia , Medicina Regenerativa/métodos , Animais , Comportamento Animal , Doença Crônica , Meios de Contraste/administração & dosagem , Cricetinae , Nanofibras/química , Nervo Óptico/patologia , Nervo Óptico/cirurgia , Peptídeos/química , Projetos Piloto , Reprodutibilidade dos Testes , Fatores de Tempo , Vias Visuais/patologia , Vias Visuais/cirurgiaRESUMO
We aim to investigate ultrasound on enhancing protein penetration into the sclera, a non-invasive method to overcome the first barrier in taking the transscleral route for delivering therapeutics. Rabbit eyes were immersed in a fluorescein isothiocyanate conjugated bovine serum albumin solution. The distances of protein penetration, with and without ultrasound (30s continuous wave, 1MHz, 0.05W/cm(2)) applied on the sclera, and at different immersion time intervals (0, 5, 15, 30 and 60min), were measured by examining the cryo-sectioned tissues under fluorescence microscope (≥60 measurements from 3 eyes for each condition). Retina was examined for structural damage by histology. It was found that ultrasound enhances the intrascleral penetration of protein, increasing the diffusivity by 1.6-folds while causing no damage to the retinal tissues. This physical modulation of the sclera is temporary, as evident by the restoration of the diffusional resistance at 15min after ultrasound treatment. The negligible effect of ultrasound-induced convection and the minimal temperature rise (<0.5°C), together with cavitation detected by acoustic emission and a decreased penetration distance at higher ultrasound frequency (30s continuous wave, 3MHz, 0.05W/cm(2)), suggest that cavitation is a possible mechanism for increasing the permeability of the sclera for diffusive transport.
Assuntos
Proteínas/metabolismo , Esclera/metabolismo , Animais , Transporte Biológico , Bovinos , Difusão , Sistemas de Liberação de Medicamentos , Microscopia de Fluorescência , Permeabilidade , Fonoforese , Proteínas/administração & dosagem , Coelhos , Retina/metabolismo , Albumina Sérica/administração & dosagem , Albumina Sérica/metabolismo , TemperaturaRESUMO
Efficient selection of potato varieties with enhanced nutritional quality requires simple, rapid, accurate, and cost-effective assays to obtain tuber chemical composition information. Our objective was to develop simple protocols to determine phenolics, anthocyanins, and antioxidant capacity in polyphenolic extracts of potatoes using Fourier transform infrared spectroscopy combined with multivariate techniques. Lyophilized potato samples (23) were analyzed. Polyphenolic compounds were extracted from potatoes and applied directly applied onto a three-bounce ZnSe crystal for attenuated total reflectance measurements in the infrared region of 4000 to 700 cm (-1). Robust models were generated (r > or = 0.99) with standard error of cross-validation values of 4.17 mg gallic acid equivalent/100 g (total phenolics), 0.87 mg pelargonidin-3-glucoside/100 g (monomeric anthocyanins), and 130.8 mumol Trolox equivalent/100 g (antioxidant capacity) potato powder. In addition, classification models discriminated potato samples at the species and variety level. Application of a simple infrared spectroscopic protocol allowed simultaneous rapid quantification of specific nutritional components in potatoes and efficient selection of value-added potato varieties.
Assuntos
Cruzamento , Flavonoides/análise , Fenóis/análise , Solanum tuberosum/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Antocianinas/análise , Antioxidantes/análise , Tubérculos/química , Tubérculos/genética , Polifenóis , Solanum tuberosum/genéticaRESUMO
The inhibitory activities of the extracts of Cantharellus cibarius and isolated compounds were investigated in an enzyme-based ELISA NF-kappaB assay. Of the tested compounds, ergosterol, ergosterol peroxide and cerevisterol were noted to have the most potent inhibition of NF-kappaB activation. The ability of the active metabolites to inhibit the NF-kappaB translocation from the cytoplasm to the nucleus was assessed using a cell-based NF-kappaB assay. The isolated compounds were elucidated through the analysis of various spectroscopic methods.
Assuntos
Basidiomycota/química , Células HeLa/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , Extratos Vegetais/farmacologia , Ergosterol/análogos & derivados , Ergosterol/isolamento & purificação , Ergosterol/farmacologia , Técnica Indireta de Fluorescência para Anticorpo , Células HeLa/metabolismo , Células HeLa/patologia , Humanos , NF-kappa B/metabolismo , Fitosteróis/isolamento & purificação , Fitosteróis/farmacologia , Extratos Vegetais/químicaRESUMO
In the present study, we studied the factors that contribute to the injury-resistant property of melanopsin-expressing retinal ganglion cells (mRGCs). Since phosphatidylinositol-3 kinase (PI3 K)/Akt signaling pathway is one of the well-known pathways for neuronal cell survival, we investigated the survival of mRGCs by applying the PI3 K/Akt specific inhibitors after injury. Two injury models, unilateral optic nerve transection and ocular hypertension, were adopted using Sprague-Dawley rats. Inhibitors of PI3 K/Akt were injected intravitreally following injuries to inhibit the PI3 K/Akt signaling pathway. Retinas were dissected after designated survival time, immunohistochemistry was carried out to visualize the mRGCs using melanopsin antibody and the number of mRGCs was counted. Co-expression of melanopsin and phospho-Akt (pAkt) was also examined. Compared to the survival of non-melanopsin-expressing RGCs, mRGCs showed a marked resistance to injury and co-expressed pAkt. Application of PI3 K/Akt inhibitors decreased the survival of mRGCs after injury. Our previous study has shown that mRGC are less susceptible to injury following the induction of ocular hypertension. In this study, we report that mRGCs were injury-resistant to a more severe type of injury, the optic nerve transection. More importantly, the PI3 K/Akt pathway was found to play a role in maintaining the survival of mRGCs after injury.
Assuntos
Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células Ganglionares da Retina/enzimologia , Células Ganglionares da Retina/patologia , Opsinas de Bastonetes/metabolismo , Animais , Axotomia , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Injeções , Traumatismos do Nervo Óptico , Inibidores de Fosfoinositídeo-3 Quinase , Fosfoproteínas/metabolismo , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Ratos , Ratos Sprague-Dawley , Células Ganglionares da Retina/efeitos dos fármacos , Colículos Superiores/efeitos dos fármacos , Colículos Superiores/enzimologia , Colículos Superiores/patologiaRESUMO
OBJECTIVE: Arterial transfer functions (TFs) describe the relationship between the pressure waveform at different arterial sites. Generalized TFs are used to reconstruct central aortic waveforms from non-invasively obtained peripheral waveforms and have been promoted as potentially clinically useful. A limitation is the paucity of information on their 'generalizability' with no information existing on the number of subjects required to construct a satisfactory TF, nor is adequate prospective validation available. We therefore investigated the uniformity of radial-aortic TFs and prospectively estimated the capacity of a generalized TF to reconstruct individual central blood pressure parameters. PATIENTS AND METHODS: Ninety-three subjects (64 male) were studied by simultaneous radial applanation and high-fidelity (Millar Mikro-tip catheter) direct measurement of central aortic BP during elective coronary procedures. Subjects were prospectively randomized to either a derivation or validation group. RESULTS: Increasing numbers of individual TFs from the derivation group were averaged to form a generalized TF. There was minimal change with greater than 20 TFs averaged. In the validation group, the error in most reconstructed parameters related to the absolute value of the directly measured parameter [systolic blood pressure (SBP) and pulse pressure, P<0.05; systolic pressure-time interval, subendocardial viability index, augmentation index, and times to the inflection point, peak and end systole, all P<0.01]. Aorto-radial delay was related to error in reconstructed central aortic SBP and pulse pressure (negatively) and time to peak systole (positively) (all P<0.001). Reconstruction of augmentation index was poor. DISCUSSION: Inclusion of more than 20 individual TFs in the construction of a generalized TF does not improve 'generalizability'. There appear to be systematic errors in derived central pressure waveforms and derived aortic augmentation index is inaccurate compared to the directly measured value.
Assuntos
Aorta/fisiologia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
The majority of retinal ganglion cells innervating the suprachiasmatic nucleus are intrinsically light sensitive, while the rest are conventional ganglion cells that collect inputs through conventional photoreceptors. Here we report a rarely encountered ganglion cell that had a dendritic field covering approximately 14.4% of retinal surface and its processes ramified in both the inner and the outer plexiform layers. This cell could have a potential role in detecting luminance changes over a large area of retinal surface.
Assuntos
Dendritos/fisiologia , Células Ganglionares da Retina/citologia , Células Ganglionares da Retina/fisiologia , Núcleo Supraquiasmático/citologia , Animais , Biotina/análogos & derivados , Biotina/metabolismo , Contagem de Células/métodos , Cricetinae , Dextranos/metabolismo , Imuno-Histoquímica/métodos , Masculino , Mesocricetus , Núcleo Supraquiasmático/metabolismoRESUMO
BACKGROUND: Electroretinography (ERG) provides a longitudinal monitoring of pathological changes in retina. Scotopic threshold response (STR) of ERG was shown to reflect inner retinal activity and is particularly useful in the evaluation of inner retinal changes in ocular hypertension models. Recently, STR was demonstrated to be attenuated after the induction of ocular hypertension using injection of hypertonic saline into episcleral veins which indicates an impairment of retinal function. However, little is known on the changes of retinal function in an ocular hypertension model induced by laser photocoagulation at episcleral veins and limbal veins. METHODS: Ocular hypertension was induced unilaterally using laser photocoagulation at episcleral veins and limbal veins in adult Sprague-Dawley rats. Intraocular pressure was monitored and the number of retinal ganglion cell loss was counted across the 8-week experimental period. The animals were dark adapted overnight and flash ERGs were measured before the laser treatment, 5 and 8 weeks after treatment. The changes of STR, scotopic negative response, a-wave and b-wave were analysed. RESULTS: Approximately 1.6-fold elevation of intraocular pressure was induced in the experimental eyes and 3% retinal ganglion cell loss per week was found. The amplitude of STR was significantly attenuated which indicates an impairment of inner retinal activities. There was also a reduction of scotopic negative response, a-wave and b-wave after the induction of ocular hypertension. CONCLUSION: The laser-induced ocular hypertension model in the present study produced a substantial reduction of retinal functions. Understanding the characteristic of pathological changes is crucial for further study using this model.
Assuntos
Modelos Animais de Doenças , Hipertensão Ocular/fisiopatologia , Retina/fisiopatologia , Animais , Contagem de Células , Adaptação à Escuridão , Feminino , Pressão Intraocular , Fotocoagulação a Laser/efeitos adversos , Hipertensão Ocular/etiologia , Estimulação Luminosa , Ratos , Ratos Sprague-Dawley , Células Ganglionares da Retina/patologiaRESUMO
During development, ephrin gradients guide retinal ganglion cell axons to their appropriate topographic locations in the superior colliculus (SC). Expression of ephrin-A2, assessed immunohistochemically in the developing hamster SC, revealed a rostral(low) to caudal (high) gradient that is most prominent at postnatal days P4 and P7 when topography is established. Double-labelling immunohistochemistry for ephrin-A2 and cell specific markers revealed that ephrin-A2 is expressed exclusively by a subset of neurons. The expression pattern has implications for mechanisms underlying establishment of topography during development and following injury.