Long duration stabilization of porous silicon membranes in physiological media: Application for implantable reactors.

The natural biodegradabilty of porous silicon (pSi) in physiological media limits its wider usage for implantable systems. We report the stabilization of porous silicon (pSi) membranes by chemical surface oxidation using RCA1 and RCA2 protocols, which was followed by a PEGylation process using a silane-PEG. These surface modifications stabilized the pSi to allow a long period of immersion in PBS, while leaving the pSi surface sufficiently hydrophilic for good filtration and diffusion of several biomolecules of different sizes without any blockage of the pSi structure.

Impact of Surface Chemistry on Copper Deposition in Mesoporous Silicon.

An easy, efficient, and safe process is developed to metallize mesoporous silicon (PSi) with Cu from the decomposition of a solution of mesitylcopper (CuMes) in an imidazolium-based ionic liquid (IL), [C1C4Im][NTf2]. The impregnation of a solution of CuMes in IL affords the deposition of metallic islands not only on the surface but also deep within the pores of a mesoporous Si layer with small pores below 10 nm. Therefore, this process is well suited to efficiently and completely metallize PSi layers.

An Efficient, Versatile, and Safe Access to Supported Metallic Nanoparticles on Porous Silicon with Ionic Liquids.

The metallization of porous silicon (PSi) is generally realized through physical vapor deposition (PVD) or electrochemical processes using aqueous solutions. The former uses a strong vacuum and does not allow for a conformal deposition into the pores. In the latter, the water used as solvent causes oxidation of the silicon during the reduction of the salt precursors.

Loss of AP-2delta reduces retinal ganglion cell numbers and axonal projections to the superior colliculus.

Background: AP-2δ is the most divergent member of the Activating Protein-2 (TFAP2) family of transcription factors. AP-2δ is restricted to specific regions of the CNS, including a subset of ganglion cells in the retina. Retinal ganglion cells (RGCs), the only output neurons of the retina, are responsible for transmitting the visual signal to the brain.

Retinal distribution of Disabled-1 in a diurnal murine rodent, the Nile grass rat Arvicanthis niloticus.

We sought to study the expression pattern of Disabled-1 (Dab1; an adaptor protein in the reelin pathway) in the cone-rich retina of a diurnal murine rodent. Expression was examined by western blotting and immunohistochemistry using well-established antibodies against Dab1 and various markers of retinal neurons. Western blots revealed the presence of Dab1 (80 kDa) in brain and retina of the Nile grass rat.

Long-term retinal cone survival and delayed alteration of the cone mosaic in a transgenic mouse model of stargardt-like dystrophy (STGD3).

Purpose: To examine the pattern of cone degeneration in the retina of a transgenic mouse model of Stargartd-like dystrophy (STGD3).

Methods: Investigations were performed on ELOVL4/TG1-2 transgenic (TG) mice and wild-type (WT) littermates from 1 to 24 months of age. Phenotypes were assessed by fundus imaging, fatty acid analysis, and electroretinogram (ERG) recording.

Retinorecipient areas in the diurnal murine rodent Arvicanthis niloticus: A disproportionally large superior colliculus.

The Nile grass rat (Arvicanthis niloticus) has a high proportion of cone photoreceptors (∼30-40%) compared with that in the common laboratory mouse and rat (∼1-3%) and may prove a preferable murine model with which to study cone-driven information processing in retina and primary visual centers. However, other than regions involved in circadian control, little is known about the retinorecipient structures in this rodent. We undertook a detailed analysis of the retinal projections as revealed after intravitreal injection of the anterograde tracer cholera toxin subunit B.

Retinorecipient areas in the diurnal murine rodent Arvicanthis niloticus: a disproportionally large superior colliculus.

The Nile grass rat (Arvicanthis niloticus) has a high proportion of cone photoreceptors (∼30-40%) compared with that in the common laboratory mouse and rat (∼1-3%) and may prove a preferable murine model with which to study cone-driven information processing in retina and primary visual centers. However, other than regions involved in circadian control, little is known about the retinorecipient structures in this rodent. We undertook a detailed analysis of the retinal projections as revealed after intravitreal injection of the anterograde tracer cholera toxin subunit B.

Dietary docosahexaenoic acid supplementation prevents age-related functional losses and A2E accumulation in the retina.

Purpose: With age, retina function progressively declines and A2E, a constituent of the toxin lipofuscin, accumulates in retinal pigment epithelial (RPE) cells. Both events are typically exacerbated in age-related retina diseases. We studied the effect of dietary docosahexaenoic acid (DHA, C22:6n-3) supplementation on these events, using a transgenic mouse model (mutant human ELOVL4; E4) displaying extensive age-related retina dysfunction and massive A2E accumulation.

Differential gene expression in eyecup and retina of a mouse model of Stargardt-like macular dystrophy (STGD3).

Purpose: To investigate differentially expressed genes in eyecup and retina of the ELOVL4 transgenic mouse, a model of Stargardt-like macular dystrophy (STGD3).

Methods: We examined gene and protein expression in known pathways relevant to retinal degeneration using PCR arrays, Western blotting, and immunohistochemistry. Investigations were performed on ELOVL4 transgenic mice at 9 months, when 50% of rod (but no cone) photoreceptors had degenerated.

Case-based lung image categorization and retrieval for interstitial lung diseases: clinical workflows.

Purpose: Clinical workflows and user interfaces of image-based computer-aided diagnosis (CAD) for interstitial lung diseases in high-resolution computed tomography are introduced and discussed.

Methods: Three use cases are implemented to assist students, radiologists, and physicians in the diagnosis workup of interstitial lung diseases.

Results: In a first step, the proposed system shows a three-dimensional map of categorized lung tissue patterns with quantification of the diseases based on texture analysis of the lung parenchyma.

Differential changes in retina function with normal aging in humans.

We evaluated the full field electroretinogram (ERG) to assess age-related changes in retina function in humans. ERG recordings were performed on healthy subjects with normal fundus appearance, lack of cataract and 20/20 acuity, aged 20-39 years (n = 27; mean age 25 ± 5, standard deviation), 40-59 years (n = 20; mean 53 ± 5), and 60-82 years (n = 18; mean 69 ± 5). Multiple ERG tests were applied, including light and dark-adapted stimulus-response function, dark adaptation and dynamic of recovery from a single bright flash under dark-adapted conditions.

Inner retina remodeling in a mouse model of stargardt-like macular dystrophy (STGD3).

Purpose. To investigate the impact of progressive age-related photoreceptor degeneration on retinal integrity in Stargardt-like macular dystrophy (STGD3). Methods.

Topographic arrangement of S-cone photoreceptors in the retina of the diurnal Nile grass rat (Arvicanthis niloticus).

Purpose: The retina of Arvicanthis niloticus, a diurnal murine rodent closely related to Rattus (rats) and Mus (mice), contains approximately 30% to 35% cones and has several cone-driven functional characteristics found in humans. In this study the organization of these cone photoreceptors was examined, with emphasis on those expressing the S-opsin photopigment (S-cones).

Methods: Cones were labeled with antibodies against M- and S-opsins.

Fetal tissue allografts in the damaged adult visual cortex: physiology and connectivity.

During the past three decades, many studies have examined the capacity of embryonic neural grafts (dissociated cells or tissue blocks) to restore lost functions following various damages to the adult mammalian brain. Only very few focused on the visual system even if it is the optimal system to examine the potential of embryonic neural grafts in repairing point-to-point networks. Collectively, these studies show that, within limits, homologous sheets of fetal tissue grafted in the occipital cortex of adult rodents integrate into the host visual circuitry and are physiologically active.

The electroretinogram (ERG) of a diurnal cone-rich laboratory rodent, the Nile grass rat (Arvicanthis niloticus).

The most widespread models to study blindness, rats and mice, have retinas containing less than 3% cones. The diurnal rodent Arvicanthis niloticus retina has around 35% cones. Using ERG recordings, we studied retina function in this species.

Retinal anatomy and visual performance in a diurnal cone-rich laboratory rodent, the Nile grass rat (Arvicanthis niloticus).

Unlike laboratory rats and mice, muridae of the Arvicanthis family (A. ansorgei and A. niloticus) are adapted to functioning best in daylight.

Heterotopic, not homotopic, fetal occipital allografts in adult hosts project to visual-related extracortical targets.

Purpose: Fetal occipital allografts implanted into the posterior cortex of adult mice project massively throughout the ipsilateral pallium of the host, but rarely outside this domain (Gaillard et al., 2004). The present study was undertaken to examine in detail whether this pattern is specific to graft location.

Cell-based therapy for retina degeneration: the promise of a cure.

Cell-based therapies in the retina have been associated with the recovery of visual function in animal models of retinal degeneration. This review covers the current status of such therapies with regard to the source of the donor cells, their integration, and their impact on the degenerating host retina. Emphasis is also put on the importance of a careful interpretation of what is meant by "recovery of visual function".

Glucose-targeted niosomes deliver vasoactive intestinal peptide (VIP) to the brain.

The aim of this study was to evaluate glucose-bearing niosomes as a brain targeted delivery system for the vasoactive intestinal peptide (VIP). To this end, VIP/125I-VIP-loaded glucose-bearing niosomes were intravenously injected to mice. Brain uptake was determined by measuring the radioactivity of 125I-labeled VIP using gamma-counting, after intravenous administration of VIP in solution or encapsulated in glucose-bearing niosomes or in control niosomes.

Axonal regrowth of layer II-III visual-projecting cortical neurons in rats fails beyond eye opening.

Fetal neurons (embryonic age E16) of occipital origin grafted in the visual cortex of albino rats at increasing postnatal stages (P0, P7, P15, P30, P60, P120) can be activated by photic stimulation. Inputs originate from five major areas of the brain ipsilateral to the graft, namely, the claustrum, the periallocortex/proisocortex, the isocortex, the visual thalamus, and some unspecific subthalamic and hypothalamic nuclei. All inputs decrease in number with the age at which grafting was performed.

Brain delivery of vasoactive intestinal peptide (VIP) following nasal administration to rats.

The aim of this work was to study in rats the nasal route for the brain delivery of the vasoactive intestinal peptide (VIP) neuropeptide. After evaluating VIP stability in solutions obtained from nasal washes, the effect of formulation parameters (pH 4-9, 0-1% (w/v) lauroylcarnitine (LC), hypo- or isoosmolality) on the brain uptake of intranasally administered VIP (10(-8)M)/125I-VIP (300,000 cpm/ml) was studied, using an in situ perfusion technique. Brain radioactivity distribution was assessed by quantitative autoradiographic analysis.

Afferents to Visually Responsive Grafts of Embryonic Occipital Neocortex Tissue Implanted into V1 (Oc1) Cortical Area of Adult Rats.

The aim of this study is to determine, as precisely as possible, the topography and the density of host afferents to visually responsive grafts of occipital embryonic cells implanted in block form into the occipital neocortex of adult rats. The presence of visual activity in the grafts was assessed through field potential and single unit electrophysiological recordings. Field potentials appeared triphasic in shape, had low peak-to-peak amplitude (= 100 micro V), and had normal time latencies (˜ 30 msec).