Influence of melatonin on the development of functional nicotinic acetylcholine receptors in cultured chick retinal cells

The influence of melatonin on the developmental pattern of functional nicotinic acetylcholine receptors was investigated in embryonic 8-day-old chick retinal cells in culture. The functional response to acetylcholine was measured in cultured retina cells by microphysiometry. The maximal functional response to acetylcholine increased 2.7 times between the 4th and 5th day in vitro (DIV4, DIV5), while the Bmax value for 125I-a-bungarotoxin was reduced. Despite the presence of a8-like immunoreactivity at DIV4, functional responses mediated by a-bungarotoxin-sensitive nicotinic acetylcholine receptors were observed only at DIV5. Mecamylamine (100 µM) was essentially without effect at DIV4 and DIV5, while dihydro-ß-erythroidine (10-100 µM) blocked the response to acetylcholine (3.0 nM-2.0 µM) only at DIV4, with no effect at DIV5. Inhibition of melatonin receptors with the antagonist luzindole, or melatonin synthesis by stimulation of D4 dopamine receptors blocked the appearance of the a-bungarotoxin-sensitive response at DIV5. Therefore, a-bungarotoxin-sensitive receptors were expressed in retinal cells as early as at DIV4, but they reacted to acetylcholine only after DIV5. The development of an a-bungarotoxin-sensitive response is dependent on the production of melatonin by the retinal culture. Melatonin, which is produced in a tonic manner by this culture, and is a key hormone in the temporal organization of vertebrates, also potentiates responses mediated by a-bungarotoxin-sensitive receptors in rat vas deferens and cerebellum. This common pattern of action on different cell models that express a-bungarotoxin-sensitive receptors probably reflects a more general mechanism of regulation of these receptors.

Dendritic thickness: a morphometric parameter to classify mouse retinal ganglion cells

To study the dendritic morphology of retinal ganglion cells in wild-type mice we intracellularly injected these cells with Lucifer yellow in an in vitro preparation of the retina. Subsequently, quantified values of dendritic thickness, number of branching points and level of stratification of 73 Lucifer yellow-filled ganglion cells were analyzed by statistical methods, resulting in a classification into 9 groups. The variables dendritic thickness, number of branching points per cell and level of stratification were independent of each other. Number of branching points and level of stratification were independent of eccentricity, whereas dendritic thickness was positively dependent (r = 0.37) on it. The frequency distribution of dendritic thickness tended to be multimodal, indicating the presence of at least two cell populations composed of neurons with dendritic diameters either smaller or larger than 1.8 µm ("thin" or "thick" dendrites, respectively). Three cells (4.5%) were bistratified, having thick dendrites, and the others (95.5%) were monostratified. Using k-means cluster analysis, monostratified cells with either thin or thick dendrites were further subdivided according to level of stratification and number of branching points: cells with thin dendrites were divided into 2 groups with outer stratification (0-40%) and 2 groups with inner (50-100%) stratification, whereas cells with thick dendrites were divided into one group with outer and 3 groups with inner stratification. We postulate, that one group of cells with thin dendrites resembles cat ß-cells, whereas one group of cells with thick dendrites includes cells that resemble cat a-cells.

Scale morphology of Prochilodus lineatus with emphasis on the scale epithelium

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sildenafil citrate on retrobulbar and retinal circulation of rabbits

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of neem oil (Azadirachta indica A. Juss) on the replacement of the midgut epithelium in the lacewing Ceraeochrysa claveri during larval-pupal metamorphosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

THE RETINAL TARGETS OF CENTRIFUGAL NEURONS AND THE RETINAL NEURONS PROJECTING TO THE ACCESSORY OPTIC-SYSTEM

In birds, neurons of the isthmo-optic nucleus (ION), as well as ''ectopic'' neurons, send axons to the retina, where they synapse on cells in the inner nuclear layer (INL). Previous work has shown that centrifugal axons can be divided into two anatomically distinct types depending on their mode of termination: either ''convergent'' or ''divergent'' (Ramon y Cajal, 1889; Maturana and Frenk, 1965). We show that cytochrome-oxidase histochemistry specifically labels ''convergent'' centrifugal axons and target neurons which appear to be amacrine cells, as well as three ''types'' of ganglion cells: two types found in the INL (displaced ganglion cells) and one in the ganglion cell layer. Labeled target amacrine cells have distinct darkly labeled ''nests'' of boutons enveloping the somas, are associated with labeled centrifugal fibers, and are confined to central retina. Lesions of the isthmo-optic tract abolish the cytochrome-oxidase labeling in the centrifugal axons and in the target amacrine cells but not in the ganglion cells. Cytochromeoxidase-labeled ganglion cells in the INL are large; one type is oval and similar to the classical displaced ganglion cells of Dogiel, which have been reported to receive centrifugal input; the other type is rounder. Rhodamine beads injected into the accessory optic system results in retrograde label in both types of cells, showing that two distinct types of displaced ganglion cells project to the accessory optic system in chickens. The ganglion cells in the ganglion cell layer that label for cytochrome oxidase also project to the accessory optic system. These have proximal dendrites that ramify in the outer inner plexiform layer. Neither the target amacrine cells nor either of the displaced ganglion cells are immunoreactive for the inhibitory transmitter gamma aminobutyric acid. At least some of the target amacrine cells may, however, be cholinoceptive: we found that the antibody to the alpha-7 subunit of the nicotinic ACh receptor labels a population of cells in the INL that are similar in location, size, and the presence of labeled bouton-like structures to those we find labeled with cytochrome oxidase. This antibody also labels neurons in the ION proper but not ectopic cells. In conclusion, it appears that cytochrome oxidase may be a marker for ''convergent'' centrifugal axons and at least one of their target cells in the INL.

Bioavailability of plant pigment phytochemicals in Angelica keiskei in older adults: A pilot absorption kinetic study

BACKGROUND/OBJECTIVES: Angelica keiskei is a green leafy vegetable rich in plant pigment phytochemicals such as flavonoids and carotenoids. This study examined bioavailability of flavonoids and carotenoids in Angelica keiskei and the alteration of the antioxidant performance in vivo.SUBJECTS AND MATERIALS: Absorption kinetics of phytochemicals in Angelica keiskei were determined in healthy older adults (>60 y, n = 5) and subjects with metabolic syndrome (n = 5). Subjects consumed 5 g dry Angelica keiskei powder encapsulated in gelatin capsules with a low flavonoid and carotenoid liquid meal. Plasma samples were collected at baseline, 0.5, 1, 2, 3, 4, 5, 6, 7, and 8 h. Samples were analyzed for flavonoids and carotenoids using HPLC systems with electrochemical and UV detection, respectively, and for total antioxidant performance by fluorometry.RESULTS: After ingestion of Angelica keiskei increases in plasma quercetin concentrations were observed at 1-3 and 6-8 hr in the healthy group and at all time points in the metabolic syndrome group compared to baseline (P < 0.05). Plasma lutein concentrations were significantly elevated in both the healthy and metabolic syndrome groups at 8 hr (P < 0.05). Significant increases in total antioxidant performance were also observed in both the healthy and the metabolic syndrome groups compared to baseline (P < 0.05).CONCLUSIONS: Findings of this study clearly demonstrate the bioavailability of phytonutrients of Angelica keiskei and their ability to increase antioxidant status in humans.

Segmentation of Cell Nuclei Regions in Epithelium of Prostate Glands

This paper proposes a method for segmentation of cell nuclei regions in epithelium of prostate glands. This structure provides information to diagnosis and prognosis of prostate cancer. In the initial step, the contrast stretching technique was applied in image in order to improve the contrast between regions of interest and other regions. After, the global thresholding technique was applied and the value of threshold was defined empirically. Finally, the false positive regions were removed using the connected components technique. The performance of the proposed method was compared with the Otsu technique and statistical measures of accuracy were calculated based on reference images (gold standard). The result of the mean value of accuracy of proposed method was 93% ± 0.07.

Development of a Yellow Pigment Based on Bismuth and Molybdenum-Doped TiO2 for Coloring Polymers

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dendrimer nanocarriers for transport modulation across models of the pulmonary epithelium

The purpose of this study was to determine the effect of PEGylation on the interaction of poly(amidoamine) (PAMAM) dendrimer nanocarriers (DNCs) with in vitro and in vivo models of the pulmonary epithelium. Generation-3 PAMAM dendrimers with varying surface densities of PEG 1000 Da were synthesized and characterized. The results revealed that the apical to basolateral transport of DNCs across polarized Calu-3 monolayers increases with an increase in PEG surface density. DNC having the greatest number of PEG groups (n = 25) on their surface traversed at a rate 10-fold greater than its non-PEGylated counterpart, in spite of their larger size. This behavior was attributed to a significant reduction in charge density upon PEGylation. We also observed that PEGylation can be used to modulate cellular internalization. The total uptake of PEG-free DNC into polarized Calu-3 monolayers was 12% (w/w) vs 2% (w/w) for that with 25 PEGs. Polarization is also shown to be of great relevance in studying this in vitro model of the lung epithelium. The rate of absorption of DNCs administered to mice lungs increased dramatically when conjugated with 25 PEG groups, thus supporting the in vitro results. The exposure obtained for the DNC with 25PEG was determined to be very high, with peak plasma concentrations reaching 5 mu gmL(-1) within 3 h. The combined in vitro and in vivo results shown here demonstrate that PEGylation can be potentially used to modulate the internalization and transport of DNCs across the pulmonary epithelium. Modified dendrimers thereby may serve as a valuable platform that can be tailored to target the lung tissue for treating local diseases, or the circulation, using the lung as pathway to the bloodstream, for systemic delivery.

Effects of biodegradable detergents in the accumulation of lipofuscin (age pigment) in gill and liver of two neotropical fish species

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cone photopigment variations in Cebus apella monkeys evidenced by electroretinogram measurements and genetic analysis

We investigated the color vision pattern in Cebus apella monkeys by means of electroretinogram measurements (ERG) and genetic analysis. Based on ERG we could discriminate among three types of dichromatic males. Among females, this classification is more complex and requires additional genetic analysis. We found five among 10 possible different phenotypes, two trichromats and three dichromats. We also found that Cebus present a new allele with spectral peak near 552 nm, with the amino acid combination SFT at positions 180, 277 and 285 of the opsin gene, in addition to the previously described SYT, AFT and AFA alleles. (C) 2009 Elsevier Ltd. All rights reserved.

Thyroid hormone action is required for normal cone opsin expression during mouse retinal development

PURPOSE. The expression of S- and M-opsins in the murine retina is altered in different transgenic mouse models with mutations in the thyroid hormone receptor (TR)-beta gene, demonstrating an important role of thyroid hormone (TH) in retinal development. METHODS. The spatial expression of S- and M-opsin was compared in congenital hypothyroidism and in two different TR mutant mouse models. One mouse model contains a ligand-binding mutation that abolishes TH binding and results in constitutive binding to nuclear corepressors. The second model contains a mutation that blocks binding of coactivators to the AF-2 domain without affecting TH binding. RESULTS. Hypothyroid newborn mice showed an increase in S- opsin expression that was completely independent of the genotype. Concerning M-opsin expression, hypothyroidism caused a significant decrease (P < 0.01) only in wild-type animals. When TR beta 1 and -beta 2 were T3-binding defective, the pattern of opsin expression was similar to TR beta ablation, showing increased S- opsin expression in the dorsal retina and no expression of M-opsin in the entire retina. In an unexpected finding, immunostaining for both opsins was detected when both subtypes of TR beta were mutated in the helix 12 AF-2 domain. CONCLUSIONS. The results show, for the first time, that the expression of S- and M-opsin is dependent on normal thyroid hormone levels during development.