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71.
Stanley A. Vinores Ellen Van Niel Jason L. Swerdloff Peter A. Campochiaro 《The Histochemical journal》1993,25(9):648-663
Summary Light-microscopic immunohistochemical staining for albumin has been used to localize sites of blood-retinal barrier (BRB) breakdown in ocular disorders, but the mechanism for BRB compromise cannot be resolved at this level. Using eyes up to 2 days post-mortem from normal patients or from patients with diabetic retinopathy, or other disorders known to cause BRB failure, electron-microscopic immunocytochemistry reveals focal breakdown of the inner BRB, comprised of the retinal vascular endothelium (RVE), which appears to be mediated by diffuse permeation of the RVE cells and by vesicular transport. Permeation of the retinal pigmented epithelial (RPE) cells that comprise the outer BRB also occurs, but there is no evidence of opening of tight junctions between RVE or RPE in any of the disorders evaluated. Increased aldose reductase (AR) expression in the RVE and RPE cells of diabetics as well as in the perivascular retinal astrocytes, which interact with RVE cells to establish the inner BRB, suggests that AR activity and the subsequent intracellular accumulation of sorbitol in these cell types may impair the function of the BRB in diabetes. 相似文献
72.
Howe GT; Bucciaglia PA; Hackett WP; Furnier GR; Cordonnier-Pratt MM; Gardner G 《Molecular biology and evolution》1998,15(2):160-175
The phytochrome photoreceptors play important roles in the photoperiodic
control of vegetative bud set, growth cessation, dormancy induction, and
cold-hardiness in trees. Interestingly, ecotypic differences in
photoperiodic responses are observed in many temperate- zone tree species.
Northern and southern ecotypes of black cottonwood (Populus trichocarpa
Torr. & Gray), for example, exhibit marked differences in the timing of
short-day-induced bud set and growth cessation, and these responses are
controlled by phytochrome. Therefore, as a first step toward determining
the molecular genetic basis of photoperiodic ecotypes in trees, we
characterized the phytochrome gene (PHY) family in black cottonwood. We
recovered fragments of one PHYA and two PHYB using PCR-based cloning and by
screening a genomic library. Results from Southern analyses confirmed that
black cottonwood has one PHYA locus and two PHYB loci, which we arbitrarily
designated PHYB1 and PHYB2. Phylogenetic analyses which included PHY from
black cottonwood, Arabidopsis thaliana and tomato (Solanum lycopersicum)
suggest that the PHYB/D duplications in these species occurred
independently. When Southern blots were probed with PHYC, PHYE, and PHYE
heterologous probes, the strongest bands that we detected were those of
black cottonwood PHYA and/or PHYB. These results suggest that black
cottonwood lacks members of the PHYC/F and PHYE subfamilies. Although black
cottonwood could contain additional PHY that are distantly related to known
angiosperm PHY, our results imply that the PHY family of black cottonwood
is less complex than that of other well-characterized dicot species such as
Arabidopsis and tomato. Based on Southern analyses of five black cottonwood
genotypes representing three photoperiodic ecotypes, substantial
polymorphism was detected for at least one of the PHYB loci but not for the
PHYA locus. The novel character of the PHY family in black cottonwood, as
well as the differences in polymorphism we observed between the PHYA and
PHYB subfamilies, indicates that a number of fundamental macro- and
microevolutionary questions remain to be answered about the PHY family in
dicots.
相似文献
73.
Yamada H Yamada E Hackett SF Ozaki H Okamoto N Campochiaro PA 《Journal of cellular physiology》1999,179(2):149-156
Mice or humans with photoreceptor degenerations experience permeability and dropout of retinal capillaries. Loss of photoreceptors results in decreased oxygen usage and thinning of the retina with increased oxygen delivery to the inner retina. To investigate the possibility that increased tissue oxygen plays a role in the vascular damage, we exposed adult mice to hyperoxia, which also increases oxygen in the retina. After 1, 2, or 3 weeks of hyperoxia, there was a statistically significant decrease in retinal vascular density that was not reversible, and endothelial cell apoptosis was demonstrated by TUNEL staining. Mice exposed to hyperoxia and mice with photoreceptor degeneration both showed decreased expression of VEGF in the retina. After complete or near-complete degeneration of photoreceptors, there was increased expression of VEGF in RPE cells, which may explain the association of photoreceptor degeneration and neovascularization in or around the RPE. Increased expression of VEGF in photoreceptors of transgenic mice failed to prevent hyperoxia-induced retinal capillary dropout. These data suggest that increased oxygen in the retina, either by increased inspired oxygen or by photoreceptor degeneration, results in endothelial cell death and dropout of capillaries. Decreased expression of VEGF may be a contributing factor, but the situation may be more complicated for mature retinal vessels than it is for immature vessels, because VEGF replacement does not rescue mature retinal vessels, suggesting that other factors may also be involved. 相似文献
74.
Usui S Oveson BC Iwase T Lu L Lee SY Jo YJ Wu Z Choi EY Samulski RJ Campochiaro PA 《Free radical biology & medicine》2011,51(7):1347-1354
In retinitis pigmentosa (RP), various mutations cause rod photoreceptor cell death leading to increased oxygen levels in the outer retina, progressive oxidative damage to cones, and gradual loss of cone cell function. We have been exploring the potential of overexpressing components of the endogenous antioxidant defense system to preserve cone cell function in rd10+/+ mice, a model of RP. rd10+/+ mice deficient in superoxide dismutase 1 (SOD1) showed increased levels of superoxide radicals and carbonyl adducts (a marker of oxidative damage) in the retina and more rapid loss of cone function than rd10+/+ mice with normal levels of SOD1. This suggests that SOD1 is an important component of the antioxidant defense system of cones, but increased expression of SOD1 in rd10+/+ mice increased oxidative damage and accelerated the loss of cone function. Coexpression of SOD1 with glutathione peroxidase 4 (Gpx4), which like SOD1 is localized in the cytoplasm, but not with catalase targeted to the mitochondria, reduced oxidative damage in the retina and significantly slowed the loss of cone cell function in rd10+/+ mice. Gene transfer resulting in increased expression of SOD2, but not coexpression of SOD2 and mitochondrial Gpx4, resulted in high levels of H2O2 in the retina. These data suggest that to provide benefit in RP, overexpression of an SOD must be combined with expression of a peroxide-detoxifying enzyme in the same cellular compartment. 相似文献
75.
Mona-Rita?YacoubEmail author Alvise?Berti Corrado?Campochiaro Enrico?Tombetti Giuseppe?Alvise?Ramirez Andrea?Nico Elisabetta?Di?Leo Paola?Fantini Maria?Grazia?Sabbadini Eustachio?Nettis Giselda?Colombo 《Clinical and molecular allergy : CMA》2016,14(1):9
Drug induced exfoliative dermatitis (ED) are a group of rare and severe drug hypersensitivity reactions (DHR) involving skin and usually occurring from days to several weeks after drug exposure. Erythema multiforme (EM), Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are the main clinical presentations of drug induced ED. Overall, T cells are the central player of these immune-mediated drug reactions. Here we provide a systematic review on frequency, risk factors, pathogenesis, clinical features and management of patients with drug induced ED. 相似文献
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Mice of the TO Swiss strain received diets containing different amounts of saturated or unsaturated fat throughout life. These diets produced characteristic changes in cardiac phospholipid fatty acid composition, but produced no significant differences in fatty acid composition of phospholipids from a crude membrane fraction of brain. When littermates of these animals were exposed to ethanol vapour in an inhalation chamber it was observed that mice which had received a diet high in saturated fat lost the righting reflex at an estimated concentration of ethanol in blood higher than that required for mice receiving a control diet, or a diet rich in polyunsaturated fat. Analysis of the brain membrane fraction from those animals which had received ethanol revealed that mice receiving the highly saturated fat diet now had a significantly greater proportion of saturated fatty acids in brain membrane phospholipids. These results are discussed in relation to the hypothesis that brain membrane lipid composition may influence the behavioural response to ethanol. 相似文献
79.
Sze SH; Roytberg MA; Gelfand MS; Mironov AA; Astakhova TV; Pevzner PA 《Bioinformatics (Oxford, England)》1998,14(1):14-19
MOTIVATION: Gene annotation is the final goal of gene prediction
algorithms. However, these algorithms frequently make mistakes and
therefore the use of gene predictions for sequence annotation is hardly
possible. As a result, biologists are forced to conduct time-consuming gene
identification experiments by designing appropriate PCR primers to test
cDNA libraries or applying RT-PCR, exon trapping/amplification, or other
techniques. This process frequently amounts to 'guessing' PCR primers on
top of unreliable gene predictions and frequently leads to wasting of
experimental efforts. RESULTS: The present paper proposes a simple and
reliable algorithm for experimental gene identification which bypasses the
unreliable gene prediction step. Studies of the performance of the
algorithm on a sample of human genes indicate that an experimental protocol
based on the algorithm's predictions achieves an accurate gene
identification with relatively few PCR primers. Predictions of PCR primers
may be used for exon amplification in preliminary mutation analysis during
an attempt to identify a gene responsible for a disease. We propose a
simple approach to find a short region from a genomic sequence that with
high probability overlaps with some exon of the gene. The algorithm is
enhanced to find one or more segments that are probably contained in the
translated region of the gene and can be used as PCR primers to select
appropriate clones in cDNA libraries by selective amplification. The
algorithm is further extended to locate a set of PCR primers that uniformly
cover all translated regions and can be used for RT-PCR and further
sequencing of (unknown) mRNA.
相似文献
80.
Zimmerman PA; Katholi CR; Wooten MC; Lang-Unnasch N; Unnasch TR 《Molecular biology and evolution》1994,11(3):384-392
Polymerase chain reaction (PCR) products were characterized for a repeated
sequence family (designated "O-150") of the human filarial parasite
Onchocerca volvulus. In phylogenetic inferences, the O-150 sequences
clustered into closely related groups, suggesting that concerted evolution
maintains sequence homology in this family. Using a novel mathematical
model based on a nested application of an analysis of variance, we
demonstrated that African rainforest and savannah strain parasite
populations are significantly different. In contrast, parasites collected
in the New World are indistinguishable from African savannah strains of O.
volvulus. This finding supports the hypothesis that onchocerciasis was
recently introduced into the New World, possibly as a result of the slave
trade.
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