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Equatorial Region (equatorial + region)

Distribution by Scientific Domains
Life Sciences50%

Selected Abstracts

Reductive Benzylation of Dimetallo Hexaaryl[70]Fullerenes on the Equatorial Region

CHEMISTRY - AN ASIAN JOURNAL, Issue 4 2010
Takeshi Fujita
Abstract Dianions of dimetallic hexa(organo)[70]fullerene [(C5R5)2Ru2C70Ar6]2, (R=H, Me; Ar=Ph, 4-MeC6H4, 4- tBuC6H4) react with benzylic bromide to yield the dibenzylated product dimetallic octa(organo)[70]fullerene (C5R5)2Ru2C70Ar6(CH2Ar,)2 (Ar,=Ph, 4-MeO2CC6H4), where the benzylic groups are attached to the equatorial belt region of [70]fullerene; this region is generally considered to be rather unreactive. This unusual structure was unambiguously determined by X-ray crystallography. Theoretical studies on the electronic properties of the monoanionic intermediate indicated that the highest spin density resides on the two carbon atoms in the belt region; one of them then couples with a benzylic radical to yield the octa(organo)fullerene product after ionic substitution of the fullerene anion with a benzylic bromide. Electrochemical analysis of the hexa(organo) and octa(organo) ruthenium complexes suggests that the modification of the belt region does not affect the electronic communication between the two metal centers. [source]

Local activation of protein kinase A inhibits morphogenetic movements during Xenopus gastrulation

DEVELOPMENTAL DYNAMICS, Issue 1 2003
Byung-Ho Song
Abstract cAMP-dependent protein kinase (PKA) has various biological roles in many organisms. However, little is known about its role in the developmental processes of vertebrates. In this study, we describe the functional analysis of PKA during gastrulation movements in Xenopus laevis. Overexpression of constitutively active PKA (cPKA) in the dorsal equatorial region of the embryo affects morphogenetic movement during gastrulation. We also show that intrinsic differences of PKA activities along the dorsoventral axis are set up and the level of PKA activity on the dorsal region is lower than that on the ventral region from late blastula to gastrula stages. In addition, PKA activation in animal explants inhibits activin-induced elongation. In cPKA-injected embryos, there were no changes in the expressions of markers involved in mesoderm specification, although the correct expression domains of these genes were altered. The effects of PKA activation can be restored by coexpression of PKI, a pseudosubstrate of PKA. We further analyzed the effects of PKA activation on the behavior of migratory gastrulating cells in vitro. Expression of cPKA in head mesoderm cells causes less polarized and/or randomized migration as demonstrated by a directional cell migration assay. Finally, we show that RhoA GTPase lies downstream of PKA, affecting activin-induced convergent extension movements. Taken together, these results suggest that overexpressed PKA can modulate a pathway responsible for morphogenetic movements during Xenopus gastrulation. Developmental Dynamics 227:91,103, 2003. © 2003 Wiley-Liss, Inc. [source]

Contributions of Mouse Genetic Background and Age on Anterior Lens Capsule Thickness

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 12 2008
Brian P. Danysh
Abstract Accurate lens capsule thickness measurements are necessary for studies investigating mechanical characteristics of the capsule. Confocal Z -axis imaging was used to measure the anterior lens capsule thickness of living intact lenses with minimal tissue manipulation. Measurements of the anterior capsule thickness is reported for the first time in young and old mice from four inbred strains, BALB/c, FVB/N, C57BL/6, and 129X1, and the outbred strain ICR. Our data demonstrates that the mouse anterior lens capsule continues to grow postnatally similar to that described in other mammals. It is also shown there is a significant difference in anterior lens capsule thickness between unrelated mouse strains, suggesting that capsule thickness is a quantitative trait shared by strains with common ancestry. Measurements, taken from other regions of FVB/N capsules revealed the anterior pole to be the thickest, followed by the equatorial region and posterior pole. In addition to mouse, anterior capsule measurements taken from intact cattle, rabbit, rat lenses, and human capsulotomy specimens correlated with the overall size of the animal. Anat Rec, 2008. © 2008 Wiley-Liss, Inc. [source]

Retinitis pigmentosa associated with peripheral sea fan neovascularization

ACTA OPHTHALMOLOGICA, Issue 5 2000
Sibel Kaday
ABSTRACT. Purpose: To describe a case with retinitis pigmentosa associated with sea fan type retinal neovascularization. Methods: Complete ocular examination including fluorescein angiography was performed in a 9-year-old girl. Results: Ophthalmoscopically, in addition to arteriolar narrowing and bone corpuscular pigmentation of both retinae, a vascular lesion with surrounding intraretinal exudation was noted in the upper equatorial region of the right eye. On fluorescein angiography, the lesion stained in the form of a sea fan neovascularization. Conclusion: Sea fan type of neovascularization can be seen in association with retinitis pigmentosa. Fluorescein angiography is important in identifying the exact nature of such a lesion. [source]