Vitreous body

Glass-ceramics are a family of materials that are polycrystalline in nature and are formed from the liquid or glassy state. A glass-ceramic article is made by the heat treatment of a vitreous body in two stages ... 

Prolonged presence of the drug at the site of injection is the aim of liposome encapsulation of drugs, which are injected in the vitreous body. Both amphotericin and gentamicin in liposome formulations were cleared from the injection site significantly more slowly than the free drug residence times depended on liposome size and, in some cases, on bilayer composition (Tremblay et al., 1985 Barza et al., 1985, 1987 Fishman et al., 1986). 

Hyaluronic acid consists of an unbranched chain of repeating disaccharide units containing GlcUA and GlcNAc. Hyaluronic acid is present in bacteria and is widely distributed among various animals and tissues, including synovial fluid, the vitreous body of the eye, cartilage, and loose connective tissues. 

Lutein and zeaxanthin are the dominant carotenoids in nonretinal eye tissue, and lycopene and p-carotene have been found in the ciliary body, which after the retina and the retinal pigment epithelium (RPE) contains the highest quantity of carotenoids (Bernstein et al. 2001). The orbital adipose tissue also contains measurable quantities of lutein and p-carotene, and possibly other carotenoids as minor constituents (Sires et al. 2001). It is also interesting to note that lutein was recently identified in the vitreous body of human fetuses, 15-28 weeks old (Yakovleva et al. 2007). However, these results may have to be considered with caution, because the vitreous bodies were described as substantially being penetrated with hyaloid blood vessels, which could have contaminated the vitreous with blood. 

Absorption/Distribution — CSF levels following IV administration are undetectable. Penetration of the drug into inflamed joints, the vitreous body of... 

Retina The ten-layered nervous tissue membrane of the eye. It is continuous with the optic nerve and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the choroid and the inner surface with the vitreous body. The outer-most layer is pigmented, whereas the inner nine layers are transparent. [NiH]... 

H. Terauchi, S. Okinami, Z. Kozaki, H. Tanihara, M. Nagata, Y. Sagawa, Experimental study on the effects of a replacement of the vitreous body with perfluorotributylamine on the rabbit eye, Nippon Ganka Gakkai Zasshi 93 (1989) 294-301. 

Haber-Weiss reaction Hyaluronate of the bovine vitreous body was similarly protected by (Cu,Zn)-SOD, by catalase, and by peroxidase. The degradation of hyaluronate in the presence of ascorbate or of Fe cations was not inhibited by (Cu,Zn)-SOD The formation of OH radicals from H O and ascorbate, in the presence of traces of Fe-EDTA, was largely independent of superoxide radicals... 

Type I, II, and III collagens are fibrillar, and are found in tendon, skin, bone, cornea, carti lage, vitreous body, and blood vessels. Types IX and XII are fibril-associated, and are found in cartilage, tendon, and ligaments. Type IV and VII form networks in basement membrane and beneath stratified squamous epithelia. 

Dreyer, E. B., Zurakowski, D., Schumer, R. A., Podos, S. M., and Lipton, S. A. (1996). Elevated glutamate levels in the vitreous body of humans and monkeys with glaucoma. Arch. Ophthalmol. 114, 299-305. 

Maurice DM. Injection of drugs into the vitreous body. In Leopold IH, Bums RP, eds. Symposium on ocular therapy. New York John Wiley Sons, 1976 59-71. 

Human vitreous body 140-340 HA concentration increases upon the maturation of this tissue. 

The individual HA molecules are present in solutions in random coil conformation and occupy large hydrated volume. This depends on the molecular mass of HA as well as on its concentration When the concentration increases, the motion of the molecular segments becomes more restricted [143]. As an important consequence, such crowded molecular system has significant viscous and elastic properties. The biological role of the HA in vitreous body and in the joint was interpreted according to these rheological properties [144]. 

Berry, M., Carlile, J., and Hunter, A., Peripheral nerve explants grafted into the vitreous body of the eye promote the regeneration of retinal ganglion cell axons severed in the optic nerve, J. Neurocytol., 25, 147, 1996. 

FIGURE 7.5 Decline of photoreceptors in the RCS retina between 15 and 60 days of life and the effects of MIF and ACTH-peptide 4-9 injected into the vitreous body. The rescue effects are significant in both cases. The counts were obtained at 60 days after birth (from... 

Two primary mechanisms of vitreal drug distribution and elimination are (i) diffusion from the lens region toward the retina with elimination via the retina-choroid-sclera and (ii) anterior diffusion with elimination via the hyaloid membrane and posterior chamber (18). Distribution to the retina from an intravitreal injection site is relatively slow, considering juxtaposition of the vitreous and retina, with the time for maximum drug concentration (tmax) in retina typically achieved at 4 to 12 hours, and reflects the inefficiency of diffusion over the distances encountered within the vitreous body. For example, ranibizumab, an ocular specific monoclonal VEGF antibody, distributes to the retina with of 6 to 24 hours. While relatively rapid therapeutically, this is slow compared with the rate of redistribution in stirred compartments. (249). 

Elevated glutamate levels in the vitreous body of humans and monkeys with glaucoma. Arch Ophthalmol 114 299-305. 

D-Glucuronate Af-Acetyl-D-glucosamine Synovial fluid, vitreous body of the eye, loose connective tissue... 

Injection of antisense oligonucleotides to synaptosomal-associated protein-25 into the vitreous body of rat embryos reduced the expression of the protein and inhibited neurite elongation by rat cortical neurons (230). 

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