PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 1083729

Coagulation factor VIII. Localization in the aqueous outflow pathways.

M Pandolfi
View original source ↗Export metadata ↓

Abstract

Antihemophilic factor A-von Willebrand factor (AHF-vWF) is a protein involved in the first phase of blood coagulation and in the mechanism of platelet adhesion. The localization of this protein has been studied in the anterior segment of fetal and adult human eye by a direct immunofluorescence method. It was found that AHF-vWF is present in the wall of aqueous outflow pathways but not in that of Schlemm canal. As it has fibrinolytic activity in the endothelium of Schlemm canal, this structure can be expected to be especially well protected against fibrin deposition and occlusion by platelets and thrombi. The ciliary processes of the adult eye had no AHF-vWF activity. Instead, fluorescein isothiocyanate-fluorescence could be seen in the vessel wall of the ciliary processes of the fetal eye. This difference may be connected with the function of aqueous secretion.

Explore related subjects

Aqueous HumorCiliary BodyEndotheliumEye ProteinsFactor VIIIFibrinolysisHumansvon Willebrand FactorJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M Pandolfi. 1976. Coagulation factor VIII. Localization in the aqueous outflow pathways.. https://doi.org/10.1001/archopht.1976.03910030326015

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Intraluminal pressure response in Baerveldt tube shunts: a comparison of modification techniques.

PURPOSE: To design an apparatus for in vitro quantification of effects of modifications to nonvalved tube shunts, and to compare the effects of these modifications done to prevent early postoperative hypotony. MATERIALS AND METHODS: A testing apparatus was designed and constructed to measure intraluminal pressure (ILP) during constant infusion of balanced salt solution at 2 microL/min through Baerveldt tube shunts mounted on cadaver eyes. Three different modifications were performed and 3 shunts were used for each modification. The modifications were partial tube occlusion with a 3-0 Supramid suture, tube perforation with a 27-gauge needle on an occluded tube, and a 1.2 mm longitudinal venting slit on an occluded tube. RESULTS: The final steady state ILP for the 3-0 Supramid partially occluded tube ranged between 1.6 and 2.8 mm Hg over 3 trials with an average final steady state ILP of 2.0 mm Hg. The 27-gauge needle perforation produced ILPs of 4.6 to 8.2 mm Hg over 3 trials with an average final steady state pressure of 5.9 mm Hg. The 1.2 mm longitudinal venting slit produced an ILP range of 12.6 to 17.3 mm Hg over 3 trials with an average final steady state ILP of 14.8 mm Hg. The differences in final steady state ILP between the 3 modification techniques were statistically significant (P=0.00036). CONCLUSIONS: The 3-0 Supramid occlusion and the 27-gauge perforation techniques produced hypotony, whereas the 1.2 mm longitudinal venting slit produced acceptable pressures in vitro.

Aqueous Humor↗
PubMed2006

Myocilin-associated exosomes in human ocular samples.

Mutations in myocilin result in ocular hypertension, likely due to decreased drainage of aqueous humor through the trabecular meshwork. Since less myocilin is found in the aqueous humor of those with disease-causing mutations, understanding myocilin's role in the aqueous humor is of clinical importance. Recently, myocilin was shown to exit cultured trabecular meshwork cells in association with shed vesicles called exosomes. To examine relevance of this finding in a physiological setting, the present study examined three different types of ocular samples for the presence of myocilin-associated exosomes. Using differential centrifugation steps, we found myocilin associated with exosomes isolated from effluent collected from human anterior segments in organ culture and aqueous humor obtained from human cadaveric eyes or from patients undergoing excisional surgery. Similar to results with cultured cells, myocilin associated predominately with exosomes in fresh samples, appeared mostly soluble at later times, and had biochemical properties (density of 1.13-1.19 g/ml in linear sucrose gradient) similar to those characteristics of exosomes. These data indicate that exosomes are present and may facilitate the transport of myocilin into the extracellular space of human ocular cells.

Aqueous Humor↗