Plasma membrane calcium adenosine triphosphatase (Ca(2+)-ATPase) is an energy-dependent protein responsible for transporting cytosolic calcium across the plasma membrane. Multiple plasma membrane Ca(2+)-ATPase isoforms are expressed from four genes (PMCA1-4) and alternative mRNA splicing. We have studied PMCA gene expression in bovine lens epithelium tissues by reverse transcription-polymerase chain reaction, Southern blot, and Northern blot hybridization. All four PMCA genes are expressed in the lens epithelium, the PMCA3 transcript being the most abundant. The transcripts for PMCA1, PMCA2, and PMCA4 exist in decreasing order of abundance. There is no evidence for the expression of any novel PMCA genes in bovine lens epithelium.

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PubMedDate not supplied

Quantification of ocular inflammation: evaluation of polymorphonuclear leucocyte infiltration by measuring myeloperoxidase activity.

Myeloperoxidase (MPO) activity was measured in rabbit cornea and iris-ciliary body to quantitate the infiltration and accumulation of polymorphonuclear leucocytes (PMN's) following an inflammatory stimulus. Following injection of clove oil into the cornea, MPO activity could be detected in the cornea at 6 hr, reaching a maximum at 12 hr, and falling to non-detectable levels at 72 hr. MPO activity was only detected in the iris-ciliary body 24 hr after intracorneal clove oil injection. MPO activity in the iris-ciliary body increased in a dose-dependent manner following intravitreal injection of endotoxin. No MPO activity could be detected in cornea. Topical administration of dexamethasone inhibited MPO activity in cornea and iris-ciliary body 24 hr after intracorneal clove oil and intravitreal endotoxin injection, respectively. Measurement of MPO activity in ocular tissues could provide a useful tool to quantitatively evaluate the severity and time course of inflammation.

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PubMedDate not supplied

The pathology of an inherited cataract of sheep.

Cataracts, inherited in an autosomal dominant manner in New Zealand Romney sheep were first detected at 1 - 2 months of age as focal anterior and posterior cortical opacities. Within a short time these coalesced to form spoke-like patterns which gradually became more diffuse. Total lens opacity developed by 10 - 11 months of age. Congenital mature cataracts occurred in two lambs believed to be homozygous for the mutant gene and in these animals lens resorption later occurred. Histology showed that new lens fibres formed normally at the equator but then underwent progressive degenerative swelling and lysis. Cytoplasmic vacuolation of anterior epithelial cells was a notable feature and occurred apparently in response to adjacent cortical degeneration. Ultrastructurally these vacuoles were interpreted as dilations of endoplasmic reticulum but there were also a number of smaller vacuoles not lined by membrane. Anterior epithelial cells also underwent metaplasia, hyperplasia, and migration beneath the posterior capsule. Analyses of lenses reflecting different stages of cataractogenesis showed a progressive increase in water, sodium and calcium ions with cataract development and a concomitant decrease in potassium and magnesium ions.

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