Alterations in the light transmission through single lens fibers during calcium-mediated disintegrative globulization.

Purpose: The purpose of this study was to examine changes in the light transmission through single cortical fibers isolated from the rat lens during the process of disintegrative globulization.

Methods: Single cortical fibers were isolated from adult rat lens by treatment with trypsin in a solution containing 10 mM HEPES, 10 mM EDTA, and 280 mM sucrose (pH 7.4, 300 to 310 mOsm) HEPES-EDTA-sucrose (HES) solution.

Delivery of liposome-sequestered hydrophobic proteins to lysosomes of normal and Batten disease cells.

We have developed a method to deliver hydrophobic proteins such as ATP synthase subunit c and ubiquitin to lysosomes of PMN (polymorphonucleocytes) and fibroblasts. ATP synthase subunit c is stored in the lysosomes of various tissues in late infantile and juvenile forms of neuronal ceriod lipofuscinosis, also called Batten disease (BD). Whether this protein storage is due to an abbreviation in protein or in the lysosomal hydrolases of BD is still not clear.

Glucose-dependent formation of free radical species in lens homogenate.

Free radicals are thought to be involved in the pathogenesis of many disease states such as diabetes, cataractogenesis, cancer, and aging. Involvement of free radicals in most of these disorders, especially diabetic cataractogenesis, however, is derived from indirect evidence only. The purpose of this study was to directly detect the free radicals generated in lens homogenate incubated under hyperglycemic conditions.

A glutathione S-transferases isozyme (bGST 5.8) involved in the metabolism of 4-hydroxy-2-trans-nonenal is localized in bovine lens epithelium.

Previous studies have suggested that a group of GST isozymes (bGST 5.8) with substrate preference for 4-hydroxy-2-trans-nonenal (4-HNE) were present in bovine retina, cornea, iris-ciliary body and sclera, but not in lens. The present studies demonstrate that bGST 5.

Acceleration of corneal wound healing in diabetic rats by the antioxidant trolox.

Several corneal complications have been reported in patients with long standing diabetes, but their exact pathogenesis is not well understood. It has been observed that the rate of epithelial wound healing in diabetic rats is delayed compared to those in normal animals. Here we present the effect of the free radial scavenger, Trolox, a water soluble vitamin E analogue, on epithelial wound healing in diabetic rat cornea.

Attenuation of 4-hydroxynonenal-induced cataractogenesis in rat lens by butylated hydroxytoluene.

Purpose: We have previously shown that 4-hydroxynonenal (4-HNE) causes opacification of cultured rat lenses and that a novel group of glutathione S-transferases (GSTs) exhibit high specific activity towards 4-HNE. Previous studies have shown that t-butylated hydroxy toluene (BHT) induced GSTs in cultured rat lens. Therefore, the purpose of the present studies was to investigate if the opacification of rat lenses exposed to 4-HNE is ameliorated by pre-culturing the lenses in media containing BHT.

A rapid HPLC method for the quantification of GSH and GSSG in ocular lens.

Unlabelled: Purpose. To develop a rapid and accurate method for the quantification of reduced glutathione (GSH) and oxidized glutathione (GSSG) using micro-quantities of ocular lens. Methods.

Role of lipid aldehydes in cataractogenesis: 4-hydroxynonenal-induced cataract.

Free radicals have extremely short half-lives and they readily oxidize lipids and initiate an autocatalytic chain reaction of lipid peroxidation, which leads to the formation of lipid peroxides. The lipid peroxides undergo degradation to form metastable lipid aldehydes such as 4-hydroxynonenal (HNE). We have shown earlier that under hyperglycemia, lipid peroxides increase; and aldose reductase, an enzyme that reduces glucose to sorbitol, efficiently reduces HNE.

Semi-quantitation of mRNA by polymerase chain reaction. Levels of oxidative defense enzymes and aldose reductase in rat lenses cultured in hyperglycemic or oxidative medium.

The high sensitivity of reverse transcriptase-polymerase chain reaction for detecting low copy number mRNA transcripts has been standardized to analyze the mRNA profiles of catalase, glutathione peroxidase, CuZn-superoxide dismutase and aldose reductase, with respect to the housekeeping gene cyclophilin, in rat lenses cultured in hyperglycemic (50mM glucose) or oxidative (100 microM H2O2) media for 24, 40 and 60 hr. In response to hyperglycemia mRNA expression of catalase appeared to be inhibited at 24 hr but attained normal levels by 40 hr. On the other hand, mRNA levels of catalase were higher than normal between 40 and 60 hr in the presence of H2O2.

Mechanism of calcium-induced disintegrative globulization of rat lens fiber cells.

Purpose: To study the role of calcium and calcium-dependent processes in the disintegrative globulization of isolated single rat lens cortical fibers.

Methods: The authors isolated viable and morphologically intact single fiber cells from rat lens cortex and studied the effect of 1 mM [Ca2+]o on the globulization of fiber cells from the outer and inner cortex. They investigated the effects of the calcium-channel blocker, verapamil; an inhibitor of calcium transport, lanthanum; various protease inhibitors; Na+ -free and K+ -free media; calcium ionophore, A23187; and calcium chelator, BAPTA, on the globulization of fiber cells exposed to 1 mM [Ca2+]o.

Speeding up the generalized adaptive neural filters.

A new class of adaptive filters called generalized adaptive neural filters (GANFs) has emerged. They share many things in common with stack filters and include all stack filters as a subset. The GANFs allow a very efficient hardware implementation once they are trained.

Structure and properties of generalized adaptive neural filters for signal enhancement.

This article addresses the structure and properties of a new class of nonlinear adaptive filters called generalized adaptive neural filters (GANFs). Various properties, such as an upper bound of the mean absolute error of the filters, are analytically derived. Experimental results are presented to demonstrate the performance of the filters for signal and image enhancement.

Traffic management of a satellite communication network using stochastic optimization.

The performance of nonhierarchical circuit switched networks at moderate load conditions is improved when alternate routes are made available. Alternate routes, however, introduce instability under heavy and overloaded conditions, and under these load conditions network performance is found to deteriorate. To alleviate this problem, a control mechanism is used where, a fraction of the capacity of each link is reserved for direct routed calls.

Lipid peroxidation product, 4-hydroxynonenal and its conjugate with GSH are excellent substrates of bovine lens aldose reductase.

There is increasing evidence that lipid aldehydes generated endogenously during the process of degradation of lipid peroxides, are causally involved in the pathophysiology effects associated with oxidative stress. We report here that 4-hydroxynonenal (HNE), which is one of the most abundant and toxic lipid aldehyde can be efficiently detoxified by the aldo-keto reductase, aldose reductase, purified from bovine lens. The enzyme displays a Km of congruent to 9 microM for HNE and 34 microM for the glutathione adduct of HNE (HNE-GS) assigning HNE and HNE-GS to be the best natural substrates of aldose reductase known so far and exposing a new efficient detoxification route of HNE.

Biochemical factors in the lens opacities. Case-control study. The Lens Opacities Case-Control Study Group.

Objective: To evaluate associations with biochemical indicators of nutritional and other risk factors in the Lens Opacities Case-Control Study.

Design: Case-control study.

Setting And Participants: The Lens Opacities Case-Control Study determined risk factors for cortical, nuclear, and posterior subcapsular opacities among 1380 participants aged 40 to 79 years.

Calcium-mediated disintegrative globulization of isolated ocular lens fibers mimics cataractogenesis.

Single viable fiber cells have been isolated from the cortex of rat ocular lens by proteolytic digestion of the intact lens in calcium-free media. In isomolar sucrose, the isolated cells maintain their fiber-shaped morphology and exclude trypan blue. The surface morphology of the isolated fiber cells appears to be largely unaffected by the isolation procedure.

ATP synthase subunit C storage in the polymorphonucleocytes of late infantile and juvenile batten patients.

In late infantile and juvenile forms of neuronal ceroid lipofuscinosis, commonly known as Batten disease (BD). ATP synthase subunit c accumulates in the lysosomes of neural cells. By using polyclonal antibodies, raised against bovine liver subunit c and an image analysis system for the quantification of antibody-linked alkaline phosphatase reaction, we have demonstrated that polymorphonucleocytes (PMN) from a late infantile and a juvenile BD patient stored several-fold more subunit c as compared to normal PMN.

Primary Hodgkin's disease of the lung.

Three cases of Hodgkin's disease presenting primarily in the lung are described. All 3 patients presented with respiratory symptoms and chest X-rays revealed discrete masses within the lung parenchyma. CT examination of the mediastinum did not reveal regional or generalized lymphadenopathy at the time of diagnosis in 2 of the cases.

Increased glomerular and urinary malondialdehyde in puromycin aminonucleoside-induced proteinuria in rats.

Puromycin aminonucleoside (PAN)-induced proteinuria in rats may be mediated by reactive oxygen metabolites (ROM), which are injurious to several cell components including membrane lipids. Increased malondialdehyde (MDA) production is indicative of lipid peroxidation. We examined if MDA content of glomeruli and its urinary excretion were increased in rats administered PAN.

A new method to optimize the satellite broadcasting schedules using the mean field annealing of a Hopfield neural network.

Reports a new method for optimizing satellite broadcasting schedules based on the Hopfield neural model in combination with the mean field annealing theory. A clamping technique is used with an associative matrix, thus reducing the dimensions of the solution space. A formula for estimating the critical temperature for the mean field annealing procedure is derived, hence enabling the updating of the mean field theory equations to be more economical.

Novel human ocular glutathione S-transferases with high activity toward 4-hydroxynonenal.

Purpose: To study the distribution and expression of glutathione S-transferase isozymes involved in detoxification of endogenously generated toxic products of lipid peroxidation, namely, 4-hydroxynonenal (4-HNE) in human lens, retina, cornea, iris, ciliary body and to study their kinetic and structural properties.

Methods: The authors have previously cloned and sequenced cDNA of mouse mGSTA4-4, which shows high activity towards 4-HNE. They have expressed it in Escherichia coli and have raised antibodies against the recombinant mGSTA4-4.

ATP-dependent transport of glutathione-N-ethylmaleimide conjugate across erythrocyte membrane.

Prevailing controversies regarding the identity and nature of S-(2,4-dinitrophenyl) glutathione (Dnp-SG) and GSSG transport system(s) led us to examine xenobiotic-SG transport from human erythrocytes and into inside-out vesicles (IOV) using N-ethyl-maleimide-glutathione conjugate (NEM-SG) as substrate. Efflux of NEM-SG from intact erythrocytes was linear over a period of 4 h, occurred against a concentration gradient, and required energy. No transport of NEM-SG was observed when endogenous ATP was exhausted by preincubation of the erythrocytes for 8 h at 37 degrees C in the absence of glucose.