Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using 31P-NMR spectroscopy, the authors observed dynamic changes in the organophosphate metabolites in the lenses of two groups of Lewis rats affected by experimental uveitis induced by injecting Salmonella lipopolysaccharide (n = 20) or S-antigen (n = 25). A comparative study was done on the metabolic changes, the degree of inflammation, and histological changes in the rat lenses. Dynamic changes in the organophosphate profile in the lenses were measured by 31P-NMR spectroscopy. Only inorganic phosphate showed a significant increase (p less than 0.05) related to the increased inflammation in the endotoxin group, but the lenses showed no morphological change. Choline phosphate, adenosine triphosphate, and inorganic phosphate increased significantly (p less than 0.01) in the acute stage of inflammation, but a significant decrease (p less than 0.01) was evident from the peak of inflammation, following the histological destruction of the lenses. Our results indicated that in experimental uveitis dynamic changes in the organophosphate profile of the lenses were closely related to the protecting reaction against the stress caused by inflammation. Furthermore, we theorized that the generation of the secondary cataract was associated with the decreased metabolism of the phosphate compounds.
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PMID:[Dynamic changes in the organophosphate metabolites of the lenses affected by endotoxin and S-antigen induced uveitis]. 150 84

The non-invasive method of 1H-nuclear magnetic resonance (1H-NMR) spectroscopy was applied to rat whole lens. The alterations of aging and experimentally induced cataract on protein structures in rat lenses were examined by comparing high resolution 1H-NMR spectra. 1H-NMR measurements were carried out using the water suppression method and resolution enhancement method. The 1H-NMR spectra of normal lens showed narrow resonance lines of lactate and broad ones of aliphatic amino acid residues of lens protein. There was no remarkable change in the spectral pattern of normal lenses within one week. There was also no effect of aging on the spectral pattern of normal lenses. On the other hand the lines due to the aliphatic amino acid residues of the galactose cataractous lens protein were narrower than those of normal lens. This finding suggests that the increase of mobilities of the residues caused by galactose cataract is reflected by the spectral pattern.
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PMID:[1H-NMR study on protein of normal and galactose cataractous rat whole lenses]. 155 69

Normal and cataractal decapsulated lenses of man were studied by NMR method-spin echo to obtain information concerning efficient coefficients of self diffusion, times of spin-spin relaxation of water protons (T2) and water content in the lens (c) at 25 degrees C in the course of cataractogenesis. It has been found that the values T2 and c at 25 degrees C are much higher in the nuclei of completely turbid lenses than in the transparent ones; the self-diffusion coefficients in the turbid lenses were also higher. At -9 degrees C a significant decrease of the content of undestroyed by frost (bound) water was observed at the stage of mature cataract as compared to transparent lenses. It is suggested that the most specific differences between the nuclei of transparent and completely turbid lenses are related to increased diffusion mobility of water molecules, apparently, at the expense of damaged plasmic membranes of the lens fibres noted during cataract development.
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PMID:[Diffusion properties of water in the human crystalline lens during cataract development]. 189 8

The prophylactic effects of a new aldose reductase inhibitor (ARI), FR74366 on streptozotocin-induced rat diabetic cataract were examined by means of proton nuclear magnetic resonance (1H-NMR) relaxation time. We compared the findings with the histological finding, and it was recognized that longitudinal and transverse relaxation times (T1, T2) were prolonged before the histological changes appeared. The ARI, FR74366, prevented histologic changes and had detected by the 1H-NMR method. The results showed that 1H-NMR could be useful in the early detection of human diabetic cataract and the evaluation of the effectiveness of anti-cataract agents, for example, AR inhibitors.
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PMID:[Quantitative study of rat diabetic cataract, by the relaxation times of nuclear magnetic resonance]. 190 17

Our laboratory has demonstrated the potential of non-invasive biophysical methods in studying cataractogenesis. Initially these studies involved in vitro spectroscopic assays (UV, fluorescence and phosphorescence) on excised lenses or lens matter. In addition, we performed NMR pulse relaxation studies on extracted lenses which demonstrated an age-related increase in the T1 and T2 values of the normal lens. The in vitro fluorescence and NMR data suggested potential parameters for monitoring human and animal lenses in vivo. We then developed in vivo lens fluorescence densitography utilizing the Scheimpflug camera and have recently employed our Magnetic Resonance Imaging (MRI) method (using specially constructed small coils) to measure the moderately bound lens water compartment (T2) in vivo. Both of these in vivo methods correlate with our in vitro data and they demonstrate age-related changes in the normal lens; - i.e. - a progressive increase in fluorescence intensity and longer T2 values. Indices have been developed which permit us to detect abnormal lens fluorescence and changes in the moderately bound lens water (T2) compared with normal values for each specific age group by decade. These 2 non-invasive biophysical techniques can detect pre-cataractous changes in the living clear lens, months to years before any type of opacity becomes manifest with the conventional slit lamp method. The MRI technique can be performed in less than 20 minutes and the lens fluorescence method requires 4-6 minutes; thus they provide a rapid and objective in vivo measure of the status of the living lens as well as a method for evaluating anti-cataract drug efficacy.
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PMID:NMR & fluorescence studies on human and animal lenses. 191 33

When monitoring for drug induced lenticular side effects and/or anti-cataract drug efficacy, it would be advantageous to detect such effects prior to the onset of a cataract. Our MRI technique can detect precataractous changes in the lens water compartments (T2 values) months to years before opacities become manifest. The in vivo human and animal studies correlate well with in vitro NMR pulse relaxation data on such lenses. The MRI technique requires 2-4 minutes per eye and provides excellent pictures of the globe as well as T2 values. These data correlate well with our in vivo lens fluorescence technique thereby providing two parameters capable of evaluating potential drug induced changes in the lens well before the cataract becomes manifest.
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PMID:Biophysical methods to monitor lens aging and pre-cataractous changes in vivo. 210 Jan 62

The rotational diffusion behavior of phosphorus metabolites present in calf lens cortical and nuclear homogenates was investigated by the NMR technique of 31P off-resonance rotating frame spin-lattice relaxation as a means of assessing the occurrence and extent of phosphorus metabolite-lens protein interactions. 31P NMR spectra of calf lens homogenates were obtained at 10 and 18 degrees C (below and above the cold cataract phase transition temperature, respectively) at 7.05 T. Effective rotational correlation times (tau 0,eff) for the major phosphorus metabolites present in cortical and nuclear bovine calf lens homogenates were derived from nonlinear least-squares analysis of R vs omega e (spectral intensity ratio vs precessional frequency about the effective field) data with the assumption of isotropic reorientational motion. Intramolecular dipole-dipole (1H-31P, 31P-31P), chemical shift anisotropy (CSA), and solvent (water) translational intermolecular dipole-dipole (1H-31P) relaxation contributions were assumed in the analyses. In those cases where the limiting value of the spectral intensity ratio failed to reach unity at large offset frequency, a modified formalism incorporating chemical exchange mediated saturation transfer between two sites was used. Values of tau 0,eff for phosphorus metabolites present in the cortex varied from a low of ca. 2 ns [L-alpha-glycero-phosphocholine (GPC)] to a high of 12 ns (alpha-ATP) at 10 degrees C, whereas at 18 degrees C the range was from ca. 1 to 9 ns. For the nucleus the tau 0,eff values ranged from ca. 3 ns (GPC) to 41 ns (Pi) at 10 degrees C; at 18 degrees C the corresponding values ranged from 4 to 39 ns. For PME (phosphomonoester; in lens the predominant metabolite is L-alpha-glycerol phosphate) at 18 degrees C evidence was obtained for binding and subsequent exchange with solid like protein domains. The diversity in tau 0,eff values for lenticular phosphorus metabolites is suggestive of differential binding to more slowly tumbling macromolecular species, most likely lens crystallin proteins. Corresponding measurement of tau 0,eff values for the mobile protein fraction present in calf lens cortical and nuclear homogenates at 10 and 18 degrees C, by 13C off-resonance rotating frame spin-lattice relaxation, provided average macromolecular correlation times that were assumed to represent the bound metabolite state. A fast-exchange model (on the T1 time scale), between free and bound forms, was employed in the analysis of the metabolite R vs omega e curves to yield the
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PMID:Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabolite rotational diffusion in bovine lens homogenates. 227 17

The pulse Fourier NMR was employed to measure the artificial diabetic cataract lens at various stages of its formation, and the lenses of the normal rats. Data obtained by using this method show that all the peaks that of water concentrate in the range of delta less than 4 ppm. The peak value at delta = 3.20 ppm is on a marked increase during the formation of cataract which is caused by the phosphate metabolites, such as GPC, ATP, ... etc, in cataract lens. With the development of the disease, the peak width at delta = 3.73 ppm becomes greater and greater, which shows that the activity of sorbitol dehydrogenase has decreased. This leads to a high concentration of the sorbitol in the cataract lens. Consequently, the osmosis pressure in the cataract lens is increased, and excessive water might dip into the crystalline lens to keep the balance of the osmosis pressure. And this might result in the hydration of the fiber cell of the crystalline lens, which might cause a swelling or blisters. These results are in favour of the prolongation of the relaxation time of cataractous lens reported in our other papers, and also support those gained by biochemical studies issued in the medical literature.
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PMID:[Detection of sorbitol content in crystalline lens of normal rats and rats with diabetic cataract by 1H-NMR]. 239 Oct 91

Using a 31P-NMR spectroscopy, we monitored the metabolic kinetics of energy organophosphate compound in rat lens during the process of generating galactose cataract. The most remarkable metabolic change in the earlier phase of galactose cataract formation was found in alpha-glycerophosphate. This increased significantly, as compared to controls, since the day 3 of giving feed containing 25% galactose. The high level lasted for up to three weeks, decrease followed by a gradual decrease and subsequently a significant decrease at five weeks. Adenosine triphosphate (ATP) showed a significant decrease in the galactose group compared to the controls from two weeks after beginning of the experiment and the decrease continued. Inorganic orthophosphate increased gradually in the galactose group as compared to the controls, the increase being of significance at one week reading a maximum at two weeks followed by a subsegment decrease. Our basic study suggests that 31P-NMR spectroscopy is a useful technique in lens of the metabolic kinetics, to noninvasively determine the pathophysiology of galactose cataract, which has been studied biochemically and histologically.
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PMID:[A study on the metabolism of galactose cataract using a 31P-NMR spectroscopy]. 281 81

The perinuclear region of the rabbit lens is susceptible to alterations in the ionic composition of incubation medium. Rabbit lenses and a comparable cell type, red blood cells, were stressed during ex vivo incubations in isotonic modified Earle's medium with 131 mM NaCl replaced by either 232 mM sucrose or 131 mM choline chloride at pH 7.2 (normal) or 9.2. Our parallel NMR study revealed that these experimental media maintain normal intracellular pH and phosphorus metabolite levels. The present study demonstrates that lens transparency, normal fiber cell ultrastructure and volume were maintained in either sodium chloride or choline chloride containing media at normal or elevated pH. Similarly, normal morphology, mean cell volume (MCV) and mean cell hemoglobin concentration (MCHC), 86.8 +/- 0.03 micron 3 and 33.2 +/- 1.0 g dl-1, respectively, were maintained in red blood cells in either sodium chloride or choline chloride containing media. In sodium chloride deficient media at both normal and elevated pH the lens developed a nuclear cataract based on slit-lamp examination; however, SEM examination showed that fiber cell morphological abnormalities were confined to a narrow band, 50 micron wide, in the perinuclear region of the transition zone. Damage consisted of ruptured cell membranes and an absence of identifiable interdigitations with the combination of sodium chloride deficiency and elevated pH. The major abnormality produced during incubation in sodium chloride deficient medium at normal pH was the presence of numerous smooth-surfaced cellular protrusions along the vertices of the perinuclear fiber cells. In addition, the sodium chloride deficient medium, pH 9.2, produced a volume loss both in the lens and RBC (4.5 +/- 1.5% and 5.6 +/- 1.1%, respectively). The sodium chloride deficient medium, pH 7.4, produced no volume loss in the lens or red blood cells (MCV 86.0 +/- 0.05 micron 3). Further studies indicated that the cataract induced by sodium chloride deficiency (pH 9.2) is irreversible. The mechanism for perinuclear opacification due to ion deficiency remains to be elucidated.
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PMID:Morphological studies of an ion-dependent perinuclear cataract model. 318 25


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