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1.
Immunohematology ; 38(3): 100-105, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-36190198

RESUMEN

Despite knowing the benefits of the type and screen (TS) method in pre-transfusion testing (PTT), most transfusion centers in developing countries continue to be reluctant to adopt a TS strategy over the conventional type and antihuman globulin (AHG) crossmatch (TX) policy in their routine laboratory practice because of the cost of obtaining antibody screening reagents. To generate strong evidence, this multicenter, observational study was conducted in which we collected data prospectively over a 1-year period from six major blood centers in India. The primary objective of this study was to identify the discordance between TS and TX results. A secondary objective was to identify the allo-antibody specificity in patients with positive antibody detection tests. All patients with orders for red blood cell transfusion who met patient selection criteria were subjected to parallel testing by column agglutination technology (CAT) for both the antibody detection test (screen) using a commercial three-cell panel and for the AHG crossmatch. A total of 21,842 patients were tested. In 148 patients with incompatible crossmatches, samples from six patients gave negative results with the antibody detection test, whereas the antibody detection test was positive in samples from 118 patients among the 21,694 crossmatch-compatible cases. The TS approach achieved a positive percent agreement of 95.95 and was found to be significantly effective in preventing the transfusion of serologically incompatible blood. The risk associated with abbreviating the AHG crossmatch was found to be 0.009 percent. Most of the identified clinically significant alloantibodies were directed to Rh antigens (D>E>c>C>e), followed by anti-K and anti-M. This study has generated sufficient robust data for the Indian population by including patients from all major geographical areas of the country and concluded a satisfactory agreement level as well as non-inferiority to the current PTT policy. Therefore, TS policy can be implemented in developing countries with no compromise on blood safety, provided sufficient technical and infrastructural support are available.


Asunto(s)
Antígenos de Grupos Sanguíneos , Isoanticuerpos , Tipificación y Pruebas Cruzadas Sanguíneas , Transfusión Sanguínea , Humanos , Políticas
2.
Cryo Letters ; 41(2): 68-74, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33988656

RESUMEN

BACKGROUND: The quality of frozen semen can be improved by supplementing Tris extender with antioxidant to prevent oxidation and maintain sperm motility. OBJECTIVE: To study the effects of adding combinations of suitable concentrations of butylated hydroxy toluene (BHT) and Vitamin E in Tris extender on the quality of frozen goat semen. MATERIALS AND METHODS: A total of 40 ejaculates collected from five Beetal bucks were used to study the effect on the quality of frozen semen of supplementing Tris extender with 200 µM BHT, 2 mM Vitamin E and 200 µM BHT + 2 mM Vitamin E. RESULTS: The sperm motility, live sperm, live intact acrosome and HOST-reacted sperm differed significantly (P<0.01) between stages and between antioxidants. There was no significant difference (P<0.05) in interaction between stages (equilibration, freezing) and antioxidants, except for HOST-reacted sperm. Critical difference test revealed that Tris extender containing 2 mM vitamin E showed significantly (P<0.05) higher sperm motility, live sperm, live intact acrosome and HOST-reacted sperm, and significantly (P<0.05) lower release of alanine transaminase (ALT) and aspartate transaminase (AST). CONCLUSION: Supplementation of Tris extender with 2 mM vitamin E maintained superior quality of frozen Beetal buck semen.


Asunto(s)
Hidroxitolueno Butilado , Criopreservación/veterinaria , Crioprotectores , Preservación de Semen , Vitamina E , Acrosoma , Animales , Hidroxitolueno Butilado/farmacología , Crioprotectores/farmacología , Masculino , Semen , Preservación de Semen/veterinaria , Motilidad Espermática , Espermatozoides , Vitamina E/farmacología
3.
Ann Med Health Sci Res ; 6(1): 19-26, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27144072

RESUMEN

BACKGROUND: Apical periodontitis (AP) is one of the most prevalent diseases of the teeth. Treatment of AP is based on the removal of the cause, i.e., bacteria from the root canals. Achievement of adequate bacterial eradication in one appointment treatment remains a controversy. AIM: This prospective study was conducted with the objective to compare the periapical healing of teeth with AP treated in (a) single visit versus (b) two visits, either with or without Vitapex as an intracanal medicament. SUBJECTS AND METHODS: Patients were selected randomly from the Department of Conservative Dentistry and Endodontics. Forty-three patients (81 teeth) met the inclusion criteria, i.e., AP (both symptomatic and asymptomatic) visible radiographically size ≥2 mm × 2 mm, not suffering from any immune-compromising disease, age between 16 and 65 years and tooth not accessed previously. Patients were randomly divided into three groups, i.e., single-visit group (Group 1), multi-visit group without any intracanal medicament (Group 2), and multi-visit group with Vitapex as interim intracanal medicament (Group 3). Comparison was done radiographically using periapical index (PAI). The primary outcome measure was the change in periapical radiolucency after 1 year assessed by PAI scores. The Mann-Whitney U-test was used to evaluate differences between groups at baseline (immediate postoperative) and at the 12-month follow-up evaluation. Change in PAI score for each group from baseline to 12-month follow-up evaluation was tested with the Wilcoxon signed rank test. The secondary outcome measures, proportion of teeth in each group that could be considered improved (decreased PAI score) or healed (PAI <2), were assessed with the Chi-square test. RESULTS: No statistically significant difference in periapical healing was found between three groups. CONCLUSION: After 1-year evaluation, no difference in periapical healing was found between single-visit treatment and multi-visit treatment groups with the given sample size.

4.
Biochim Biophys Acta ; 542(1): 28-38, 1978 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-208649

RESUMEN

1. Activities of superoxide dismutase (superoxide: superoxide oxidoreductase, EC 1.15.1.1) have been estimated in eye tissues. In rabbit eye, superoxide dismutase is present in corneal epithelium, corneal endothelium, lens, iris, ciliary body and retina. In lens the activity is in capsule epithelium. 2. Copper chelator diethyldithiocarbamate inhibited lens superoxide dismutase in vitro and in vivo in rabbit. 3. H2O2 caused inhibition of superoxide dismutase activity of lens extract, and this inhibition was potentiated by the catalase inhibitor 3-amino-1H-1,2,4-triazole (3-aminotriazole) or NaN3. 3-Aminotriazole or NaN3 had no effect on lens superoxide dismutase. Thus endogenous catalase of lens affords protection to the lens superoxide dismutase from inactivation by H2O2. 4. In rabbit having early cataract (vacuolar stage) induced by feeding-3-aminotriazole, there was a decrease in superoxide dismutase of lens, a fall in ascorbic acid of ocular humors and lens, and a 2--3-Fold increase in H2O2 of aqueous humor and vitreous humor. We conclude that catalase of eye affords protection to the lens from H2O2 and it also protects superoxide dismutase of lens from inactivation by H2O2. Superoxide dismutase, in turn, protects the lens from the superoxide radical, O2.-. It is likely that inhibition of these enzymes may lead to production of the highly reactive oxidant, the hydroxyl radical, under pathological conditions when H2O2 concentration in vivo exceeds physiological limits as in cataract induced by 3-aminotriazole. A scheme of reaction mechanism has been proposed to explain the relative functions of ocular catalase and superoxide dismutase. Such a mechanism may be involved in cataractogenic process in the human.


Asunto(s)
Catalasa/fisiología , Peróxido de Hidrógeno/farmacología , Cristalino/enzimología , Superóxido Dismutasa/fisiología , Amitrol (Herbicida)/toxicidad , Animales , Ácido Ascórbico/metabolismo , Catalasa/antagonistas & inhibidores , Catarata/etiología , Ditiocarba/farmacología , Ojo/enzimología , Femenino , Humanos , Técnicas In Vitro , Cristalino/fisiología , Masculino , Fenómenos Fisiológicos Oculares , Conejos , Superóxido Dismutasa/antagonistas & inhibidores , Superóxidos/toxicidad
5.
Biochim Biophys Acta ; 497(3): 641-51, 1977 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-889879

RESUMEN

Activities of catalase (H2O2: H2O2 oxidoreductase, EC 1.11.1.6) and GSH peroxidase (GSH: H202 oxidoreductase, EC 1.11.1.9) have been measured in iris, ciliary body, retina, corneal epithelium, corneal endothelium, lens capsule-epithelium and decapsulated lens. 3-Amino-1H-1,2,4-triazole is a specific inhibitor of catalase and a potent cataractogenic agent. We observed marked inhibition of catalase activity in these tissues 1--6 h after the administration of a single intravenous dose of 1 g 3-aminotriazole per kg body weight in rabbit. This was associated with a 2--3-fold increase in the H2O2 concentrations of aqueous humor and vitreous humor. The increased peroxide concentrations were restored to the physiological levels as the catalase activity of eye tissues gradually returned to normal with time after injection. Under the conditions, GSH peroxidase activity of the afore-mentioned eye tissues was unaltered, GSH and protein sulfhydryl of lens were not changed, and ascorbic acid of aqueous humor and vitreous humor was not significantly altered. Based on these findings our conclusion is that catalase of eye tissues regulates the endogenous H2O2 in eye humors to the physiological level. We speculate that H2O2 may be the triggering factor in cataract induced by 3-aminotriazole.


Asunto(s)
Amitrol (Herbicida)/farmacología , Catalasa/metabolismo , Ojo/enzimología , Glutatión Peroxidasa/metabolismo , Peróxido de Hidrógeno/metabolismo , Peroxidasas/metabolismo , Triazoles/farmacología , Animales , Humor Acuoso/efectos de los fármacos , Humor Acuoso/enzimología , Ácido Ascórbico/metabolismo , Ojo/efectos de los fármacos , Femenino , Cinética , Cristalino/efectos de los fármacos , Cristalino/enzimología , Masculino , Especificidad de Órganos , Conejos , Factores de Tiempo
6.
Biochim Biophys Acta ; 1285(1): 21-8, 1996 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-8948471

RESUMEN

We have previously demonstrated by TLC an additional phospholipid spot between phosphatidylethanolamine (PE) and phosphatidylserine (PS) in human cataract. This was further identified as a fluorescent Schiff-base conjugate resulting from crosslinking of reactive carbonyl groups of malondialdehyde (MDA) with the primary amino groups of membrane phospholipids. Evidence presented here shows that such an adduct could be formed in rabbit lens subjected to oxidative stress in vitro. TLC analysis of a lipid extract of a crude membrane fraction obtained from the lens homogenate incubated with 1 mM H2O2, tert-butyl hydroperoxide (TBHP) or MDA for 1-6 h at 25 degrees C, showed that the oxidants and MDA produced time-dependent crosslinking of aminophospholipids. Under identical conditions of incubation with TBHP or MDA, development of the Schiff-base lipid fluorochrome in lens with peak emission at 470 nm when excited at 360 nm also showed a time-dependent increase. The PE.MDA.PS produced in cellular membranes of the lenses cultured for 3 h in Krebs-Ringer medium was 151 nmol/mumol PE, and addition of 1 mM H2O2, TBHP or MDA, increased it to 881, 610 and 375 nmol/mumol PE, respectively. Adduct was also formed when authentic samples of PE and PS were reacted with pure MDA. From the results it is clear that oxidants viz., H2O2 and TBHP, or MDA were effective in promoting crosslinking of lens membrane aminophospholipids by Schiff-base conjugation of primary amino groups with the carbonyl groups of the aldehyde, a breakdown product of lipid peroxides.


Asunto(s)
Cristalino/química , Lípidos de la Membrana/química , Oxidantes/química , Estrés Oxidativo , Animales , Membrana Celular/química , Reactivos de Enlaces Cruzados , Femenino , Humanos , Peróxidos Lipídicos/química , Masculino , Malondialdehído/química , Oxidación-Reducción , Fosfatidiletanolaminas/química , Fosfatidilserinas/química , Conejos , Especies Reactivas de Oxígeno , Bases de Schiff/química
7.
Biochim Biophys Acta ; 1156(3): 239-44, 1993 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-8461312

RESUMEN

Chondroitin 4-sulfate (Ch 4-S), three dermatan sulfates (DS18, DS45a, DS45b) and hyaluronic acid (HA) were the major glycosaminoglycans (GAG) isolated from the skin of 4 groups of albino rats. The yields from Group 1 (control) were: Ch 4-S, 0.015%; HA, 0.028% and DS (total), 0.098% (w/w). Traces of heparin were detected only in rats irradiated with ultraviolet (UV) light (Group II), in the GAG pool isolated with 45% ethanol. Yields increased by at least 28% (w/w) in Group II, but decreased, except HA's, also by at least 28%, below the level of the control, in irradiated rats that also ingested vitamin E (Group III). The sulfate composition of these GAG determined by infrared spectroscopy was as follows: approx. 17% (w/w) for DS18, 21-30% for DS45a, 21-35% for DS45b and 26-44% for Ch 4-S. A 60-70% (mol/mol) N-acetylation of hexosamine in DS45 was estimated by Fourier transform 1H-NMR spectroscopy; the IdUA composition of this DS was 30-46% (mol/mol), and the uronic acid/hexosamine ratio ranged from 2.50:1 to 1.6:1. The data show UV light irradiation of rat skin to result in an abnormally elevated production of the major GAG and oversulfation of Ch 4-S and DS. These effects are reversed, except for the sulfation of DS45b, when the irradiated animals also ingest vitamin E.


Asunto(s)
Glicosaminoglicanos/efectos de la radiación , Protectores contra Radiación/farmacología , Piel/efectos de la radiación , Rayos Ultravioleta , Vitamina E/farmacología , Animales , Sulfatos de Condroitina/metabolismo , Sulfatos de Condroitina/efectos de la radiación , Dermatán Sulfato/metabolismo , Dermatán Sulfato/efectos de la radiación , Dieta , Glicosaminoglicanos/metabolismo , Ácido Hialurónico/metabolismo , Ácido Hialurónico/efectos de la radiación , Ratas , Ratas Sprague-Dawley
8.
Free Radic Biol Med ; 12(4): 251-61, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1315709

RESUMEN

1-[(2s)-3-Mercapto-2-methylpropionyl]-L-proline (captopril), an antihypertensive and free radical scavenger, protected the rabbit lens from peroxidative and oxidative damage induced by 1 mM diquat in vitro. To evaluate the anticataract efficacy of captopril, an experimental group of five rabbits was treated with topical captopril (1% in 0.15 M NaCl, w/v), and 50 microliters was instilled onto both eyes four times a day for a total of 8 weeks. Following the same procedure, the eyes of five rabbits were treated with topical 0.15 M NaCl as a control for captopril treatment. At the end of the first week of treatment, a single intravitreal dose of 120 nmole diquat in 30 microliters of 0.15 M NaCl was injected into the right eye of each rabbit of both the groups. As a control for intravitreal diquat injection, the left eye of all the rabbits were injected with the diluent, 30 microliters per eye. The intravitreal diquat or its diluent injection was only for one time. From slit-lamp biomicroscopic observation of the diquat-injected right eyes, the anticataract effect of captopril in the treatment group was indicated by the finding that in four of five rabbits the cataract did not advance; whereas in four of five rabbits treated with the diluent the cataract progressed to grade 3. The lenses in the diluent-injected control left eyes of the rabbits treated with the captopril or diluent were normal. However, since the number of animals used for the in vivo studies was few, further confirmation of the anticataract effect of captopril is necessary. In diquat-injected right eyes of animals treated with captopril, the integrated rate of O2- production was about 50% less (p less than .001) in the aqueous humor, vitreous humor, and lens, compared with O2-, 33.49 +/- 2.26 microM (mean +/- SEM) in the aqueous humor, 17.12 +/- 0.75 microM in the vitreous humor, and 31.44 +/- 1.29 nmole/g wet weight in the lens of the diquat-injected right eyes treated with the diluent. Similar significant (p less than .01) differences in the production of .OH and H2O2 in eye tissues were also observed.(ABSTRACT TRUNCATED AT 400 WORDS)


Asunto(s)
Antioxidantes/farmacología , Captopril/uso terapéutico , Catarata/tratamiento farmacológico , Diquat , Administración Tópica , Animales , Ácido Ascórbico/metabolismo , Captopril/administración & dosificación , Captopril/farmacología , Catarata/inducido químicamente , Catarata/metabolismo , Ojo/efectos de los fármacos , Ojo/metabolismo , Femenino , Peróxido de Hidrógeno/metabolismo , Cristalino/efectos de los fármacos , Cristalino/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Masculino , Conejos , Compuestos de Sulfhidrilo/metabolismo , Superóxidos/metabolismo
9.
Mech Ageing Dev ; 113(3): 205-18, 2000 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-10714939

RESUMEN

In this study the mRNAs encoding epidermal growth factor receptor (EGFR), basic fibroblast growth factor receptor (FGFR-2) and insulin-like growth factor receptor (IGFR-1) genes of the human normal lenses at ages varying from 0.5 to 72 years, were identified by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Regulation of EGFR gene expression in the lens did not change with aging, and of FGFR-2 and IGFR-1 genes also remained unaltered up to age 53 years. However, expressions of FGFR-2 and IGFR-1 genes were decreased at ages above 60 years. EGFR, FGFR-2 and IGFR-1 proteins were detected by immunoblot analysis in the epithelial cell membranes of lens at age varying from 40 to 72 years. There was no detectable amount of EGFR protein in fiber cell membranes of the lens, and the levels of FGFR-2 and IGFR-1 proteins were much lower than those in the epithelial cell membranes. The low levels of these receptor proteins in the fiber cell membranes of lens, suggest their possible role in keeping the differentiated function of these unique transparent cells. The findings of the increased protein levels with age of EGFR with the appearance of some degradation products at age 48 years and higher, and the increased FGFR-2 protein at age 60 years and higher in the epithelial cell membranes of lens, were of interest. It appears that this could be a compensatory protective response of the lens to aging process for lifelong continuation of normal growth by proliferation and differentiation of its epithelial cells into new fiber cells in the germinative zone at the equatorial region. Thus, these results could provide a basis for further studies on growth factor receptor gene and protein regulations in the mechanism of lens aging and progression of age-related human cataract.


Asunto(s)
Envejecimiento/genética , Receptores ErbB/genética , Cristalino/metabolismo , Proteínas Tirosina Quinasas Receptoras/genética , Receptor IGF Tipo 1/genética , Receptores de Factores de Crecimiento de Fibroblastos/genética , Adolescente , Adulto , Anciano , Secuencia de Bases , Catarata/etiología , Niño , Preescolar , Cartilla de ADN/genética , Regulación del Desarrollo de la Expresión Génica , Humanos , Lactante , Cristalino/crecimiento & desarrollo , Persona de Mediana Edad , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos
10.
Mech Ageing Dev ; 34(3): 289-96, 1986 May.
Artículo en Inglés | MEDLINE | ID: mdl-3724254

RESUMEN

Lipid extracts of the human cataractous and normal lenses were analyzed by thin-layer chromatography (TLC) using a solvent system consisting of CHCl3/CH3OH/CH3COOH/H2O (50:25:7:3 by vol.). A novel phospholipid having a Rf intermediate between phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS) was detected besides the four major phospholipids viz., PE, PS, phosphatidyl choline (PC) and sphingomyelin (SP). The novel phospholipid was found to be molybdenum positive and ninhydrin negative having a characteristic fluorescence of Schiff-base conjugate formed between PE, malondialdehyde (MDA) and PS. It was possible to resolve this adduct into PE and PS after acid hydrolysis using two dimensional TLC with CHCl3/CH3OH/NH3 (7 M) (65:25:4 by vol.) as the second solvent. In cataract PE . MDA . PS adduct increased significantly as did diene conjugates and MDA. In plasma membrane lipid extract of cataractous lenses there was a marked increase in fluorescence at 460 nm when excited at 365 nm showing a characteristic fluorescence of a typical Schiff-base conjugate. The evidence suggests that peroxidation of lenticular plasma membrane lipids is one of the molecular mechanisms involved in cataract in the human.


Asunto(s)
Catarata/metabolismo , Malonatos/metabolismo , Malondialdehído/metabolismo , Fosfatidiletanolaminas/metabolismo , Fosfatidilserinas/metabolismo , Cromatografía en Capa Delgada , Humanos , Cristalino/metabolismo , Peróxidos Lipídicos/metabolismo , Bases de Schiff , Espectrometría de Fluorescencia
11.
Invest Ophthalmol Vis Sci ; 28(6): 921-6, 1987 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-3473055

RESUMEN

Prostaglandin (PG) F2 alpha (250 micrograms in 50 microliters saline) or epinephrine 2% solution (50 microliters) was topically applied twice daily for 2 weeks to one eye of six cynomolgus monkeys for each agent. Contralateral control eyes received their respective vehicles. A trace aqueous humor flare response occurred in some PGF2 alpha-treated eyes, which reached significance (P less than 0.05) only when observed 4 hr after the first or seventh dose. No significant anterior chamber cellular response was observed in treated as compared to control eyes. Slit-lamp biomicroscopic evaluation of the cornea, iris, and lens showed no differences in treated as compared to control eyes throughout the study. Aqueous humor samples were obtained from all eyes 4 hr after the ninth consecutive dose. Soluble protein concentration was significantly (P less than 0.01) greater in the PGF2 alpha-treated eyes (1.22 +/- 0.30 mg/ml) as compared to control (0.56 +/- 0.17 mg/ml) or to epinephrine-treated eyes (0.59 +/- 0.18 mg/ml). Microscopic examination of sediments obtained after centrifugation of the aqueous humor revealed no cells in experimental or control samples. Both PGF2 alpha and PGE2 levels were significantly (P less than 0.025) greater in PGF2 alpha-treated eyes, and showed a trend towards being greater in epinephrine-treated compared to control eyes. Neither cystoid macular edema nor other retinal abnormalities were evident by fluorescein angiography in any eyes during the second week of treatment. Multiple dosing of PGF2 alpha in monkey eyes does not appear to produce clinically significant adverse effects in either the anterior or posterior segment which would contraindicate its use in a multiple-dose clinical trial in glaucoma patients.


Asunto(s)
Humor Acuoso/metabolismo , Epinefrina/farmacología , Ojo/efectos de los fármacos , Prostaglandinas F/farmacología , Animales , Humor Acuoso/patología , Dinoprost , Dinoprostona , Proteínas del Ojo/metabolismo , Femenino , Angiografía con Fluoresceína , Macaca fascicularis , Prostaglandinas E/metabolismo , Prostaglandinas F/metabolismo
12.
Life Sci ; 38(16): 1463-71, 1986 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-3702587

RESUMEN

Lipid peroxidation was investigated as one of the possible mechanisms of cataractogenesis in the human. Malondialdehyde (MDA), a major breakdown product of lipid peroxides, was significantly higher in cataractous lenses as compared to that in normal lenses. 2-Thiobarbituric acid-reactive material, isolated from cortical cataracts and purified by Sephadex G-10 column chromatography, was identified as MDA. In cataractous lenses the enzymic defenses against reactive species of O2 were impaired as evidenced by the significant decrease in activities of superoxide dismutase, catalase and glutathione peroxidase. Hydrogen peroxide in aqueous humor and vitreous humor of human eyes associated with cataract was increased 2-3 fold. It is possible that carbonyl groups of MDA could interact with primary amino groups of proteins and phospholipids of lenticular plasmalemmae by a cross-linking reaction forming Schiff-base conjugates and these mechanisms might be involved in the pathogenesis of cataract.


Asunto(s)
Catarata/metabolismo , Peróxidos Lipídicos/metabolismo , Adolescente , Adulto , Anciano , Envejecimiento , Humor Acuoso/análisis , Catalasa/metabolismo , Niño , Glutatión Peroxidasa/metabolismo , Humanos , Peróxido de Hidrógeno/análisis , Cristalino/crecimiento & desarrollo , Cristalino/metabolismo , Malondialdehído/metabolismo , Persona de Mediana Edad , Valores de Referencia , Superóxido Dismutasa/metabolismo , Cuerpo Vítreo/análisis
13.
Curr Eye Res ; 3(1): 67-81, 1984 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-6317286

RESUMEN

A free radical mechanism of cataractogenesis involving enzymatic and nonenzymatic reactions, is proposed. Supporting experimental evidence is briefly reviewed. H2O2, which is one of the toxic metabolites of oxygen, was significantly increased 2-3 fold in ocular humors in several experimental cataracts and in human senile cataract. Various cataractogenic agents were also found to increase H2O2 in ocular humors in vivo prior to cataract formation. Enzymatic defenses against O2-. and H2O2 provided by superoxide dismutase, catalase and glutathione peroxidase were impaired in cataracts. In some cataracts, catalase and superoxide dismutase were affected earlier. Malondialdehyde (MDA), a major breakdown product of lipid peroxides was significantly increased by 2-4-fold in human senile cataract, in cataracts induced in rabbit and rat, and in hereditary cataracts in mice. All the reactive species of O2 (O2-., H2O2, OH. and 1 delta gO2) may participate in initiating lipid peroxidation of lens in vitro. Various scavengers of these species were capable of preventing lenticular lipid peroxidation, amongst which OH. scavengers were found to be the most effective. Biological antioxidant, vitamin E afforded 44% prevention of lipid peroxidation in lens. The important observation was that vitamin E was therapeutically effective in about 50% of animals in arresting cataract induced in rabbit by 3-aminotriazole. In these rabbits, H2O2 and ascorbic acid of ocular humors and MDA of lens were close to normal. It is our working hypothesis that the carbonyl groups of MDA and amino groups of amino acids, proteins, nucleic acids and their bases, and phospholipids could interact in a cross-linking reaction producing high molecular weight aggregates by Schiff-base conjugate formation in addition to disulfide cross-linking of proteins, and finally resulting in cataract.


Asunto(s)
Catarata/etiología , Peróxidos Lipídicos/biosíntesis , Oxígeno/farmacología , Animales , Antioxidantes/uso terapéutico , Catarata/tratamiento farmacológico , Catarata/metabolismo , Radicales Libres , Humanos , Peróxido de Hidrógeno/metabolismo , Cristalino/efectos de los fármacos , Cristalino/metabolismo , Ratones , Oxígeno/metabolismo , Conejos , Ratas , Superóxidos/farmacología
14.
Curr Eye Res ; 16(6): 519-26, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9192159

RESUMEN

PURPOSE: We evaluated the effect of the free-radical generator, menadione, on the time of occurrence of cataract in the Emory mouse, a model for human cataract. Concomitant experiments were done to compare production and level of reactive metabolites of oxygen in the Emory mouse and its cataract resistant (CR) genetic control. METHODS: Test and control mice were fed both a normal diet and a diet supplemented with menadione, and the lenses were evaluated for the time of occurrence of cataract and the level of membrane ATPases. Effects of menadione were determined on incubated lenses of Emory and CR mice, assaying reactive species of oxygen, levels of antioxidant enzymes, and formation of the lipid peroxidation product, malondialdehyde. RESULTS: Systemic administration of menadione markedly accelerated the onset of Emory mouse cataract, and decreased ATPase activities suggested oxidative damage to membrane proteins. Cumulative levels of O2.-, H2O2, .OH and malondialdehyde were significantly higher than controls in the lenses incubated in the presence of menadione, showing that it generates oxidative stress. However, [GSH] in lenses decreased equally in test and control mice. The observed increases in catalase and glutathione peroxidase activities in the test lenses indicated an early protective response to oxidative insult. CONCLUSIONS: Acceleration by menadione of the appearance of cataract in the Emory mouse demonstrates that oxidative stress is a risk factor in late-onset cataract. This quinone caused a greater increase in the production and levels of reactive metabolites of oxygen in Emory mice than in CR mice, indicative of a higher susceptibility of the former to oxidative insult.


Asunto(s)
Catarata/inducido químicamente , Estrés Oxidativo , Vitamina K , Animales , Catalasa/metabolismo , Femenino , Cristalino/metabolismo , Peróxidos Lipídicos/metabolismo , Masculino , Ratones , Ratones Endogámicos , Técnicas de Cultivo de Órganos , Especies Reactivas de Oxígeno/metabolismo , Compuestos de Sulfhidrilo/metabolismo , Superóxido Dismutasa/metabolismo , Factores de Tiempo , Vitamina K/farmacología
15.
Curr Eye Res ; 2(9): 595-606, 1982.
Artículo en Inglés | MEDLINE | ID: mdl-7184712

RESUMEN

Lipid peroxidation has been shown to be involved in the pathogenesis of some types of cataract. The possibility of such a mechanism was investigated in Emory mouse cataract. Malondialdehyde, a breakdown product of lipid peroxides, increased 4-fold in advanced cataract. Studies on cation transport revealed that in early cataract there was no alteration in permeability and active transport of cations. However, these functions were significantly altered in advanced cataract as evidenced by about 300% increase in cellular influx of 22Na+ (140 mM) and 50% fall in cellular uptake of 86Rb+ (5 mM). At this stage of cataract, the ouabain- inhibitable component of uptake of Rb+ was drastically decreased, whereas the ouabain-resistant component was unchanged. The mannitol-space increased markedly with progression of cataract. Altered transport of cations in cataract was indicative of damaged membranes which may be due to peroxidation of unsaturated fatty acids in the lipid bilayers concomitant with oxidation of sulfhydryl groups of proteins of the plasma membrane. Superoxide dismutase, catalase and glutathione peroxidase, the defensive enzymes against reactive species of oxygen, were decreased 54%, 57% and 62% respectively in cataract, exposing the lens to oxidants such as 02(-), H202, 0H. and 1 delta 02, which can initiate lipid peroxidation and/or oxidation of protein.


Asunto(s)
Catarata/metabolismo , Peróxidos Lipídicos/metabolismo , Animales , Catalasa/metabolismo , Femenino , Glutatión Peroxidasa/metabolismo , Masculino , Malondialdehído/metabolismo , Ratones , Ratones Endogámicos , Rubidio/metabolismo , Sodio/metabolismo , Superóxido Dismutasa/metabolismo
19.
Free Radic Res Commun ; 12-13 Pt 2: 621-7, 1991.
Artículo en Inglés | MEDLINE | ID: mdl-1648014

RESUMEN

It is our hypothesis that oxygen free radicals are the triggering agents in cataractogenesis. However, besides H2O2 there is no direct evidence of generation of oxy radicals in the eye tissues. Due to extremely short life of O2-. and OH. it is not possible to measure their cellular steady state levels. We found that indirect spectrophotometric techniques based on superoxide dismutase (SOD)-inhibitable cytochrome c reduction for estimation of O2-., salicylate hydroxylation for OH. and peroxidase catalysed reoxidation of 2,6-dichlorophenolindophenol for H2O2, were suitable, sensitive and reproducible for measurements of the reactive species of O2 produced in the eye tissues by oxy radical enhancer, diquat in the rabbit eye in vivo. After a single intravitreal injection of 60, 120 or 300 nmole diquat in the right eyes, there was a dose-dependent rise in O2. levels, 106-265 fold in the aqueous humor, 34-87 fold in the vitreous humor, 6-19 fold in the lens, and 43-88 fold in the retina as compared to 0.16 microM, 0.21 microM, 2.47 nmole/g and 5.56 nmole/g in tissues of the normal eyes, respectively. There were similar increases of OH. in the eye tissues, and of H2O2 in the aqueous humor and vitreous humor after diquat injection. We propose that endogenous reductants of the eye tissues univalently reduce diquat to its free radical which spontaneously reacts with O2 generating O2. in excessive amounts, further giving rise to H2O2 and OH. triggering cataractogenesis.


Asunto(s)
Diquat/toxicidad , Ojo/metabolismo , Radicales Libres , Oxígeno/metabolismo , Animales , Diquat/metabolismo , Relación Dosis-Respuesta a Droga , Ojo/efectos de los fármacos , Femenino , Peróxido de Hidrógeno/metabolismo , Hidróxidos/metabolismo , Radical Hidroxilo , Inyecciones , Masculino , Conejos , Superóxidos/metabolismo , Cuerpo Vítreo
20.
Biochem Biophys Res Commun ; 265(2): 345-9, 1999 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-10558869

RESUMEN

Thioredoxin (TRX)-1 and TRX-2 redox-regulatory genes were analyzed in the lens and some other tissues of the Emory mouse, a model for age-related human cataract. The cDNA transcripts of mRNAs encoding TRX-1 and TRX-2 genes were isolated and cloned by RT-PCR from the lens, liver, kidney, and tail, and the cDNA sequences were similar to the reported sequences of murine TRX-1 and TRX-2 genes. In vivo photochemical oxidative stress to the Emory mice resulted in fivefold upregulation of the lens TRX-1 gene at 3 weeks and declined thereafter. Western blot analysis revealed a fourfold increase of TRX-1 protein in the lens at 3 weeks after oxidative stress. The TRX-2 gene in the lens was not changed up to 5 weeks and decreased by 50% thereafter. However, the expressions of these genes in the liver, kidney, and tail were not changed. Fluorescent light or riboflavin alone did not affect the expressions of TRX-1 and TRX-2 genes in the lens. Thus, we show the expressions of TRX-1 and TRX-2 genes in the lens, liver, kidney, and tail and lens-specific upregulation of the TRX-1 gene and protein expressions, possibly as a protective response to the altered redox state of the lens after in vivo oxidative stress to the Emory mouse.


Asunto(s)
Cristalino/metabolismo , Cristalino/efectos de la radiación , Tiorredoxinas/genética , Tiorredoxinas/metabolismo , Envejecimiento/genética , Envejecimiento/metabolismo , Animales , Catarata/etiología , Catarata/genética , Catarata/metabolismo , Clonación Molecular , ADN Complementario/genética , Modelos Animales de Enfermedad , Femenino , Regulación de la Expresión Génica/efectos de la radiación , Humanos , Cristalino/química , Masculino , Ratones , Oxidación-Reducción , Estrés Oxidativo , Fotoquímica , ARN Mensajero/genética , ARN Mensajero/metabolismo , Distribución Tisular
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