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1.
Eur Rev Med Pharmacol Sci ; 26(6): 2117-2123, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35363361

RESUMEN

OBJECTIVE: This study was aimed at investigating the role of serum asprosin level in diabetic retinopathy pathogenesis and differential diagnosis diabetic and non-diabetic retinopathy. PATIENTS AND METHODS: The cross-sectional study was conducted between May 2021 and August 2021. A total of 21 subjects with diabetic retinopathy, 21 subjects with non-diabetic retinopathy, 21 subjects with type 2 diabetes mellitus (T2DM) without retinopathy and 21 healthy controls were included in the study. Biochemical parameters, serum asprosin, serum IL-6 and TNF-α levels were measured in all participants. RESULTS: Fasting blood glucose (FBG), HbA1c, HOMA-IR and LDL levels were higher in diabetic patients than non-diabetic. The blood asprosin levels were higher in the diabetic retinopathy group compared to the healthy control group (p=0.001), T2DM without diabetic retinopathy (p=0.010), and non-diabetic retinopathy group (p=0.043). There is a significant positive relationship between asprosin level and high FBG, HbA1c and HOMA-IR scores. CONCLUSIONS: Serum asprosin level is significantly increased in DRP group than others. A high asprosin level might be a risk factor for the development of diabetic complications, such as diabetic retinopathy. These findings suggest that the measurement of serum asprosin level may support clinicians in determining the risk of DRP development.


Asunto(s)
Diabetes Mellitus Tipo 2 , Retinopatía Diabética , Estudios Transversales , Diabetes Mellitus Tipo 2/complicaciones , Fibrilina-1 , Humanos , Factores de Riesgo
2.
Br Poult Sci ; 47(2): 209-15, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16641032

RESUMEN

Arginine silicate inositol complex (ASIdagger; arginine 49.5%, silicon 8.2%, inositol 25%) is a novel material which is a bioavailable source of silicon and arginine. ASI offers potential benefits for vascular and bone health. Poor eggshell quality has been a major economic concern to commercial egg producers. Poor egg quality, skeletal abnormalities and architectural deterioration of bone tissue are common problems under hot conditions and in older birds. The effects of ASI supplementation on egg production, egg quality, levels of osteocalcin (OC) and bone mineral content were investigated in heat-stressed Japanese quail during the later part of the laying period. The birds were randomly assigned to six treatment groups consisting of six replicates of five birds each in a 2 x 3 factorial arrangement of treatments (temperatures, ASI levels). The birds were kept in wire cages in a temperature-controlled room at either 22 degrees C (TN) or 34 degrees C (HS) for 8 h/d and fed either a basal (control) diet or the basal diet supplemented with either 500 or 1000 g of ASI/kg. Heat exposure reduced egg production, egg quality and bone mineralisation when the basal diet was fed. ASI supplementation had no effect on feed intake or egg production under TN or HS conditions. However, ASI supplementation increased egg weight, shell thickness, shell weight and Haugh unit in both TN and HS groups during the late laying period. Bone mineral density (BMD) was significantly improved by ASI supplementation in both TN and HS groups. Serum osteocalcin (OC) concentrations and alkaline phosphatase (ALP) activity increased linearly with dietary ASI supplementation during the late laying period. The amount of calcium and phosphorus in the excreta decreased, while ash, mineral content, calcium and phosphorus concentrations in tibia increased in ASI-supplemented quail in both TN and HS groups during the late laying period. ASI supplementation significantly improved egg quality and bone mineralisation in quail during the late laying period and did not affect feed consumption or egg production.


Asunto(s)
Arginina/administración & dosificación , Densidad Ósea/efectos de los fármacos , Coturnix/fisiología , Proteínas en la Dieta/administración & dosificación , Calor , Inositol/administración & dosificación , Complejo Vitamínico B/administración & dosificación , Fosfatasa Alcalina/metabolismo , Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Disponibilidad Biológica , Densidad Ósea/fisiología , Coturnix/metabolismo , Relación Dosis-Respuesta a Droga , Cáscara de Huevo/efectos de los fármacos , Cáscara de Huevo/fisiología , Huevos/normas , Femenino , Necesidades Nutricionales , Osteocalcina/sangre , Oviposición/efectos de los fármacos , Oviposición/fisiología , Distribución Aleatoria , Silicatos
3.
Poult Sci ; 85(3): 486-92, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16553280

RESUMEN

Skeletal abnormalities, low bone mass, bone deformities, and bone fractures increase the risk of osteoporosis and osteoarthritis, which are of concern from both a public standpoint and a cost-of-care burden standpoint. Arginine silicate inositol complex (ASI; Arg = 49.47%, silicone = 8.2%, inositol = 25%) is a novel, bioavailable source of Si and Arg and one that offers potential benefits for vascular and bone health. Skeletal abnormalities and architectural deterioration of bone tissue are common under hot climate conditions in the poultry industry. In this study, we evaluated the effects of ASI supplementation on performance and bone mineral density (BMD) in Japanese quail (Coturnix coturnix japonica) exposed to the high ambient temperature of 34 degrees C. The birds (n = 180; 10 d old) were randomly assigned to 6 treatment groups consisting of 10 replicates of 3 birds. Birds were kept in wire cages in a temperature-controlled room at either 22 degrees C (thermoneutral; TN) or 34 degrees C (heat stress; HS) for 8 h/d (0900 to 1700 h until the end of study) and were fed a basal (control) diet or the basal diet supplemented with either 500 or 1,000 mg of ASI/kg of diet. Heat exposure decreased performance and bone mineralization when the basal diet was fed (P = 0.001). The ASI supplement had no effect on feed intake, BW, feed efficiency, and carcass traits (P > 0.05) in quails reared under TN or HS conditions. The BMD was significantly improved by ASI supplementation in both TN and HS groups [0.72 (TN) vs. 0.60 (HS); P < or = 0.05]. Serum osteocalcin, dehydroepiandrosterone concentrations, and alkaline phosphatase activity increased, whereas tumor necrosis factor-alpha and Creactive protein concentrations decreased, as dietary ASI supplementation increased in quail reared under HS. This improvement was linear with increased doses of supplement (P = 0.001). In the ASI group, the amount of Ca, P, Mg, and Mn in the excreta decreased (P < or = 0.05), and the concentrations of these minerals in tibia ash increased in quail reared under HS conditions (P < or = 0.05). In conclusion, ASI supplementation to the basal diet significantly improved bone mineralization in quail and did not impact feed consumption, BW gain, or feed efficiency.


Asunto(s)
Arginina/farmacología , Calcificación Fisiológica/efectos de los fármacos , Coturnix/fisiología , Inositol/farmacología , Silicatos/farmacología , Animales , Arginina/química , Densidad Ósea , Coturnix/crecimiento & desarrollo , Coturnix/metabolismo , Dieta/veterinaria , Suplementos Dietéticos , Relación Dosis-Respuesta a Droga , Metabolismo Energético/efectos de los fármacos , Heces/química , Calor , Inositol/química , Silicatos/química
4.
Br Poult Sci ; 46(4): 457-63, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16268103

RESUMEN

1. The effects of chromium picolinate and biotin supplementation alone and in combination on performance, carcase characteristics, malondialdehyde (MDA), vitamin C, vitamin E, glucose and cholesterol levels were evaluated in Japanese quail exposed to high ambient temperature. 2. Two hundred and forty quails (10d old) were assigned randomly to 4 dietary treatments at room temperature (22 degrees C; thermoneutral, TN) or ambient (34 degrees C for 8 h/d; heat stress, HS). Both TN and HS were fed either on a basal (control) diet or the basal diet supplemented with 400 microg of Cr/kg (Cr group), 0.5 mg of biotin/kg of diet (biotin group) or both (Cr + Biotin group). 3. Supplementing the diet of heat-stressed quails with chromium picolinate improved live weight gain, feed intake, feed efficiency and carcase traits. Biotin supplementation during TN and HS conditions did not have any beneficial effects on body weight gain, feed intake, feed efficiency or carcase traits. 4. Either in combination or alone, chromium picolinate increased serum concentrations of vitamins C and E, but decreased MDA, glucose and cholesterol concentrations in birds kept at high ambient temperature. There was no difference in vitamins C and E and MDA concentrations between birds given chromium picolinate and birds receiving chromium picolinate plus biotin, while glucose and cholesterol levels were significantly lower in all groups. The lowest concentrations of cholesterol and glucose were found in the combination group under both TN and HS conditions. An interaction between diet and temperature was detected for glucose and cholesterol concentrations. 5. Excretion rates for zinc, iron and chromium were lower in TN groups than in the corresponding HS groups. Supplementing diet with chromium picolinate and chromium picolinate plus biotin decreased excretion of minerals while biotin alone did not effect excretion of minerals. 6. Chromium supplementation, but not biotin supplementation, attenuated the decline in performance and antioxidant status resulting from heat stress.


Asunto(s)
Coturnix/metabolismo , Calor , Ácidos Picolínicos/uso terapéutico , Enfermedades de las Aves de Corral/tratamiento farmacológico , Enfermedades de las Aves de Corral/metabolismo , Estrés Fisiológico/tratamiento farmacológico , Estrés Fisiológico/veterinaria , Animales , Biotina/administración & dosificación , Biotina/farmacología , Biotina/uso terapéutico , Suplementos Dietéticos , Quimioterapia Combinada , Ácidos Picolínicos/administración & dosificación , Ácidos Picolínicos/farmacología , Enfermedades de las Aves de Corral/fisiopatología , Estrés Fisiológico/metabolismo , Estrés Fisiológico/fisiopatología , Temperatura , Aumento de Peso
5.
Poult Sci ; 84(6): 882-7, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15971524

RESUMEN

Two sources of zinc [ZnSO4.H2O or ZnPicolinate (ZnPic)] supplementation were evaluated for their effects on performance, carcass weight, levels of malondialdehyde, and vitamins C, E, A in Japanese quail (Coturnix coturnix Japonica) exposed to high ambient temperature of 34 degrees C. The birds (n = 360; 10-d-old) were randomly assigned to 12 treatment groups consisting of 3 replicates of 10 birds each in a 2 x 2 x 3 factorial arrangement of treatments (temperatures, zinc sources, zinc levels). Birds were kept in wire cages in a temperature-controlled room at either 22 degrees C (thermoneutral) or 34 degrees C (heat stress) for 8 h/d (0900 to 1700 h) until the end of study, and fed a basal (control) diet or the basal diet supplemented with either 30 or 60 mg of Zn as ZnSO4 H2O or ZnPic/kg of diet. Heat exposure decreased (P = 0.001) live weight gain, feed intake, feed efficiency, and carcass weight when the basal diet was fed. A linear increase in feed intake (P = 0.01) and BW (P = 0.01), and improvement in feed efficiency (P = 0.01) and carcass weight (P < or = 0.05) were found in zinc-supplemented quail reared under heat-stress conditions. Serum vitamin C (P = 0.04), E (P = 0.05), and cholesterol (P = 0.01) concentrations increased linearly, whereas malondialdehyde concentrations decreased linearly (P = 0.02) as dietary zinc sulfate and ZnPic supplementation increased. An interaction between dietary zinc sources, temperature, and levels of supplementation (P < or = 0.05) for these parameters was detected. Serum vitamins C, E, and A concentrations were not different in supplemented birds reared at thermoneutral temperature. Supplementation with zinc improved carcass weight and antioxidant status of birds, and the effects of ZnPic were relatively greater than those of ZnSO4.H2O in heat-stressed quail. Results of the present study suggest that supplementation with ZnPic could be considered to be more protective than ZnSO4.H2O by reducing the negative effects of oxidative stress induced by heat stress in quail.


Asunto(s)
Antioxidantes/análisis , Coturnix/fisiología , Dieta , Calor , Zinc/administración & dosificación , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Ácido Ascórbico/sangre , Colesterol/sangre , Suplementos Dietéticos , Ingestión de Alimentos , Hígado/anatomía & histología , Hígado/química , Masculino , Malondialdehído/análisis , Tamaño de los Órganos , Ácidos Picolínicos/administración & dosificación , Vitamina E/sangre , Aumento de Peso , Sulfato de Zinc/administración & dosificación
6.
Gynecol Obstet Invest ; 59(2): 108-12, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15591805

RESUMEN

BACKGROUND: We have investigated the effects of surgical menopause and estrogen replacement therapy (ERT) on serum paraoxonase 1 (PON1) activity and plasma malondialdehyde (MDA) levels in surgically postmenopausal women. METHODS: Thirty-six healthy perimenopausal women who underwent total abdominal hysterectomy and bilateral salpingo-oopherectomy for uterine myoma were enrolled in this study. Blood samples were taken from the subjects 1 day before surgery, 1 day before starting ERT (30 days after the operation) and on the 30th day after the start of therapy. RESULTS: After surgical menopause, there were significant increases in plasma MDA levels (p < 0.05) and a decrease in serum PON1 activity (p < 0.05). ERT significantly increased the PON1 activity (p < 0.05) and reduced MDA levels (p < 0.05). There was a positive correlation between serum high-density lipoprotein cholesterol and PON1 activity (r = 0.7, p < 0.001, n = 36) and a negative correlation between serum PON1 activity and plasma MDA levels (r = -0.63, p < 0.006, n = 36). CONCLUSIONS: The present study suggests that postmenopausal women tend to have high levels of plasma MDA and reduced PON1 activity, and ERT reverses these effects. The effect of ERT on lipid peroxidation seems to be associated with serum PON1 activity.


Asunto(s)
Arildialquilfosfatasa/sangre , Terapia de Reemplazo de Estrógeno , Histerectomía , Malondialdehído/sangre , Menopausia , Ovariectomía , Arildialquilfosfatasa/efectos de los fármacos , Femenino , Humanos , Histerectomía/efectos adversos , Leiomioma/cirugía , Peroxidación de Lípido , Ovariectomía/efectos adversos , Resultado del Tratamiento , Neoplasias Uterinas/cirugía
7.
Biol Trace Elem Res ; 101(2): 181-92, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15557680

RESUMEN

Chromium picolinate is used in the poultry diet because of its antistress effects in addition to the fact that the requirement for it is increased during stress. This study was conducted to determine if the negative effects of high ambient temperature (34 degrees C) on egg production, egg quality, antioxidant status, and cholesterol and mineral content of egg yolk could be alleviated by combination of chromium picolinate and biotin (0.6/2.0; Diachrome, as formulated by Nutrition 21 Inc.), in laying Japanese quails (Coturnix coturnix japanica). Quails (n= 240; 50 d old) were divided into 8 groups, 30 birds per group. The quails were fed either a basal diet or the basal diet supplemented with 2, 4, or 8 mg of Diachrome/kg diet. Birds were kept at 22 degrees C and 53% relative humidity (RH). At 14 wk of age, the thermoneutral (TN) group remained in the same temperature as at the beginning of experiment, whereas the heat stress (HS) group was kept in an environment-controlled room (34 degrees C and 41% RH) for 3 wk. Heat exposure decreased performance when the basal diet was fed (p = 0.001). Diachrome supplementation at 4 and 8 mg/kg diet, increased feed intake (p = 0.05), egg production (p = 0.05), feed efficiency (p = 0.01), egg weight (p = 0.05), and Haugh unit (p = 0.01) in quails reared under heat stress conditions. Heat exposure increased concentrations of serum malondialdehyde (MDA) (p = 0.001), glucose, and cholesterol (p = 0.01), which were elevated by supplemental Diachrome (p < or = 0.05). Egg yolk Cr, Zn, and Fe (p = 0.01) concentrations increased linearly, whereas MDA and cholesterol concentrations decreased (p = 0.05) as dietary Diachrome supplementation increased in HS groups. Similar effects of supplementation on serum levels of glucose and cholesterol (p = 0.05) and egg yolk concentrations of cholesterol (p = 0.05) and Cr (p = 0.01) were observed in TN groups. No significant differences in other values were observed in the TN groups. Results of the present study suggest that supplementation with Diachrome protects the quail by reducing the negative effects of heat stress.


Asunto(s)
Biotina/administración & dosificación , Colesterol/metabolismo , Cromo/administración & dosificación , Coturnix/fisiología , Dieta , Yema de Huevo/metabolismo , Huevos , Trastornos de Estrés por Calor/metabolismo , Animales , Biotina/metabolismo , Cromo/metabolismo , Coturnix/metabolismo , Femenino
8.
Br Poult Sci ; 45(1): 116-22, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15115209

RESUMEN

1. The effects of ascorbic acid (L-ascorbic acid) and melatonin supplementation on performance, carcase characteristics, malondialdehyde (MDA) as lipid peroxidation indicator, ascorbic acid, retinol, tocopherol and mineral status in the Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature were evaluated. 2. Two hundred and forty Japanese quails (10 d old) were randomly assigned to 8 treatment groups consisting of 10 replicates of three birds each. The birds were kept in a temperature-controlled room at 22 degrees C (Thermoneutral, TN groups) or 34 degrees C (for 8 h/d; 09:00 to 17:00 h; Heat stress, HS groups). Birds in both TN and HS were fed either a basal (control) diet or the basal diet supplemented with 250 mg of L-ascorbic acid/kg of diet (Ascorbic acid group), 40 mg of melatonin/kg of diet (Melatonin group) or both (Ascorbic acid + Melatonin group). 3. Supplementing heat-stressed quails with ascorbic acid and melatonin improved performance compared with the control group. Effects generally were greatest in quails supplemented with both ascorbic acid and melatonin. 4. Although supplementation did not consistently restore the concentrations of serum ascorbic acid, retinol and tocopherol to those of TN groups, these concentrations increased significantly with supplementation. Furthermore, serum and liver MDA and serum cholesterol and glucose concentrations were lower in the supplemented groups than in the heat-stressed controls. 5. Within each environment, excretion of Ca, P, Mg, Zn, Fe and Cr were lowest in the combination group and, in all cases, highest in the HS group. Interactions between diet and temperature were detected for live weight gain, cold carcase weight, MDA, ascorbic acid, tocopherol concentrations and excretion of zinc. 6. The results of the study indicate that ascorbic acid and melatonin supplementation attenuate the decline in performance and antioxidant and mineral status caused by heat stress and such supplementation may offer protection against heat-stress-related depression in performance of Japanese quails.


Asunto(s)
Antioxidantes/farmacología , Ácido Ascórbico/farmacología , Coturnix/metabolismo , Trastornos de Estrés por Calor/veterinaria , Melatonina/farmacología , Estrés Oxidativo , Animales , Ácido Ascórbico/sangre , Glucemia/metabolismo , Peso Corporal/efectos de los fármacos , Colesterol/sangre , Ingestión de Alimentos/efectos de los fármacos , Heces/química , Trastornos de Estrés por Calor/tratamiento farmacológico , Malondialdehído/sangre , Tocoferoles/sangre , Vitamina A/sangre
9.
Arch Anim Nutr ; 58(6): 463-71, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15732579

RESUMEN

Genistein, a phytoestrogen found in soybeans, is a powerful antioxidant. We evaluated the effects of genistein supplementation on performance, carcass characteristics, levels of malondialdehyde (MDA), homocysteine, vitamins C, E, A in Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature of 34 degrees C. Two hundred and forty Japanese quails (10 d old) were randomly assigned to eight treatment groups consisting of 10 replicates of three birds. The birds were kept in an environmental controlled room either for 24 h/d at 22 degrees C with (thermoneutral, TN groups) or for 16 h/d at 22 degrees C and for 8 h/d (09.00 am to 05.00 pm) at 34 degrees C (heat stress, HS groups). Birds were fed either a basal (control) diet (TN and HS) or the basal diet supplemented with 200, 400 or 800 mg of genistein per kg of diet. Heat exposure decreased birds' performance when basal diet was fed. Increase in feed intake and body weight, and improvement of feed efficiency and carcass traits were found in genistein-supplemented quails reared under heat stress conditions. Growth rate and feed efficiency improved in quails reared under thermo-neutral conditions as well. Concentration of serum vitamins C, E, and A increased in supplemented birds reared at high temperature, while non-significant changes occurred in TN groups. With genistein supplementation homocysteine levels in serum and MDA levels in serum and liver decreased in all birds of both TN and HS groups. Effects of genistein were relatively greater in heat-stressed quails than in quails kept under thermo-neutral conditions. Results of the present study suggest that supplementation with genistein can be considered to be protective by reducing the negative effects of oxidative stress induced by heat stress in quail.


Asunto(s)
Antioxidantes/farmacología , Coturnix/crecimiento & desarrollo , Genisteína/farmacología , Trastornos de Estrés por Calor/veterinaria , Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Antioxidantes/administración & dosificación , Coturnix/metabolismo , Suplementos Dietéticos , Relación Dosis-Respuesta a Droga , Ingestión de Alimentos/efectos de los fármacos , Genisteína/administración & dosificación , Trastornos de Estrés por Calor/tratamiento farmacológico , Distribución Aleatoria , Aumento de Peso/efectos de los fármacos
10.
J Nutr ; 133(6): 1882-6, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12771333

RESUMEN

We evaluated the effects of vitamin C (L-ascorbic acid) and folic acid supplementation on performance, carcass characteristics and concentrations of the oxidative stress markers [malondialdehyde (MDA), homocysteine], adrenocorticotropic hormone (ACTH), vitamins C, E, A, B-12 and folic acid, and mineral status in broiler Japanese quail (Coturnix coturnix japonica) exposed to high ambient temperature (34 degrees C, 8 h/d, 0900-1700 h). The birds (n = 150; 10-d-old) kept at 34 degrees C were fed a basal diet (HS group) or the basal diet supplemented with 250 mg of L-ascorbic acid/kg of diet (Vit C group), 1 mg of folic acid/kg of diet (FA group) or both (Vit C + FA group), whereas birds kept at 22 degrees C were fed the basal diet (TN group). Supplementing heat-stressed quail with vitamin C and folic acid improved performance compared to the HS group. Effects generally were greatest in quail supplemented with both. Although supplementation did not consistently restore concentrations to those of the TN group, it increased serum concentrations of the vitamins under study. Furthermore, serum and tissue MDA, homocysteine and ACTH concentrations were lower in the supplemented groups than in the heat-stressed controls. Retention of N, ash, Ca, P, Zn, Fe, Cu and Cr were highest in the Vit C + FA group and lowest in the HS group (P < 0.05). The results of the study indicate that vitamin C and folic acid supplementation attenuates the decline in performance and antioxidant status caused by heat stress. Such supplementation may offer protection against heat stress-related depression in performance of Japanese quail.


Asunto(s)
Ácido Ascórbico/farmacología , Coturnix , Suplementos Dietéticos , Ácido Fólico/farmacología , Trastornos de Estrés por Calor/veterinaria , Enfermedades de las Aves de Corral/terapia , Crianza de Animales Domésticos , Animales , Ácido Ascórbico/administración & dosificación , Dieta , Ácido Fólico/administración & dosificación , Trastornos de Estrés por Calor/metabolismo , Trastornos de Estrés por Calor/fisiopatología , Trastornos de Estrés por Calor/terapia , Actividad Motora/efectos de los fármacos , Enfermedades de las Aves de Corral/dietoterapia , Enfermedades de las Aves de Corral/tratamiento farmacológico
11.
Arch Med Res ; 32(5): 432-5, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11578759

RESUMEN

BACKGROUND: The presence of arginase and ornithine carbamoyltransferase (OTC'ase) enzymes in human vitreous humor after death was investigated in this study. To the best of our knowledge, there is no prior report on the activity of arginase or ornithine carbamoyltransferase in human vitreous humor. METHODS: The presence of arginase and OTC'ase activities were examined in the human vitreous humor of 19 samples. Spectrophotometric methods were used to determine activities of arginase and OTC'ase. RESULTS: Arginase activity was detected in human vitreous humor, whereas OTC'ase activity was below the detection limit. Therefore, we focused on biochemical analysis of arginase in human vitreous humor. Kinetic properties of arginase activity in vitreous humor were optimized. In contrast to other arginases, optimal preincubation temperature and pH were 40 degrees C and 8.8, respectively. Km of vitreous arginase for L-arginine was 6 mM. Preincubation of the enzyme with Mn(2)+ ions caused a significant increase (33%) in arginase activity. CONCLUSIONS: The activity and presence of arginase as well as its kinetics in human vitreous are documented in this study. Biochemical functions and the importance of arginase in vitreous humor are not well understood. However, its presence may be explained by means of its involvement in polyamine biosynthesis as observed in the other extrahepatic tissues.


Asunto(s)
Arginasa/análisis , Proteínas del Ojo/análisis , Ornitina Carbamoiltransferasa/análisis , Cuerpo Vítreo/enzimología , Adulto , Arginina/metabolismo , Femenino , Humanos , Concentración de Iones de Hidrógeno , Cinética , Masculino , Manganeso/farmacología
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