P301 INHIBITION of HUMAN CATALASE by TRIARYLMETHANE DYES

P301

INHIBITION of HUMAN CATALASE by TRIARYLMETHANE DYES

Triarylmethane (TAM⁺) dyes are extensively used in inks, used as a dye for wood, silk, and paper, used as a biological stain, a blood purging agent in blood transmission, as microbicide, and anthelmintic, and also used traditionally as an antifungal agent in aquaculture although they are not currently approved for use by the Food and Drug Administration (FAD). Since TAM⁺ dyes have been recently shown to interact with plasma proteins and cellular components to cause some irreversible redox changes in their targets possibly mediated by TAM⁺-derived free radicals and to have toxic and carcinogenic effects on mammalian tissues, three TAM⁺ dyes, malachite green (MG⁺), leucomalachite green (LMG⁺) and gentian violet (GV⁺), were tested for their inhibitory actions on human catalase. Catalase, one of the key protective enzymes against the reactive oxygen species (ROS) produced in the cell, was isolated from human erythrocytes with a spesific activity of 160 U/mg. The K_m and the V_max values of the crude enzyme were found as 27 mM and 200 mmol/min/mg protein, respectively. All of the TAM⁺ dyes tested inhibited the human catalase non-competetively and irreversibly by incubating the enzyme with inhibitors at the various concentrations for 0-60 minutes at 37⁰C. K_i values were found as 8-20 mM at these conditions. The enzyme was completely inactivated with the relatively high concentrations of MG⁺ and LMG⁺ up to 40 mM . Although the mode of the inhibition of catalase with TAM⁺ dyes appeared as non-competitive, the mechanism seemed complex. These preliminary results suggested that irreversible inhibiton of erythrocyte redox enzymes by TAM⁺ dyes which might lead an increase in the ROS production and lipid peroxidation in the cell could play an important role in cell demage in human.

Insulin-like growth factor-I (IGF-I) is an essential factor for longitudinal bone growth and stimulation of both proliferation and differentiation of osteoblasts. Early epidemiologic studies examining the association of 3-hydroxy-3methylglutaryl coenzyme A reductase inhibitors (statins) in preventive therapy of osteoporotic hip fractures produced encouraging results. In the present study, we aimed to investigate the early serum changes in IGF-I and IGF binding protein-3(IGFBP-3), which is the major binding protein of IGF-1, levels before and after three months of statin medication. Thirty women with untreated postmenopausal osteoporosis were taken into the study. Blood samples were obtained before and after 3 months of statin treatment. Serum IGF-I and IGFBP-3 levels were assessed by enzyme-linked immunosorbent assay method by DSL (Diagnostic Systems Laboratories, Inc. Webster, Texas, USA) reagents. Bone turnover markers of osteocalcin, parathyroid hormone, and C-telopeptide of type 1 collagen (CTX) levels were assessed on serum samples by automated chemiluminescence method by commercial reagents on autoanalyzer (E170 Modular System, Roche Diagnostics Corporation, Indianapolis, USA). Total cholesterol, triglyceride, HDL cholesterol, LDL cholesterol, calcium, phosphorus and total alkaline phosphatase were assessed by enzymatic methods on autoanalyzer (Integra Roche Diagnostics Corporation, Indianapolis, USA). Bone alkaline phosphatase was assessed by heat inactivation method. Bone mineral density was assessed by dual energy X-ray absorbtiometry. We found significant (p<0.05) difference in IGFBP-3 levels before and after statin treatment. However we did not find any significant difference between the remaining biochemical bone turnover markers. In conclusion, although our results revealed a positive effect of statin on osteoporosis in postmenopausal women, we are of the opinion that the long term effects of statin medication should be further studied.

SALIVA LEPTIN AND DIABETES

S. Aydin, F. Erman, N. Kilic, *Ozkan Y, S. P.Guzel, Halifeoglu I

Department of Biochemistry and Clinical Biochemistry, *Department of Intermal Medicine Firat University, Elazig, TURKEY 23119

LEPTIN, the product of the ob gene, is a hormone secreted primarily by adipocytes, and recently, leptin has been also identified in saliva. The aim of this study was to determine whether saliva leptin concentrations was the same with serum leptin concentrations or not.

Serum,and saliva leptin concentrations were examined in 17 clinically healthy men and 16 men with type I diabetes. Blood and saliva samples were collected from subjects between 8.00am and 10.00 am following a 12-hour fast. The extracted blood and saliva samples were then centrifuged at 4000 rpm for 10 minutes and stored at –70 degrees until the assay was performed. Serum and saliva leptin levels were determined by enzyme immunoassay technique.

The mean leptin and saliva level were statistically greater (P < .001; P < .002, respectively) in the diabetic men than in the healthy men (8.43 +/- 0.56 ng/mL; 7.31+/- 0.44 ng/mL vs. 21.07 +/- 1.42 ng/mL; 16.03 +/- 1.21 ng/mL respectively). The concentrations of serum and saliva leptin were similar, but sometimes saliva leptin concentrations indicated some diparity.

Our results suggest that saliva leptin concentrations may be used clinically instead of serum leptin concentrations because of being sample collection not invasive

P304

Directory: 2003
2003 -> Tr-41. 4-03-05-024 Telecommunications
2003 -> Review of some tsunamis in canada
2003 -> The skill of multi-model seasonal forecasts of the wintertime North Atlantic Oscillation
2003 -> 2930 Kerry Forest Parkway
2003 -> Canadian Interuniversity Sport (cis) Athletes of the Week
2003 -> Senior Airman Jason Plite Hometown
2003 -> Technical announcements: My apologies for the comparison pages; they were
2003 -> Pool Play Round 1 9: 20: 00 am
2003 -> 2004 Division II men's Golf Championships Final Round Results deland, fla
2003 -> Go Figure Edited by Kostya Kennedy and Mark Bechtel 645 Passing yards, an ncaa division II record, by University of Indianapolis quarterback Matt Kohn, in a 59-52 victory over Michigan Tech

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