[Determination of sialyl transferase activity and effect of phosphorylation and dephosphorylation mechanisms]

Previous reports show that phosphorylation and dephosphorylation mechanisms involve in regulation of sialyl transferase activity. The aim of this research was to study sialyl transferase activity with phosphorylation and dephosphorylation mechanisms. This experimental trial study performed on 25 rats without signs of illness. Rat brains were pulled out and brain homogenization was done and then sialyl transferase purified from rat brain. Homogenization of rat brain is performed in the cephadex chromatography. We added protein kinaseokadaic acid and forbol to different groups. Data were statistically analyzed using SPSS soft wave. Results showed a significant increase in sialyl transferase activity in the control group, comparing with protein kinase C and okadaic acid groups. Results showed a significant decrease in sialyl transferase activity in control group, comparing with protein phosphatase and forbol groups. Our findings show that sialyl transferase of rat brain with protein kinase decreases enzyme activity and these results were in accordance with other studies in this respect. We found that treatment of rat brain sialyl transferase by protein phosphatase increases its activity

release of residual monomeric methyl methacrylate in human saliva after using acrylic dentures

Autopolymerized and heat polymerized acrylic resins are widely used in dentistry for various purposes, Despite the polymerization method, the conversion of monomer into polymer is not complete and varying amounts of free or unreacted monomer [residual monomer] remain in the polymerized resin. The aim of this study was to determine the residual monomeric methyl metacrylate content in the saliva of patients using acrylic dentures, at different time intervals. Informed consents were obtained from 25 patients with complete dentures, ranging in age from 35 to 65 years. 1 mL samples of whole saliva were collected upon insertion of the dentures and l day, 1 week and 1 month after wearing them. Methyl methacrylate [MMA] levels were measured by use of gas chromatography. Data were analyzed by repeated measurement ANOVA and paired sample T-tests. The maximum concentration of monomer released into saliva was detected one day after insertion of the dentures. The Mean [SD] MMA content in saliva was 0.4 +/- 0.12 [ng/ml] upon insertion, and 0.7 +/- 0.16 [ng/ml], 0.5 +/- 0.13 [ng/ml], and 0.38 +/- 0.1 [ng/ml] on the 1st day, 1st week and 1st month post-insertion, respectively. The maximum amount of monomer released by heat-polymerized poly-MMA was observed on the first day after insertion, which, while not a toxic or primary irritant dose, could sensitize patients or elicit an allergic reaction. For minimization of the adverse effects, patients could be advised not to wear their dentures overnight, 24 hours after delivery

[Determination of urine Methanol in subjects exposure to Methylmethacrylate]

Background and Objective: due to volatile property of monomer from Methylmethacrylate and its well known toxic side effects, in case of absorption via skin or respiratory system. Also, due to allergic reactions of it, consideration of suitable ventilation systems and using protective methods is very important. To decrease direct contact with it, the capabilities of technician and improves his health and work place, we investigate relationship between Methanol level and exposure to Methylmethacrylate

Materials and Methods: in a case-control [In vivo] study of 32 dental laboratory technicians in Babol and Sari before and after working and 32 normal subjects, urine samples were collected. Urine Methanol levels were analyzed by paper and gas chromatography

Results: mean concentration of Methanol in case group [1.2 micro mol/l] was significantly more than control group [0.78 micro mol/l]. Also, Methanol level was significantly higher after work [1.45 micro mol/l] when compared to before work [1.27 micro mol/l], [P<0.05]. No relation between work history and urine Methanol level was observed

Conclusion: due to significant increase of Methanol concentration during work in work place, the use of protective methods such as suitable ventilation, wearing mask and gloves, also, using vapor absorbing tubes can be useful in increasing dental laboratory workplace safety

simple and economical procedure for the purification of immunoglobulin Y from egg yolk by T-gel chromatography

The use of immunoglobulin Y [IGY] instead of polyclonal antibodies prepared in mammals has been reported recently. These antibodies are found to have better properties in terms of specificity and ease of large scale production. In this study, proteins from egg yolk were extracted with acid and chloroform. The result of cellulose acetate electrophoresis at pH 9 showed some extra bands which were further purified with sodium sulfate precipitation [20%]. The purified band was observed in the Y globulin region. SDS-PAGE electrophoresis of the product showed impurities which were removed by T-gel chromatography. Following that only H-chain-of immunoglobulin Y with a molecular weight of about 66 KD was observed. Using the above procedure, a yield of around 40.7 mg IGY / egg was obtained

Significant changes in the activity of GABA transaminase and succinate semialdehyde dehydrogenase of mouse hypothalamus following peripheral injection of cholecystokinin-8 and/or caerulein

The activities of 4-aminobutyric-2-oxoglutaric acid transaminase [GABA-T] and succinate semialdehyde dehydrogenase [SSADH] were determined in mouse hypothalamus after peripheral injections of cholecystokinin-8 [CCK-8] and/or caerulein [CLN]. GABA transaminase activity was measured utilizing endogenous succinate semialdehyde dehydrogenase to convert the product of GABA-T, succinate semialdehyde, to succinate. The concurrently formed NADH was used as an estimate of GABA-T activity. Similarly, the activity of SSADH was determined in terms of NADH. Injection of CCK-8 and/or CLN inhibited the GABA-T and SSADH activities in dose-dependent responses. The activities of GABA-T and SSADH were diminished by 52 and 66% respectively. 30 minutes after injection of CCK-8 [50 micro g/kg body weight].Similarly, peripheral injection of CLN [50 micro g/kg body weight] reduced the activity of GABA-T and SSADH by 56 and 65% respectively, in 30 minutes. Using in vitro models, the full activities of GABA-T and/ or SSADH, after incubation with CCK-8 and/or CLN, were restored following 30 hours of dialysis at 4°C. These results indicate direct and reversible interactions between the catabolizing enzymes of GABA [GABA-T and SSADH] and the peptides CCK-8 and CLN

High-performance liquid chromatographic analysis of sulfur mustard reaction with amino acids and proteins

The interaction of sulfur mustard with aminoacids and proteins has been investigated in this study. Rats were injected with sublethal doses of sulfur mustard subcutaneously and intraperitoneally. At different time intervals, plasma and urine samples were collected. The binding affinity of sulfur mustard with urinary and plasma proteins and enzymes was studied for the first time using non-ideal size exclusion high-performance liquid chromatography [HPLC]. We observed that sulfur mustard reacts with proteins and enzymes containing cystein, arginine, and lysine residues