scholarly journals Carbofuran Modulating Functions of Acetylcholinesterase from Rat Brain In Vitro

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Vivek Kumar Gupta ◽  
Ashutosh Pathak ◽  
Nikhat Jamal Siddiqi ◽  
Bechan Sharma
Keyword(s):  
Rat Brain ◽  
Kinetic Studies ◽  
Biochemical Properties ◽  
Brain Functions ◽  
Brain Ache ◽  
Acetylthiocholine Iodide ◽  
Nonionic Detergent ◽  
Environmental Xenobiotic ◽  
The Impact

Carbofuran, a potential environmental xenobiotic, has the ability to cross blood brain barrier and to adversely influence brain functions. In the present study, the impact of carbofuran on the biophysical and biochemical properties of rat brain AChE has been evaluated in vitro. This enzyme was membrane-bound which could be solubilised using Triton-X100 (0.2%, v/v), a nonionic detergent, in the extraction buffer (50 mM phosphate, pH 7.4). The enzyme was highly stable up to one month when stored at -20°C and exhibited optimum activity at pH 7.4 and 37°C. AChE displayed a direct relationship between activity and varying substrate concentrations (acetylthiocholine iodide (ATI)) by following Michaelis-Menten curve. The Km and Vmax values as computed from the Lineweaver-Burk double reciprocal plot of the data were found to be 0.07 mM and 0.066 µmole/mL/min, respectively. The enzyme exhibited IC50 value for carbofuran equal to 6.0 nM. The steady-state kinetic studies to determine mode of action of carbofuran on rat brain AChE displayed it to be noncompetitive in nature with Ki value equal to 5 nm. These experiments suggested that rat brain AChE was very sensitive to carbofuran and this enzyme might serve as a significant biomarker of carbofuran induced neurotoxicity.

scholarly journals Transglutaminase 3 crosslinks secreted MUC2 and stabilizes the colonic mucus layer

2021 ◽  
Author(s):  
Jack Sharpen ◽  
Brendan Dolan ◽  
Elisabeth Nyström ◽  
George Birchenough ◽  
Liisa Arike ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Biochemical Properties ◽  
Layered System ◽  
Transferase Activity ◽  
Mucus Layer ◽  
Commensal Flora ◽  
The Impact ◽  
Gel Network ◽  
Increased Susceptibility

Abstract The colonic mucus layer is organized as a two-layered system providing a physical barrier against pathogens and simultaneously harboring the commensal flora. The factors contributing to the organization of this gel network are not well understood. In this study, the impact of transglutaminase activity on this architecture was analyzed. Here, we show that transglutaminase TGM3 is the major TGM isoform expressed and synthesized in the colon. Furthermore, intrinsic extracellular TGM activity in the secreted mucus was demonstrated in vitro and ex vivo. Absence of this acyl-transferase activity resulted in faster degradation of the major mucus component the MUC2 mucin and changed the biochemical properties of mucus. Finally, TGM3-deficient mice showed an early increased susceptibility to DSS-induced colitis. Thus, these observations suggest that natural isopeptide cross-linking by TGM3 is important for mucus homeostasis and protection of the colon from inflammation, a suggested pre-stage of colon carcinoma.

scholarly journals Transglutaminase 3 crosslinks the secreted gel-forming mucus component Mucin-2 and stabilizes the colonic mucus layer

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Jack D. A. Sharpen ◽  
Brendan Dolan ◽  
Elisabeth E. L. Nyström ◽  
George M. H. Birchenough ◽  
Liisa Arike ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Biochemical Properties ◽  
Layered System ◽  
Transferase Activity ◽  
Mucus Layer ◽  
Transglutaminase Activity ◽  
Commensal Flora ◽  
Mucin 2 ◽  
The Impact

AbstractThe colonic mucus layer is organized as a two-layered system providing a physical barrier against pathogens and simultaneously harboring the commensal flora. The factors contributing to the organization of this gel network are not well understood. In this study, the impact of transglutaminase activity on this architecture was analyzed. Here, we show that transglutaminase TGM3 is the major transglutaminase-isoform expressed and synthesized in the colon. Furthermore, intrinsic extracellular transglutaminase activity in the secreted mucus was demonstrated in vitro and ex vivo. Absence of this acyl-transferase activity resulted in faster degradation of the major mucus component the MUC2 mucin and changed the biochemical properties of mucus. Finally, TGM3-deficient mice showed an early increased susceptibility to Dextran Sodium Sulfate-induced colitis. Here, we report that natural isopeptide cross-linking by TGM3 is important for mucus homeostasis and protection of the colon from inflammation, reducing the risk of colitis.

scholarly journals Impact of the Interaction of R207910 with Rifampin on the Treatment of Tuberculosis Studied in the Mouse Model

2008 ◽  
Vol 52 (10) ◽  
pp. 3568-3572 ◽  
Author(s):  
Nacer Lounis ◽  
Tom Gevers ◽  
Joke Van Den Berg ◽  
Koen Andries
Keyword(s):  
Mouse Model ◽  
Kinetic Studies ◽  
Bactericidal Effect ◽  
New Drugs ◽  
Significant Activity ◽  
Bacterial Clearance ◽  
Background Regimen ◽  
The Difference ◽  
The Impact

ABSTRACT New drugs are needed to shorten the duration of tuberculosis treatment. R207910, a diarylquinoline, is very active against Mycobacterium tuberculosis both in vitro and in mice. In healthy volunteers, the coadministration of R207910 and rifampin induced the increased metabolism of R207910, resulting in a 50% reduction in the level of R207910 exposure. We assessed the impact of reducing the dose of R207910 on its efficacy when R207910 was combined with a background regimen of isoniazid, rifampin, and pyrazinamide. Addition of 25 mg/kg of body weight or 12.5 mg/kg R207910 to the background regimen resulted in faster bacterial clearance and culture negativity. The difference in efficacy between the two doses was not statistically significant. The minimal bactericidal dose of R207910 when it was tested as part of the combination was identical to that when it was tested as monotherapy. Because of the drug-drug interaction in humans, the activity of R207910 in humans could be less than that expected from studies with mice. Our data from the mouse model demonstrate that R207910 has significant activity, even when its exposure is reduced by 50% and when it is added to a strong background regimen of isoniazid, rifampin, and pyrazinamide. In killing kinetic studies, the bactericidal effect of R207910 in mice was modest during the first week of treatment, but it increased in the following 3 weeks, while the bactericidal activity of isoniazid was limited to the first week of treatment.

The deacylation of phosphatidylinositol by rat brain preparations

1979 ◽  
Vol 57 (12) ◽  
pp. 1359-1367 ◽  
Author(s):  
T. Y. P. Shum ◽  
N. C. C. Gray ◽  
K. P. Strickland
Keyword(s):  
Oleic Acid ◽  
Fatty Acid ◽  
Rat Brain ◽  
Divalent Cations ◽  
Brain Homogenate ◽  
Phospholipase A ◽  
Ph Optimum ◽  
Major Activity ◽  
Nonionic Detergent

The deacylation of phosphatidylinositol (PI) in rat brain was studied in vitro. Using 1-acyl, 2-[1-14C-oleoyl] sn-glycerol-3-phosphoinositol and [U-14C]phosphatidylinositol as substrates, a release of 14C-free fatty acid was found when incubations were conducted with the PI labelled in the 2 position, both in the 12 000 – 106 000 g pellet (microsomal) and in the 106 000 g supernate prepared from rat brain homogenate. With the 106 000 g pellet the deacylation activity was linear with time up to 15 min and was directly proportional to the amount of protein added. Two pH optima were observed, one in the region of pH 7.5 which constituted the major activity and the other in the region of pH 6.0. The apparent Km for the enzyme activity at pH 7.5 was found to be 6.2 × 10−4 M and the Vmax was 1.24 nmol of [14C]oleic acid released per minute per milligram of protein. The Ca2+ ion stimulated the activity maximally at 5 mM while other divalent cations such as Mg2+, Mn2+, Cd2+, Co2+, Cu2+, Fe2+, Hg2+, Ni2+, Pb2+, and Zn2+ either partially or completely inhibited the activity. The nonionic detergent, Triton X-100, stimulated the deacylation more than twofold at a concentration of 0.01%. The sulfydryl reagents, p-chloromercuribenzoate, N-ethylmaleimide, and iodoacetamide showed partial inhibition of the reaction which was reversed by the addition of dithiothreitol. The deacylation activity in the 106 000 g supernate from rat brain was found to be directly proportional to the amount of protein added, and to the time (up to 15 min). A pH optimum was observed in the region of pH 6.0. Substrate concentration studies showed that the apparent Km was 5.0 × 10−4 M and the Vmax was 3.93 nmol of [14C]oleic acid released per minute per milligram of protein. "lyso-PI," diacylglycerol, and fatty acid were formed at pH 6.0 and pH 7.5. The data obtained indicate that from 54 (pH 7.5) to 70% (pH 6.0) of the altered PI is due to phospholipase A2 activity, 24 (pH 6.0) to 28% (pH 7.5) is due to phospholipase "C-like" activity, and from 2 (pH 6.0) to 22% (pH 7.5) may be due to phospholipase A1 activity. These results provide evidence for the deacylation component of a deacylation–reacylation cycle for the generation of specific molecular species of PI.

Insulin secretion in the spiny mouse (Acomys cahirinus). Dose and time kinetic studies with glucose in vivo and in vitro

Diabetes ◽  
1975 ◽  
Vol 24 (12) ◽  
pp. 1094-1100 ◽  
Author(s):  
A. Rabinovitch ◽  
A. Gutzeit ◽  
A. E. Renold ◽  
E. Cerasi
Keyword(s):  
Insulin Secretion ◽  
Kinetic Studies ◽  
Spiny Mouse ◽  
Acomys Cahirinus

Gastroretentive System of Fluvastatin Sodium by Using Natural Mucilage and Synthetic Polymer

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Umamaheswara G. ◽  
Anudeep D.
Keyword(s):  
Half Life ◽  
Release Kinetics ◽  
Kinetic Studies ◽  
Diffusion Path ◽  
Synthetic Polymer ◽  
In Vitro Dissolution ◽  
Direct Compression ◽  
Drug Content ◽  
Biological Half Life

Fluvastatin sodium is a novel compound used as cholesterol lowering agent which acts through the inhibition of 3- hydroxyl-3- methyl glutaryl- coenzyme A (HMG-Co A) reductase. It has short biological half life (1-3h) in humans required a dosing frequency of 20 to 40mg twice a day. Due to its short variable biological half life it has been developed to a sustained gastroretentive system with a natural and synthetic polymer and to study how far the natural mucilage improves the sustained activity. Floating tablets were prepared by direct compression method using in combination of natural mucilage and synthetic polymer. Prior to the preparation of tablets the physical mixtures were subjected to FT IR studies and pre compression parameters. After preparation of tablets they were subjected to various tests like swollen index, drug content, In vitro dissolution and release kinetics with pcp disso software etc. The tablets prepared by direct compression shown good in thickness, hardness and uniformity in drug content, the prepared tablets floated more than 12h except FS1 and FS2 shows 9 and 11h. Swollen index studies shows with increase in concentration of polymer the swelling increases the diffusion path length by which the drug molecule may have to travel and cause lag time. In vitro results shows that on increasing the amount of hibiscus polymer the sustain activity is increased because of its integrity and forms a thick swollen mass and reduces the erosion property of the HypromelloseK100M, kinetic studies shows that FS 1, FS2, FS3 followed the Korsmeyer peppas model and the rest FS 4, FS 5, FS6 follows the zero order respectively. Based on n value indicating that the drug release followed super case II transport mechanism due to the erosion of the polymer.

Formulation and Evaluation of Atenolol and Indapamide SR Matrix Tablets for Treatment of Hypertension

2014 ◽  
Vol 7 (2) ◽  
pp. 2450-2458
Author(s):  
Sarika Pundir ◽  
Ashutosh Badola
Keyword(s):  
Kinetic Studies ◽  
Film Coating ◽  
Matrix Tablets ◽  
Wet Granulation ◽  
Simultaneous Estimation ◽  
Matrix Tablet ◽  
Release Agent ◽  
Disintegration Time ◽  
Weight Variation

In the present study we have formulated (F1 to F6) matrix tablets of atenolol and indapamide for the management of hypertension. As in simultaneous estimation of these drugs it was found that a confined release can be formulated. In the formulation of SR matrix tablet by using different concentration of delayed release agent DCP and pregelatinized starch as disintegrant we prepared tablets by wet granulation method. For sustained release action HPMC polymers were used for film coating. Preformulation studies were performed prior to compression. The compressed SR matrix tablets were evaluated for weight variation, hardness, friability, drug content, disintegration time and in vitro drug release using USP dissolution apparatus type 2 (paddle). It was found that the optimized formulation showed 49.33%, 48.90%, 48.52%, 47.65%, 46.84% and 46.51% release for atenolol in 12 hours respectively. However, indapamide released 49.62%, 49.39%, 48.72%, 48.27%, 47.59% and 47.36% at the end of 12 hr. The IR spectrum study revealed that there is no disturbance in the principal peaks of pure drugs atenolol and indapamide. This confirms the integrity of pure drugs and no incompatibility of them with excipients. The stability studies were carried out for the optimized batch for one months and it showed satisfactory results. The kinetic studies of the formulations revealed that diffusion is the predominant mechanism of drug and release follows Zero-order, Super case II transport.

The Predominant microRNAs in β-cell Clusters for Insulin Regulation and Diabetic Control

2020 ◽  
Vol 21 (7) ◽  
pp. 722-734
Author(s):  
Adele Soltani ◽  
Arefeh Jafarian ◽  
Abdolamir Allameh
Keyword(s):  
Mirna Expression ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Diabetic Control ◽  
In Vitro Proliferation ◽  
Cell Functions ◽  
Mirna Expression Profiles ◽  
Multiple Processes ◽  
The Impact

micro (mi)-RNAs are vital regulators of multiple processes including insulin signaling pathways and glucose metabolism. Pancreatic β-cells function is dependent on some miRNAs and their target mRNA, which together form a complex regulative network. Several miRNAs are known to be directly involved in β-cells functions such as insulin expression and secretion. These small RNAs may also play significant roles in the fate of β-cells such as proliferation, differentiation, survival and apoptosis. Among the miRNAs, miR-7, miR-9, miR-375, miR-130 and miR-124 are of particular interest due to being highly expressed in these cells. Under diabetic conditions, although no specific miRNA profile has been noticed, the expression of some miRNAs and their target mRNAs are altered by posttranscriptional mechanisms, exerting diverse signs in the pathobiology of various diabetic complications. The aim of this review article is to discuss miRNAs involved in the process of stem cells differentiation into β-cells, resulting in enhanced β-cell functions with respect to diabetic disorders. This paper will also look into the impact of miRNA expression patterns on in vitro proliferation and differentiation of β-cells. The efficacy of the computational genomics and biochemical analysis to link the changes in miRNA expression profiles of stem cell-derived β-cells to therapeutically relevant outputs will be discussed as well.

Dehydroepiandrosterone (DHEA) and its Sulphate (DHEAS) in Alzheimer’s Disease

2020 ◽  
Vol 17 (2) ◽  
pp. 141-157 ◽  
Author(s):  
Dubravka S. Strac ◽  
Marcela Konjevod ◽  
Matea N. Perkovic ◽  
Lucija Tudor ◽  
Gordana N. Erjavec ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Therapeutic Potential ◽  
Relevant Literature ◽  
Comprehensive Overview ◽  
Brain Functions ◽  
Specific Effects ◽  
And Behavior

Background: Neurosteroids Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone Sulphate (DHEAS) are involved in many important brain functions, including neuronal plasticity and survival, cognition and behavior, demonstrating preventive and therapeutic potential in different neuropsychiatric and neurodegenerative disorders, including Alzheimer’s disease. Objective: The aim of the article was to provide a comprehensive overview of the literature on the involvement of DHEA and DHEAS in Alzheimer’s disease. Method: PubMed and MEDLINE databases were searched for relevant literature. The articles were selected considering their titles and abstracts. In the selected full texts, lists of references were searched manually for additional articles. Results: We performed a systematic review of the studies investigating the role of DHEA and DHEAS in various in vitro and animal models, as well as in patients with Alzheimer’s disease, and provided a comprehensive discussion on their potential preventive and therapeutic applications. Conclusion: Despite mixed results, the findings of various preclinical studies are generally supportive of the involvement of DHEA and DHEAS in the pathophysiology of Alzheimer’s disease, showing some promise for potential benefits of these neurosteroids in the prevention and treatment. However, so far small clinical trials brought little evidence to support their therapy in AD. Therefore, large-scale human studies are needed to elucidate the specific effects of DHEA and DHEAS and their mechanisms of action, prior to their applications in clinical practice.

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