Search results for "Intracellular"

2013

Nitric oxide, produced by the neuronal nitric oxide synthase (nNOS) from L-arginine is an important second messenger molecule in the central nervous system: It influences the synthesis and release of neurotransmitters and plays an important role in long-term potentiation, long-term depression and neuroendocrine secretion. However, under certain pathological conditions such as Alzheimer’s or Parkinson’s disease, stroke and multiple sclerosis, excessive NO production can lead to tissue damage. It is thus desirable to control NO production in these situations. So far, little is known about the substrate supply to human nNOS as a determinant of its activity. Measuring bioactive NO via cGMP form…

General Cytotoxicity Assessment by Means of the MTT Assay

2014

Cytotoxicity assays were among the first in vitro bioassay methods used to predict toxicity of substances to various tissues. In vitro cytotoxicity testing provides a crucial means for safety assessment and screening, and for ranking compounds. The choice of using a particular cytotoxicity assay technology may be influenced by specific research goals. As such, four main classes of assays are used to monitor the response of cultured cells after treatment with potential toxicants. These methods measure viability, cell membrane integrity, cell proliferation, and metabolic activity. In this chapter, we focus on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reducti…

Zinc and inflammatory/immune response in aging

2007

Life-long antigenic burden determines a condition of chronic inflammation, with increased lymphocyte activation and proinflammatory cytokine production. A large number of studies have documented changes in zinc metabolism in experimental animal models of acute and chronic inflammation and in human chronic inflammatory conditions. In particular, modification of zinc plasma concentration, as well as intracellular disturbance of antioxidant intracellular pathways, has been found in aging and in some age-related diseases. Zinc deficiency is diffused in aged individuals in order to avoid meat and other high zinc content foods due to fear of cholesterol. Rather, they increase the consumption of r…

Antioxidant effect of casein phosphopeptides compared with fruit beverages supplemented with skimmed milk against H2O2-induced oxidative stress in Ca…

2008

Abstract Casein phosphopeptides (CPPs) have been proposed as potential dietary antioxidants on designing new functional products. A fruit beverage, with/without milk, was subjected to in vitro digestion. Caco-2 cultures were preincubated with soluble fractions or isolated CPPs, the latter obtained from skimmed milk. The mitochondrial activities (MTT test), intracellular GSH and GSH-reductase activity (GSH-Rd), cell cycle analysis and RNA distribution in cycle phases were studied after inducing oxidative stress status (5 mM H2O2). MTT conversion was better preserved by soluble fractions of fruit beverages, either with or without milk. GSH concentration was equally decreased, and GSH-Rd was i…

Activation and Inactivation of Tetanus Toxin in Chromaffin Cells

1993

Tetanus toxin is produced by Clostridium tetani as a single chain, almost non-toxic, protein with a molecular weight of approximately 150.000 representing 1315 amino acids. Bacterial proteases cleave the molecule between positions A 457 and S 458 (extracellular activation), yielding a heavy chain (MW 100.000) and a light chain (MW 50.000) tetanus toxin (HC-TeTx, LC-TeTx). Both chains remain connected to each other by a disulphur bond between positions C 439 and C 467 (Dichain-TeTx)1. The cleavage or nicking dramatically increases the biological activity2. HC-TeTx is involved in binding DC-TeTx to gangliosides lodged in the plasma membrane, which is a prerequisite for incorporation into the …

THE FINE STRUCTURE OF O2 Hb BINDING IN ANIMALS: SALMO IRIDEUS

1980

Publisher Summary This chapter discusses the experimental results on study of the fine structure of O 2 Hb binding in animals. It is evident that the n ( S ) function represents a new tool to look at homotropic interactions, both qualitatively and quantitatively. At the moment, there are four applications: (1) study of molecular mechanism; (2) study of effectors, also pharmacological; (3) improved characterization of O 2 Hb binding, also in pathological cases; and (4) comparative studies in animals. Whole blood of fish is also investigated because usually there are found several hemoglobins. During registration of the O 2 binding curve, pH is not kept constant. Assuming that the Donnan fact…

Sterigmatocystin-induced cytotoxicity via oxidative stress induction in human neuroblastoma cells.

2020

Abstract Sterigmatocystin (STE) is a mycotoxin produced by fungi of the genus Aspergillus. Considering that the effect of STE on neuronal system has not been well studied, the aim of the present study consists to investigate the cytotoxic effects of STE in human neuroblastoma (SH-SY5Y) cells. Moreover, the role of oxidative stress and intracellular defense systems was assessed by evaluating reactive oxygen species (ROS) generation, lipid peroxidation (LPO) and antioxidant no-enzymatic (GSH) levels and enzymatic (GPx, GST, CAT and SOD) activity. Our results revealed that STE decreased cell viability in a dose and time-dependent manner. Furthermore, after 24 h of exposure, STE induced an incr…

The role of mitochondria in sterigmatocystin-induced apoptosis on SH-SY5Y cells

2020

Mitochondria are cellular organelles involved in many crucial functions, such as generation of energy (ATP) and initiation of apoptosis. The aim of the present study was to evaluate the role of mitochondria in the toxicity induced by sterigmatocystin (STE), a mycotoxin produced by fungi of the genus Aspergillus, on SH-SY5Y cells. Our results showed that STE exposure decreased cell viability in a time- and concentration-dependent manner by MTT assay and caused mitochondrial dysfunction, as highlighted by the increase of STE cytotoxicity in cells forced to rely on mitochondrial oxidative phosphorylation. Furthermore, intracellular ATP depletion and increased mitochondrial reactive oxygen spec…

Human recombinant vasostatin-1 may interfere with cell-extracellular matrix interactions

2006

Vasostatin-1 (VS-1), the N-terminal fragment derived from the cleavage of chromogranin A (CgA), has been shown to exert several biological activities on several tissues and organs. Recently, it has been reported that human recombinant VS-1 (STA-CGA(1-78)) may alter myocardial contractility in eel, frog., and rat hearts. In this article we have explored if STA-CGA(1-78) can induce intracellular cascades interacting both with adhesion molecules and/or extracellular matrix (ECM), components, that is, involvement of the heat shock protein 90 (HSP90) and the endothelial NOS (eNOS), known to be implicated in signal transduction mechanisms affecting myocardial contractility. We used 3D cultured ad…

Circadian variations of ?synaptic? bodies in the pineal glands of Brattleboro rats

1990

The function of the mammalian pineal gland is regulated primarily by the sympathetic system. Arginine-vasopressin (AVP) may also be involved in the regulation of pineal melatonin synthesis under experimental conditions. The present study was conducted in the AVP-deficient rat strain, the Brattleboro rat, to investigate whether the numbers and rhythms of pineal "synaptic" bodies in this strain are different from those found in intact rats. AVP or its non-vasoconstrictive analog, deamino-D-AVP, was also injected intra-arterially in Brattleboro or Sprague-Dawley rats to test whether this procedure influences "synaptic" body numbers. Brattleboro rats were killed at different time-points through…