Search results for "Trace"

Current Trends in Advanced Alginate-Based Wound Dressings for Chronic Wounds

2021

Chronic wounds represent a major public health issue, with an extremely high cost worldwide. In healthy individuals, the wound healing process takes place in different stages: inflammation, cell proliferation (fibroblasts and keratinocytes of the dermis), and finally remodeling of the extracellular matrix (equilibrium between metalloproteinases and their inhibitors). In chronic wounds, the chronic inflammation favors exudate persistence and bacterial film has a special importance in the dynamics of chronic inflammation in wounds that do not heal. Recent advances in biopolymer-based materials for wound healing highlight the performance of specific alginate forms. An ideal wound dressing shou…

Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicl…

2018

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles ("MISEV") guidelines fo…

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 …

Native and subunit molecular mass and quarternary structure of the hemoglobin from the primitive branchiopod crustacean Triops cancriformis

2006

Many branchiopod crustaceans are endowed with extracellular, high-molecular-weight hemoglobins whose exact structural characteristics have remained a matter of conjecture. By using a broad spectrum of techniques, we provide precise and coherent information on the hemoglobin of one of the phylogenetically ‘oldest’ extant branchiopods, the tadpole shrimp Triops cancriformis. The hemoglobin dissociated under reducing conditions into two subunits, designated TcHbA and TcHbB, with masses of 35 775 ± 4 and 36 055 ± 4 Da, respectively, determined by ESI-MS. Nonreducing conditions showed only two disulfide-bridged dimers, a homodimer of TcHbA, designated D1 (71 548 ± 5 Da), and the heterodimer D2 (…

2015

Primary neuronal cultures share many typical features with the in vivo situation, including similarities in distinct electrical activity patterns and synaptic network interactions. Here, we use multi-electrode array (MEA) recordings from spontaneously active cultures of wildtype and GAD67-GFP transgenic mice to evaluate which spike parameters differ between GABAergic interneurons and principal, putatively glutamatergic neurons. To analyze this question we combine MEA recordings with optical imaging in sparse cortical cultures to assign individual spikes to visually-identified single neurons. In our culture system, excitatory and inhibitory neurons are present at a similar ratio as described…

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…

A New Method to Reconstruct Quantitative Food Webs and Nutrient Flows from Isotope Tracer Addition Experiments

2020

Understanding how nutrients flow through food webs is central in ecosystem ecology. Tracer addition experiments are powerful tools to reconstruct nutrient flows by adding an isotopically enriched element into an ecosystem and tracking its fate through time. Historically, the design and analysis of tracer studies have varied widely, ranging from descriptive studies to modeling approaches of varying complexity. Increasingly, isotope tracer data are being used to compare ecosystems and analyze experimental manipulations. Currently, a formal statistical framework for analyzing such experiments is lacking, making it impossible to calculate the estimation errors associated with the model fit, the…

Ekstracelulārā matriksa sintēzes un degradācijas loma ādas dzīšanā un tās analīze biotehnoloģiski veidotos ādas audos

2015

Darba mērķis ir izstrādāt ādas audu modeli in vitro, balstītu uz ādas šūnu kokultūru kultivēšanu trīsdimensionālā fibrīna matriksā, kā arī noteikt izveidotajos audos ekstracelulārā matriksa (ECM) komponentu sintēzi un degradāciju. Papildus tika ievākti arī hronisku brūču eksudātu paraugi, kuriem tika veikta dažādu – ar brūču dzīšanu saistītu marķieru analīze. Mērķa sasniegšanai tika izmantotas šūnu, molekulārās bioloģijas un imunoloģijas metodes. Darbā iegūtie rezultāti parāda ECM komponentu, to degradējošo enzīmu un augšanas faktoru produkcijas izmaiņas audu kultivēšanas laikā un ļauj izvēlēties optimālu ādas audu modeļsistēmas veidošanas un kultivēšanas metodiku. Darbs tika izstrādāts Pau…

In vitro modeļa izveide ļaundabīgā audzēja ekstracelulāro vezīkulu endocitozes pētīšanai mezenhimālajās šūnās

2016

Ekstracelulārās vezīkulas (EV) pārnes dažādas funkcionālas molekulas, nodrošinot informācijas pārnesi starp šūnām un ierosinot dažādus patoloģiskus procesus. Cilvēka mezenhimālās cilmes šūnas (MCŠ) ir vienas no audzēju stromas komponentēm, kas veicina audzēja augšanu un angioģenēzi. Darba mērķis bija noskaidrot, vai ādas MCŠ uzņem normoksijā un hipoksijā kultivētu kolorektālā audzēja šūnu līniju SW620 un SW480 EV, un izpētīt iespējamo endocitozes ceļu. Lai to noskaidrotu, tika izveidots in vitro modelis audzēja EV uzņemšanas pētījumiem MCŠ un noteiktas optimālās endocitozes inhibitoru koncentrācijas. Pētījuma rezultāti parāda, ka optimālā endocitozes inhibitoru citohalazīna-D un hlorpromazī…