Search results for "VITRO"
showing 10 items of 2786 documents
Isolated in-vitro perfusion of pig hearts obtained from the abattoir: an alternative to animal experiments?
1994
Isolated pig hearts (German farm pigs) were characterized after global in-vivo ischaemia as a potential alternative to in-vivo animal studies. Hearts were harvested from adult farm swine at the abattoir 10.3 +/- 2.1 min after incision of the carotid artery. They were immediately perfused and thereafter stored in ice-cold cardioplegic (St Thomas's) solution. After 38 +/- 3 min, retrograde perfusion was started with oxygenated pig blood (37 degrees C; 5000 U Heparin.l-1; pH 7.38 +/- 0.1; 11 mmol glucose.l-1) at a flow rate of 85 ml.min-1 100 g-1 wet weight (gww-1) for 30 min (n = 10). Additionally, shortly after obtaining the hearts, ATP and CP content were measured by enzymatic tests in 10 p…
Sorbitol-penetration enhancer containing vesicles loaded with baicalin for the protection and regeneration of skin injured by oxidative stress and UV…
2018
Abstract Aiming at improving the protective effects of baicalin on the skin, new highly-biocompatible penetration enhancer containing vesicles (PEVs) were developed by modifying the base formulation of transfersomes with sorbitol, thus obtaining sorbitol-PEVs. An extensive evaluation of the physico-chemical features of both transfersomes and sorbitol-PEVs was carried out. Transfersomes were mainly close-packed, multi-compartment vesicles, while sorbitol-PEVs appeared mostly as single, spherical, unilamellar vesicles. All the vesicles were small in size (∼128 nm) and negatively charged (∼−67 mV), without significant differences between the formulations. The in vitro delivery of baicalin to i…
Presentation of insulin and insulin A chain peptides to mouse T cells: involvement of cysteine residues.
1991
The requirements for insulin presentation and recognition by A alpha b A beta b- and A alpha b A beta k-restricted mouse T cells were studied using a variety of derivatives of the insulin A chain. It was found that A chain peptides with irreversibly blocked Cys residues are non-stimulatory for the T cells. This suggests that at least one of the Cys residues is essential for recognition. On the other hand, all A chain peptides containing Cys residues modified in a way reversible by reaction with thiols are stimulatory yet differ in antigenic potency. All these A chain derivatives including a 14 amino acid fragment require uptake by antigen presenting cells (APC) for efficient presentation. D…
Triiodothyronine accelerates the synthesis of synapsin I in developing neurons from fetal rat brain cultured in a synthetic medium.
1990
The effect of Triiodothyronine (T3) on Synapsin I appearance in rat cortical neurons has been investigated in vitro. Neuronal cultures from 16-day-old fetal rat brain grown in the absence of T3, express immunohystochemically detectable Synapsin I at the 14th day in vitro. The addition of the hormone to the culture medium determines an early (at the 7th day in vitro) appearance of fluorescent dots specific for Synapsin I. © 1990 Plenum Publishing Corporation.
Long-Term Potentiation in Slices from Human Hippocampus
1988
Long-term potentiation (LTP) has been observed in slices from human hippocampi removed for intractable epilepsy using extra- and intracellular recording in vitro. Furthermore the effects of several neuroactive substances with possible relevance for synaptic plasticity was investigated. Human hippocampal neurones in vitro display properties very similar to the respective rodent cells.
Synaptobrevin cleavage by the tetanus toxin light chain is linked to the inhibition of exocytosis in chromaffin cells
1994
AbstractExocytosis of secretory granules by adrenal chromaffin cells is blocked by the tetanus toxin light chain in a zinc specific manner. Here we show that cellular synaptobrevin is almost completely degraded by the tetanus toxin light chain within 15 min. We used highly purified adrenal secretory granules to show that synaptobrevin, which can be cleaved by the tetanus toxin light chain, is localized in the vesicular membrane. Proteolysis of synaptobrevin in cells and in secretory granules is reversibly inhibited by the zinc chelating agent dipicolinic acid. Moreover, cleavage of synaptobrevin present in secretory granules by the tetanus toxin light chain is blocked by the zinc peptidase …
Design, synthesis, and biological evaluation of novel aminobisphosphonates possessing an in vivo antitumor activity through a gammadelta-T lymphocyte…
2008
A small series of aminobisphosphonates (N-BPs) structurally related to zoledronic acid was synthesized with the aim of improving activity toward activation of human gammadelta T cells and in turn their in vivo antitumor activity. The absence of the 1-OH moiety, together with the position and the different basicity of the nitrogen, appears crucial for antitumor activity. In comparison to zoledronic acid, compound 6a shows a greater ability to activate gammadelta T cells expression (100 times more) and a proapoptotic effect that is better than zoledronic acid. The potent activation of gammadelta T cells, in addition to evidence of the in vivo antitumor activity of 6a, suggests it may be a new…
Reversible effect of MR and ELF magnetic fields (0.5 T and 0.5 mT) on human lymphocyte activation patterns.
2006
Purpose: The aim of this study was to investigate the effects of magnetic fields (MF) of different intensity generated by a magnetic resonance (MR) unit (0.5 Tesla) and a double cylindrical coil (0.5 mTesla) on human CD4+ T cell lines. Materials and methods: CD4+ T cells were exposed for two hours under isothermal conditions (37 ± 0.5°C) to the above mentioned MF; a control group was provided for each exposed sample. After exposure, the samples were analysed in the laboratory for the following endpoints: Release of cytokines, expression of surface markers, cell proliferation and levels of cytosolic free-calcium. Results: Exposure to MF for 2 h and subsequent in vitro stimulation in the pres…
TCR V alpha chain expression influences reactivity to the hapten TNP.
1997
We have recently demonstrated a remarkable selection of in vitro cultivated, TNP-specific polyclonal T cell lines for the expression of a TCR beta chain encoded by the V beta 8.2 gene. The goal of the present study was to analyse V alpha usage in V beta 8.2 T cells responsive to TNP, using TNP-specific T cell lines derived from three common strains of mice, as well as from V beta 8.2 transgenic mice. Results indicate that in vitro TNP stimulation of T cells from TNP-immune mice results in significant skewing of V alpha usage among responding V beta 8.2+ T cells, with overexpression observed for V alpha 3.2 and V alpha 8. These results indicate that V alpha expression influences recognition …
Suppressive effects of C3b on monocyte-dependent T cell proliferation.
1987
The effect of C3b treatment of human monocytes on secondary antigen-dependent T cell response was studied. When antigen-specific T cell blasts were cultivated together with C3b-treated monocytes the proliferative response was inhibited in a dose-dependent fashion. This suppressive effect was specific for C3b because heat-inactivated C3b or buffer alone had no influence on T cell proliferation. In part, this suppressive effect is mediated through a C3b-induced decreased expression of class II antigens on the surface of treated monocytes, but another suppressive mechanism exists because the C3b pretreatment of monocytes also led to an inhibition of the proliferative response in a class II ant…