Search results for "Derivative"
showing 10 items of 1074 documents
Inhibitory effects of N-valproyl-L-tryptophan on high potassium, low calcium and low magnesium-induced CA1 hippocampal epileptiform bursting activity…
2012
N-valproyl-l-tryptophan (VPA-Tryp), new antiepileptic drug, was tested on CA1 hippocampal epileptiform bursting activity obtained by increasing potassium and lowering calcium and magnesium concentrations in the fluid perfusing rat brain slices. Each slice was treated with a single concentration (0.2, 0.5, 1 or 2 mM) of Valproate (VPA) or VPA-Tryp. Both burst duration and interburst frequency during and after treatment were off-line compared with baseline values. For both parameters, the latency and the length of statistically significant response periods as well as the magnitude of drug-induced responses were calculated. VPA-Tryp evoked fewer and weaker early excitatory effects than VPA on …
Report on Intrauterine Drug Exposure During Second Trimester of Pregnancy in a Heroin-Associated Death
1999
A 17-year-old girl was found dead in a public toilet with fresh needle puncture marks. She was 18-20 weeks pregnant with a male fetus. Drug screening of her blood and urine indicated recent heroin use. Chronic drug use was confirmed by hair analysis. Amniotic fluid as well as fetal and maternal tissues and body fluids were analyzed by GC/MS and HPLC. All the fetal specimens were investigated, and the following levels of drugs were found: 6-monoacetyl-morphine (blood: 152 ng/g; amniotic fluid: 128 ng/g; brain: 140 ng/g; lung: 110 ng/g; liver: 2 ng/g; kidney: 40 ng/g), morphine (blood: 1360 ng/g; amniotic fluid: 604 ng/g; brain: 710 ng/g; lung: 1030 ng/g; liver: 2060 ng/g; kidney: 1100 ng/g),…
Effects of hypertonic/hyperoncotic treatment and surgical evacuation after acute subdural hematoma in rats*
2007
Objective: The treatment of acute subdural hematoma (ASDH) consists mainly of surgical evacuation of the hematoma. It is conceivable that early preoperative neuroprotection with hypertonic/hyperoncotic treatment (HHT) can improve survival rates. The present study investigated the benefit of treatment with hypertonic/hyperoncotic solution on functional and histologic outcome as supportive therapy accompanying surgical intervention. Design: Laboratory experiment. Setting: University laboratory. Subjects: Male Sprague-Dawley rats weighing 296–350 g (n = 56). Interventions: ASDH was induced through subdural infusion of 400 μL of autologous venous blood. Thirty minutes after subdural blood infus…
Accumulation of hydroxyethyl starch (HES) in the liver of patients with renal failure and portal hypertension
1986
Summary Hydroxyethyl starch (HES) has gained wide clinical acceptance as a colloidal plasma substitute. We were able to study the liver biopsies of two patients with renal failure who developed ascites after repeated infusions of HES. All types of liver cells displayed massive accumulation of HES with the morphologic resemblance to a storage disease. These changes could be distinguished clearly from the lesions of a hereditary disorder by light and electron microscopy. Although it is difficult to establish a causative role for HES in the development of ascites on the bases of morphological changes alone, one should be cautious about giving HES to patients with renal failure until exact data…
Sympathetic Nerve Stimulation on the perfused rat heart. Affinities of N-methylatropine and pirenzepine at pre- and postsynaptic muscarine receptors.
1982
Rat isolated hearts with the sympathetic nerves attached were perfused with (-)-3H-noradrenaline in order to label the storage vesicles of the adrenergic nerves. Release was induced either by electrical stimulation of the nerves (3 Hz, 1 min) or by perfusion with high K+ solution (54 mM). The overflow of 3H-noradrenaline and its metabolites was determined by liquid scintillation counting after separation of the compounds by column chromatography. The experimental conditions ensured a minor contribution of 3H-metabolites to the evoked total tritium overflow. The release of 3H-noradrenaline evoked by nerve stimulation or high K+ solution was decreased in the presence of the muscarinic agonist…
N-valproyl-L-tryptophan for CNS-targeting: synthesis, characterization and efficacy in vitro studies of a new potential antiepileptic drug.
2010
A new aminoacidic derivative of valproic acid (VPA) has been synthesized and characterized by analytical and spectral data. The rationale for the preparation of such potential antiepileptic agent is based on the observation that chemical combination of the anticonvulsant pharmacophore, VPA with essential aminoacids could afford more effective and less toxic actives. The synthesis, characterization, physico-chemical parameters functional for crossing Blood Brain Barrier of N-valproyl-L-tryptophan (4) are reported. The Log D pH7.4 (0.3) indicates that (4) is adequate to cross biological membranes. Its chemical and enzymatic stability were assessed. The experiments indicate high stability of c…
Halogen bonding stabilizes a cis-azobenzene derivative in the solid state : A crystallographic study
2017
Crystals oftrans- andcis-isomers of a fluorinated azobenzene derivative have been prepared and characterized by single-crystal X-ray diffraction. The presence of F atoms on the aromatic core of the azobenzene increases the lifetime of the metastablecis-isomer, allowing single crystals of thecis-azobenzene to be grown. Structural analysis on thecis-azobenzene, complemented with density functional theory calculations, highlights the active role of the halogen-bond contact (N...I synthon) in promoting the stabilization of thecis-isomer. The presence of a long aliphatic chain on the azobenzene unit induces a phase segregation that stabilizes the molecular arrangement for both thetrans- andcis-i…
Hyaluronic Acid Derivative with Improved Versatility for Processing and Biological Functionalization
2016
A hydrophobic/amino functionalized derivative of hyaluronic acid (HA-EDA-C18 ) has been processed by salt leaching technique as porous scaffold without need of chemical crosslinking. Aim of this work is to demonstrate the improved versatility of HA-EDA-C18 in terms of processing and biological functionalization. In particular, the chemical procedure to tether thiol bearing RGD peptide has been described. Moreover, the possibility to load and to control the release of slightly water soluble effectors has been demonstrated by using dexamethasone. First, the swelling and degradation profiles of the scaffolds have been investigated, then the evaluation of metabolic activity of bovine chondrocyt…
From anthraquinone to heterocoronene as stable red chromophore
2018
Using the commercially available 1,4,5,8-tetrachloroanthraquinone (1) as starting material, a N-heterocoronene derivative 3 was synthesized via a straightforward two-step reaction. Compound 3 shows a similar photostability as perylene dyes, qualifying it as a promising colorant.
Discrimination between two memory channels by molecular alloying in a doubly bistable spin crossover material
2019
[EN] A multistable spin crossover (SCO) molecular alloy system [Fe1-xMx(nBu-im)(3)(tren)](P1-yAsyF6)(2) (M = Zn-II, Ni-II; (nBu-im)(3)(tren) = tris(n-butyl-imidazol(2-ethylamino))amine) has been synthesized and characterized. By controlling the composition of this isomorphous series, two cooperative thermally induced SCO events featuring distinct critical temperatures (T-c) and hysteresis widths (Delta T-c, memory) can be selected at will. The pristine derivative 100As (x = 0, y = 1) displays a strong cooperative two-step SCO and two reversible structural phase transitions (PTs). The low temperature PTLT and the SCO occur synchronously involving conformational changes of the ligand's n-buty…