OBJECTIVES: The aim of the study was to demonstrate that direct measurement of hydroxyl radicals and singlet oxygen in the tail of living rats is possible. The basic level of hydroxyl radicals and singlet oxygen were measured and the effects of antioxidants on their levels were studied in the tail of living anaesthetized rats after acute postoperative pain. Laparotomy was performed as the source of acute abdominal pain. After closure of the abdominal cavity, the animals began to awaken within 30-60 minutes. They were left to recover for 2-3 hours; then they were reanesthetized and the effect of antioxidants was measured on the numbers of hydroxyl radicals and singlet oxygen via blood in the tail. METHODS: The laparotomy was preformed under general anesthesia (Xylazin and Ketamin) using Wistar rats. After recovery and several hours of consciousness they were reanaesthetized and free radicals and singlet oxygen were measured. An antioxidant mixture (vitamins A, C, D and Selenium) was administered intramuscularly prior to the laparotomy. All measurements were done on the tail of anaesthetized animals. In this particular article, the effect of antioxidants is only reported for hydroxyl radicals. RESULTS: After laparotomy, which represented both somatic and visceral pain, hydroxyl radicals and singlet oxygen were increased. Antioxidant application prior to laparotomy decreased the numbers of hydroxyl radicals. CONCLUSION: Results are in agreement with our previous finding regarding the increase in hydroxyl free radicals and singlet oxygen following nociceptive stimulation, in this case a combination of both somatic and visceral pain. The administered antioxidants mitigated the increase. This is further confirmation that direct measurement of free radicals and singlet oxygen represents a very useful method for the biochemical evaluation of pain and nociception.
- MeSH
- Antioxidants pharmacology MeSH
- Pain etiology metabolism MeSH
- Electron Spin Resonance Spectroscopy MeSH
- Hydroxyl Radical metabolism MeSH
- Rats MeSH
- Laparotomy MeSH
- Tail metabolism drug effects MeSH
- Oxidative Stress drug effects MeSH
- Rats, Wistar MeSH
- Singlet Oxygen metabolism MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
One obstacle to the successful delivery of nanodrugs into solid tumors is the heterogeneity of an enhanced permeability and retention (EPR) effect as a result of occluded or embolized tumor blood vessels. Therefore, the augmentation of the EPR effect is critical for satisfactory anticancer nanomedicine. In this study, we focused on one vascular mediator involved in the EPR effect, carbon monoxide (CO), and utilized two CO generating agents, one is an extrinsic CO donor (SMA/CORM2 micelle) and another is an inducer of endogenous CO generation via heme oxygenase-1 (HO-1) induction that is carried out using pegylated hemin. Both agents generated CO selectively in solid tumors, which resulted in an enhanced EPR effect and a two- to three-folds increased tumor accumulation of nanodrugs. An increase in drug accumulation in the normal tissue did not occur with the treatment of CO generators. In vivo imaging also clearly indicated a more intensified fluorescence of macromolecular nanoprobe in solid tumors when combined with these CO generators. Consequently, the combination of CO generators with anticancer nanodrugs resulted in an increased anticancer effect in the different transplanted solid tumor models. These findings strongly warrant the potential application of these CO generators as EPR enhancers in order to enhance tumor detection and therapy using nanodrugs.
- Publication type
- Journal Article MeSH
OBJECTIVES: The aim of the study was to demonstrate the ability to measure free radicals and singlet oxygen, using EPR methods, in the tail of anaesthetized rats. The advantage of this method lies in the potential for continuous evaluation of free radicals and singlet oxygen during nociceptive processes.
- MeSH
- Antioxidants pharmacology MeSH
- Pain metabolism MeSH
- Electron Spin Resonance Spectroscopy veterinary MeSH
- Financing, Organized MeSH
- Hydroxyl Radical analysis metabolism MeSH
- Rats MeSH
- Pain Measurement methods instrumentation MeSH
- Tail metabolism MeSH
- Nitrogen Oxides analysis metabolism MeSH
- Rats, Wistar MeSH
- Pain Threshold physiology drug effects MeSH
- Singlet Oxygen analysis metabolism MeSH
- Free Radicals analysis metabolism MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
Effect of UV irradiation on free radicals in different types of melanins and melanin complexes with diamagnetic Cd(II) and paramagnetic Cu(II) was examined by the use of electron paramagnetic resonance (EPR) spectroscopy. The aim of this studies was to compare o-semiquinone free radicals formation in two model eumelanins synthesized from 3,4-dihydroxyphenylalanine (DOPA) and tyrosine in the presence of tyrosinase, and in synthetic pheomelanin, under exposition on ultraviolet, because of the important role of free radicals and melanins in human organism. UV may change free radical concentrations in melanin. Changes in EPR spectra of DOPA-melanin-Cd(II) and DOPA-melanin-Cu(II) complexes after UV irradiation were determined. Diamagnetic Cd(II) strongly increased free radical concentrations in DOPA-melanin. UV irradiation during 30 and 60 min slightly increased and decreased free radical concentrations in DOPA-melanin-Cd(II) complexes, respectively. Paramagnetic Cu(II) quenched free radical lines of DOPA-melanin, and only the Cu(II) signals were detected for both UV-irradiated and nonirradiated samples. Free radical concentration in both eumelanins increased after UV irradiation, but it decreased in irradiated pheomelanin. EPR spectra of free radicals in the studied samples were homogeneously broadened. Slow spin-lattice relaxation processes exist in all the examined melanins and DOPA-melanin-Cd(II) complexes. Fast spin-lattice relaxation processes characterized Cu(II) in DOPA-melanin-Cu(II) complexes.
- MeSH
- Dihydroxyphenylalanine radiation effects MeSH
- Electron Spin Resonance Spectroscopy * methods utilization MeSH
- Epidermis immunology radiation effects MeSH
- Humans MeSH
- Melanins * isolation & purification radiation effects MeSH
- Melanocytes immunology radiation effects MeSH
- Statistics as Topic MeSH
- Monophenol Monooxygenase biosynthesis radiation effects MeSH
- Ultraviolet Rays * diagnostic use adverse effects MeSH
- Free Radicals isolation & purification adverse effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
Electron paramagnetic resonance (EPR) spin trapping spectroscopy is an important method used in free radical research; however, its application in biological systems is hindered by EPR silencing of spin adducts. Previous studies in superoxide-generating chemical systems have shown that spin adducts can be partially stabilized by cyclodextrins. In this work, for the first time, this proposed protective effect of cyclodextrins is investigated in a real biological sample-in isolated thylakoid membranes and photosystem II (PSII) particles with EMPO as a spin trap. It is shown that (i) randomly methylated beta-cyclodextrin and 2-hydroxypropyl-beta-cyclodextrin form inclusion complexes with EMPO-superoxide adducts (EMPO-OOH), (ii) both cyclodextrins increase the intensity of the EMPO-OOH EPR signal in PSII particles up to five times, (iii) higher EMPO-OOH EPR signal intensity is a result of increased stability of EMPO-OOH, and (iv) the extent of the protection of EMPO-OOH adduct provided by cyclodextrins is different in thylakoids and PSII particles. Along with the spin trapping data, the toxicity of cyclodextrins is also discussed with particular focus on photosynthetic preparations. The presented data show that both tested cyclodextrins can be used as valuable tools to improve the sensitivity of spin trapping in biological samples.
- MeSH
- beta-Cyclodextrins pharmacology MeSH
- Cyclodextrins pharmacology MeSH
- Electron Spin Resonance Spectroscopy methods MeSH
- Photosystem II Protein Complex chemistry isolation & purification metabolism MeSH
- Pyrroles MeSH
- Sensitivity and Specificity MeSH
- Spin Trapping MeSH
- Spinacia oleracea MeSH
- Superoxides chemistry metabolism MeSH
- In Vitro Techniques MeSH
- Thylakoids chemistry drug effects metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
This review focuses on the influence of oxidized phosphatidylcholines (oxPCs) on the biophysical properties of model membranes and is limited to fluorescence, EPR, and MD studies. OxPCs are divided into two classes: A) hydroxy- or hydroperoxy-dieonyl phospatidylcholines, B) phospatidylcholines with oxidized and truncated chains with either aldehyde or carboxylic group. It was shown that the presence of the investigated oxPCs in phospholipid model membranes may have the following consequences: 1) decrease of the lipid order, 2) lowering of phase transition temperatures, 3) lateral expansion and thinning of the bilayer, 4) alterations of bilayer hydration profiles, 5) increased lipid mobility, 6) augmented flip-flop, 7) influence on the lateral phase organisation, and 8) promotion of water defects and, under extreme conditions (i.e. high concentrations of class B oxPCs), disintegration of the bilayer. The effects of class A oxPCs appear to be more moderate than those observed or predicted for class B. Many of the abovementioned findings are related to the ability of the oxidized chains of certain oxPCs to reorient toward the water phase. Some of the effects appear to be moderated by the presence of cholesterol. Although those biophysical alternations are found at oxPC concentrations higher than the total oxPC concentrations found under physiological conditions, certain organelles may reach such elevated oxPC concentrations locally. It is a challenge for the future to correlate the biophysics of oxidized phospholipids to metabolic studies in order to define the significance of the findings presented herein for pathophysiology. This article is part of a Special Issue entitled: Oxidized phospholipids-their properties and interactions with proteins.
- MeSH
- Biophysical Phenomena * MeSH
- Electron Spin Resonance Spectroscopy MeSH
- Fluorescence MeSH
- Phospholipids chemistry metabolism MeSH
- Humans MeSH
- Lipid Bilayers chemistry metabolism MeSH
- Oxidation-Reduction MeSH
- Molecular Dynamics Simulation * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
The Enhanced Permeability and Retention (EPR) effect is extensively used in drug delivery research. Taking into account that EPR is a highly variable phenomenon, we have here set out to evaluate if contrast-enhanced functional ultrasound (ceUS) imaging can be employed to characterize EPR-mediated passive drug targeting to tumors. Using standard fluorescence molecular tomography (FMT) and two different protocols for hybrid computed tomography-fluorescence molecular tomography (CT-FMT), the tumor accumulation of a ~10 nm-sized near-infrared-fluorophore-labeled polymeric drug carrier (pHPMA-Dy750) was evaluated in CT26 tumor-bearing mice. In the same set of animals, two different ceUS techniques (2D MIOT and 3D B-mode imaging) were employed to assess tumor vascularization. Subsequently, the degree of tumor vascularization was correlated with the degree of EPR-mediated drug targeting. Depending on the optical imaging protocol used, the tumor accumulation of the polymeric drug carrier ranged from 5 to 12% of the injected dose. The degree of tumor vascularization, determined using ceUS, varied from 4 to 11%. For both hybrid CT-FMT protocols, a good correlation between the degree of tumor vascularization and the degree of tumor accumulation was observed, within the case of reconstructed CT-FMT, correlation coefficients of ~0.8 and p-values of <0.02. These findings indicate that ceUS can be used to characterize and predict EPR, and potentially also to pre-select patients likely to respond to passively tumor-targeted nanomedicine treatments.
- MeSH
- Acrylamides administration & dosage MeSH
- Enbucrilate MeSH
- Contrast Media administration & dosage MeSH
- Blood Volume MeSH
- Drug Delivery Systems * MeSH
- Microbubbles MeSH
- Mice, Nude MeSH
- Cell Line, Tumor MeSH
- Neoplasms blood supply metabolism physiopathology ultrasonography MeSH
- Permeability MeSH
- Regional Blood Flow MeSH
- Tomography methods MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
V práci sa popisuje samovoľný rozpad kyseliny D,L-2,3-difenylvínnej v propán-2-ole, ktorý prebieharadikálovo pri laboratórnej teplote. Prvotným produktom tohto rozpadu sú krátko žijúce fenylglyoxálovéketylové radikály, ktoré sú zachytávané a stabilizované pomocou spinovej pasce N-terc-butyl-α-fenylnitrónu. Tento samovoľný rozpad kyseliny D,L-2,3-difenylvínnej v propán-2-ole bolpoužitý ako zdroj radikálov na zisťovanie antioxidačného účinku niektorých antioxidantov (C-vitamínu,E-vitamínu a D,L-selenometionínu). Zistili sme, že vyššie spomínané antioxidanty sú účinnýmivychytávačmi fenylglyoxálových ketylových radikálov. Na základe týchto skutočností môžemetúto metódu odporúčať pre testovanie antioxidačných vlastností iných zlúčenín ako potenciálnychantioxidantov.
The paper describes spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol,which takes place via radicals at ambient temperature. The primary product of the decompositionis short-living ketyl radicals of phenylglyoxalic acid, which are captured and stabilized by means ofthe spin trap of N-terc-butyl-α-phenylnitrone. The spontaneous decomposition of D,L-2,3-diphenyltartaricacid in propane-2-ol served as the source of radicals for the determination of the antioxidativeeffect of known antioxidants: C-vitamin, E-vitamin, and selenomethionine. It was found thatthe above-mentioned antioxidants are effective scavengers of radicals of phenylglyoxalic acid. Onthe basis of these data, the method can be recommended for testing the antioxidative properties ofother substances as potential antioxidants.
- MeSH
- Antioxidants pharmacology MeSH
- Electron Spin Resonance Spectroscopy methods instrumentation MeSH
- Phenylglyoxal diagnostic use MeSH
- Research Support as Topic MeSH
- Ascorbic Acid physiology MeSH
- Spin Trapping MeSH
- Vitamin E physiology MeSH
- Free Radicals chemistry metabolism MeSH
- Publication type
- Review MeSH
- Comparative Study MeSH
Tumors are characterized by leaky blood vessels, and by an abnormal and heterogeneous vascular network. These pathophysiological characteristics contribute to the enhanced permeability and retention (EPR) effect, which is one of the key rationales for developing tumor-targeted drug delivery systems. Vessel abnormality and heterogeneity, however, which typically result from excessive pro-angiogenic signaling, can also hinder efficient drug delivery to and into tumors. Using histidine-rich glycoprotein (HRG) knockout and wild type mice, and HRG-overexpressing and normal t241 fibrosarcoma cells, we evaluated the effect of genetically induced and macrophage-mediated vascular normalization on the tumor accumulation and penetration of 10-20 nm-sized polymeric drug carriers based on poly(N-(2-hydroxypropyl)methacrylamide). Multimodal and multiscale optical imaging was employed to show that normalizing the tumor vasculature improves the accumulation of fluorophore-labeled polymers in tumors, and promotes their penetration out of tumor blood vessels deep into the interstitium.
- MeSH
- Polymethacrylic Acids metabolism pharmacokinetics MeSH
- Drug Delivery Systems methods MeSH
- Mice, Inbred C57BL MeSH
- Mice, Knockout MeSH
- Mice MeSH
- Cell Line, Tumor MeSH
- Neoplasms blood supply genetics metabolism MeSH
- Drug Carriers metabolism pharmacokinetics MeSH
- Permeability MeSH
- Proteins genetics metabolism MeSH
- Tissue Distribution MeSH
- Up-Regulation MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
