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International Journal of Nanomedicine 2013Silver nanoparticles (AgNPs) were prepared in aqueous colloid dispersions by the reduction of Ag(+) with glucose in alkaline medium. Tetraethyl orthosilicate and... (Comparative Study)
Comparative Study
Silver nanoparticles (AgNPs) were prepared in aqueous colloid dispersions by the reduction of Ag(+) with glucose in alkaline medium. Tetraethyl orthosilicate and L-asparagine were added as stabilizers of NPs. The AgNPs were characterized, and their interaction with three local anesthetics (procaine, dibucaine, or tetracaine) was investigated. Optical spectra show the characteristic absorption band of AgNPs, due to surface plasmon resonance. Modifications in the position and shape of this band reflect the self-assembly of metal NPs mediated by anesthetic molecules and the progress in time of the aggregation process. Zeta-potential measuring was applied in order to characterize the electrostatic stability of the NPs. The size and shape of the AgNPs, as well as the features of the assemblies formed by their association in the presence of anesthetics, were evidenced by transmission electron microscopy images. Atomic force microscopy images showed the characteristics of the films of AgNPs deposited on glass support. The effect of the anesthetics could be described in terms of electrostatic forces between the negatively charged AgNPs and the anesthetic molecules, existing also in their cationic form at the working pH. But also hydrophobic and hydrogen bonding interactions between the coated nanoparticles and anesthetics molecular species should be considered.
Topics: Adsorption; Anesthetics, Local; Binding Sites; Materials Testing; Metal Nanoparticles; Particle Size; Silver
PubMed: 24143090
DOI: 10.2147/IJN.S51063 -
Biochimica Et Biophysica Acta Mar 2015Interactions of two local anesthetics, dibucaine and tetracaine have been studied with phospholipid vesicles containing cholesterol and/or monosialogangliosides (GM1)...
Interactions of two local anesthetics, dibucaine and tetracaine have been studied with phospholipid vesicles containing cholesterol and/or monosialogangliosides (GM1) using fluorescence spectroscopy. The fluorescence intensity of tetracaine showed a marked increase with the increasing molar ratio of the phospholipid to tetracaine, while that of dibucaine showed opposite effects. Steady state anisotropy and the wavelength of maximum emission (λmax) decreased with the increasing phospholipids to tetracaine ratio. The extent of such changes in anisotropy and λmax in the presence and absence of two important components of neuronal membranes, cholesterol and GM1 indicated differential membrane localization of the two local anesthetics. To understand the intercellular mode of action of local anesthetics, we have also studied the interactions of dibucaine and tetracaine with brain spectrin which indicate differential spectrin interactions with similar binding strength. Thermodynamic parameters associated with such binding reveal that binding is favored by entropy. Tetracaine brings about distinct structural changes in spectrin compared to dibucaine, as reflected in the tryptophan mean lifetime and far-UV CD spectra. Tetracaine also exhibits a detergent-like property inducing concentration dependent decrease in spectrin anisotropy, further indicating structural changes in brain spectrin with probable implications in its anesthetic potential.
Topics: Algorithms; Anesthetics, Local; Animals; Brain; Cell Membrane; Cholesterol; Circular Dichroism; Dibucaine; G(M1) Ganglioside; Kinetics; Membrane Lipids; Models, Chemical; Models, Molecular; Phospholipids; Protein Binding; Sheep; Spectrin; Spectrometry, Fluorescence; Tetracaine; Thermodynamics
PubMed: 25482358
DOI: 10.1016/j.bbamem.2014.11.022 -
Proceedings of the Royal Society of... Feb 1968
Review
Topics: Alleles; Apnea; Cholinesterase Inhibitors; Cholinesterases; Dibucaine; Drug Hypersensitivity; Electrophoresis; Female; Fluorides; Genes, Recessive; Genetic Variation; Genetics, Medical; Humans; Metabolism, Inborn Errors; Pharmacogenetics; Succinylcholine
PubMed: 4866551
DOI: No ID Found -
Journal of Clinical Pathology Jul 1965A rapid micro technique for the estimation of serum cholinesterase is described. Acetylcholine bromide is incubated with serum within the capillary of the Astrup...
A rapid micro technique for the estimation of serum cholinesterase is described. Acetylcholine bromide is incubated with serum within the capillary of the Astrup electrode. The enzyme hydrolyses the substrate with the liberation of acetic acid. This causes a fall of pH which is seen on the galvanometer of the instrument and the rate of this fall is shown to be proportional to enzyme concentration. The method has been calibrated in international units and compared with a more conventional technique. The values found in homozygotes with normal dibucaine-resistant enzymes and in heterozygotes are reported, together with their dibucaine and fluoride numbers.
Topics: Cholinesterases; Clinical Enzyme Tests; Dibucaine; Equipment and Supplies; Fluorides; Phosphates
PubMed: 14318694
DOI: 10.1136/jcp.18.4.435 -
PloS One 2011Spreading depolarizations that occur in patients with malignant stroke, subarachnoid/intracranial hemorrhage, and traumatic brain injury are known to facilitate neuronal...
BACKGROUND
Spreading depolarizations that occur in patients with malignant stroke, subarachnoid/intracranial hemorrhage, and traumatic brain injury are known to facilitate neuronal damage in metabolically compromised brain tissue. The dramatic failure of brain ion homeostasis caused by propagating spreading depolarizations results in neuronal and astroglial swelling. In essence, swelling is the initial response and a sign of the acute neuronal injury that follows if energy deprivation is maintained. Choosing spreading depolarizations as a target for therapeutic intervention, we have used human brain slices and in vivo real-time two-photon laser scanning microscopy in the mouse neocortex to study potentially useful therapeutics against spreading depolarization-induced injury.
METHODOLOGY/PRINCIPAL FINDINGS
We have shown that anoxic or terminal depolarization, a spreading depolarization wave ignited in the ischemic core where neurons cannot repolarize, can be evoked in human slices from pediatric brains during simulated ischemia induced by oxygen/glucose deprivation or by exposure to ouabain. Changes in light transmittance (LT) tracked terminal depolarization in time and space. Though spreading depolarizations are notoriously difficult to block, terminal depolarization onset was delayed by dibucaine, a local amide anesthetic and sodium channel blocker. Remarkably, the occurrence of ouabain-induced terminal depolarization was delayed at a concentration of 1 µM that preserves synaptic function. Moreover, in vivo two-photon imaging in the penumbra revealed that, though spreading depolarizations did still occur, spreading depolarization-induced dendritic injury was inhibited by dibucaine administered intravenously at 2.5 mg/kg in a mouse stroke model.
CONCLUSIONS/SIGNIFICANCE
Dibucaine mitigated the effects of spreading depolarization at a concentration that could be well-tolerated therapeutically. Hence, dibucaine is a promising candidate to protect the brain from ischemic injury with an approach that does not rely on the complete abolishment of spreading depolarizations.
Topics: Animals; Brain Ischemia; Child; Cortical Spreading Depression; Dendrites; Dibucaine; Female; Humans; In Vitro Techniques; Male; Mice; Mice, Inbred C57BL; Neocortex
PubMed: 21789251
DOI: 10.1371/journal.pone.0022351 -
The Journal of Biological Chemistry Jul 1978The effect of colchicine, Nocodazole, and dibucaine on the assembly of Semliki Forest virus was investigated. Colchicine, Nocodazole, and dibucaine reduced the...
The effect of colchicine, Nocodazole, and dibucaine on the assembly of Semliki Forest virus was investigated. Colchicine, Nocodazole, and dibucaine reduced the production of extracellular virus by 75 to 90%. Lumicolchicine had no effect on virus growth. Other control experiments showed no effect by these drugs on the incorporation of [3H]leucine into material precipitated by trichloroacetic acid. Colchicine (100 micron) disrupted the microtubles of the baby hamster kidney cells (BHK-21), whereas dibucaine did not alter microtubule polymerization. The stage of virus assembly inhibited by colchicine and dibucaine was studied by experiments with [3H]-leucine or [35S]methionine. At various times after addition of one of these drugs, the incorporation of the labeled precursors into viral proteins associated with fractions enriched for endoplasmic reticulum or plasma membrane from the cell was evaluated. The results clearly show that the envelope and nucleocapsid proteins of the virus move to the plasma membrane of the cell where they accumulate. The studies strongly suggest that the cytoskeletal system is involved in the final stages of morphogenesis of Semliki Forest virus from the plasma membrane.
Topics: Cell Membrane; Cells, Cultured; Colchicine; Dibucaine; Leucine; Semliki forest virus; Viral Proteins
PubMed: 659435
DOI: No ID Found -
British Journal of Anaesthesia Feb 1995We report a case of prolonged neuromuscular block after administration of mivacurium 0.2 mg kg-1 to a 16-yr-old patient where the duration of block was 2.5 h. The...
We report a case of prolonged neuromuscular block after administration of mivacurium 0.2 mg kg-1 to a 16-yr-old patient where the duration of block was 2.5 h. The interesting points in this case were that the patient had homozygous atypical plasma cholinesterase deficiency (both parents had a normal phenotype) following liver transplantation. Investigations showed low plasma cholinesterase activity (343 iu litre-1; normal 600-1400) and dibucaine number was 25 (normal 76-83). Despite possessing atypical enzyme normally associated with markedly prolonged duration of suxamethonium, on two occasions the patient received suxamethonium and responded normally. This had not previously been reported. The patient demonstrated prolonged block with mivacurium as a result of atypical enzyme (despite normal metabolism of suxamethonium).
Topics: Adolescent; Anesthesia Recovery Period; Cholinesterases; Female; Humans; Isoquinolines; Liver Transplantation; Mivacurium; Nerve Block; Neuromuscular Junction; Neuromuscular Nondepolarizing Agents; Postoperative Complications; Succinylcholine; Time Factors
PubMed: 7696076
DOI: 10.1093/bja/74.2.234 -
Korean Journal of Family Medicine Sep 2019It has been reported that in 62.5% of cases of incurable cancer pain, the complaint is due to myofascial pain syndrome. Trigger point injections using dibucaine...
BACKGROUND
It has been reported that in 62.5% of cases of incurable cancer pain, the complaint is due to myofascial pain syndrome. Trigger point injections using dibucaine hydrochloride help patients with such cancer pain. This study evaluated the efficacy of trigger point injections for alleviating pain in patients with advanced cancer.
METHODS
Twenty patients with advanced cancer who had a life expectancy of 6 months or less and had been diagnosed with myofascial pain syndrome were treated with trigger point injections. Prior to treatment, a Visual Analog Scale (VAS) was used to measure the resting pain level and discomfort upon application of pressure on the site of pain. These values were compared with last treatment measurements.
RESULTS
The mean pre-treatment VAS scores for pain at rest and upon application of pressure on the pain site were 7.3 and 9.0, respectively. These scores decreased significantly to 1.95 and 3.2, respectively, after the treatment (P<0.05).
CONCLUSION
Trigger point injection is an alternative and effective pain control modality for advanced cancer patients with myofascial pain syndrome.
PubMed: 31487973
DOI: 10.4082/kjfm.18.0065 -
The Journal of Biological Chemistry Jan 1985The pharmacologic agents verapamil, nifedipine, diltiazem, prenylamine, N-oleoylethanolamine, R 24571, trifluoperazine, dibucaine, and quinacrine are examined as...
The pharmacologic agents verapamil, nifedipine, diltiazem, prenylamine, N-oleoylethanolamine, R 24571, trifluoperazine, dibucaine, and quinacrine are examined as potential inhibitors of rat liver mitochondrial phospholipase A2 acting on endogenous phospholipid. Their potency as inhibitors of the enzyme is compared to their activities as inhibitors of phospholipase A2-dependent swelling and ruthenium red-induced Ca2+ release in intact mitochondria. For verapamil, diltiazem, trifluoperazine, dibucaine, and quinacrine, there is complete agreement between the relative potencies as inhibitors of phospholipase A2 and the two other processes. Nifedipine and prenylamine, which are weak inhibitors of phospholipase A2, produce a permeable inner membrane, provided that the mitochondrial have accumulated Ca2+. R 24571, which strongly inhibits the enzyme, disrupts mitochondria by a Ca2+-independent mechanism. N-Oleoylethanolamine, which is an effective inhibitor of swelling, does not inhibit phospholipase A2 or ruthenium red-induced Ca2+ release. The results support a proposed scheme wherein ruthenium red-induced Ca2+ release is viewed as reverse activity of the Ca2+-uptake uniporter occurring subsequent to decline in the proton motive force. The latter effect is proposed to arise from a specific phospholipase A2-dependent increase in inner-membrane H+ conductance of mitochondrial subpopulations. It is further shown that mitochondrial membranes display cyclic oscillations in free fatty acid content which are not dependent on the presence of Ca2+ or on the capacity to generate acylcoenzyme A.
Topics: Animals; Calcium; Calcium Channel Blockers; Fatty Acids, Nonesterified; Intracellular Membranes; Male; Mitochondria, Liver; Phospholipases; Phospholipases A; Phospholipases A2; Rats; Rats, Inbred Strains; Ruthenium; Ruthenium Red; Serum Albumin, Bovine
PubMed: 2578123
DOI: No ID Found -
Journal of Pharmacy & Pharmaceutical... 2007To characterize the physicochemical properties of drug-loaded oil-in-water (o/w) and water-in-oil (w/o) Brij 97-based microemulsions in comparison to their blank...
PURPOSE
To characterize the physicochemical properties of drug-loaded oil-in-water (o/w) and water-in-oil (w/o) Brij 97-based microemulsions in comparison to their blank counterparts and to investigate the influence of microemulsion type on in vitro skin permeation of model hydrophobic drugs and their hydrophilic salts.
METHODS
The microemulsion systems were composed of isopropyl palmitate (IPP), water and a 2:1 w/w mixture of Brij 97 and 1-butanol. The samples were characterized by visual appearance, pH, refractive index, electrical conductivity, viscosity and determination of the state of water and IPP in the formulations using differential scanning calorimetry (DSC). Transdermal flux of lidocaine, tetracaine, dibucaine and their respective hydrochloride salts through heat-separated human epidermis was investigated in vitro using modified Franz diffusion cells.
RESULTS
The physicochemical properties of drug-loaded microemulsions and their blank counterparts were generally similar; however, slight changes in some physicochemical properties (apparent pH and conductivity) were observed due to the intrinsic properties of the drugs. The o/w microemulsions resulted in the highest flux of lidocaine, tetracaine and dibucaine as compared to the other formulations with in the same group of drugs.
CONCLUSIONS
The characterization results showed that incorporation of the model drugs into the microemulsions did not change the microemulsion type. The permeation data exhibited that the nature of the microemulsions was a crucial parameter for transdermal drug delivery. The o/w microemulsions containing hydrophobic drugs provided the highest skin permeation enhancement. In addition, skin permeation was depended on the molecular weight of the model drugs.
Topics: 1-Butanol; Administration, Cutaneous; Anesthetics, Local; Calorimetry, Differential Scanning; Dibucaine; Electric Conductivity; Emulsions; Epidermis; Humans; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; In Vitro Techniques; Lidocaine; Molecular Weight; Palmitates; Permeability; Plant Oils; Polyethylene Glycols; Skin Absorption; Tetracaine; Viscosity; Water
PubMed: 17727792
DOI: No ID Found