Sodium salicylate ameliorates exercise-induced muscle damage in mice by inhibiting NF-kB signaling

BACKGROUND

Eccentric muscle contraction can cause muscle damage, which reduces the efficiency of exercise. Previous evidence suggested that Sodium salicylate (SS) could improve the repair of aged muscle. This study intends to investigate whether SS can impact skeletal muscle damage caused by eccentric exercise.

METHODS

Eccentric treadmill exercise was performed to induce muscle damage in mice. Plasma levels of muscle damage markers were estimated. RT-qPCR was employed for detecting mRNA levels of proinflammatory mediators in murine gastrocnemius muscle. Immunofluorescence staining of laminin/DAPI was utilized for quantifying centrally nucleated myofibers in the gastrocnemius muscle. Western blotting was implemented to examine protein levels of mitsugumin 53 (MG53), matrix metalloproteinase (MMP)-2/9, and NF-κB signaling-related markers.

RESULTS

SS administration reduced muscle damage marker production in the plasma and decreased the levels of proinflammatory mediators, MG53 and MMP-2/9 in mice after exercise. SS alleviated the severity of muscle damage in the gastrocnemius of mice after eccentric exercise. SS blocked NF-κB signaling pathway in the gastrocnemius muscle.

CONCLUSION

SS administration ameliorates skeletal muscle damage caused by eccentric exercise in the mouse model.

Influence of sodium salicylate on rosmarinic acid, carnosol and carnosic acid accumulation by Salvia officinalis L. shoots grown in vitro

OBJECTIVES

To evaluate sodium salicylate (NaSA) as an elicitor of rosmarinic acid (RA) and phenolic diterpenes, carnosol (C) and carnosic acid (CA) production, in a culture of Salvia officinalis shoots.

RESULTS

In sage shoots grown in vitro, 28 polyphenolic compounds (phenolic acids, flavonoids, and phenolic diterpenes) were identified. In shoots treated for 1 week with increasing NaSA concentrations, the content of C increased from 2.3 in control to 5.7 mg g(-1) DW in shoots treated with 500 µM NaSA. In shoots that were recovered on basal medium for 3 weeks, the maximal amount of C (14 mg/g(-1) DW) was with 150 µM NaSA treatment. In treated and recovered shoots, the increase in C was accompanied with a decrease in CA, resulting in 1.9-fold increase in the C/CA ratio. Accumulation of RA was not affected by the NaSA treatment. However, elicitation by NaSA was accompanied with growth retardation.

CONCLUSIONS

NaSA can improve C production in sage shoot culture, probably by stimulating the conversion of CA to C.

Differential cyclooxygenase-2 transcriptional control in proliferating versus quiescent fibroblasts

Cyclooxygenase-2 (COX-2) overexpression is associated with cancer. One potential mechanism is DNA damage caused by COX-2 derived oxidants. Since DNA in proliferating cells is highly vulnerable to oxidative damage and mutation, we propose that COX-2 transactivation by exogenous stimuli is suppressed in proliferating cells compared to quiescent cells. In this review, we provide evidence for reduced COX-2 transcriptional expression in response to phorbol esters (PMA), lipopolysaccharide (LPS), interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha). Our results show that COX-2 transcription in proliferating fibroblasts is suppressed by a small molecular weight compound produced by proliferating cells. By contrast, COX-2 expression in response to exogenous stimuli is robust in quiescent cells. The quiescent cells in human body may play a primary role in mounting response to exogenous stimuli. Salicylate inhibits COX-2 transcriptional activation in quiescent cells but not in serum-driven proliferating cells by blocking C/EBPbeta DNA binding. These studies suggest that COX-2 expressions in quiescent and proliferating cells are regulated by different mechanisms. Further investigations into their transcriptional control mechanisms will have great impact on the fundamental understanding of the division of cell functions between quiescent and proliferating cells and the design of novel therapeutic strategies.

Biodegradation of phenol and sodium salicylate mixtures by suspended Pseudomonas putida CCRC 14365

The biodegradation of single phenol and sodium salicylate (SA) and their binary mixtures in water by free Pseudomonas putida (P. putida) CCRC 14365 was experimentally studied at 30 degrees C and pH 7. The initial concentration of the cells, adapted with either phenol or SA, was maintained at 0.025 g/L. Single substrate experiments were performed in the substrate level range 0.53-3.18 mM. The Haldane model has shown that phenol was biodegraded more quickly (mu(max)=0.245 h(-1)) than SA (0.137 h(-1)) under the ranges studied, and SA had a more inhibitory effect on cell growth (K(I)=5.21 mM) than phenol (12.6 mM) at low substrate levels even by SA-adapted cells. Binary substrate experiments were carried out at two fixed total substrate levels of 1.06 and 3.18 mM, with a varying molar concentration ratio of 0.33-3.0. The presence of a small amount of phenol to SA could significantly enhance the biodegradation of SA, particularly when the phenol-adapted cells were employed. On the other hand, the addition of a small amount of SA to phenol would retard the biodegradation of phenol, especially at higher total substrate levels (3.18 mM).

Enhanced biodegradation of mixed phenol and sodium salicylate by Pseudomonas putida in membrane contactors

A polypropylene (PP) hollow fiber membrane contactor was used as a reactor to enhance the biodegradation of equimolar phenol and sodium salicylate (SA) by Pseudomonas putida CCRC 14365 at 30 degrees C and pH 7. Experiments were performed at a fixed initial cell density of 0.025 g/L and in the total substrate level range 5.32-63.8 mM. The degradation experiments by free cells were also studied for comparison. With pristine hydrophobic fibers, the degradation of SA was started only after phenol was completely consumed. Substrate inhibitory effect was avoided due to sufficiently low substrate levels in the cell medium; however, the biodegradation was time consuming. With ethanol-wetted fibers, both substrates were completely degraded much faster than the use of pristine fibers. Although the wetted fibers were unable to prevent movement of substrates through the pores, biofilm formed on the outer surfaces of the fibers could enhance the tolerance limit of substrate toxicity. This greatly extended the treatment range to high-level substrate mixtures, as long as the water was nearly neutral and free of concentrated inorganic salts.

Effects of salicylate on voltage-gated sodium channels in rat inferior colliculus neurons

To investigate the effects of the tinnitus inducer, sodium salicylate, on voltage-gated sodium channels, we studied freshly dissociated inferior colliculus neurons of rats by the whole-cell voltage clamp method. Salicylate blocked sodium channels in concentration-dependent manner (0.1-10 mM), and the IC50 value of salicylate was estimated to be 1.43 mM after application. The sodium conductance-voltage curve did not shift along the voltage axis with salicylate application. In contrast, the steady-state sodium channel inactivation curve was shifted by about 9 mV in the hyperpolarizing direction. In addition, salicylate delayed the sodium channel recovery from inactivation by increasing the slow time constant. It was concluded that salicylate bound to the resting and inactivated sodium channels to cause blocking, with a higher affinity for the latter state. Our results suggest that salicylate causes a concentration-dependent blockade of voltage-gated sodium channels and shifts the inactivation curve to more hyperpolarized potentials, which could be related to the mechanism of salicylate-induced tinnitus.

PepN is the major aminopeptidase in Escherichia coli: insights on substrate specificity and role during sodium-salicylate-induced stress

PepN and its homologues are involved in the ATP-independent steps (downstream processing) during cytosolic protein degradation. To obtain insights into the contribution of PepN to the peptidase activity in Escherichia coli, the hydrolysis of a selection of endopeptidase and exopeptidase substrates was studied in extracts of wild-type strains and two pepN mutants, 9218 and DH5alphaDeltapepN. Hydrolysis of three of the seven endopeptidase substrates tested was reduced in both pepN mutants. Similar studies revealed that hydrolysis of 10 of 14 exopeptidase substrates studied was greatly reduced in both pepN mutants. This decreased ability to cleave these substrates is pepN-specific as there is no reduction in the ability to hydrolyse exopeptidase substrates in E. coli mutants lacking other peptidases, pepA, pepB or pepE. PepN overexpression complemented the hydrolysis of the affected exopeptidase substrates. These results suggest that PepN is responsible for the majority of aminopeptidase activity in E. coli. Further in vitro studies with purified PepN revealed a preference to cleave basic and small amino acids as aminopeptidase substrates. Kinetic characterization revealed the aminopeptidase cleavage preference of E. coli PepN to be Arg>Ala>Lys>Gly. Finally, it was shown that PepN is a negative regulator of the sodium-salicylate-induced stress in E. coli, demonstrating a physiological role for this aminoendopeptidase under some stress conditions.

Facilitation of iontophoretic drug delivery through intact and caries-affected dentine

AIM

To investigate the facilitative role of iontophoresis in drug delivery through intact and caries-affected dentine into the pulp.

METHODOLOGY

Forty-eight intact dentine or caries-affected dentine discs were prepared from freshly extracted human third molars. The hydraulic conductance was measured before and after the experiments. Drug diffusion with and without iontophoresis (0.05 mA, 10 min) was evaluated using a split-chamber device. The enamel side chamber was filled with metronidazole (MN), sodium salicylate (SS) or naproxen sodium (NA), while the pulpal side was circulated with phosphate buffered saline (PBS) and pressurized (15 cmH2O). Samples were collected after 1 h. Drug concentrations of the pulpal side solution were determined using a spectrophotometer. Then, electrical impedance of each dentine disc was measured. Finally, the dentine disc surfaces were observed by scanning electron microscopy.

RESULTS

Drug diffusion was significantly influenced by iontophoresis, caries-induced changes in dentine and the drugs used (three-way anova, P < 0.05). The diffusion of all the drugs through caries-affected dentine was significantly less than that through intact dentine (independent t-test, P < 0.05). Also, iontophoresis facilitated the diffusion of all the drugs through intact and caries-affected dentine. The drug diffusion of SS was significantly higher than MN and NA (one-way anova, P < 0.05), independent of iontophoresis.

CONCLUSIONS

Presence of dental caries may inhibit drug diffusion through dentine into the pulp. However, iontophoresis could enhance the delivery of ionized drugs through both intact and caries-affected dentine.

Evaluation of anhydride oligomers within polymer microsphere blends and their impact on bioadhesion and drug delivery in vitro

The effect of the addition of small molecular weight anhydride oligomers to polymer microspheres was evaluated and increased bioadhesion of the composite was demonstrated. Blends of low molecular weight anhydride oligomers with thermoplastic poly(fumaric-co-sebacic anhydride) [p(FASA)] and polycaprolactone were examined. The effects of anhydride oligomers on polymer microsphere degradation, crystallinity, and surface morphology were also explored. The results demonstrated that fumaric anhydride oligomer remained within polymer microspheres for several hours after exposure to phosphate buffer, formed a homogenous crystalline blend, increased bioadhesion as measured on rat intestine, and enhanced drug delivery in vitro as measured by the everted sac technique.

Identification of sodium salicylate as an hsp inducer using a simple screening system for stress response modulators in mammalian cells

As heat shock proteins (Hsps) are involved in protecting cells and also in the pathophysiology of diseases such as inflammation, cancer and neurodegenerative disorders, modulators of Hsp expression in mammalian cells would seem to be useful for the treatment of various diseases. In this study, we isolated mammalian cell lines for screening of Hsp modulators; mouse C3H10T1/2 cells stably transfected with a plasmid containing the mouse Hsp105 or human Hsp70B promoter upstream of a luciferase or beta-galactosidase reporter gene, respectively. Using these cells, we examined the effect of sodium salicylate (SA), which may induce the transcription of hsp genes, on stress response in mammalian cells. When these cells were treated with SA for 1 h at 37 degrees C, both promoter activities were up-regulated by SA at concentrations of more than 45 mm. The activation of heat shock factor and the subsequent accumulation of Hsp105alpha and Hsp70 were detected in cells treated with SA at concentrations of more than 20 and 45 mm, respectively. Furthermore, SA induced resistance against a subsequent lethal stress. These findings suggested that SA is a potent hsp inducer, and may be used to protect cells against deleterious stressors.

A comparison of biodegradation of phenol and homologous compounds by Pseudomonas vesicularis and Staphylococcus sciuri strains

Pseudomonas vesicularis and Staphylococcus sciuri were isolated as dominant strains from phenol-acclimated activated sludge. P. vesicularis was an efficient degrader of phenol, catechol, p-cresol, sodium benzoate and sodium salicylate in a single substrate system. Under similar conditions S. sciuri degraded only phenol and catechol from among aromatic compounds that were tested. Cell-free extracts of P. vesicularis grown on phenol (376 mg l(-1)), sodium benzoate (576 mg l(-1)) and sodium salicylate (640 mg l(-1)) showed catechol 2,3-dioxygenase activity initiating an extradiol (meta) splitting pathway. The degradative intradiol (ortho) pathway as a result of catechol 1,2-dioxygenase synthesis was induced in P. vesicularis cells grown on catechol (440 mg l(-1)) orp-cresol (432 mg l(-1)). Catechol 1,2-dioxygenase and the ortho-cleavage has been also reported in S. sciuri cells capable of degrading phenol (376 mg l(-1)) or catechol (440 mg l(-1)). In cell-free extracts of S. sciuri no meta-cleavage enzyme activity was detected. These results demonstrated that gram-positive S. sciuri strain was able to effectively metabolize some phenols as do many bacteria of the genus Pseudomonas but have a different capacity for degrading of these compounds.

Enhancement of population size of a biological control agent and efficacy in control of bacterial speck of tomato through salicylate and ammonium sulfate amendments

Sodium salicylate and ammonium sulfate were applied to leaf surfaces along with suspensions of the biological control agents Pseudomonas syringae Cit7(pNAH7), which catabolizes salicylate, and Cit7, which does not catabolize salicylate, to determine whether enhanced biological control of bacterial speck of tomato could be achieved. Foliar amendment with salicylate alone significantly enhanced the population size and the efficacy of Cit7(pNAH7), but not of Cit7, on tomato leaves. Application of ammonium sulfate alone did not result in enhanced population size or biological control efficacy of either Cit7(pNAH7) or Cit7; however, when foliar amendments with both sodium salicylate and ammonium sulfate were applied, a trend toward further increases in population size and biological control efficacy of Cit7(pNAH7) was observed. This study demonstrates the potential of using a selective carbon source to improve the efficacy of a bacterial biological control agent in the control of a bacterial plant disease and supports previous conclusions that the growth of P. syringae in the phyllosphere is primarily carbon limited and secondarily nitrogen limited.

Isolation and characterisation of new Planococcus sp. strain able for aromatic hydrocarbons degradation

New Planococcus sp. strain S5 able to grow on salicylate or benzoate as sole carbon source was isolated from activated sludge adapted to sodium salicylate degradation. S5 was determined to be a strictly aerobic, gram-positive, catalase positive, oxidase negative, non-motile, non-spore forming coccus. The strain harboured a plasmid, named pLS5. The S5 strain when grown on salicylate expressed both catechol 1,2-dioxygenase and catechol 2,3-dioxygenase activities and degraded this substrate by both the ortho and meta pathways while grown on benzoate expressed only catechol 1,2-dioxygenase activity. Curing of the plasmid from the strain showed that plasmid pLS5 was involved in salicylate degradation by the meta pathway.

Inhibition of p-cresol on aerobic biodegradation of carbazole, and sodium salicylate by Pseudomonas putida

A PAH- and phenol-degrading microorganism, Pseudomonas putida (ATCC 17484), was used to study the substrate interactions during cell growth on carbazole-containing mixtures with p-cresol and sodium salicylate. Both p-cresol and sodium salicylate could be utilised by the bacteria as the sole carbon and energy sources. When cells grew on the mixture of carbazole, p-cresol and sodium salicylate, strong substrate interactions were observed. Carbazole degradation started only after p-cresol was significantly or completely removed, and the removal of carbazole was incomplete when the initial p-cresol concentration was higher than 20 mg/l. No carbazole was removed at all when the initial p-cresol concentration in the system was higher than 120 mg/l. When cells grew on the ternary substrates, the specific growth rate was found to increase with p-cresol concentration up to 50 mg/l (from 0.33 to 0.45 h(-1)) but decreased monotonically with higher concentrations. At 120 mg/l p-cresol, specific growth rate fell to 0.33 h(-1). The inhibitory effect of p-cresol was demonstrated where carbazole degradation was immediately halted when 50 mg/l p-cresol was spiked to a system containing carbazole and sodium salicylate. Besides, the addition of p-cresol was also found to inhibit the degradation of sodium salicylate. With p-cresol, an increase in lag time was observed and the utilisation of sodium salicylate as carbon source was severely retarded.

Effect of media composition on yield values of bacteria growing on binary and ternary substrate mixtures in continuous culture

Pseudomonas aeruginosa 142 and a presumed variant were grown axenically in chemostats on salicylate/benzoate or salicylate/glucose binary feeds. Each substrate was supplied at 2, 10, 50, 90, 98, or 100% of the total energy flux. Two experiments were also run with ternary mixtures using the same substrates. Aliquots were transferred to fed-batch reactors receiving the same substrates at the same specific rates as the chemostat, but with one substrate radiolabeled with 14C. Radiolabel incorporated into biomass, 14CO2, and soluble microbial products over a period of 8 minutes was used to establish the biomass yield, CO2 yield, and product yield, respectively, associated with a given substrate. The effect of the percent substrate in the feed on the yields depended on the pair of substrates supplied. When benzoate comprised 50% or more of the applied substrate in salicylate/benzoate feeds, the fraction of benzoate in the feed had a small effect on the yield values associated with benzoate. However, when benzoate constituted 2% or 10% of the feed, CO2 yields were lower, biomass yields were slightly lower, and product yields were higher. In contrast, the percent of salicylate in the feed had little effect on any of the salicylate yields for cells growing on the salicylate/benzoate feeds. When salicylate was mixed with glucose, the yields associated with salicylate behaved quite differently. Biomass and CO2 yields were lower and product yields higher when salicylate was 2% or 10% of the feed than when it was higher. In the same substrate mixtures, glucose-based biomass yields were higher and CO2 yields were lower when glucose constituted 2% or 10% of the feed but were constant for higher percentages. The results suggest that the fate of a substrate is relatively independent of the feed composition as long as the substrate in question constitutes a significant percentage of the mixture. Thus, in those situations the assumption of a constant biomass yield in multicomponent substrate modeling is justified. However, when a given substrate constitutes a small percentage of the feed, significant changes in yield may occur.

Selective suppression of CCAAT/enhancer-binding protein beta binding and cyclooxygenase-2 promoter activity by sodium salicylate in quiescent human fibroblasts

The anti-inflammatory actions of salicylates cannot be explained by inhibition of cyclooxygenase (COX) activity. This study demonstrates that sodium salicylate at a therapeutic concentration suppressed COX-2 gene transcription induced by phorbol 12-myristate 13-acetate and interleukin 1beta by inhibiting the binding of CCAAT/enhancer-binding protein beta to its promoter region of COX-2. By contrast, salicylate did not inhibit nuclear factor kappaB-dependent COX-2 induction by tumor necrosis factor alpha. The inhibitory effect of sodium salicylate was restricted to serum-deprived quiescent cells. These findings indicate that contrary to the current view that salicylate acts via inhibition of nuclear factor kappaB the pharmacological actions of aspirin and salicylates are mediated by inhibiting CCAAT/enhancer-binding protein beta binding and transactivation. These findings have a major impact on the conceptual understanding of the mechanism of action of salicylates and on new drug discovery and design.

Salicylate and cocaine: interactive toxicity during chicken mid-embryogenesis

Increased free radical production, due to ischemia and reperfusion, has been postulated as a cause of cocaine's (COC) developmental toxicity. Salicylate reacts with hydroxyl free radicals (*OH) to form stable, quantifiable reaction products, which can be measured with high-pressure liquid chromatography (HPLC). To determine if chicken embryos' brains and hearts were exposed to increased *OH concentrations after injection of COC, an injection of a nontoxic dose of sodium salicylate (NaSAL, 100 mg/kg egg, or 5 mg/egg), followed by 5 injections of COC (13.5 mg/kg or 0.675 mg/egg, every 1.5 h), was administered to eggs containing embryos on the 12th day of embryogenesis (E12). In addition to finding increased *OH concentrations in E12 embryonic hearts and brains, we observed that the developmental toxicity of COC, manifest as vascular disruption (hemorrhage) and lethality, was enhanced by NaSAL injection. These results confirm and extend results of similar experiments performed upon older embryos (E18), and indicate that increased &z.rad;OH concentration in embryonic tissues after COC exposure and toxic interactions of COC and NaSAL can also occur at an earlier stage of development. The results are discussed in light of possible exposure of human fetuses to both COC and salicylates, since COC-abusing pregnant women can be misdiagnosed with pre-eclampsia and aspirin is used to treat this syndrome.

NMR diffusion and relaxation study of drug-protein interaction

In this work, NMR diffusion and relaxation measurements are applied to the study of the interaction between the anti-inflammatory drug salicylate and the human serum albumin (HSA) in solutions. The self-diffusion coefficients and the spin-lattice relaxation rates of salicylate are measured as a function of the concentration. The dissociation constant, Kd, for drug/HSA complexes and the number of binding sites, n, are evaluated.

Glibenclamide, an antagonist of ATP sensitive K+ channels, blocks free radical generation in the rat myocardium

The present study examined the effect of glibenclamide, an ATP-sensitive K+ (K(ATP)) channels antagonist, on the potassium chloride (KCl)-induced hydroxyl free radical (.OH) generation. Sodium salicylate in Ringer's solution (0.5 nmol/microl per min) was infused directly through a microdialysis probe to detect the generation of .OH as reflected by the formation of dihydroxybenzoic acid (DHBA) in the myocardium of anesthetized rat. The high concentration of KCl (70 mM) significantly increased the level of 2,3- and 2,5-DHBA by the action of depolarization by KCl. However, in the presence of glibenclamide (10 microM), KCl failed to increase the 2,3- and 2,5-DHBA formation. Moreover, when allopurinol (10 mg/kg), a xanthine oxidase inhibitor, was administered by i.v. injection, the elevation of DHBA was not observed. These results suggest that openings of cardiac K(ATP) channel by depolarization evokes .OH generation via xanthine oxidase reaction.

Prevention of reoxygenation injury by sodium salicylate in isolated-perfused rat liver

Sodium salicylate can be used as a chemical trap for hydroxyl radicals, the most damaging reactive oxygen species. Because reactive oxygen species are involved in the pathogenesis of hepatic hypoxia/reoxygenation injury, the goal of this study was to determine if trapping hydroxyl radicals with salicylate would prevent or at least ameliorate such injury. Isolated rat livers, continuously perfused with Krebs-Henseleit bicarbonate buffer in the presence or absence of salicylate (2 mM), were exposed, after 30 min of recovery, to 60 min of hypoxia, followed by 30 min of reoxygenation. During reoxygenation, control livers experienced a sharp increase in the rate of lactic dehydrogenase release, taken as index of cell injury, protein carbonyl content, and malondialdehyde, taken as index of protein oxidation and lipid peroxidation, respectively. The presence of salicylate in the solution perfusion significantly reduced the rate of lactic dehydrogenase release, protein carbonyl content, and malondialdehyde production during reoxygenation. Hepatic histology documented a significantly reduced cell injury in salicylate-perfused livers compared to control livers. These data suggest that the hydroxyl radical chemical trap sodium salicylate, acting as an antioxidant, may represents an effective agent to reduce liver injury due to hypoxia/reoxygenation in a model of isolated-perfused rat liver.

Enhanced in vitro percutaneous penetration of salicylate by ion pair formation with alkylamines

The apparent octanol/water partition coefficient (APC) of salicylate (SA) increased as the concentration of alkylamine (amyl, hexyl, heptyl, octyl and nonylamine) in aqueous phase increased, presumably through intermolecular ion pair formation between the negatively charged SA moiety and the alkylamine cation. The true partition coefficient (TPC) and the formation constant (Kf) of the ion pair were calculated from the partition data. The skin permeability of SA increased as the APC of SA increased, when 20-fold molar excess of alkylamine was added to the donor compartment. Permeability of ion pairs (PAB) from the aqueous phase to a shed snake skin was estimated from the permeability data assuming 1:1 ion pair. The methylene group contribution to the free energy of transfer of ion pairs from water to the shed snake skin was less than the reported value for nonionized drugs. This suggests that the ion pair is more polar by nature than nonionized molecules, even if ionic characteristics are masked to some extent by ion pair formation.

Hydroxyl radical generation in the cat retina during reperfusion following ischemia

There is increasing evidence that oxygen-derived free radicals are generated during the early phase of reperfusion, and account for part of the damage caused by transient ischemia in various tissues. To study this in the retina, cats were injected intravenously with sodium salicylate (100 mg kg-1), which reacts as a hydroxyl radical trap to form 2,3- and 2,5-dihydroxybenzoic acids (DHBA). Thirty minutes following injection, the retina of one eye of each animal was subjected to ischemia by intraocular pressure elevation via cannulation of the anterior chamber, while the fellow eye served as a sham-operated control. Ischemia was induced for 60 min (six eyes) and 90 min (eight eyes) followed by 5 min of reperfusion. In six other eyes, ischemia was induced for 90 min without reperfusion. After enucleation, the retinas were immediately removed, placed in ice-cold buffer and the retinal levels of 2,3- and 2,5-DHBA were quantitated by high pressure liquid chromatography, coupled with electrochemical detection. Results were normalized and expressed as ng DHBA microgram-1 salicylate mg-1 retinal protein. After 60 min of ischemia followed by reperfusion the normalized levels of 2,3- and 2-5-DHBA were no different in the experimental and control retinas. However, the levels of both 2,3- and 2,5-DHBA were significantly higher in the retinas subjected to 90 min ischemia followed by reperfusion than in the control tissues (P = 0.012 and P = 0.036, n = 8 respectively). Following 90 min ischemia without reperfusion, the normalized dihydroxybenzoate levels in the retinas were no higher than in their controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous absorption-enhancing activity of urea derivatives

The effect of urea and urea derivatives on the percutaneous absorption of salicylic acid and sodium salicylate through the skin of rabbit from petrolatum ointment was investigated. It was found that addition of urea or urea derivatives to the ointment base significantly increased the percutaneous absorption of the drugs in proportion to the concentration of the additive. The percutaneous absorption-enhancing activities of these compounds were that urea derivatives with the more and longer alkyl substituents showed the stronger activities. These activities of urea and urea derivatives were ascribed to the binding of these compounds with the lipids and proteins of the stratum corneum of the skin and the swelling of the tissues, which leads to the reduction of the barrier property of the layer. The preliminary skin irritation test showed that urea and urea derivatives were quite non-irritating to the skin. These results suggest that urea derivatives have a strong possibility to be developed as a percutaneous absorption enhancer.

Dry adsorbed emulsions: an oral sustained drug delivery system

The oral sustained drug delivery system "dry adsorbed emulsion" was defined as an organized dispersion of hydrophilic and hydrophobic particles whose structure was initiated by the structure of a water-in-oil (W/O) emulsion. Sodium salicylate was dissolved in the aqueous phase of the primary W/O emulsion as an active drug. The aqueous phase of the W/O emulsion was adsorbed by a hydrophilic silica and then a hydrophobic silica was added to the preparation to obtain a stable and solid pulverulent form. The physicochemical structure of a "dry adsorbed emulsion" was described and observed by electron microscopy. The effect of different oils, castor oil and a silicone oil, on the sustained drug release was studied at two different pH values, 1.2 and 7.4, to simulate the gastric and intestinal medium, respectively. The properties of these forms were retained for more than one year at room temperature storage.

Skin permeability in the newborn

Skin permeability to drugs was assessed in the newborn infant using an in vitro method. Excised skin samples were studied in a Franz-type cell, and permeability to 0.1 M sodium salicylate was measured. Fourteen samples were studied, from infants of 25-41 weeks gestation and up to 8 days old. Gestation markedly affected skin permeability to salicylate, absorption being 10(2)-10(3) times greater in infants of 30 weeks gestation or less than in term infants. There are important implications for the high permeability of the preterm infant's skin; accidental poisoning from absorption of topically applied agents can easily occur, and the percutaneous route offers an alternative method of therapeutic drug administration.

Use of salicylate to estimate the "threshold" inducer level for de novo synthesis of the phenol-degrading enzymes in Pseudomonas putida strain H

A special approach was used to elucidate the "threshold" inducer concentration for coordinative de novo synthesis of phenol hydroxylase(s), catechol 2,3-dioxygenase and the 2-hydroxymuconic semialdehyde-metabolizing enzymes which initiate phenol catabolism in Pseudomonas putida strain H. It is based on cell-precultivation with glucose (as the carbon and energy source) in the presence of different concentrations of sodium salicylate which proved to be a potent non-metabolizable inducer in strain H of these enzymes. Subsequent estimation of the activity status of resting cell suspensions and cell-free extracts, respectively, prepared from those strain H cultures clearly revealed failing de novo synthesis of the mentioned phenol-degrading enzymes at salicylate concentrations lower than 0.2 mg/l.

Interactions between diphtheria toxin entry and anion transport in vero cells. III. Effect on toxin binding and anion transport of tumor-promoting phorbol esters, vanadate, fluoride, and salicylate

When Vero cells were incubated with TPA (12-O-tetradecanoylphorbol 13-acetate) and related tumor promoters, their ability to bind diphtheria toxin in a functional way was rapidly reduced to less than 1% of the normal value. Upon further incubation with TPA, the cells recovered their ability to bind the toxin, apparently because they became resistant to TPA. Treatment with Na3VO4 reduced the ability of the cells to bind diphtheria toxin to approximately the same extent as treatment with TPA, but the reduction required longer time to develop and it persisted upon prolonged incubation with Na3VO4. ATP depletion of the cells prevented the reduction in binding capability. Such treatment also prevented the reduction in toxin binding induced by treatment with salicylate or fluoride. Treatment with TPA, fluoride, vanadate, and salicylate altered the ability of the cells to carry out anion transport and interfered with their ability to regulate the transport. The results indicate that the binding sites for diphtheria toxin on Vero cells are modulated by TPA, Na3VO4, salicylate, and fluoride by a process which requires ATP. The possibility is discussed that the modulation consists in phosphorylation of the toxin binding sites, which may be identical with, or closely linked to, the anion antiporter in the cells.

The effect of age on salicylate-induced nephrotoxicity in male rats

The administration of 500 mg/kg sodium [14C]salicylate to 3- and 12-month-old male rats produced proximal tubular necrosis in the older animals but only mild nonspecific cellular changes in the younger group. The onset of renal damage was similar for both 3- and 12-month-old rats but recovery time was prolonged in the older rats. Covalent binding of salicylate equivalents was present in renal cortices from all rats and was largely confined to the mitochondrial fraction; however, older rats displayed five times more binding to this organelle than younger rats. Also the mitochondrial pathway for salicylurate synthesis was significantly inhibited in the older animals. These results demonstrate the existence of an age-dependent susceptibility to salicylate nephrotoxicity and suggest that mitochondrial injury may play an important role in the development of salicylate-induced proximal tubular necrosis.

Salicylate kinetics in old age

Salicylate kinetics were determined in 28 subjects 25 to 92 years old who received single, oral doses of sodium salicylate (1 gm/1.73 m2). The serum AUCinfinity of total salicylate did not correlate with age. There was a weak positive correlation between the AUCinfinity of free (unbound) drug and age, but there was no apparent difference between the AUCinfinity values of the 15 women and 13 men. Seven of the 16 subjects greater than 70 years of age cleared salicylate at about the same rate as the younger subjects. A comparison of these seven subjects with the nine greater than 70 years old who were slow eliminators of salicylate revealed that the latter group consisted of more bedridden patients and that these patients had somewhat lower serum albumin concentrations, but they did not differ from the more rapid eliminators with respect to serum creatinine or urea nitrogen levels, SGOT, average age, female/male ratio, and average body weight. The serum protein binding of salicylate decreased with increasing age, apparently due mainly to decreasing serum albumin concentrations.

Influence of intravenous acetylsalicylic acid and sodium salicylate on human renal function and lithium clearance

The influence of intravenous acetylsalicylic acid (ASA; D,L-lysine-mono-acetylsalicylate), equimolar doses of sodium salicylate (SA) and placebo (P) on renal function has been studied in 6 healthy female volunteers, in 150 mmol sodium balance, and in lithium (Li) steady state with a plasma Li between 0.6 and 0.8 mmol/l. Following a bolus injection of 0.5 g ASA, 0.444 g SA or P (50 ml saline) given over 10 min and a subsequent continuous infusion of 1.5 g ASA, 1.332 SA or P (150 ml saline) over 170 min, urine was collected for 3 h as well as 6 plasma samples at 30-min intervals. Plasma ASA levels were between 13.8 and 22.1 micrograms/ml and for SA they were 20.8 to 82.6 microgram/ml during ASA infusion, and between 22.5 and 108.9 microgram/ml for SA during SA infusion. Neither ASA nor SA caused a significant change in urine volume, in the renal clearances of Na, K, free water, osmolality, creatinine, inulin and p-aminohippurate (PAH) or in plasma Li level. Renal Li clearance was slightly reduced by SA, from 37.8 to 29.4 ml/min (p less than 0.05). Since renal prostaglandin (PG) synthesis (urinary PGE2 excretion) was 60.6% suppressed by ASA and was not affected by SA, the decrease in Li clearance cannot be related to inhibition of cyclooxygenase in the kidney.

Should corneas from donors receiving a high dose of salicylate be used as grafts: an animal experimentation

Rabbits were injected intravenously with a single dose of sodium salicylate (350 mg kg-1) in order to study the following in vivo: (i) the distribution of the drug in the various eye tissues and fluids, particularly the cornea and aqueous humour, and (ii) transfer of the drug from corneal grafts obtained from donors receiving sodium salicylate to the eye tissues of the recipient. In additional experiments, the in vitro effects of sodium salicylate on the growth and protein synthesis of corneal cells grown in tissue culture were also studied. In vivo experiments showed that the periods during which we observed the highest concentration of salicylate in the serum and in the eye tissues were within 30 min and 2 hr respectively following the injection. These experiments also showed that salicylate was transferred from the treated donor via corneal graft to the recipient's eye tissues where it could still be detected 48 hr after the operation. In vitro experiments showed that a 50% inhibition of cell growth was obtained at a concentration of about 1000 micrograms salicylate ml-1 while protein synthesis was decreased by 50% at a concentration of about 200 micrograms ml-1. A consideration of our data from the in vivo and in vitro experiments together suggests that ingestion by the donor of high concentrations of salicylate may have the potentiality of subjecting the corneal endothelial cells to cytotoxic concentrations of the drug thus jeopardizing the success rate of corneal graft operations.

Effect of pregnancy on tissue distribution of salicylate in rats

The effect of pregnancy on tissue distribution of salicylate was studied by comparing both pharmacokinetic and protein-binding parameters between 20-day-pregnant rats and nonpregnant (control) rats. In the pregnant rats, the volume of distribution increased significantly (p less than 0.05) from 164 ml/kg of the control to 225 ml/kg, and the total body clearance also increased significantly (p less than 0.05) from 12.1 ml/hr/kg of the control to 19.8 ml/hr/kg. But these changes did not affect the plasma disappearance half-life of salicylate in the pregnant rats. The serum unbound fraction (fs) of the pregnant rats at 8 hr after iv administration of salicylate increased remarkably from 0.14 of the control to 0.67. The fs in the fetal serum (0.41) was lower than that in the maternal serum in spite of the lower albumin concentration in the fetal serum. A nonlinear serum protein binding was observed both in the control and in the fetal rats, but not observed in the pregnant rats. In the pregnant rats, the tissue-to-serum concentration ratios (Kp) of all tissues studied were larger than those in the control rats, and the values of Kp in the fetal were larger than those in the maternal. To elucidate these difference in Kp values between the pregnant and control rats, a mathematical model was proposed, where salicylate was distributed in the interstitial fluid, bound to the interstitial albumin, and translocated into the intracellular fluid according to the pH partition theory. The Kp values of most tissues in the control and pregnant rats were predicted successfully by using this model.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro and in vivo evaluation of controlled-release and enteric-coated formulations of sodium salicylate

The bioavailability and pharmacokinetics of salicylic acid (SA) were studied after single and multiple doses of a new slow-release formulation, based on porous membrane diffusion of sodium salicylate (NaSA). A solution of NaSA and an enteric-coated tablet of NaSA were used for comparison. Dissolution rate studies were carried out at various pH values, and both solid formulations showed pH-dependent release rates. The enteric-coated tablet released its content rapidly at intestinal pH but slowly and irregularly at gastric pH. The dissolution from the controlled-release formulation at intestinal pH was completed after 6h and the drug was delivered at a constant rate. At gastric pH the release rate was lower but complete release was obtained within 24h. The novel formulation appeared to offer complete bioavailability of SA and an even and sustained release of SA, allowing twice-daily medication without increased fluctuations in SA concentrations.

Salicylate pharmacokinetics in the dog at 6 ATA in air and at 2.8 ATA in 100% oxygen

Hyperbaric air and hyperbaric hyperoxia, which have been shown to decrease both liver plasma flow and plasma volume in dogs, may potentially affect the disposition of drugs whose distribution and/or elimination are dependent upon those actions. This study examined the effects of those conditions on the disposition of salicylic acid, using the dog as a model. The drug was administered to six mixed-breed dogs as a 10 mg sodium salicylate/kg i.v. bolus at 1 ATA breathing air (control), at 2.8 ATA breathing 100% O2, and at 6 ATA breathing air, followed by serial blood sampling for 8 h. Statistical analysis showed a significant increase (p less than 0.05) in salicylate clearance at 2.8 ATA compared to control with a subsequent, although not statistically significant, increase in elimination half-life. There were no significant differences between the values observed at 6 ATA and either control or 2.8 ATA. As 100% O2 at 2.8 ATA is used during hyperbaric oxygen medical therapy and during decompression, this change in disposition of this commonly used agent may have implications in man. Studies in man must be conducted, however, to determine if the same conclusions apply.

Distribution of salicylate in lens and intraocular fluids and its effect on cataract formation

Retrospective studies on cataract development in patients with rheumatoid arthritis or osteoarthritis revealed a retardant effect of aspirin on diabetic and non-diabetic cataracts. The effect of aspirin is dose-dependent. The correlation coefficient between years delay for various cataracts subcategories versus aspirin taken (in tablets per day X years of intake) was 0.69. The ocular pharmacokinetics of 14C acetylsalicylic acid or salicylate were determined after intravenous or intraperitoneal administration to rabbits. 14C acetylsalicylic acid penetrates rapidly into rabbit lens and aqueous humor after intravenous administration. After intraperitoneal administration, salicylate levels in rabbit plasma, similar to those of humans receiving four to six aspirin tablets (325 mg each), result in accumulation of salicylate by lens (mean +/- SD) of 405 +/- 72 mumoles/g and 620 +/- 30 mumoles/g at two and four hours, respectively. At those dosages, salicylate is cleared in 24 hours from rabbit plasma and intraocular fluids, but retained by lens. Penetration of salicylate into rabbit lens and rat lens is dose-dependent. The retardant aspirin effect in diabetic cataracts is linked to inhibition of tissue aldose reductase and lens protein glycosylation. Deceleration of galactose cataract formation in rats occurs after daily salicylate intraperitoneal injections of 100 mg/kg a day.

The thin-film adsorber hemoperfusion device: detailed mass transfer and flow characteristics

Further testing and evaluation of the thin-film adsorber (TFA) type of hemoperfusion device is reported here to complement an earlier paper describing the development of these devices and clearance tests performed with them. The present paper describes the results of pressure drop tests, flow uniformity tests, and detailed studies of the mass transfer characteristics of the components of the TFA units. The TFA units consist of powdered activated charcoal embedded in thin films of cellulose nitrate. These films are sprinkled with small particles of granular charcoal and then wound into spools, which are then placed in a plastic housing. The use of powdered charcoal exploits the enormous rate-of-uptake advantage of powdered charcoal over the granular sorbents used in other hemoperfusion devices. The present tests showed that the pressure drops in the TFA devices are intrinsically low, but that their priming volumes are only marginally acceptable. Significant flow nonuniformities also exist. Despite this, the overall mass transfer resistance values for the TFA devices are lower than those for available commercial hemoperfusion units. Measurements of diffusion coefficients in the carbon and in the carbon-loaded polymer film showed that in the carbon-loaded film, the slowest diffusion step involves the carbon particles themselves. Other tests disclosed that the liquid external to the film (i.e., in the flow spaces) offers even greater mass transfer resistance than does the carbon-loaded film. Further evaluations of the TFA type of device are suggested, particularly concerning its thrombogenic properties.

Central neural stimulation of respiration by sodium salicylate

Phrenic nerve responses to intravenous administration of sodium salicylate were measured in anesthetized, paralyzed cats whose vagi and carotid sinus nerves had been cut. Three groups of animals were studied. One consisted of animals with intact central nervous systems. The other two were identical except that the spinal cords had been transected at either T4-T5 or C7-T1. Salicylate led to a significant increase in respiration and whole body metabolism in all three groups. Transection of the spinal cord had no effect on the magnitude of the respiratory response to salicylate. We also studied another group of animals in which salicylate was injected directly into the third cerebral ventricle. This led to a significant increase in respiration without an increase in whole body metabolism. We conclude that salicylate stimulates respiration by a mechanism other than one related to its ability to increase whole body metabolism and that this mechanism is located within the central nervous system.

Sex differences in absorption kinetics of sodium salicylate

Sodium salicylate in aqueous solution (9 mg/kg) was given by oral and intravenous routes to normal male and female subjects. Because the bioavailability of salicylate was complete, salicylate was given orally in all subsequent experiments. There were sex differences in time required to attain peak salicylate concentration (tmax), but not in maximum plasma salicylate concentration (Cmax). There were no sex differences in apparent volume of distribution, plasma salicylate clearance, or area under the concentration-time curve. In female subjects, tmax tended to reach a nadir at the middle of the menstrual cycle, when gastric emptying time is shortest, whereas Cmax remained relatively unchanged throughout the menstrual cycle. Equilibrium dialysis studies on the binding of sodium salicylate and of 14C-racemic warfarin to plasma from 25 normal male and 25 normal female subjects of similar age disclosed no sex differences either in the extent of binding of these drugs or in serum albumin concentration. The possibility of sex differences in rates of gastrointestinal absorption of other drug should be investigated.

Pharmacological studies on iridoid compounds. III. The choleretic mechanism of iridoid compounds

We made a study on choleretic property and mechanism of action of iridoid compounds as well as dehydrocholate (DHC), cholate (CA), and salicylate (SA), examining their effects on factors such as bile flow, bile acids, electrolytes (Na+, K+, Cl-, and HCO3-), and their metabolites. Each sample showed a characteristic property, respectively. Genipin and patrinoside decreased biliary concentrations of bile acids, Na+, Cl-, and HCO3-, corresponding to their rapid choleretic actions which were due to bile acids independent fraction. The choleretic action of DHC is approximately twice as potent as that of CA. Their actions were due to bile acids-dependent fraction. CA gave a marked increase in Na+ concentration but DHC did not. And both compounds gave a marked diminution in Cl- concentration and weakly decreased HCO3- concentration. SA showed a weak and durable choleretic action and also gave a marked increase in HCO3- concentration. The main metabolite detected from the bile given genipin was genipin-1-O-glucuronic acid (GGA). The periodical pattern of GGA level in bile was in agreement with that of genipin- induced choleretic action, and quantitatively cation, anion gap produced was nearly compensated by biliary concentration of GGA. From out various results, the choleretic mechanism of iridoid compounds is considered to be as follows: The hemiacetal moiety of them undergoes conjugation in the liver to give glucuronide. Glucuronide thus formed is secreted into the biliary tree being coupled mainly with Na+ and water is passively excreted.

Salicylate metabolite kinetics after several salicylates

Single oral doses of aspirin (ASA, 1,500 mg), sodium salicylate (NaSA, 1,500 mg, 1,200 mg), and salicyluric acid (SUA, 500 mg) were given to five subjects. Serial plasma and urine samples were collected for 24 hr (plasma) and up to 48 hr (urine); salicylic acid (SA), SUA, and gentisic acid (GA) were measured by high-pressure liquid chromatography. The plasma concentration/time profiles for SUA after ASA and NaSA were fitted to the empirical equation CpSUA = A-Bt-Ce-alpha t -- (A-C)e-beta t. Michaelis constants (Vm and Km) for the conversion of SA to SUA were calculated from the equation (formula see text), where Cl is the renal clearance of SUA, ke is the rate constant of elimination of SUA, CpSA is the plasma concentration of salicylic acid. The term Cl (formula see text) is the estimated rate of formation of SUA from SA at any time (t). The calculated values (mean +/- SD) of Vm, Km, and Kmf (Km in terms of unbound SA) were 43.4 +/- 10.1 mg SA/hr, 14.3 +/- 3.4 mg SA/l plasma, and 0.75 +/- 0.15 mg unbound SA/l plasma. The Vm values were in accord with those reported, but the value for Km was considerably lower. Renal clearances of SUA and GA were 340 +/- 51 and 65 +/- 10 ml/min.

Sodium salicylate: effect on determinants of bile flow and cholesterol solubility in rhesus monkeys

To study the mechanism of salicylate-induced choleresis in rhesus monkeys, we utilized animals with indwelling common bile duct catheters under phencyclidine anesthesia. Bile flow, [14C]erythritol clearance (an estimate of canalicular flow), and bile acid secretion were measured during baseline and for 1 1/2 hr during salicylate infusion. Bile flow increased from 91.2 +/- 7.3 ml/24 hr (SEM) to 180.1 +/- 8.0 ml/24 hr (P less than 0.001) with salicylate infusion and [14D]erythritol clearance from 114.5 +/- 8.9 ml/24 hr to 222.3 +/- 10.7 ml/24 hr (P less than 0.001), but bile acid secretion was unchanged, suggesting increased bile acid-independent canalicular bile flow. Salicylate concentration in bile averaged 1.48 +/- 0.08 mmol/liter, and salicylate concentration in extra bile produced by salicylate was unlikely to result in chloeresis of the magnitude observed. [3H]inulin bile-plasma ratios, measured in these same studies, were unchanged after salicylate administration, suggesting that permeability of the biliary tree was not altered. Bile lipid secretion, like bile acid secretion, was unchanged after salicylate administration, so no change occurred in the lithogenic index of the bile. These results demonstrate that salicylate is a potent choleretic in rhesus monkeys because of enhancement of bile acid-independent bile flow. Salicylate produced no change in the lithogenic index of the bile.

[Pharmacokinetic characteristics of salicylates in old animals]

Experimental study of absorption, distribution, metabolism and excretion of salicylic acid and salicylate upon ageing showed that the sodium salicylate absorption rate is considerably decreased in old rats and rabbits. As a result, the plasma of old animals shows the low content of salicylates compared to adult ones. The level of salicylic acid in tissues and capacity of serum protein for salicylate binding are decreased. Excretion of salicylates in old rats was delayed compared to that in adult ones, the half-life in old rats was 2--3 times as long as that in adult species. The revealed features of salicylate pharmacokinetics in old animals confirm advisability of their further study in order to determine adequate doses of the drugs to be applied in geriatrics and to prevent their adverse on the ageing organism.

The distribution of sodium salicylate in the human fetus

The distribution of sodium salicylate was investigated in the fetuses of 18 mothers in the fifth or sixth month of pregnancy which had to be interrupted for medical reasons. Ninety-six min after drug administration, the salicylic acid levels in mother and fetus blood are almost equal. The highest drug levels in fetus tissue were found in the kidney, the lowest in the brain. In amniotic fluid, only traces of salicylic acid were estimated. A limited number of suitable cases made the exact statistical evaluation impossible.