Free radicals from plastic syringes

Buettner, Garry R.; Scott, Brook D.; Kerber, Richard E.; Mügge, Andreas

doi:10.1016/0891-5849(91)90189-a

Cited by 25 publications

(14 citation statements)

References 2 publications

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“…Investigating the literature revealed that a variety of contamination sources could possibly play a role. These sources include, but are not limited to: glue from the adhesive tape used for cleaving HOPG 50 , poor quality solvents 51 , plastic syringes 52,53 , flexible tubes, and air quality. Also, when employing the ethanol-exchange to nucleate nanobubbles a lot of care has to be taken as ethanol is especially susceptible to distribute any organic contaminants present in the nucleation procedure.…”

Section: A) B)mentioning

confidence: 99%

Exposing nanobubble-like objects to a degassed environment

et al. 2014

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The primary attribute of interest of surface nanobubbles is their unusual stability and a number of theories trying to explain this have been put forward. Interestingly, the dissolution of nanobubbles is a topic that did not receive a lot of attention yet. In this work we applied two different experimental procedures which should cause gaseous nanobubbles to completely dissolve. In our experiments we nucleated nanobubble-like objects by putting a drop of water on HOPG using a plastic syringe and disposable needle. In method A, the nanobubble-like objects were exposed to a flow of degassed water (1.17 mg/l) for 96 hours. In method B, the ambient pressure was lowered in order to degas the liquid and the nanobubble-like objects. Interestingly, the nanobubblelike objects remained stable after exposure to both methods. After thorough investigation of the procedures and materials used during our experiments, we found that the nanobubble-like object were induced by the use of disposable needles in which PDMS contaminated the water. It is very important for the nanobubble community to be aware of the fact that, although features look and behave like nanobubbles, in some cases they might in fact be or induced by contamination. The presence of contamination could also resolve some inconsistencies found in the nanobubble literature.

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Section: A) B)mentioning

confidence: 99%

Exposing nanobubble-like objects to a degassed environment

et al. 2014

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“…Furthermore, a recent report has suggested that plastic syringes can release free radicals into the fluids they hold (Buettner, Scott, Kerber & Muegge, 1991). The free radical species which is leached by these materials has been tentatively identified as nitroxide (aminoxyl radical).…”

Section: Actions Of Dtt On Nmda -Activated Unitary Conductancesmentioning

confidence: 99%

The modulation of N‐methyl‐D‐aspartate receptors by redox and alkylating reagents in rat cortical neurones in vitro.

Tang

Aizenman

1993

The Journal of Physiology

118

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SUMMARY1. The properties of sulfhydryl redox modulation of the N-methyl-D-aspartate (NMDA) receptor have been examined in rat cortical neurones in culture. Electrophysiological measurements were performed with the whole-cell and outsideout patch variants of the patch-clamp technique.2. The disulphide reducing agent dithiothreitol (DTT; 0 1-10 mM) potentiated 10 /iM NMDA-mediated whole-cell currents when applied slowly alone via the superfusate. The initial rate of reduction, as well as the degree of potentiation, was dependent on the concentration of DTT although the process was complicated by the fact that a second, large component appeared at a concentration of 10 mm of this agent.3. DTT (0-1-10 mM) was also rapidly applied together with the agonist from a perfusion pipette. With this method, the second component was not readily apparent, and the concentration of DTT producing a half-maximal potentiation of the NMDA response was 1-9 + 0-3 mm. Two other disulphide reducing agents, ethylene glycol bisthioglycolate and meso-bis(NN-dimethyl)adipamide-2,5-dithiol, also potentiated NMDA responses, but were not as effective as DTT. 4. Following a 4 mm DTT treatment, we observed that the NMDA receptor underwent spontaneous oxidation with a half-time of 1-9 min. In contrast, the sulfhydryl oxidizing agent 5,5'-dithio-bis-(2-nitro-benzoic acid) (DTNB; 500,UM) produced a more rapid reversal of the effects of DTT (th = 0-6 min). The spontaneously oxidized receptor could be further oxidized with DTNB and fully reduced with DTT.5. After receptor oxidation with 500 JtM DTNB, NMDA produced whole-cell responses with an EC50 of 68-4 + 9-4 ,jM, whereas after reduction with 4 mm DTT the EC50 for NMDA was 32'5 + 3-4 /tM. In addition, the maximum response after reduction with DTT was substantially increased over that observed after oxidation. 6. Single channel measurements performed on outside-out patches revealed that reduction produced a dramatic increase in the number of NMDA-induced channel openings. We observed a 2-1 +0-2-fold increase in the frequency of openings during reduction with 500 Itm DTT when compared to patches which had been exposed to 500 EM DTNB. Small but significant differences were observed in the single channel MS 1122 L. -H. TANG ANlD E. AIZENMAN conductance for the oxidized (34-6 + I 1 pS) and reduced (37±6 + 1P5 pS) states of the receptor. In contrast, no significant changes were seen in the arithmetic mean channel open time between the two redox conditions (5-4+0 3 ms after oxidation, 60+007 ms after reduction).7. The site or sites responsible for the redox modulation of the NMDA receptor were alkylated with NV-ethylmaleimide (NEM; 300-500 aM) following reduction with DTT. Alkylation of the receptor produced responses which were permanently potentiated and largely insensitive to oxidation by DTNB.8. The actions of the NMDA receptor modulatory agents Zn2+ (20,aM), Mg2+(1 mm), protons (pH 6 8) and glycine (3 JIM) were tested before and after alkylation.We observed that while the blocking effects of pro...

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“…1). Since EPR contamination by plastics was recently reported in a brief communication by others, 10 all plastic was removed from the experiment, including syringes, disposable needles, intravenous catheters, etc. These items were replaced by glass (syringes) or stainless steel (needles).…”

Section: Resultsmentioning

confidence: 99%

Detection of free radicals in reperfused dog skin flaps using electron paramagnetic resonance spectroscopy: A pilot study

1999

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This is a preliminary investigation of the usefulness of spin-trapping electron paramagnetic resonance (EPR) in detecting oxygen-derived free radicals after reperfusion of ischemic skin flaps. Fourteen island skin flaps approximately 12 cm long by 6 cm wide based on the caudal superficial epigastric vessels were isolated in seven dogs. Seven of the paired skin flaps were subjected to 4 hours of arterial and venous occlusion. The opposite skin flap on each dog served as a perfused control. Spin trapping-EPR was able to detect radical adducts in five of the seven reperfused skin flaps. Hyperfine splitting constants of the radical adducts from the blood of three of the flaps confirmed biologically derived free radical production. Contaminating EPR signals from free radicals created in the manufacture of plastics probably masked any biologically derived radical adducts in the remaining flaps. The authors conclude that EPR-spin trapping may be a valuable tool in the study of the importance of oxygen-derived free radicals in the failure of skin flaps subjected to transient ischemia.

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Free radicals from plastic syringes

Cited by 25 publications

References 2 publications

Exposing nanobubble-like objects to a degassed environment

Exposing nanobubble-like objects to a degassed environment

The modulation of N‐methyl‐D‐aspartate receptors by redox and alkylating reagents in rat cortical neurones in vitro.

Detection of free radicals in reperfused dog skin flaps using electron paramagnetic resonance spectroscopy: A pilot study

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