Browsing by keyword "Collodion"

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    • A two-step procedure for efficient electrotransfer of both high-molecular-weight (greater than 400,000) and low-molecular-weight (less than 20,000) proteins
      Otter, Tim; King, Stephen M.; Witman, George B. (1987-05-01)
      We have developed conditions for the efficient electrotransfer from polyacrylamide gels to nitrocellulose sheets of a broad size range of proteins (Mr 8,000 to Mr greater than 400,000). The important features of this procedure include a two-step electrotransfer, beginning with elution of low-molecular-weight polypeptides at a low current density (approximately 1 mA/cm2) for 1 h, followed by prolonged electrotransfer (16-20 h) at high current density (approximately 3.5-7.5 mA/cm2) in conditions that favor the elution of high-molecular-weight proteins. The transfer buffer includes 0.01% sodium dodecyl sulfate to enhance protein elution, and 20% methanol to improve the retention of proteins on the nitrocellulose sheet. The nitrocellulose is air-dried after transfer is complete to eliminate loss of proteins during subsequent processing. This transfer procedure works well with proteins prepared from many different cell types, and is suitable for use with all polyacrylamide gel systems tested. With little or no modification, our method should also be applicable to transfer membranes other than nitrocellulose.

    • Comparison of artifacts between paste and collodion method of electrode application in pediatric EEG
      Brigham, Danielle; Shah, Yash; Singh, Kanwaljit; Pavkovic, Ivan; Karkare, Shefali; Kothare, Sanjeev V. (2019-11-30)
      Objectives: Children pose challenges to obtain quality EEG data due to excessive artifact. Collodion is used in EEG electrodes due to its water resistance and strong adhesive qualities. This study was done to evaluate differences in artifacts between the collodion and paste method. Methods: 115 subjects (children age > 3 years) were randomized into paste and collodion groups and artifacts evaluated at baseline and every hour over 30s increments. Age, sleep state, and number of electrodes with artifact were also documented. T-test was performed to determine differences in the various parameters between the two groups. Results: 61 subjects were in the paste group and 54 in the collodion group. Mean of total seconds of artifact from 0 to 24h were 41.8s in paste group versus 30.3s in collodion group (P=0.02). Children > 11 years old had less artifact than younger children from 0 to 24h (24.3 versus 41.2s, P=0.03), and from 24 to 48h (33.1 versus 43.1s, P=0.03). There was a significant effect of sleep vs. awake state recordings on artifact from 0 to 24h (30.3 versus 50.2s, P=0.01). Conclusion: Electrode problems are common with both collodion and paste in prolonged AEEG monitoring. However, for studies less than 24h, collodion may be a better alternative. Significance: Our study provides evidence that in some cases collodion may be a better alternative to paste in terms of decreased artifacts.