Archives

  • 2018-07
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • In comparing the amounts of total GST activity of

    2022-10-01

    In comparing the amounts of total GST activity of the rabbit cornea, porcine cornea and Hemicornea construct (Fig. 4A), the construct was found to exhibit an obviously lower level of GST activity. To assess these findings, it Bikinin will be necessary to compare them to the level in the human cornea. However, the total GST activity of one human cornea has not yet been determined. Nevertheless, this level can be estimated based on the data reported in various publications (Gondhowiardjo and van Haeringen, 1993; Singh et al., 1985, Tai et al., 1997) (Supplementary data, Table B1). Evaluation of the provided data indicates a total GST activity level of between 55 and 160 nmol/min/human cornea. However, the standard deviations (SDs) of the published GST activity values are either high or were not provided. Furthermore, the activity values used for this estimate were strongly rounded and sometimes differed considerably, leading to a rough approximation of the level. Despite these limitations, the level of total GST activity of the human cornea appears to be comparable to those of the Hemicornea construct, porcine cornea and rabbit cornea (22.2, 40.4 and 106.5 nmol/min/cornea or construct, respectively). Due to the low informative value of the calculated GST activity in the human cornea, these data should be supplemented by additional GST activity measurements. It should be noted that the cytosol of the excised animal corneas was prepared approximately one hour later than that of the Hemicornea construct due to the distance to the breeder or slaughterhouse. Therefore, it is quite possible that the true levels of GST activity in the porcine and rabbit corneas might be higher than those observed in this study. However, the expected low SD values relative to those for the excised animal corneas were not obtained using the Hemicornea construct. In the case of the total GST activity, the SD values for the construct and the porcine cornea were approximately 25%. In contrast, the SD value for the rabbit cornea was approximately 60%. The latter high SD value may due to the origin of the rabbit eyes. The corneas of rabbits of various races were pooled for each experiment. With regard to the GSTO1‐1 activity levels, the highest SD value was obtained for the Hemicornea construct. This result might be due to the measured values being very close to the detection limit. Overall, the comparatively high SD values obtained for all of the samples may be explained by the necessarily high number of experimental steps, which is particularly the case for the cytosol preparations of the excised animal corneas, which cannot be simplified. However, SD values of approximately 80% have been reported for the activities of the human cornea (Gondhowiardjo and van Haeringen, 1993). Therefore, the standardized human Hemicornea construct is preferable to the human cornea for further studies. In general, mean values with similar or lower SDs were obtained using the construct compared with those obtained using porcine or rabbit corneas. As the total GST activity of a whole human cornea has never been determined, its specific GSTP1‐1 activity is also unknown. However, the expression of GSTP1‐1 protein was detected in the human cornea (Ahmad et al., 1988). In addition, Singh et al. evaluated the GSTP1‐1 activity level per 1mg of total protein purified from the 10,000 g supernatant of a human corneal homogenate (Singh et al., 1985). Briefly, fractions containing GST were purified by GSH-linked affinity chromatography. Subsequently, these fractions were pooled and subfractions were separated by isoelectric focusing. Based on the published data, an approximate retrospective calculation can be made (Supplementary data, Table B2). The estimated GSTP1‐1 activity is approximately 2.83 nmol/min/human cornea. This level of GSTP1‐1 activity is similar to those of the Hemicornea construct, porcine cornea and rabbit cornea (1.59, 10.48 and 9.02 nmol/min/cornea or construct, respectively). Thus, the Hemicornea construct appeared to exhibit a level of GSTP1‐1 activity more similar to that of the human cornea than to those of the excised animal corneas (Fig. 4C). However, considering the strong rounding of the data and the many assumptions involved, this calculation can only suggest that the magnitude of the GSTP1‐1 activity of the human cornea is similar to those of the excised corneas and the Hemicornea construct.