Gradeability and Reproducibility of Geographic Atrophy Measurement in GATHER-1, a Phase II/III Randomized Interventional Trial

Objective

To validate GATHER-1 inclusion criteria and the study's primary anatomic end point by assessing the reproducibility of geographic atrophy (GA) measurements and factors that affect reproducibility.

Design

Post hoc analysis of phase II/III clinical trial.

Subjects

All 286 participants included in the GATHER-1 study.

Methods

For each subject, blue-light fundus autofluorescence (FAF), color fundus photographs, fluorescein angiograms, and OCT scans were obtained on the study eye and fellow eye. Geographic atrophy area and other lesion characteristics were independently graded by 2 experienced primary readers. If the 2 readers differed on gradeability, GA area (> 10%) or other lesion characteristics, the image was graded by an arbitrator whose measurement or characterization was the final grade.

Main Outcome Measures

The main outcome measures were gradeability and reproducibility of FAF imaging data. Imaging data included lesion area, confluence of GA with peripapillary atrophy (PPA), whether GA involved the foveal centerpoint, and type of hyperautofluorescence pattern.

Results

A total of 2004 images (1002 visits, 286 participants) were analyzed. Gradeability (90.5%) and interreader gradeability concordance (90.2%) were high across all visits. Study eye images were more gradable compared with fellow-eye images. A greater proportion of smaller lesions required arbitration, but interreader reproducibility was consistently high for all images. There was no difference in gradeability, gradeability concordance, or lesion-area concordance for images with PPA-confluent GA compared with those with nonconfluent PPA. Foveal centerpoint-involving lesions had lower gradeability and lesion-area concordance. Images with diffuse patterns of hyperautofluorescence had better gradeability and gradeability concordance than those with nondiffuse patterns but had no difference in lesion-area or lesion-area concordance.

Conclusions

There is high gradeability and excellent reproducibility measures across all images. These data support the validity of conclusions from GATHER-1 and the chosen inclusion criteria and end point.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Wide-Field Swept-Source Optical Coherence Tomography of Optic Disc Pit Maculopathy Demonstrates Connection Between Vitreous and Subretinal Fluid

The source of subretinal or intraretinal fluid in patients with optic disc pit maculopathy (ODP-M) remains unclear and is often thought to be either vitreous or cerebrospinal fluid.1 Here, we present the case of a 40-year-old man who developed ODP-M. Further imaging with wide-field swept-source optical coherence tomography demonstrated that the macular fluid was tracking from a nasal optic disc pit with superonasal communication to the vitreous. This suggests that swept-source optical coherence tomography can be a useful tool for determining the origin of macular fluid in patients with ODP-M. [Ophthalmic Surg Lasers Imaging Retina 2022;53:579-581.].

Ocular adverse events following intravitreal brolucizumab for neovascular age-related macular degeneration at a single tertiary care center

PURPOSE

To determine the incidence of ocular adverse effects (AEs) following brolucizumab injection for neovascular age-related macular degeneration at a tertiary academic institution.

DESIGN

Retrospective, single center cohort study.

PARTICIPANTS

All patients who received an intravitreal injection of brolucizumab 6 mg for neovascular age-related macular degeneration between October 7, 2019 and July 31, 2020.

METHODS

Medical records of all patients who received brolucizumab 6 mg during the aforementioned time period were carefully reviewed and all ocular adverse effects after injection were charted.

MAIN OUTCOME MEASURES

Incidence of post-injection ocular AEs, including intraocular inflammation (IOI), and time to development of AEs after injection.

RESULTS

A total of 77 patients received brolucizumab 6 mg for a total of 115 administrations during the study period. There were 4 AEs (3.5%), including three cases of IOI (2.6%), one central retinal artery occlusion, and one retinal detachment. Two men and two women were affected.

CONCLUSION

Ocular AEs, including those leading to severe vision loss, may develop after intravitreal brolucizumab 6 mg. A careful discussion of benefits and risks to brolucizumab should be conducted with all patients.

PRECIS

In this first case series of ocular adverse effects after brolucizumab 6 mg injection at a single tertiary care center, the incidence of ocular adverse effects was 3.5%, including a 2.6% incidence of intraocular inflammation.

Trends in Leadership and Award Recognition Among Women in the American Society of Retina Specialists

Purpose

This work evaluates trends in achievement of women in the retina field, through an analysis of gender representation in the American Society of Retina Specialists (ASRS).

Methods

This retrospective, longitudinal study spans 1983 to 2020. Historical data classified by male or female gender were collected from ASRS's overall membership, board of directors and officers, and recipients of the 4 society awards. The proportion of each benchmark held by women was compared with prior decades since the founding of ASRS using the Fisher's exact test.

Results

Women's representation increased from 11% of ASRS members in 2007 to 19.7% in 2020. From 2010 to 2019, women received a higher proportion of society awards (21.1%) compared with membership prior to the start of that decade. In 2020, women were proportionally well represented in board of director positions (21.9%) and held a significantly higher proportion of board positions than in the period 1983 to 1989 (P = .02). From 1983 to 2020, women held 4.3% (1 of 23) of presidencies.

Conclusions

Although the number of women in retina is increasing, women remain underrepresented in the leadership of ASRS. Interventions to increase exposure to female mentorship and improve childcare benefits are warranted to engage female ophthalmology trainees in retina and ultimately society leadership.

Quality, Readability, and Accessibility of Online Content From a Google Search of “Macular Degeneration”: Critical Analysis

Purpose:

This work aims to assess the quality, accountability, readability, accessibility, and presence of Spanish translation in online material through a Google search of “macular degeneration”.

Methods:

In this retrospective cross-sectional analysis of website results from a Google search of “macular degeneration”, the quality and accountability for each website were assessed using the DISCERN criteria and the Health on the Net Foundation Code of Conduct (HONcode) principles. All 31 sites were independently graded by 2 ophthalmologists. Readability was evaluated using an online tool. The presence of accessibility features on the website and Spanish translation was recorded. The primary outcome measure was the DISCERN and HONcode quality and accountability scores of each website. Secondary outcome measures included the readability, accessibility, and presence of Spanish translation.

Results:

The mean ± SD of each criterion across all 15 DISCERN questions was 2.761 ± 0.666 (out of 5). The mean HONcode score for all websites was 7.355 ± 3.123. The mean consensus reading grade level was 10.258 ± 2.49. There were no statistically significant differences in any score between the top 5 websites and the bottom 26 websites evaluated. Accessibility was available on 10 of 31 websites. Spanish translation was available on 10 of 31 websites.

Conclusions:

The top 5 websites that appeared on a Google search did not have better quality or readability of online content. Improving quality, accountability, and readability can help improve patients’ health literacy regarding macular degeneration.

Whole-Exome Sequencing of Patients With Posterior Segment Uveitis

OBJECTIVE

To elucidate molecular risk factors for posterior segment uveitis using a functional genomics approach.

DESIGN

Genetic association cohort study.

METHODS

Setting: Single-center study at an academic referral center.

STUDY POPULATION

164 patients with clinically diagnosed uveitis of the posterior segment.

MAIN OUTCOME MEASURES

Exome sequencing was used to detect variants identified in 164 patients with posterior segment uveitis. A phenotype-driven analysis, protein structural modeling, and in silico calculations were then used to rank and predict the functional consequences of key variants.

RESULTS

A total of 203 single nucleotide variants, in 23 genes across 164 patients, were included in this study. Both known and novel variants were identified in genes previously implicated in specific types of syndromic uveitis-such as NOD2 (Blau syndrome) and CAPN5 NIV (neovascular inflammatory vitreoretinopathy)-as well as variants in genes not previously linked to posterior segment uveitis. Based on a ranked list and protein-protein-interaction network, missense variants in NOD-like receptor family genes (NOD2, NLRC4, NLRP3, and NLRP1), CAPN5, and TYK2 were characterized via structural modeling and in silico calculations to predict how specific variants might alter protein structure and function. The majority of analyzed variants were notably different from wild type.

CONCLUSIONS

This study implicates new pathways and immune signaling proteins that may be associated with posterior segment uveitis susceptibility. A larger cohort and functional studies will help validate the pathogenicity of the mutations identified. In specific cases, whole-exome sequencing can help diagnose nonsyndromic uveitis in patients harboring known variants for syndromic inflammatory diseases.

Assessment of Online Sites Reliability, Accountability, Readability, Accessibility, and Translation for Intravitreal Injections

PURPOSE

Patients increasingly use the internet to access health-related information to better understand their treatments. This study compares the quality, accountability, readability, accessibility, and presence of translation between private and academic online source material available to the public regarding intravitreal injections (IVIs).

DESIGN

Cross-sectional analysis.

PARTICIPANTS

Top 20 websites on a Google search for the terms eye injections, intravitreal injections, and anti-VEGF injections.

METHODS

Websites were classified as private or academic. Quality and accountability were assessed using the internationally recognized DISCERN criteria and the Health on the Net Code of Conduct (HONcode). Readability was evaluated using an online tool that provides a consensus readability grade. The presence of and languages available for translation were recorded.

MAIN OUTCOME MEASURES

The primary outcome measure was a comparison of the DISCERN and HONcode quality and accountability scores between academic and private websites. Secondary outcome measures included evaluating readability, accessibility, and presence of translation (in particular, Spanish).

RESULTS

Eleven academic and 9 private websites were included. The overall mean score using DISCERN criteria for the academic websites (3.11 ± 0.46) was significantly higher than that of private websites (2.23 ± 0.61; P < 0.007). Similarly, of a possible total of 14 points for the HONcode, the average quality score for academic websites (10.91 ± 2.66) was higher compared with that for private websites (6.44 ± 3.36; P < 0.009). The mean consensus reading grade level was similar between academic (11.73 ± 1.68) and private (11.78 ± 1.48) websites (P = 0.94). Spanish translation was offered by only 7 of the 20 websites (5 academic and 2 private websites).

CONCLUSIONS

The overall quality and accountability of online content for academic sites was significantly higher compared with that of private websites. Translation was rarely provided, and the readability grade level was significantly higher for both groups than recommended. Improving the quality, accountability, readability, and accessibility and incorporating translation in websites can help to improve patients' health literacy regarding IVIs, potentially leading to increased adherence to therapy plans and improved treatment outcomes.

Proteomic analysis of intermediate uveitis suggests myeloid cell recruitment and implicates IL-23 as a therapeutic target

Purpose

To profile vitreous protein expression of intermediate uveitis (IU) patients.

Observations

We identified a mean of 363 ± 41 unique proteins (mean ± SD) in IU vitreous and 393 ± 69 unique proteins in control samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of liquid vitreous biopsies collected during pars plana vitrectomy. A total of 233 proteins were differentially expressed among control and IU samples, suggesting a protein signature that could distinguish the two groups. Pathway analysis identified 22 inflammatory mediators of the interleukin-12 (IL-12) signaling pathway in IU vitreous. Upstream regulator analysis identified downstream mediators of IL-23 and myeloid differentiation primary response protein (MYD88), both of which are involved in the recruitment and differentiation of myeloid cells. Taken together, our results suggest the recruitment of myeloid cells as an upstream pathway in the pathogenesis of IU.

Conclusions

This study provides insights into proteins that will serve as biomarkers and therapeutic targets for IU. These biomarkers will help design future clinical trials using rational molecular therapeutics.

Abstract 2457: Investigating the functional significance of novel, recurrent noncoding mutations of TBC1D12 in bladder cancer

Somatic noncoding mutations remain widely unexplored despite examples of critical importance such as driver mutations in the promoter of the TERT gene. We recently identified novel somatic mutations in the regulatory Kozak sequence (just upstream of the translation start site) of TBC1D12 in ~15% of bladder cancer patients, making it one of the most frequently mutated noncoding regions in any cancer (Araya et. al 2016). TBC1D12 was not previously implicated in cancer, and little is currently known about its function. It is a member of the TBC1 superfamily, suggesting a role in intracellular trafficking as a RAB-specific GTPase-activating protein (GAP). To investigate the functional implications of TBC1D12 mutations in bladder cancer, we undertook a combined computational and experimental approach. We analyzed clinical correlates, identified downstream effector candidates, and assessed the impact of these mutations on gene expression.

To determine the clinical relevance of the TBC1D12 mutation, we did correlation and survival analyses of clinical data of bladder cancer patients from TCGA. We found that TBC1D12 mutations confer slightly worse survival but were not linked to other clinical correlates. To identify potential downstream effectors, we used reverse phase protein array (RPPA) data from 127 patients to search for proteins that were differentially expressed or phosphorylated between patients with or without TBC1D12 mutations. We found differential expression of GSK3 and differential phosphorylation of p90RSK and c-Jun, suggesting three potential downstream effector candidates. Hierarchical clustering of RPPA data for these three proteins revealed 4 subgroups with distinct molecular phenotypes. Furthermore, most of the TBC1D12 mutants were clustered within one molecular subtype. To experimentally test these downstream effector candidates and identify new ones, we modulated the levels of TBC1D12 in bladder cancer cell line Ku-19-19 using overexpression plasmids or siRNAs. After validating that these transfections were effective in changing TBC1D12 expression, we performed RNA-Seq experiments. Results from this study are expected to be presented at the meeting.

In summary, these studies suggest that the novel and recurrent noncoding mutations in TBC1D12 may affect patient survival and alter the expression or post-translational modification of downstream targets. Potential molecular mechanisms associated with the presence of TBC1D12 mutations will be discussed, and a series of follow-up studies are underway. These studies also demonstrate that applying both computational and experimental approaches can help develop and test evidence-based hypotheses, contributing to an understanding of the clinical and functional impact of TBC1D12.

Citation Format: Angela S. Li, Jason A. Reuter, Can Cenik, Michael P. Synder. Investigating the functional significance of novel, recurrent noncoding mutations of TBC1D12 in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2457. doi:10.1158/1538-7445.AM2017-2457

Estimation of individual cumulative ultraviolet exposure using a geographically-adjusted, openly-accessible tool

Background

Estimates of an individual’s cumulative ultraviolet (UV) radiation exposure can be useful since ultraviolet radiation exposure increases skin cancer risk, but a comprehensive tool that is practical for use in the clinic does not currently exist.

The objective of this study is to develop a geographically-adjusted tool to systematically estimate an individual’s self-reported cumulative UV radiation exposure, investigate the association of these estimates with skin cancer diagnosis, and assess test reliability.

Methods

A 12-item online questionnaire from validated survey items for UV exposure and skin cancer was administered to online volunteers across the United States and results cross-referenced with UV radiation indices. Cumulative UV exposure scores (CUES) were calculated and correlated with personal history of skin cancer in a case–control design. Reliability was assessed in a separate convenience sample.

Results

1,118 responses were included in the overall sample; the mean age of respondents was 46 (standard deviation 15, range 18 – 81) and 150 (13 %) reported a history of skin cancer. In bivariate analysis of 1:2 age-matched cases (n = 149) and controls (n = 298), skin cancer cases were associated with (1) greater CUES prior to first skin cancer diagnosis than controls without skin cancer history (242,074 vs. 205,379, p = 0.003) and (2) less engagement in UV protective behaviors (p < 0.01). In a multivariate analysis of age-matched data, individuals with CUES in the lowest quartile were less likely to develop skin cancer compared to those in the highest quartile. In reliability testing among 19 volunteers, the 2-week intra-class correlation coefficient for CUES was 0.94. We have provided the programming code for this tool as well as the tool itself via open access.

Conclusions

CUES is a useable and comprehensive tool to better estimate lifetime ultraviolet exposure, so that individuals with higher levels of exposure may be identified for counseling on photo-protective measures.

Electronic supplementary material

The online version of this article (doi:10.1186/s12895-016-0038-1) contains supplementary material, which is available to authorized users.

DNA breakage induced by 1,2,4-benzenetriol: relative contributions of oxygen-derived active species and transition metal ions

We report here the relative roles of metals and selected reactive oxygen species in DNA damage by the genotoxic benzene metabolite 1,2,4-benzenetriol, and the interactions of antioxidants in affording protection. 1,2,4-Benzenetriol induces scission in supercoiled phage DNA in neutral aqueous solution with an effective dose (ED(50)) of 6.7 microM for 50% cleavage of 2.05 microg/ml supercoiled PM2 DNA. In decreasing order of effectiveness: catalase (20 U/ml), formate (25 mM), superoxide dismutase (20 U/ml), and mannitol (50 mM) protected, from 85 to 28%. Evidently, H(2)O(2) is the dominant active species, with O(2)(*)(-) and *OH playing subordinate roles. Desferrioxamine or EDTA inhibited DNA breakage by 81-85%, despite accelerating 1,2,4-benzenetriol autoxidation. Consistent with this suggestion of a crucial role for metals, addition of cupric, cuprous, ferric, or ferrous ions enhanced DNA breakage, with copper being more active than iron. Combinations of scavengers protected more effectively than any single scavenger alone, with implications for antioxidants acting in concert in living cells. Synergistic combinations were superoxide dismutase with *OH scavengers, superoxide dismutase with desferrioxamine, and catalase with desferrioxamine. Antagonistic (preemptive) combinations were catalase with superoxide dismutase, desferrioxamine with *OH scavengers, and catalase with *OH scavengers. The most striking aspect of synergism was the extent to which metal chelation (desferrioxamine) acted synergistically with either catalase or superoxide dismutase to provide virtually complete protection. Concluding, 1,2,4-benzenetriol-induced DNA damage occurs mainly by site-specific, Fenton-type mechanisms, involving synergism between several reactive intermediates. Multiple antioxidant actions are needed for effective protection.

[The chromosome-specific PCR marker's screening and identification of barley 6H chromosome]

Two barley 6H chromosome specific RAPD markers were obtained by screening DNA of barley Hordeum vulgare (Betzes) and wheat-barley 6H addition line with 200 primers, then the RAPD markers were changed into specific PCR markers. Checking different plant materials by the PCR markers, it revealed that there was a specific band in those materials containing 6H chromosome such as Betzes, Igri, CS6H, and there was no specific band if the material did not contain 6H chromosome, such as Triticum aestivum, Secale cereale, Agropyron intermedium, Haynaldia villosa, Thinopyrum elongatum. Therefore, those PCR markers specific to chromosome 6H of barley are established. Southern hybridization indicated that the two cloned DNA fragments belong to barley genomic specific high-copy repeat sequence and low-copy sequence in wheat and barley genomes respectively.

DNA-breaking versus DNA-protecting activity of four phenolic compounds in vitro

Given the paradoxical effects of phenolics in oxidative stress, we evaluated the relative pro-oxidant and antioxidant properties of four natural phenolic compounds in DNA nicking. The phenolic compounds differed dramatically in their ability to nick purified supercoiled DNA, with the relative DNA nicking activity in the order: 1,2,4-benzenetriol (100% nicking) > gallic acid > caffeic acid > gossypol (20% nicking). Desferrioxamine (0.02 mM) decreased DNA strand breakage by each phenolic, most markedly with gallate (85% protection) and least with caffeic acid (26% protection). Addition of metals accelerated DNA nicking, with copper more effective (approximately 5-fold increase in damage) than iron with all four phenolics. Scavengers revealed the participation of specific oxygen-derived active species in DNA breakage. Hydrogen peroxide participated in all cases (23-90%). Hydroxyl radicals were involved (32-85%), except with 1,2,4-benzenetriol. Superoxide participated (81-86%) with gallic acid and gossypol, but not with caffeic acid or 1,2,4-benzenetriol. With 1,2,4-benzenetriol, scavengers failed to protect significantly except in combination. Thus, in the presence of desferrioxamine, catalase or superoxide dismutase inhibited almost completely. When DNA breakage was induced by Fenton's reagent (ascorbate plus iron) the two catechols (caffeic acid and gossypol) were protective, whereas the two triols (1,2,4-benzenetriol and gallic acid) exacerbated damage.

Effect of non-steroidal anti-inflammatory drugs on gastric and duodenal prostaglandin concentrations in patients with Helicobacter pylori infection

BACKGROUND/AIMS

Both Helicobacter pylori and non-steroidal anti-inflammatory drugs are reported to affect gastroduodenal prostaglandin synthesis. However, their influence on gastric mucosal prostaglandins remains unclear. The aim of this study was to investigate the influence of nonsteroidal anti-inflammatory drugs on mucosal prostaglandin synthesis in patients with Helicobacter pylori infection.

METHODOLOGY

We enrolled 87 Helicobacter pylori-infected patients in this study (gastric ulcer: 33, duodenal ulcer: 41, and non-ulcer dyspepsia: 13). Of them, 27 patients received non-steroidal anti-inflammatory drugs. Endoscopy was performed and biospy specimens from gastric body, antrum and duodenal bulb were assessed for Helicobacter pylori and prostaglandin concentration.

RESULTS

A significantly lower mucosal prostaglandin E2 level at gastric body (142.2 +/- 28.1 ng/mg vs. 222.0 +/- 12.4 ng/mg, mean +/- SEM) and antrum (131.3 +/- 26.4 ng/mg vs. 226.0 +/- 19.0 ng/mg) was noted in Helicobacter pylori-infected gastric ulcer patients with non-steroidal anti-inflammatory drugs ingestion than in that of patients without non-steroidal anti-inflammatory drugs ingestion (p < 0.05). Using a multivariate analysis, we found that non-steroidal anti-inflammatory drug was an independent variable affecting gastric and duodenal mucosal prostaglandin E2 synthesis in patients with Helicobacter pylori-infected gastric ulcer.

CONCLUSIONS

Non-steroidal anti-inflammatory drugs decrease gastroduodenal mucosal prostaglandin E2 synthesis in gastric ulcer patients with Helicobacter pylori infection.

[Clinical and experimental studies on preventing and treating anaphylactic asthma with Zusanli point immunotherapy]

We have studied on preventing and treating anaphylactic asthma with Zusanli (S36) point immunotherapy (ZPIT). Sixty-nine patients were observed. The results showed that the clinical curative effect of ZPIT was not only much higher than that of conventional desensitization therapy, but also the patients' total IgE level was reduced, anti-acarid IgE was lowered, SIgA level was raised, the absolute eosinophilic granulocyte level dropped and pulmonary function recovered. Animal experiment results showed that the ZPIT could more effectively suppress the guinea pigs' anaphylactic asthma allergized by albumin and more obviously resist the guinea pigs' bronchial spasm induced by histamine and acetylcholine than the conventional desensitization therapy and injected normal saline. The immunomodulating action of the ZPIT are elucidated from clinical study and animal experiment in the paper.

Genetic transformation of Lycium barbarum L. via A. tumefaciens

A system for transformation and regeneration of Lycium barbarum L., an important Chinese medical plant, has been established. Young stem segments from Lycium barbarum L. were infected with Agrobacterium tumefaciens C58cl(pGV3850::neo1103), and the transformed calli selected from the callus induction medium containing 50 micrograms/ml kanamycin could regenerate buds on differentiation medium containing 25 micrograms/ml kanamycin. 30% of the regenerated buds were normal in morphology. The normal buds could develop into whole plantlets after they were transferred to the rooting medium to induce roots. Nopaline detection, NPT-II enzyme activity assay and Southern blotting hybridization indicated that the foreign genes had been integrated into the genome of Lycium barbarum L. and expressed in the plant. In the processes of experiments, it was found that (i) after the pre-processes, the explants which formed callus quickly were easy to transform; (ii) the rate of normal regenerated plants from transgenic calli was higher than that from the untransgenic ones.

The NoH value in EPR spin trapping: a new parameter for the identification of 5,5-dimethyl-1-pyrroline-N-oxide spin adducts

The ratio of the nitrogen to hydrogen hyperfine splittings (aN/aH) of spin adducts derived from the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) has been found to be a useful parameter for adduct identification. For example, this parameter makes it possible to distinguish between the superoxide (aN/aH = 1.22-1.26) and peroxyl (aN/aH = 1.33-1.40) radical adducts of DMPO in aqueous solution. Since the aN to aH ratio corrects for minor differences in EPR spectrometer calibration, it is a more reproducible parameter than the aN and aH values themselves.

Superoxide dismutase amplifies dye photosensitized production of desferal free radical: an electron spin resonance study

Desferal free radical (DFFR) photogenerated from dye sensitization was studied by electron spin resonance. When irradiated at the visible maximum in the presence of O2, both rose bengal and riboflavin sensitized the oxidation of Desferal (DF) and generated the DFFR. The yield of DFFR was amplified by superoxide dismutase (SOD). The SOD enhancement was attributed to the inhibition of superoxide-induced DFFR destruction. Similar SOD enhancement was observed with dyes Rhodamine 123 and Gentian Violet. Our studies suggest that when Desferal is used as a chelating agent in the presence of SOD, systems involving O2- could face interference from DFFR even at concentrations as low as 10 microM DF. DFFR may interfere with the chain reaction of lipid peroxidation resulting in an apparent protective action which, in fact, has very little to do with chelating the catalytic iron.

In vitro pollen plant induction and embryoid clone establishment of Panax ginseng

In anther culture of Panax ginseng, its callus formation showed a wide adaptability to culture media. Large numbers of calli were induced on media exhibiting better effects of induction. Supplements of 5 mg 2,4-D/1 and 1 mg KT/1 to the media proved to be much effective. Regeneration of the whole plantlets from anther culture of Panax ginseng is usually quite difficult. During the past three years, however, sixteen of the 100 medium formulae tested were proved to be suitable. The formulae of MS + 0.5 mg BA/1 + 2 mg GA/1 + 1000 mg LH/1 + 3% sucrose were considered good and effective. A visibly differentiated body, which was light-milky white and later turned into a light green spot, was formed 40 days after the callus was transferred to the differentiation media. This body differentiated subsequently into buds, roots and, eventually, seedlings. The embryoid clones have been established in order to maintain its ability of continual differentiation into plantlets through successive culturings of many generations. The test-tube ginseng thus formed were transferred to regular flowerpots and grew well. Based upon chromosome examination of the callus cells and the root tips, we tentatively affirmed that the majority of these regenerated from anther of Panax ginseng were originated from pollen cells.

O2- photogenerated from aqueous solutions of tetracycline antibiotics (pH 7.3) as evidenced by DMPO spin trapping and cytochrome c reduction

UV-irradiation of several tetracycline antibiotics in aqueous buffer (pH 7.3) resulted in the generation of the superoxide anion radical (O2-) which was detected by cytochrome c reduction and by spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide and was inhibited by superoxide dismutase. A comparison of the O2- yields from the tetracyclines examined showed the trend chlortetracycline (CTC) greater than oxytetracycline (OXY) greater than demeclocycline (DEM) much greater than (doxycycline (DOXY) = tetracycline (TC) = minocycline (MINO) = 0). This trend is in reasonable agreement with clinical reports that CTC, OXY and DEM are potent photosensitizers, TC is only weakly phototoxic whereas MINO is not. These findings suggest that the O2- production may be involved in tetracycline-induced phototoxicity. While the two methods for O2- detection gave comparable results for most of the tetracyclines, the spin trapping technique was clearly superior for DOXY which reduced cytochrome c in the dark.