1,720,974 research outputs found
Response to "Comment on "Safety of silicone oils as intraocular medical device: An in vitro cytotoxicity study" by M. R. Romano et al. (Exp. Eye Res. Vol 194, May 2020, 108018)"
No full textEx vivo evaluation of retinal cytotoxicity after the use of multiple medical devices in pars plana vitrectomy in porcine eyes
No full textThis study aimed to evaluate viability of retinal cells after the use of multiple intraoperative devices, namely a vitreal dye (triamcinolone acetonide,TA), a ERM/ILM dye (solution of trypan blue 0.15% and brilliant blue 0.025%), and two intraocular tamponades, namely perfluoro-n-octane, (PFO) and silicone oil (SO 1000 cSt), with minimal and maximal removal of their residues, during a simulated pars plana vitrectomy (PPV) in porcine eyes ex-vivo. The in vitro cytotoxicity of each of these compounds was verified on ARPE-19 cells by direct tests according to the ISO 10993-5 (2009). Pars plana vitrectomy was performed on 25 enucleated porcine eyes divided in five groups according to the following conditions: Group A) No surgery control: eye bulbs were kept at room temperature for 40 min; Group B) Sham surgery: PPV with the sole use of BSS for 40 min; Group C) Cytotoxic control: PPV with BSS infusion (20 min) followed by intravitreal injection of 1H-PFO (contact time: 20 min); Group D) Surgery with residues: PPV with BSS infusion and sequential intravitreal injection of TA, ERM/ILM dye, PFO and SO, with minimal removal of each compound after a specified contact-time (overall duration: 40 min); Group E) Surgery with minimal residues: PPV performed as in group D, but with maximal removal of each compound (overall duration: 40 min). All the experimental procedures were performed at room temperature. Immediately after surgery, the retina was extracted from each eye bulb and samples of 3-mm diameter were prepared. Retinal viability was determined for each sample by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay. A cell viability <70% was considered the cytotoxicity threshold. Kruskal-Wallis test was used to evaluate the differences in retinal viability between groups. No cytotoxicity was detected in retinal samples in groups A, B and E. Samples from eye bulbs that had undergone surgery with minimal removal of residues (group D) and cytotoxic controls (group C) showed high retinal cytotoxicity. The tested conditions indicated that the combined use of TA, ERM/ILM dye, PFO and SO during PPV does not affect retinal cells viability if all the devices are properly removed, whereas the cytotoxicity detected in group D may suggest that the presence and accumulation of the residues of the compounds used intraoperatively could negatively impact retinal viability due to a cumulative and/or synergistic cytotoxic effect between them, supporting the crucial role of an optimal removal of the intraoperative medical devices to ensure a safe vitrectomy to the patient
H-Content Is Not Predictive of Perfluorocarbon Ocular Endotamponade Cytotoxicity in Vitro
Get PDFIn recent years, cases of retinal toxicity occurred in some European, Middle Eastern, and South American countries following the use of perfluorocarbon liquids (PFCLs) on vitreoretinal surgeries owing to impurities in the product. Moreover, Spanish ophthalmologists reported several toxic cases on the use of perfluoro-n-octane Ala Octa (Alamedics, Dornstadt, Germany), raising the necessity of reviewing the current validated methods used for assessing the safety of PFCLs. We proved that in samples of PFCLs contaminated on purpose with impurities previously detected in Ala Octa devices, the determination of the so-called H-content using a 1H NMR quantitative assay implemented with the electronic reference to access in vivo concentrations 2 technology failed to demonstrate a correlation between the H-content and in vitro cytotoxicity test in ARPE-19 and BALB 3T3 cell lines. Therefore, direct information on the safety of PFCLs was provided only by the cytotoxicity test in vitro validated according to ISO 10993-5, and the H-content was not predictive of perfluorocarbon ocular endotamponade cytotoxicity in vitr
Toxicity threshold of perfluorocarbon liquids for intraocular use: Dose–response assessment of in vitro cytotoxicity of possible contaminants
Get PDFPurpose: This study assessed the cytotoxicity of the impurities detected in the perfluorooctane (PFO) batches for vitreoretinal surgery that were associated with serious adverse incidents of ocular toxicity, namely, the perfluorooctanoic acid (PFOA), 1H,1H,7H-dodecafluoro-1-heptanol (DFH), 1H-perfluorooctane (1H-PFO), ethylbenzene, anhydrous p-xylene, and perfluoro-2-butyltetrahydrofurane, and two additional substances 1H,1H,1H,2H,2H-perfluorooctane (5H-PFO) and hexafluoro-1,2,3,4-tetrachlorobutane. Methods: Serial dilutions were tested by in vitro direct contact cytotoxicity test, validated in accordance with the ISO 10993-5:2009 standard using BALB3T3 and ARPE-19 cell lines, after sample application for 24 hours. Results: Six of the eight tested substances were cytotoxic according to the above-mentioned ISO standard. Anhydrous p-xylene, ethylbenzene, and PFOA were the most cytotoxic impurities as traces 1.55 ppm, 1.06 ppm, and 28.4 ppm reached the cytotox-icity limit, respectively. Hexafluoro-1,2,3,4-tetrachlorobutane, DFH, and 1H-PFO were cytotoxic at 980, 22,500, and 123,000 ppm, respectively. Both 5H-PFO and perfluoro-2-butyltetrahydrofuran were non-cytotoxic at the highest available concentrations (≥970,000 ppm). The dose-response curves allowed to calculate the cytotoxic concen-tration (CC30 )foreachtestedsubstancethatwouldreduce30%ofcellviabilityandcorre-sponding to the cytotoxicity threshold according to ISO 10993-5. Conclusions: Our study determined the in vitro cytotoxicity of several impurities in PFO associated with serious adverse incidents in retinal surgery patients
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A new storage medium containing amphotericin B versus Optisol-GS for preservation of human donor corneas
No full textBackground/Aim: We compared the quality of human donor corneas stored in a cold storage medium containing 2.5 μg/ml of amphotericin B (Kerasave, AL.CHI.MI.A. S.R.L., Ponte San Nicolò, Italy) and Optisol-GS (Bausch & Lomb Inc., Bridgewater, NJ, USA) for 14 days. Methods: Sixteen pairs of human donor corneas were collected in Eusol-C (AL.CHI.MI.A. S.R.L., Ponte San Nicolò, Italy). Next, all tissues underwent the first evaluation that included the assessments of central corneal thickness (CCT), endothelial cell density (ECD) measured using both trypan blue staining and specular microscopy, endothelial cell (EC) mortality and morphology, and corneal transparency within 24 hours from recovery (Day 1). Afterwards, one cornea of each pair was transferred into Kerasave or Optisol-GS. ECD and CCT were also assessed at Day 7, and all the metrics were evaluated again at the end of the storage period (Day 14). Results: At all tested time points, no differences were found in the qualitative (corneal transparency, EC morphology) and quantitative metrics (ECD, CCT, EC mortality) between the Kerasave and the Optisol-GS storage groups. At Day 14, the corneas stored in Kerasave and Optisol-GS showed ECD of 2312±98 and 2335±128 cells/mm2 (p=0.886), CCT of 717±17 and 697±19 μm (p=0.454) and central EC mortality of 0.54%±0.40% and 0.14%±0.14% (p=0.719), respectively. Conclusions: The new amphotericin B-containing medium Kerasave was comparable to Optisol-GS in terms of preservation of corneal characteristics at 2-8°C for 14 days
Killing efficacy of a new hypothermic corneal storage medium against the micro-organisms frequently found in human donor cornea intended for transplantation
Get PDFObjective To study the in vitro killing efficacy of Kerasave (AL.CHI.MI.A Srl), a medium provided with amphotericin B tablet for hypothermic storage of human donor corneas, against relevant contaminants associated with postkeratoplasty infections. Methods and Analysis The antimicrobial activity of Kerasave was determined after 0, 3 and 14 days of incubation at 2°C-8°C, inoculating Kerasave and the control medium with 10 5 -10 6 colony forming units (CFU) of Candida albicans (CA), Fusarium solani (FS), Aspergillus brasiliensis (AB), Staphylococcus aureus (SA), Enterococcus faecalis (EF), Bacillus subtilis spizizenii (BS), Pseudomonas aeruginosa (PA), Enterobacter cloacae (EC) and Klebsiella pneumoniae (KP). Log 10 reductions at different time intervals were determined by assessing the number of viable CFU using the serial dilution plating technique. Results After 3 days, Kerasave induced the highest log 10 decrease in the concentrations of KP, PA, CA and EC (5.37, 4.15, 2.97 and 2.67, respectively; all p<0.001). The log 10 decreases of SA and EF were 2.27 and 2.11, respectively (all p<0.001). The lowest log 10 decrease was observed in BS, AB and FS concentrations (0.25, 0.30 and 0.67, respectively; p<0.001 for BS and AB and p=0.004 for FS). After 14 days, the microbial count of CA, FS, SA, EF, PA and EC further decreased (p=0.006 for FS; p<0.001 for the others). Conclusion Kerasave effectively reduced or kept unchanged the microbial concentration of almost all tested strains after 3 days. Thus, this novel medium represents a valuable tool to control the microbial contamination of human donor corneas during hypothermic storage for up to 14 days before transplantation
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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