| 1. |
- Bäckman, Anders, et al.
(författare)
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The efficiency of cross-linking methods in eradication of bacteria is influenced by the riboflavin concentration and the irradiation time of ultraviolet light
- 2014
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Ingår i: Acta Ophthalmologica. - Hoboken, USA : John Wiley & Sons. - 1755-375X .- 1755-3768. ; 92:7, s. 656-661
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To determine bacterial eradication using numerous riboflavin concentrations and different ultraviolet light A (UVA) radiant and exposure time in an experimental model.Methods: Dilutions of Staphylococcus epidermidis were mixed with riboflavin at varying concentrations (0.007-0.09%). Effects on bacterial growth were evaluated after 0, 3, 6, 30 and 60min of UVA exposure (irradiance 30 and 3mW/cm(2)). Standard settings of UVA were compared with high-power UVA approach. Different fluid thicknesses of the exposed dilutions were also examined to improve the model.Results: Bacterial eradication (%) was increased after 60 compared with 30min of UVA exposure for concentrations of 0.03-0.07% but not for 0.09% riboflavin. There was a significant difference between the efficacy between 0.03 and 0.09% and eradication dropped from 80% to 50% (p=0.01). A correlation could be calculated for the amount of riboflavin at 60min of UVA and the ability to kill bacteria (p=0.01). The antibacterial effect was more pronounced when the tested bacterial suspension thickness was reduced. High-power UVA method was less potent in microbial elimination, eradicating only 60% of bacteria after 6min versus 97-99% after 60min in the low-power setting, compared with respective controls (p=0.02).Conclusions: In these in vitro experiments, a longer UVA exposure time in combination with lower riboflavin levels were found to be favourable in killing bacteria as compared to the standard cross-linking settings. Further studies are needed to evaluate the clinical relevance of these findings.
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| 2. |
- Hellander Edman, Anna, et al.
(författare)
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Corneal cross-linking in 9 horses with ulcerative keratitis
- 2013
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Ingår i: BMC Veterinary Research. - London, United Kingdom : BioMed Central (BMC). - 1746-6148. ; 9, s. 128-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Corneal ulcers are one of the most common eye problems in the horse and can cause varying degrees of visual impairment. Secondary infection and protease activity causing melting of the corneal stroma are always concerns in patients with corneal ulcers. Corneal collagen cross-linking (CXL), induced by illumination of the corneal stroma with ultraviolet light (UVA) after instillation of riboflavin (vitamin B2) eye drops, introduces crosslinks which stabilize melting corneas, and has been used to successfully treat infectious ulcerative keratitis in human patients. Therefore we decided to study if CXL can be performed in sedated, standing horses with ulcerative keratitis with or without stromal melting.Results: Nine horses, aged 1 month to 16 years (median 5 years) were treated with a combination of CXL and medical therapy. Two horses were diagnosed with mycotic, 5 with bacterial and 2 with aseptic ulcerative keratitis. A modified Dresden-protocol for CXL could readily be performed in all 9 horses after sedation. Stromal melting, diagnosed in 4 horses, stopped within 24 h. Eight of nine eyes became fluorescein negative in 13.5 days (median time; range 4-26 days) days after CXL. One horse developed a bacterial conjunctivitis the day after CXL, which was successfully treated with topical antibiotics. One horse with fungal ulcerative keratitis and severe uveitis was enucleated 4 days after treatment due to panophthalmitis.Conclusions: CXL can be performed in standing, sedated horses. We did not observe any deleterious effects attributed to riboflavin or UVA irradiation per se during the follow-up, neither in horses with infectious nor aseptic ulcerative keratitis. These data support that CXL can be performed in the standing horse, but further studies are required to compare CXL to conventional medical treatment in equine keratitis and to optimize the CXL protocol in this species.
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| 3. |
- Makdoumi, Karim, 1977-, et al.
(författare)
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A prospective long-term follow-up study of optic disc pit maculopathy treated with pars plana vitrectomy, drainage of subretinal fluid and peeling of internal limiting membrane
- 2020
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Ingår i: Acta Ophthalmologica. - : Wiley-Blackwell. - 1755-375X .- 1755-3768. ; 98:8, s. 822-827
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To describe the long-term results of surgical repair of patients with optic disc pit maculopathy (ODP-M).METHODS: Prospective, consecutive, noncomparative follow-up study including 12 patients with ODP-M treated by pars plana vitrectomy (PPV), peeling of internal limiting membrane followed by gas tamponade. Subretinal fluid (SRF) was drained in 11 eyes through a retinotomy without laser photocoagulation. Preoperatively, macular detachment with retinoschisis was seen in 9 out of 12 eyes with three eyes having only subretinal fluid in the macular area. The median age at surgery was 20 years (range 9-60 years).RESULTS: Follow-up time from initial surgery was 63 months (median). Eight eyes were anatomically reattached after one operation without remaining SRF in the macula. Two patients required a reoperation due to leakage from the retinotomy and another two underwent a second PPV procedure due to late recurrences. Successful healing was at follow-up control observed in 11 of 12 eyes. There was no statistically significant difference in visual acuity between patients before and after surgery (p = 0.24). Central visual field defects with depressed mean deviation were detected in all treated eyes.CONCLUSION: In this long-term study of ODP-M final outcome regarding healing was relatively efficacious, however, a relatively large proportion had complications associated to retinotomies. We conclude that drainage of SRF should likely be avoided since it appears to contribute little to the resorption rate of SRF and seems to linked to unnecessary risks.
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| 4. |
- Makdoumi, Karim, 1977-, et al.
(författare)
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Comparison of UVA- and UVA/riboflavin-induced growth inhibition of Acanthamoeba Castellanii
- 2013
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Ingår i: Graefe's Archives for Clinical and Experimental Ophthalmology. - New York, USA : Springer. - 0721-832X .- 1435-702X. ; 251:2, s. 509-514
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To investigate whether ultraviolet light (UVA) at 365 nm can inhibit/eliminate Acanthamoeba growth and if riboflavin would potentiate such an association.Method: Acanthamoeba castellanii in a fluid medium with a concentration of approximately 1.7 x 10(4) protozoa/ml were prepared with (0.01 %) and without riboflavin. Exposure of UVA (dose 5.475 J/cm(2)) took place twice, with each illumination period followed by culturing of 10 mu l in peptone yeast-extract glucose (PYG) medium for 7 days. Every suspension prepared had a non-exposed control solution. Determination of Acanthamoeba was conducted daily, by count in Burker chamber days 4 through 7 after exposure. Statistical analysis was done by repeated-measurement ANOVA and post-hoc analysis for unpaired samples.Results: The exposure of ultraviolet light resulted in an inhibited growth of Acanthamoeba compared to the non-exposed solutions, with a statistically significant reduction over time (p = 0.0003). The addition of riboflavin did not amplify the effect, and there were no tendencies for an interaction effect between UVA and riboflavin. The antiprotozoal effect of the UVA wavelength, utilized in CXL, is solely mediated by ultraviolet light, and riboflavin does not seem to amplify the antimicrobial efficacy.
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| 5. |
- Makdoumi, Karim, 1977-, et al.
(författare)
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Different photodynamic effects of blue light with and without riboflavin on methicillin-resistant Staphylococcus aureus (MRSA) and human keratinocytes in vitro
- 2019
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Ingår i: Lasers in Medical Science. - : Springer. - 0268-8921 .- 1435-604X. ; 34:9, s. 1799-1805
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Tidskriftsartikel (refereegranskat)abstract
- Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of infections in humans. Photodynamic therapy using blue light (450 nm) could possibly be used to reduce MRSA on different human tissue surfaces without killing the human cells. It could be less harmful than 300–400 nm light or common disinfectants. We applied blue light ± riboflavin (RF) to MRSA and keratinocytes, in an in vitro liquid layer model, and compared the effect to elimination using common disinfection fluids. MRSA dilutions (8 × 105/mL) in wells were exposed to blue light (450 nm) ± RF at four separate doses (15, 30, 56, and 84 J/cm2). Treated samples were cultivated on blood agar plates and the colony forming units (CFU) determined. Adherent human cells were cultivated (1 × 104/mL) and treated in the same way. The cell activity was then measured by Cell Titer Blue assay after 24- and 48-h growth. The tested disinfectants were chlorhexidine and hydrogen peroxide. Blue light alone (84 J/cm2) eliminated 70% of MRSA. This dose and riboflavin eradicated 99–100% of MRSA. Keratinocytes were not affected by blue light alone at any dose. A dose of 30 J/cm2 in riboflavin solution inactivated keratinocytes completely. Disinfectants inactivated all cells. Blue light alone at 450 nm can eliminate MRSA without inactivation of human keratinocytes. Hence, a high dose of blue light could perhaps be used to treat bacterial infections without loss of human skin cells. Photodynamic therapy using riboflavin and blue light should be explored further as it may perhaps be possible to exploit in treatment of skin diseases associated with keratinocyte hyperproliferation.
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| 6. |
- Makdoumi, Karim, 1977-, et al.
(författare)
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Levels of beta-trace protein in optic disc pit with macular detachment
- 2017
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Ingår i: Acta Ophthalmologica. - : Wiley-Blackwell Publishing Inc.. - 1755-375X .- 1755-3768. ; 95:8, s. 815-819
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To report beta-trace protein (βTP) levels in the subretinal fluid (SRF) of four patients with a macular detachment associated with optic disc pit (ODP).METHODS: Four patients with a serous retinal detachment involving the macula was operated by pars plana vitrectomy (PPV) with C2 F6 gas tamponade and peeling of internal limiting membrane (ILM). Patients with a follow-up period exceeding one year postoperatively were included in the study. The SRF was drained using a fine cannula without laser photocoagulation, and the samples were analysed using particle-enhancing nephelometry. The levels of βTP were compared to 20 routine cerebrospinal fluid (CSF) samples.RESULTS: In four of the five samples from SRF had relatively low βTP levels, with a mean concentration of 6.6 mg/l (range 2.0 to 23.1 mg/l) compared to 16.0 mg/l (range 6.3-26.8 mg/l) in CSF. The only SRF sample within the range corresponding to normal CSF was the first sample from patient 4, and the analysis of the renewed aspirate during the second operation was 2.8 mg/l. Postoperatively, the regression of SRF was slow, but regression of SRF in the foveal region took place in all cases; however, visual acuity (VA) was improved in only half of the patients.CONCLUSION: The results from the analysed SRF regarding βTP concentration in these patients indicate that the SRF in ODP is not identical to CSF, as the concentrations of βTP differ.
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| 7. |
- Makdoumi, Karim, 1977-, et al.
(författare)
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Photochemical eradication of methicillin-resistant Staphylococcus aureus by blue light activation of riboflavin
- 2017
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Ingår i: Acta Ophthalmologica. - Hoboken, USA : Wiley-Blackwell Publishing Inc.. - 1755-375X .- 1755-3768. ; 95:5, s. 498-502
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare elimination of methicillin-resistant Staphylococcus aureus (MRSA) by exposure of blue light alone and with riboflavin.Methods: A reference strain of MRSA was cultured and diluted in PBS with and without riboflavin (0.01%). Fifteen microlitre was added on a microscope slide, creating a fluid layer with a thickness of around 400 microns. Both of the bacterial suspensions were exposed to blue light, and the effect between exposure with and without riboflavin was compared. Evaluation involved two different wavelengths (412 and 450 nm) of blue light with a lower (5.4 J/cm(2) ) and higher dose (approximately 28.5 J/cm(2) ). The effect of 412 nm light was also evaluated for a thicker fluid layer (1.17 mm). After exposure, colony-forming units (CFUs) were determined for each solution. All measurements were repeated eight times.Results: The reductions in bacteria were similar for both wavelengths. With riboflavin, a statistically significant elimination was observed for both 412 and 450 nm (p < 0.001). At both dosages, the mean reduction was more pronounced with the presence of riboflavin than without it. Using the higher dose, CFU reduction was 99% and 98%, respectively, for 412 and 450 nm light. The bactericidal efficacy was high also in the deeper fluid layer (93%, higher dose).Conclusion: Riboflavin enhanced the antibacterial effect on the exposed MRSA strain of blue light for both 412 and 450 nm blue light. This indicates that blue light could be considered for possible implementation in deep corneal infections.
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| 8. |
- Makdoumi, Karim, 1977-, et al.
(författare)
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Photodynamic UVA-riboflavin bacterial elimination in antibiotic-resistant bacteria
- 2016
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Ingår i: Clinical and Experimental Ophthalmology. - : Wiley-Blackwell. - 1442-6404 .- 1442-9071. ; 44:7, s. 582-586
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Tidskriftsartikel (refereegranskat)abstract
- Background: To evaluate the bactericidal effect of clinical ultraviolet A (UVA) settings used in photoactivated chromophore for infectious keratitis (PACK)-collagen cross-linking (CXL) in antibiotic-resistant and non-resistant bacterial strains.Methods: Well-characterized bacterial strains from clinical isolates, without and with antibiotic resistance, were studied in a pairwise comparison. The evaluated pathogens were Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis. Bacteria were dispersed in PBS and diluted to a concentration of approximately 4x10(5)/ml. Riboflavin was added to a concentration of 0.01%. By spreading the solution on a microscope slide, a fluid film layer, with a thickness of around 400mm, was formed and UVA exposure followed. Eight separate exposures were made for each strain (n=8). The degree of elimination in resistant and non-resistant pathogens was compared.Results: The bactericidal efficacy of exposure differed between the tested microorganisms, and the mean elimination ranged between 60 and 92%, being most extensive in both of the evaluated Pseudomonas strains and least in the E. faecalis strains. Similar reductions were seen in antibiotic-resistant and non-resistant strains, with the exception of S. aureus, in which the resistant strain metchicillin-resistant Staphylococcus aureus (MRSA) was eradicated in a greater extent than the non-resistant strain (P=0.030).Conclusion: UVA-riboflavin settings used in PACK-CXL are effective in reducing both antibiotic-resistant and non-resistant bacteria. Antibiotic resistance does not appear to be protective against the photooxidative exposure.
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| 9. |
- Makdoumi, Karim, 1977-, et al.
(författare)
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The risk for ophthalmological conditions in ulcerative colitis : A population-based case-control study. Is silica dust-exposure associated with inflammatory eye disease?
- 2024
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Ingår i: Acta Ophthalmologica. - : John Wiley & Sons. - 1755-375X .- 1755-3768.
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To study the risk for eye diseases in individuals with Ulcerative Colitis (UC), and to assess whether silica dust-exposure could contribute to the development of inflammatory eye diseases.METHODS: A case-control study was conducted using a patient register processed by the National Board of Health and Welfare (NBHW) and Statistics Sweden. Cases were diagnosed with UC between 2007 and 2016. Matching was done with two random controls having the same age, sex and county of residence, without a systemic inflammatory disease. Using a job-exposure matrix, cases and controls were assessed for work-related silica dust exposure. The risk for eye disease was estimated by Cox regression analysis with calculation of Hazard Ratio (HR).RESULTS: A total of 58 989 individuals were included, comprising 19 663 cases and 39 326 controls. The sex distribution was similar. Overall, individuals with UC had an increased risk for eye disease, specified in ICD 10 chapter VII (H00-H59) with HR 1.25 (CI 1.20-1.32). The highest HR on block-level for cases was 1.52 (CI 1.36-1.70), (H15-H22), which includes episcleritis, keratitis and anterior uveitis. The risk for ocular disease was higher in silica dust-exposed than non-exposed with a HR of 1.44 (CI 1.16-1.78) and 1.25 (CI 1.19-1.31), respectively. Among cases, the risk for iridocyclitis (H20) was further elevated by silica dust exposure, with HR of 3.84 (CI 1.64-8.97) in exposed compared to 1.94 (1.57-2.41) in non-exposed.CONCLUSION: UC is associated with an increased risk for eye diseases, including inflammatory conditions. Our findings highlight that silica dust-exposure may be of importance in the pathogenesis of uveitis.
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| 10. |
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