| 1. |
- Abdalla Elsayed, Maram E.A., et al.
(författare)
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Sickle cell retinopathy. A focused review
- 2019
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Ingår i: Graefe's Archive for Clinical and Experimental Ophthalmology. - : Springer Science and Business Media LLC. - 0721-832X .- 1435-702X. ; 257:7, s. 1353-1364
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Forskningsöversikt (refereegranskat)abstract
- Purpose: To provide a focused review of sickle cell retinopathy in the light of recent advances in the pathogenesis, multimodal retinal imaging, management of the condition, and migration trends, which may lead to increased prevalence of the condition in the Western world. Methods: Non-systematic focused literature review. Results: Sickle retinopathy results from aggregation of abnormal hemoglobin in the red blood cells in the retinal microcirculation, leading to reduced deformability of the red blood cells, stagnant blood flow in the retinal precapillary arterioles, thrombosis, and ischemia. This may be precipitated by hypoxia, acidosis, and hyperosmolarity. Sickle retinopathy may result in sight threatening complications, such as paracentral middle maculopathy or sequelae of proliferative retinopathy, such as vitreous hemorrhage and retinal detachment. New imaging modalities, such as wide-field imaging and optical coherence tomography angiography, have revealed the microstructural features of sickle retinopathy, enabling earlier diagnosis. The vascular growth factor ANGPTL-4 has recently been identified as a potential mediator of progression to proliferative retinopathy and may represent a possible therapeutic target. Laser therapy should be considered for proliferative retinopathy in order to prevent visual loss; however, the evidence is not very strong. With recent development of wide-field imaging, targeted laser to ischemic retina may prove to be beneficial. Exact control of intraoperative intraocular pressure, including valved trocar vitrectomy systems, may improve the outcomes of vitreoretinal surgery for complications, such as vitreous hemorrhage and retinal detachment. Stem cell transplantation and gene therapy are potentially curative treatments, which may prevent retinopathy. Conclusions: There is lack of evidence regarding the optimal management of sickle retinopathy. Further study is needed to determine if recent progress in the understanding of the pathophysiology and diagnosis of sickle retinopathy may translate into improved management and outcome.
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| 2. |
- Al-Barki, Abdulrahman, et al.
(författare)
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Comparison of short-pulse subthreshold (532 nm) and infrared micropulse (810 nm) macular laser for diabetic macular edema
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to assess both anatomic and functional outcomes between short-pulse continuous wavelength and infrared micropulse lasers in the treatment of DME. This was a prospective interventional study from tertiary care eye hospital—King Khaled Eye Specialist Hospital (Riyadh, Saudi Arabia). Patients with center-involving diabetic macular edema were treated with subthreshold laser therapy. Patients in the micropulse group were treated with the 810-nm diode micropulse scanning laser TxCell (IRIDEX Corporation, Mountain View, CA, USA) (subthreshold micropulse—STMP group). Laser was applied according to recommendations for MicroPulse (125 microns spot size, 300 ms pulse duration and power adjustment following barely visible testing burn) in a confluent mode (low intensity/high density) to the entire area of the macular edema. Patients in the short-pulse group were treated with grid pattern laser with 20 ms pulse PASCAL laser 532 nm (TopCon Medical Laser Systems, Tokyo, Japan) with EndPoint algorithm, which was either 30% or 50% of testing burn (EndPoint 30% and EndPoint 50% groups, respectively). Main outcome measures included best-corrected visual acuity (BCVA in logMAR) and foveal thickness at baseline and the last follow-up visit at 6 months. There were 44 eyes in the micropulse group, 54 eyes in the EndPoint 50% group and 18 eyes in the EndPoint 30% group. BCVA for the whole cohort (logMAR) was 0.451 (Snellen equivalent 20/56) at baseline, 0.495 (Snellen equivalent 20/62) (p = 0.053) at 3 months, and 0.494 (Snellen equivalent 20/62) at the last follow-up (p = 0.052). Foveal thickness for the whole cohort was 378.2 ± 51.7 microns at baseline, 347.2 ± 61.3 microns (p = 0.002) at 3 months, and 346.0 ± 24.6 microns at the final follow-up (p = 0.027). As such the short-pulse system yields more temporary reduction in edema. Comparison of BCVA between baseline and 6 months for EndPoint 30%, EndPoint 50% and STMP groups was p = 0.88, p = 0.76 and p = 0.003, respectively. Comparison of foveal thickness between baseline and 6 months for EndPoint 30%, EndPoint 50% and STMP groups was p = 0.38, p = 0.22 and p = 0.14, respectively. We conclude that the infrared micropulse system seems to improve functional outcomes. When applied according to previously published reports, short-pulse system may yield more temporary reduction in edema while infrared micropulse system may yield slightly better functional outcomes.
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| 3. |
- Gielnik, Maciej, et al.
(författare)
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The engineered peptide construct NCAM1-Aβ inhibits fibrillization of the human prion protein (PrP)
- 2022
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Ingår i: Acta Biochimica Polonica. - : Polskie Towarzystwo Biochemiczne (Polish Biochemical Society). - 0001-527X .- 1734-154X. ; 69:1, s. 257-261
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Tidskriftsartikel (refereegranskat)abstract
- In prion diseases, the prion protein (PrP) becomes misfolded and forms fibrillar aggregates that are responsible for prion infectivity and pathology. So far, no drug or treatment procedures have been approved for prion disease treatment. We have previously shown that engineered cell-penetrating peptide constructs can reduce the amount of prion aggregates in infected cells. However, the molecular mechanism underlying this effect is unknown. Here, we use atomic force microscopy (AFM) imaging to show that the amyloid aggregation and fibrillization of the human PrP protein can be inhibited by equimolar amounts of the 25 residues long engineered peptide construct NCAM1-Aβ.
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| 4. |
- Gielnik, Maciej, et al.
(författare)
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Zn(II) binding causes interdomain changes in the structure and flexibility of the human prion protein
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The cellular prion protein (PrP(C)) is a mainly alpha-helical 208-residue protein located in the pre- and postsynaptic membranes. For unknown reasons, PrP(C) can undergo a structural transition into a toxic, beta-sheet rich scrapie isoform (PrPSc) that is responsible for transmissible spongiform encephalopathies (TSEs). Metal ions seem to play an important role in the structural conversion. PrP(C) binds Zn(II) ions and may be involved in metal ion transport and zinc homeostasis. Here, we use multiple biophysical techniques including optical and NMR spectroscopy, molecular dynamics simulations, and small angle X-ray scattering to characterize interactions between human PrP(C) and Zn(II) ions. Binding of a single Zn(II) ion to the PrP(C) N-terminal domain via four His residues from the octarepeat region induces a structural transition in the C-terminal alpha-helices 2 and 3, promotes interaction between the N-terminal and C-terminal domains, reduces the folded protein size, and modifies the internal structural dynamics. As our results suggest that PrP(C) can bind Zn(II) under physiological conditions, these effects could be important for the physiological function of PrP(C).
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| 5. |
- Harbi, Majed Al, et al.
(författare)
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Association between sickle cell trait and the prevalence and severity of diabetic retinopathy
- 2016
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To determine whether Sickle cell trait (SCT) is associated with an increased severity of diabetic retinopathy. Methods This was a single center retrospective study case control study of 100 eyes of 100 patients with diabetes mellitus (DM) with SCT (SCT group) and 100 eyes of 100 age-matched patients with DM without SCT (control group). The main outcome measure was the difference in the prevalence of sight threatening DR [here defined as diabetic macular edema (DME) and/or proliferative diabetic retinopathy (PDR)], between the SCT and control groups. Secondary outcome measures included differences in visual acuity, ocular comorbidities, intraocular pressure, glycemic control as assessed by random blood glucose measurement, diabetes duration, nephropathy, hyperlipidemia and hypertension. Results The SCT group had statistically significantly shorter duration of DM (median [25% quartile] 15 [8.3] years versus 20 [14.7] years, respectively)(P
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| 6. |
- Kozak, Igor, et al.
(författare)
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Teleophthalmology image-based navigated retinal laser therapy for diabetic macular edema : a concept of retinal telephotocoagulation
- 2017
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Ingår i: Graefe's Archive for Clinical and Experimental Ophthalmology. - : Springer Science and Business Media LLC. - 0721-832X .- 1435-702X. ; 255:8, s. 1509-1513
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Tidskriftsartikel (refereegranskat)abstract
- Background: To determine the feasibility and efficacy of a retinal telephotocoagulation treatment plan for diabetic macular edema. Methods: Prospective, interventional cohort study at two clinical sites. Sixteen eyes of ten subjects with diabetic macular edema underwent navigated focal laser photocoagulation using a novel teleretinal treatment plan. Clinic 1 (King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia) collected retinal images and fundus fluorescein angiogram. Clinic 2 (Palmetto Retina Center, West Columbia, SC, USA) created image-based treatment plans based on which macular laser photocoagulation was performed back at clinic 1. The primary outcome of the study was feasibility of image transfer and performing navigated laser photocoagulation for subjects with diabetic macular edema between two distant clinics. Secondary measures were change in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) by spectral-domain optical coherence tomography at 3 months after treatment. Results: The teleretinal treatment plan was able to be successfully completed in all 16 eyes. The mean logMAR BCVA at baseline was 0.49 ± 0.1, which remained stable (0.45 ± 0.1) 3 months after treatment (p = 0.060). The CRT improved from 290.1 ± 37.6 μm at baseline to 270.8 ± 27.7 μm 3 months after treatment (p = 0.005). All eyes demonstrated improvement in the area of retinal edema after laser photocoagulation, and no eyes demonstrated visual acuity loss 3 months after treatment. Conclusion: This study introduces the concept of retinal telephotocoagulation for diabetic macular edema, and demonstrates the feasibility and safety of using telemedicine to perform navigated retinal laser treatments regardless of geographical distance.
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| 7. |
- Kozak, Mariya, et al.
(författare)
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Polyphosphate Ester-Type Transporters Improve Antimicrobial Properties of Oxytetracycline
- 2023
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Ingår i: MDPI. - : MDPI AG. ; 12:3, s. 1-12
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Prolonged use of antibiotics can cause toxicity in human and animal cells and lead to the development of antibiotic resistance. The development of drug delivery systems for enhanced antibacterial properties of antibiotics could reduce toxic effects and minimize the development of resistance. The aim of this study was to evaluate the effectiveness of oxytetracycline in complexes with new polyphosphate ester-type transporters and to investigate the antimicrobial effect of these complexes on Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus growth in vitro. Two polyphosphate ester-type transporters with different molecular weights were synthesized, and oxytetracycline was attached through the phosphorus groups. To determine the sensitivities of microorganisms, oxytetracycline hydrochloride and oxytetracycline complexes with polyphosphate ester-type transporters (P4 and P6) were added to liquid and solid media with E. coli, P. aeruginosa, and S. aureus in different doses. Oxytetracycline in complex with polyphosphate ester-type transporters at low doses (2.3 to 3.8 μg/disk or μg/mL) in both solid and liquid media inhibits the growth of S. aureus more effectively than oxytetracycline alone. The maximum influence on E. coli growth on solid media is observed at a dose of 8 μg/disk of oxytetracycline in combination with both P4 and P6 polyphosphate ester-type transporters. P. aeruginosa growth under the influence of oxytetracycline in combination with polyphosphate-ester type transporters in a liquid medium depends on the dose of antibiotic and the day of cultivation.
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| 8. |
- Taskintuna, Ibrahim, et al.
(författare)
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Comparison of outcomes of four different treatment modalities for diabetic vitreous haemorrhage
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- We compared outcomes of four different management modalities for diabetic VH. Patients with diabetic VH were identified in this retrospective study undertaken at King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. Eyes were grouped based on the treatment received: control (observation only), intravitreal bevacizumab (IVB) injection(s), pars plana vitrectomy (PPV), and preoperative single IVB injection before PPV. Best-corrected visual acuity (BCVA) and status of VH were noted at baseline and the last follow up (Minimum: 6 months, maximum: 29 months). The proportion of eyes with Snellen BCVA improvement by two lines or more and VH clearance at the last follow up were compared between groups. The four groups – Control, IVB, PPV, and IVB-before-PPV had 23, 29, 17, and 20 eyes, respectively. The proportion of eyes gaining ≥2 lines was substantially higher in the IVB-before-PPV and PPV groups (90% and 77%, respectively) compared with IVB and observation groups (41% and 22%, respectively). Surgical treatment was associated with a 2.38 times higher likelihood of gaining ≥2 lines than the non-surgical one (incidence ratio: 2.38, 95% CI 1.19, 4.78 P = 0.015) after adjusting for age, hyperglycemia and BCVA at presentation. Less invasive treatment such as IVB injections did not result in the same amount of improvement in vision as did PPV. Prospective randomized studies are needed to better define the role of IVB injections in the management of diabetic VH.
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