| 1. |
- Berman, Anne H., Professor, et al.
(författare)
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Transdiagnostic and tailored internet intervention to improve mental health among university students : Research protocol for a randomized controlled trial
- 2024
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Ingår i: Trials. - : Springer Nature. - 1745-6215. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Emerging adulthood is often associated with mental health problems. About one in three university students report symptoms of depression and anxiety that can negatively affect their developmental trajectory concerning work, intimate relationships, and health. This can interfere with academic performance, as mood and anxiety disorders are key predictors of dropout from higher education. A treatment gap exists, where a considerable proportion of students do not seek help for mood and anxiety symptoms. Offering internet interventions to students with mental health problems could reduce the treatment gap, increase mental health, and improve academic performance. A meta-analysis on internet interventions for university students showed small effects for depression and none for anxiety. Larger trials are recommended to further explore effects of guidance, transdiagnostic approaches, and individual treatment components.Methods: This study will offer 1200 university students in Sweden participation in a three-armed randomized controlled trial (RCT) evaluating a guided or unguided transdiagnostic internet intervention for mild to moderate depression and anxiety, where the waitlist control group accesses the intervention at 6-month follow-up. Students reporting suicidal ideation/behaviors will be excluded and referred to treatment within the existing healthcare system. An embedded study within the trial (SWAT) will assess at week 3 of 8 whether participants in the guided and unguided groups are at higher risk of failing to benefit from treatment. Those at risk will be randomized to an adaptive treatment strategy, or to continue the treatment as originally randomized. Primary outcomes are symptoms of depression and anxiety. Follow-ups will occur at post-treatment and at 6-, 12-, and 24-month post-randomization. Between-group outcome analyses will be reported, and qualitative interviews about treatment experiences are planned.Discussion: This study investigates the effects of a transdiagnostic internet intervention among university students in Sweden, with an adaptive treatment strategy employed during the course of treatment to minimize the risk of treatment failure. The study will contribute knowledge about longitudinal trajectories of mental health and well-being following treatment, taking into account possible gender differences in responsiveness to treatment. With time, effective internet interventions could make treatment for mental health issues more widely accessible to the student group.
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| 2. |
- Galichanin, Konstantin, et al.
(författare)
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Characterization of Molecular Mechanisms of In vivo UVR Induced Cataract
- 2012
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Ingår i: Journal of Visualized Experiments. - : MyJove Corporation. - 1940-087X. ; :69
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Tidskriftsartikel (refereegranskat)abstract
- Cataract is the leading cause of blindness in the world (1). The World Health Organization defines cataract as a clouding of the lens of the eye which impedes the transfer of light. Cataract is a multi-factorial disease associated with diabetes, smoking, ultraviolet radiation (UVR), alcohol, ionizing radiation, steroids and hypertension. There is strong experimental (2-4) and epidemiological evidence (5,6) that UVR causes cataract. We developed an animal model for UVR B induced cataract in both anesthetized (7) and non-anesthetized animals (8). The only cure for cataract is surgery but this treatment is not accessible to all. It has been estimated that a delay of onset of cataract for 10 years could reduce the need for cataract surgery by 50% (9). To delay the incidence of cataract, it is needed to understand the mechanisms of cataract formation and find effective prevention strategies. Among the mechanisms for cataract development, apoptosis plays a crucial role in initiation of cataract in humans and animals (10). Our focus has recently been apoptosis in the lens as the mechanism for cataract development (8,11,12). It is anticipated that a better understanding of the effect of UVR on the apoptosis pathway will provide possibilities for discovery of new pharmaceuticals to prevent cataract. In this article, we describe how cataract can be experimentally induced by in vivo exposure to UVR-B. Further RT-PCR and immunohistochemistry are presented as tools to study molecular mechanisms of UVR-B induced cataract.
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| 3. |
- Kronschlager, Martin, et al.
(författare)
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Apoptosis in Rat Cornea After In Vivo Exposure to Ultraviolet Radiation at 300 nm
- 2015
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Ingår i: Cornea. - 0277-3740 .- 1536-4798. ; 34:8, s. 945-949
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Tidskriftsartikel (refereegranskat)abstract
- Purpose:Peak toxicity for in vivo ultraviolet radiation (UVR) exposure to the lens is in the 300-nm wavelength region. However, little is known about corneal cell damage at 300 nm. The purpose of the study was to determine the time evolution of apoptosis in the cornea after in vivo exposure to 300-nm UVR.Methods:Altogether, 16 Sprague Dawley rats were divided into 4 groups and unilaterally exposed to 5 kJ/m(2) UVR ((max): 300 nm; (0.5): 10 nm) for 15 minutes. After a predetermined latency period of 1, 5, 24, and 120 hours, depending on the group, the animals were killed and eyes were enucleated. Eye globes were further cryosectioned in 10-m thick midsagittal sections. For the detection of apoptosis, the TUNEL method was applied.Results:TUNEL-positive signals were observed in the superficial epithelial cells in the exposed and control eyes at all latency periods. At 5 hours, TUNEL staining was detected in the exposed corneas in epithelial cells, keratocytes, and endothelial cells with a maximum signal at 24 hours. At 120 hours, no TUNEL staining was found in endothelial cells and only occasionally in keratocytes in exposed corneas. Signs of ulceration and stromal thinning were observed at 120 hours.Conclusions:UVR in the 300-nm wavelength region induces TUNEL staining in all 3 corneal layers. TUNEL staining of all 3 corneal layers is an early postexposure event observed after a 5-hour latency period. Corneal sterile keratolysis occurs in the time window of 24 to 120 hours probably induced by neutrophils.
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| 4. |
- Kronschläger, Martin, et al.
(författare)
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Caffeine eye drops protect against UV-B cataract
- 2013
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835 .- 1096-0007. ; 113, s. 26-31
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate if topically applied caffeine protects against in vivo ultraviolet radiation cataract and if so, to estimate the protection factor. Three experiments were carried out. First, two groups of Sprague-Dawley rats were pre-treated with a single application of either placebo or caffeine eye drops in both eyes. All animals were then unilaterally exposed in vivo to 8 kJ/m(2) UV-B radiation for 15 min. One week later, the lens GSH levels were measured and the degree of cataract was quantified by measurement of in vitro lens light scattering. In the second experiment, placebo and caffeine pre-treated rats were divided in five UV-B radiation dose groups, receiving 0.0, 2.6, 3.7, 4.5 or 5.2 kJ/m(2) UV-B radiation in one eye. Lens light scattering was determined after one week. In the third experiment, placebo and caffeine pre-treated rats were UV-B-exposed and the presence of activated caspase-3 was visualized by immunohistochemistry. There was significantly less UV-B radiation cataract in the caffeine group than in the placebo group (95% confidence interval for mean difference in lens light scattering between the groups = 0.10 +/- 0.05 tEDC), and the protection factor for caffeine was 1.23. There was no difference in GSH levels between the placebo- and the caffeine group. There was more caspase-3 staining in UV-B-exposed lenses from the placebo group than in UV-B-exposed lenses from the caffeine group. Topically applied caffeine protects against ultraviolet radiation cataract, reducing lens sensitivity 1.23 times.
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| 5. |
- Kronschläger, Martin, et al.
(författare)
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Evolution of TUNEL-labeling in the Rat Lens After In Vivo Exposure to Just Above Threshold Dose UVB
- 2013
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Ingår i: Current Eye Research. - : Informa UK Limited. - 0271-3683 .- 1460-2202. ; 38:8, s. 880-885
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Tidskriftsartikel (refereegranskat)abstract
- Purpose/Aim:To quantitatively analyse the evolution of TUNEL-labeling, after in vivo exposure to UVB.Methods:Altogether, 16 Sprague Dawley rats were unilaterally exposed in vivo for 15 min to close to threshold dose, 5 kJ/m(2), of ultraviolet radiation in the 300nm wavelength region. Animals were sacrificed in groups of 4 at 1, 5, 24 and 120 h after exposure. For each animal, both eye globes were removed and frozen. The frozen eye was cryo-sectioned in 10 mm thick midsagittal sections. From each globe, three midsagittal sections with at least five sections interval in between were mounted on a microscope slide. Sections were TUNEL-labeled and counter stained with DAPI. For quantification of apoptosis, a fluorescence microscope was used. In sections with a continuous epithelial cell surface, the number of lens epithelial cell nuclei and the number of TUNEL-positive epithelial cell nuclei was counted. The total number of TUNEL-positive epithelial cell nuclei for all three sections of one lens in relation to the total number of epithelial cell nuclei for all three sections of the same lens was compared between exposed and contralateral not exposed lens for each animal.Results:The relative difference of the fraction of TUNEL-positive nuclei between exposed and contralateral not exposed lens increased gradually, peaked in the time interval 5-120 h after exposure, and then declined.Conclusions:Close to threshold dose of UVB induces TUNEL-labeling that peaks in the time window 5-120 h after exposure to UVB.
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| 6. |
- Kronschläger, Martin, et al.
(författare)
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Pharmacokinetics for topically applied caffeine in the rat
- 2014
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835 .- 1096-0007. ; 122, s. 94-101
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Tidskriftsartikel (refereegranskat)abstract
- Topically applied caffeine was recently identified as a promising candidate molecule for cataract prevention. Little is known about the pharmacokinetics for topically applied caffeine. Potential toxicity of 72 mM caffeine on the ocular surface and the lens was qualitatively monitored and no toxic effects were observed. The concentration of caffeine was measured in the lens and the blood after topical application of 72 mM caffeine to groups of 10 animals sacrificed at 30, 60, 90 and 120 min after topical application. The lens concentration decreased throughout the observation period while the blood concentration increased up to 120 min. Further, the concentration of caffeine in the lens and blood was measured 30 min after topical application of caffeine, the concentration of caffeine being 0.72, 3.34, 15.51 and 72 mM depending on group belonging, in groups of 10 animals. The caffeine concentration in lens and blood, respectively, increased proportionally to the caffeine concentration topically applied. The rat blood concentrations achieved were far below the equivalent threshold dose of FDA recommended daily dose for humans. This information is important for further development of caffeine eye drops for cataract prevention.
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| 7. |
- Kronschläger, Martin, et al.
(författare)
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Topically applied caffeine induces miosis in the ketamine/xylazine anesthetized rat
- 2014
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Ingår i: Experimental Eye Research. - : Elsevier BV. - 0014-4835 .- 1096-0007. ; 127, s. 179-183
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to examine if topically applied caffeine influences pupil size in ketamine/xylazine anesthetized animals. Two experiments were carried out. In the first experiment, caffeine was topically applied to one of the eyes of 10 ketamine/xylazine anesthetized animals, while vehicle only was topically applied to the contralateral eye. In the second experiment, caffeine was topically applied to both eyes in one group of 10 ketamine/xylazine anesthetized rats, while in another group both eyes vehicle only was topically applied to both eyes. In both experiments pupil diameter was measured at 0, 10, 20, 40 and 60 min after topical application. In three of the animals, the pupil was dilated with tropicamide 5 mg/ml at 60 min after the topical application of caffeine and the pupil diameter was measured. The first experiment showed a relative miosis in caffeine treated eyes as compared to the vehicle treated eye, that changed over time. The second experiment in line with the first experiment, also showed that topically applied caffeine causes a relative miosis as compared to vehicle only that changes over time. Eyes treated with caffeine reacted with quick dilatation after tropicamide application. Topical caffeine antagonizes ketamine/xylazine anesthesia induced mydriasis in a time dependent manner.
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| 8. |
- Söderberg, Per, 1956-, et al.
(författare)
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Does infrared or ultraviolet light damage the lens?
- 2016
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Ingår i: Eye (London. 1987). - : Springer Science and Business Media LLC. - 0950-222X .- 1476-5454. ; 30:2, s. 241-246
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Tidskriftsartikel (refereegranskat)abstract
- In daylight, the human eye is exposed to long wavelength ultraviolet radiation (UVR), visible radiation and short wavelength infrared radiation (IRR). Almost all the UVR and a fraction of the IRR waveband, respectively, left over after attenuation in the cornea, is absorbed in the lens. The time delay between exposure and onset of biological response in the lens varies from immediate-to-short-to-late. After exposure to sunlight or artificial sources, generating irradiances of the same order of magnitude or slightly higher, biological damage may occur photochemically or thermally. Epidemiological studies suggest a dose-dependent association between short wavelength UVR and cortical cataract. Experimental data infer that repeated daily in vivo exposures to short wavelength UVR generate photochemically induced damage in the lens, and that short delay onset cataract after UVR exposure is photochemically induced. Epidemiology suggests that daily high-intensity short wavelength IRR exposure of workers, is associated with a higher prevalence of age-related cataract. It cannot be excluded that this effect is owing to a thermally induced higher denaturation rate. Recent experimental data rule out a photochemical effect of 1090 nm in the lens but other wavelengths in the near IRR should be investigated.
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| 9. |
- Söderberg, Per G., et al.
(författare)
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Near infrared radiation damage mechanism in the lens
- 2015
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Ingår i: OPHTHALMIC TECHNOLOGIES XXV. - : SPIE. - 9781628413977
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Konferensbidrag (refereegranskat)abstract
- The current data strongly indicates that there is no photochemical effect of in vivo exposure to 1090 nm near IRR radiation within the pupil. Four groups of 20 Sprague-Dawley rats were unilaterally exposed in vivo to 96 W.cm(-2) centered inside the pupil for 10, 18, 33 and 60 min, respectively depending on group belonging. This resulted in radiant exposure doses of 57, 103, 198 and 344 kJ.cm(-2). Temperature evolution at the limbus during the exposure and difference of intensity of forward light scattering between the exposed and the contralateral not exposed eye was measured at 1 week after exposure. The temperature at the limbus was found to increase exponentially towards an asymptote with an asymptote temperature of around 7 degrees C and a time constant (1/k) of around 15 s. No increase of light scattering was found despite that the cumulated radiant exposure dose was [80; 250] times the threshold for photochemically induced cataract suggested by previous empirical data. It is concluded that at 1090 nm near IRR there is no photochemical effect.
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| 10. |
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| 11. |
- Söderberg, Per, 1956-, et al.
(författare)
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Katarakt - : ett optiskt problem i ögats lins
- 2016
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Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 113, s. 1532-1536
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Tidskriftsartikel (refereegranskat)abstract
- Katarakt definieras som nedsatt syn på grund av en optisk störning i ögats lins.Cirka 50 procent av kataraktsjukdomen antas associerad med genetiska faktorer.Ultraviolett strålning är epidemiologiskt starkt associerad med barkkatarakt, och rökning med kärnkatarakt.Störning av proteinkoncentrationsgradienten i linsen orsakar ljusspridning.Kemiska förändringar i linsens vattenlösliga proteiner kan orsaka aggregation av dessa.Betydande teknisk utveckling inom kataraktkirurgi reflekteras i en linjär ökning av antalet kataraktoperationer i Sverige under de senaste 35 åren.I snö och vid vatten bör solglasögon av filterkategori 3 användas för att skydda ögonen.
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| 12. |
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| 13. |
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| 14. |
- Talebizadeh, Nooshin, 1977-
(författare)
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Caspase-3 in lens epithelium
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: To model the time evolution of active caspase-3 protein expression in a healthy lens, and in a lens exposed to UVR-300 nm (UVR-B). To develop an automated method to classify the fluorescent signal of biomarkers in the lens epithelial cells.Methods: Six-week old Sprague-Dawley rats were used. Firstly, expression of active caspase-3 was studied in the lens epithelium of healthy rats. Secondly, rats were unilaterally exposed in vivo to 1 kJ/m2 UVR-B for 15 minutes. At 0.5, 8, 16, and 24 hours after the UVR-B exposure, the exposed and the contralateral non-exposed lenses were removed. Immunohistochemistry was done on three mid-sagittal sections from each lens. The florescent labelling for active caspase-3 in each lens section was counted three times. The time evolution of active caspase-3 expression in response to UVR-B exposure was modelled as a function of cell position in the lens epithelium. An automated objective method was developed to quantify the lens epithelial cells and to classify the fluorescent signal of active caspase-3. Active caspase-3 was selected as a model signal.Results: Active caspase-3 was abundant in the anterior pole of the normal lenses. Spatial distribution of active caspase-3 labelling in the lens epithelium was fitted to a logistic model. The probability of active caspase-3 expression was higher in the UVR-B exposed lenses (95% CI = 0.12 ± 0.01). There was no difference in the expression of active caspase-3 between the 0.5 and the 24 hours groups or between the 8 and the 16 hours groups. A difference was noted, when comparing the 0.5 and 24 hours groups with the 8 and 16 hours groups (Test statistic 7.01, F1;36;0.95= 4.11). Exposure to UVR-B has an impact on the average probability of labelling for active caspase-3 as a function of cell position. The probability of labelling as a function of cell number also varied as a function of time after UVR-B exposure. The automated method counted the lens epithelial cells and estimated the proportion of active caspase-3 labelling in the lens epithelium.Conclusions: Active caspase-3 is present in the healthy lens epithelial cells. Active caspase-3 exhibits higher expression at the anterior pole of the lens and the expression decreases towards the periphery. After UVR-B exposure, the expression of active caspase-3 in the lens epithelium increases with a peak of expression occurring around 16 hours after exposure. The average probability of labelling in the lens epithelium is dependent on both the UVR-B exposure and the time period elapsed after the exposure. The automated method enables objective and fast quantification of lens epithelial cells and the expression of fluorescent signal in the lens cells.
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| 15. |
- Talebizadeh, Nooshin, 1977-, et al.
(författare)
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Modelling the time evolution of active caspase-3 protein in the rat lens after in vivo exposure to Ultraviolet radiation-B : Model for active caspase-3 expression after in vivo exposure to UVR-300 nm
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:9, s. e106926-
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To introduce a model for the time evolution of active caspase-3 protein expression in albino rat lens up to 24 hours after in vivo exposure to low dose UVR in the 300 nm wavelength region (UVR-300 nm).Methods: Forty Sprague-Dawley rats were unilaterally exposed in vivo to 1 kJ/m2 UVR-300 nm for 15 minutes. At 0.5, 8, 16, and 24 hours after the UVR exposure, the exposed and contralateral not-exposed lenses were removed and processed for immunohistochemistry. The differences in the probability of active caspase-3 expression at four different time points after exposure were used to determine the time evolution of active caspase-3 expression. A logistic model was introduced for the expression of active caspase-3. The parameters for the exposed and the not exposed lenses were estimated for the observation time points.Results: The exposure to UVR-300 nm impacted on the parameters of the logistic model. Further, the parameters of the model varied with time after exposure to UVR-300 nm.Conclusion: The logistic model predicts the impact of exposure to UVR-300 nm on the spatial distribution of probability of active caspase-3 protein expression, depending on time.
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| 16. |
- Talebizadeh, Nooshin, et al.
(författare)
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Objective automated quantification of fluorescence signal in histological sections of rat lens
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: To develop an automated method to delineate lens epithelial cells and to quantify expression of fluorescent signal of biomarkers in each nucleus and cytoplasm of lens epithelial cells in a histological section.Methods: An automated algorithm was developed in Matlab™ to localize and quantify fluorescence signal in lens epithelial cells in histological images. A region of interest representing the lens epithelium was manually demarcated in each input image. Individual cell nuclei within the region of interest were automatically delineated based on watershed segmentation and thresholding. Fluorescence signal was quantified within nuclei and cytoplasms. The classification of fluorescence signal was based on local background. Classification of cells as labelled or not labelled was thereafter optimized as compared to visual classification of a limited dataset.The performance of the automated classification was evaluated by asking eleven independent blinded observers to classify all cells (n=395) in one lens image. Time consumed by the automatic algorithm and visual /manual classification of nuclei, was recorded.Results: On an average, 77 % of the cells were correctly classified as compared to the majority vote of the visual observers. The average agreement among visual observers was 83 %. However, variation among visual observers was high, and agreement between two visual observers was as low as 71 % in the worst case. Automated classification was on average 10 times faster than manual scoring.Conclusion: The presented method enables objective and fast detection of lens epithelial cells and quantification of expression of fluorescent signal in a histological section of rat lens, with accuracy comparable to the variability between different visual observers. Furthermore, automated scoring is unbiased and reproducible, and results in a 10-fold increase in throughput.
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| 17. |
- Talebizadeh, Nooshin, 1977-, et al.
(författare)
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Objective automated quantification of fluorescence signal in histological sections of rat lens
- 2017
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Ingår i: Cytometry Part A. - : Wiley. - 1552-4922 .- 1552-4930. ; 91:8, s. 815-821
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Tidskriftsartikel (refereegranskat)abstract
- Visual quantification and classification of fluorescent signals is the gold standard in microscopy. The purpose of this study was to develop an automated method to delineate cells and to quantify expression of fluorescent signal of biomarkers in each nucleus and cytoplasm of lens epithelial cells in a histological section. A region of interest representing the lens epithelium was manually demarcated in each input image. Thereafter, individual cell nuclei within the region of interest were automatically delineated based on watershed segmentation and thresholding with an algorithm developed in Matlab™. Fluorescence signal was quantified within nuclei, cytoplasms and juxtaposed backgrounds. The classification of cells as labelled or not labelled was based on comparison of the fluorescence signal within cells with local background. The classification rule was thereafter optimized as compared with visual classification of a limited dataset. The performance of the automated classification was evaluated by asking 11 independent blinded observers to classify all cells (n = 395) in one lens image. Time consumed by the automatic algorithm and visual classification of cells was recorded. On an average, 77% of the cells were correctly classified as compared with the majority vote of the visual observers. The average agreement among visual observers was 83%. However, variation among visual observers was high, and agreement between two visual observers was as low as 71% in the worst case. Automated classification was on average 10 times faster than visual scoring. The presented method enables objective and fast detection of lens epithelial cells and quantification of expression of fluorescent signal with an accuracy comparable with the variability among visual observers.
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| 18. |
- Talebizadeh, Nooshin, 1977-, et al.
(författare)
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Specific spatial distribution of caspase-3 in normal lenses
- 2014
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Ingår i: Acta Ophthalmologica. - : Wiley. - 1755-375X .- 1755-3768. ; 93:3, s. 289-292
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo determine the distribution of active caspase-3 in rat eye lens epithelium.MethodsIn total, 120 sagittal sections from forty rats were assessed for active caspase-3 labelling using immunohistochemistry. Lens epithelial cells were counted, and the fraction of active caspase-3 labelled cells and their relative positions were identified in each section.ResultsActive caspase-3 is present in normal lens epithelium. The active caspase-3 expression was higher in the anterior pole of the lens. Probability of radial spatial distribution of labelling was fitted with a logistic model. The increase rate and the inflection point were estimated as CI (0.95) to 23 ± 3 cells and 114 ± 3 cells, respectively.ConclusionThe gradually decreasing active caspase-3 labelling from the anterior pole to the periphery suggests that active caspase-3 may be involved in normal protein turnover caused by, for example, incident light.
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| 19. |
- Talebizadeh, Nooshin, et al.
(författare)
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Time evolution of active caspase-3 labelling after in vivo exposure to UVR-300 nm
- 2014
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Ingår i: Acta Ophthalmologica. - : Wiley. - 1755-375X .- 1755-3768. ; 92:8, s. 769-773
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:To determine the time evolution of active caspase-3 protein expression in albino rat lens after in vivo exposure to low-dose UVR-300 nm, as detected by immunofluorescence.METHODS:Forty Sprague-Dawley rats were unilaterally exposed in vivo to 1 kJ/m2 UVR-300 nm for 15 min. At 0.5, 8, 16 and 24 hr after the UVR exposure, the exposed and contralateral nonexposed lenses were removed and processed for immunohistochemistry. Three mid-sagittal sections from each lens were stained. The cells labelled for active caspase-3 in each section of both the exposed and nonexposed lenses were counted and recorded three times. The difference of the proportion of labelling between the exposed and contralateral nonexposed lenses within each animal was calculated. The differences of active caspase-3 labelling at four different time-points after exposure were used to determine the time evolution of active caspase-3 expression.RESULTS:Caspase-3 expression was higher in the exposed than in contralateral nonexposed lenses. The mean difference between the exposed and contralateral nonexposed lenses, including all lenses from all time intervals, was 0.12 ± 0.01 (= CI 95%). The mean differences between the exposed and contralateral nonexposed lenses were 0.11 ± 0.02, 0.13 ± 0.02, 0.14 ± 0.01 and 0.09 ± 0.03 (= CI 95%) for the 0.5-, 8-, 16- and 24-hr time groups, respectively. The orthogonal comparison showed no difference in the expression of active caspase-3 between the 0.5- and the 24-hr groups (Test statistic 1.50, F1,36 = 4.11, p < 0.05) or between the 8- and the 16-hr groups (test statistic 0.05, F1,36 = 4.11, p < 0.05). There was a difference when comparing the 0.5- and 24-hr groups to the 8- and 16-hr groups (test statistic 7.01, F1,36 = 4.11, p < 0.05).CONCLUSION:The expression of active caspase-3 in the lens epithelium increases after UVR exposure. There is a peak of expression approximately 16 hr after the exposure.
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| 20. |
- Yu, Zhaohua, 1983-, et al.
(författare)
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1090 nm infrared radiation at close to threshold dose induces cataract with a time delay
- 2015
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Ingår i: Acta Ophthalmologica. - : Wiley. - 1755-375X .- 1755-3768. ; 93:2, s. e118-e122
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo investigate if infrared radiation induced cataract is instant or is associatedwith a time delay between the exposure and the onset of lens light scattering after anexposure to just above threshold dose.MethodsSix-weeks-old albino Sprague-Dawley female rats were unilaterally exposedto 197 W/cm2 infrared radiation at 1090 nm within the dilated pupil. In the firstexperiment, the animals were exposed with four exposure times of 5, 8, 13 and 20 s,respectively. At 24 h after exposure, the light scattering in both exposed andcontralateral not exposed lenses was measured. Based on the first experiment, fourpost exposure time groups were exposed unilaterally to 1090 nm infrared radiation of197 W/cm2 for 8 s. At 6, 18, 55 and 168 h after exposure, the light scattering in bothlenses was measured.ResultsA 197 W/cm2 infrared radiation induced light scattering in the lens withexposures of at least 8 s. Further, after exposure to infrared radiation of 197 W/cm2for 8 s, the light scattering increase in the lens was delayed approximately 16 h afterthe exposure.ConclusionThere is a time delay between the exposure and the onset of cataract afterexposure to close to threshold dose implicating that either near infrared radiationcataract is photochemical or there is a time delay in the biological expression ofthermally induced damage.
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| 21. |
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| 22. |
- Yu, Zhaohua, 1983-, et al.
(författare)
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Measuring temperature in the lens during experimental heat load indirectly as light scattering increase rate
- 2017
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Ingår i: Journal of Biomedical Optics. - 1083-3668 .- 1560-2281. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- The current study aims to experimentally estimate the temperature in the lens due to heat load indirectly from the measurement of increase rate of temperature-induced light scattering. The lens was extracted from Sprague-Dawley rats and put into a temperature-controlled cuvette filled with balanced salt solution. Altogether, 80 lenses were equally divided on four temperature groups. Each lens was exposed for 5 minutes to temperature depending on group belonging while the intensity of forward light scattering was recorded. The inclination coefficient of light scattering increase at the temperature 37, 40, 43, and 46 ºC was estimated as a CI(0.95), 3.1±0.8, 4.4±0.8, 5.5±0.9 and 7.0±0.8 x10-4 tEDC/s, respectively. The Arrhenius equation implies that the natural logarithm of the inclination coefficient is linearly dependent on the inverse of the temperature. The proportionality constant and the intercept were 9.6±2.4 x103 K and 22.8±7.7. The activation energy was 8.0±2.0 x101 kJ·mol-1. The current experiment implies that if averaging 20 measurements of inclination coefficients in a new experiment at constant heat load, the confidence limits for predicted temperature correspond to ±1.9 °C. With the proportionality constant and the intercept estimated in the current experiment, the in vivo temperature in the lens can be determined retrospectively with sufficient resolution.
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| 23. |
- Yu, Zhaohua, 1983-, et al.
(författare)
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Ocular temperature elevation induced by threshold in vivo exposure to 1090 nm infrared radiation and associated heat diffusion
- 2014
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Ingår i: Journal of Biomedical Optics. - 1083-3668 .- 1560-2281. ; 19:10, s. 105008-
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Tidskriftsartikel (refereegranskat)abstract
- An in vivo exposure to 197 W/cm2 1090 nm infrared radiation (IRR) requires a minimum 8 s for cataract induction. The present study aims to determine the ocular temperature evolution and the associated heat flow at the same exposure conditions. Two groups of 12 rats were unilaterally exposed within the dilated pupil with a close to collimated beam between lens and retina. Temperature was recorded with thermocouples. Within 5 min after exposure, the lens light scattering was measured. In one group, the temperature rise in the exposed eye, expressed as CI(0.95), was 11±3 ºC at the limbus, 16±6 ºC in the vitreous behind lens and 16±7 ºC on the sclera next to the optic nerve, respectively. In the other group, the temperature rise in the exposed eye was 9±1 ºC at the limbus and 26±11 ºC on the sclera next to the optic nerve, respectively. The difference of forward light scattering between exposed and contralateral not exposed eye was 0.01±0.09 tEDC. An exposure to 197 W/cm2 1090 nm IRR for 8 s induces a temperature increase of 10 °C at the limbus and 26 °C close to the retina. IRR cataract is probably of thermal origin.
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| 24. |
- Yu, Zhaohua, 1983-, et al.
(författare)
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Temperature-controlled in vivo ocular exposure to 1090-nm radiation suggests that near-infrared radiation cataract is thermally induced
- 2015
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Ingår i: Journal of Biomedical Optics. - 1083-3668 .- 1560-2281. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- The damage mechanism for near infrared radiation induced (IRR) cataract is unclear. Both a photochemical and a thermal mechanism were suggested.The current paper aims to elucidate a photochemical effect based on investigation of irradiance-exposure time reciprocity.Groups of 20 rats were unilaterally exposed to 96 W/cm2 IRR at 1090 nm within the dilated pupil accumulating 57, 103, 198, 344 kJ/cm2 respectively. Temperature was recorded at the limbus of the exposed eye. Seven days after exposure, the lenses were macroscopically imaged and light scattering was measured quantitatively.The average maximum temperature increase for exposure time 10, 18, 33, 60 minutes was expressed as CI(0.95); 7.0±1.1, 6.8±1.1, 7.6±1.3, 7.4±1.1 ºC at the limbus of the exposed eye. The difference of light scattering in the lenses between exposed and contralateral not exposed eyes was 0.00±0.02, 0.01±0.03, -0.01±0.02, -0.01±0.03 tEDC, respectively and no apparent morphological changes in the lens were observed.An exposure to 96 W/cm2 1090 nm IRR projected on the cornea within the dilated pupil accumulating radiant exposures up to 344 kJ/cm2 does not induce cataract if the temperature rise at the limbus is below 8 °C. This is consistent with a thermal damage mechanism for IRR induced cataract.
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