Biomedical subjects
Publications and source records attributed to M Unal.
It has been reported that many different viruses cause hepatitis. Amongst these the Epstein-Barr Virus can cause parenchymal lesions and hepatitis. In a study we examined 100 cases viral hepatitis with respect to age, sex and occupation of the patients. We tried to deduce the role of Epstein-Barr Virus (EBV) in this disease employing the Paul-Bunnell technique.
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PURPOSE: To report the outcome of a step-by-step treatment approach for congenital nasolacrimal duct obstruction (CNDO). METHODS: Three-hundred and fifty eyes with CNDO were included in the study. A number of treatment methods were applied systematically until a successful outcome was achieved. Listed in order from simple to more complex, the following methods were used: conservative management (massage and topical antibiotics), high-pressure syringing, probing, and silicone intubation. Treatment efficacy was determined according to age (Group 1: 0-6 months, Group 2: 7-12 months, Group 3: 13-24 months, Group 4: 25-72 months) and success rates were compared. RESULTS: Conservative management was applied only in children less than 1 year of age, and was successful in 91.8% of Group 1 and 60% of Group 2 eyes. The difference between these two success rates was significant (p = 0.003). High-pressure syringing was performed in children under 24 months of age, with success rates of 41.7% in Group 1, 33.3% in Group 2, and 12.5% in Group 3. The overall success rate for first probing in all groups was 76.1%, with a range of 69.4% to 80.9%. After second probing, the overall cure rate for the entire cohort was 88.0%, with a range of 74.9% to 94.8%. There was no real difference in probing cure rates relative to age (p > 0.05). Silicone intubation was indicated and performed in two eyes of Group 2 children, three eyes of Group 3, and nine eyes of Group 4. Two ducts in Group 4 eyes remained obstructed after silicone intubation. CONCLUSIONS: The systematic treatment approach to CNDO, including conservative management and minimally invasive procedures such as high-pressure syringing, probing, and silicone intubation, is highly successful. In this study, the cure rate for this combined approach was 100% in youngsters under 2 years of age and 94.5% in children 2 to 6 years old.
PURPOSE: To study the in vitro effect of silicone oil of different viscosities and liquid perfluorocarbons on platelet aggregation. METHODS: Silicone oil with a viscosity of 5700 cs and 1000 cs and liquid perfluorocarbons of perfluoroperhydrophenantren and perfluorodecaline were studied to investigate the effect of these agents on platelet aggregation under in vitro conditions. The experiments were performed by using platelet rich plasma with an aggregometer. Aggregation was induced with three different agonists, including 5"-adenosine diphosphate (ADP), epinephrine (EPI), and collagen (Col). The results were obtained as a percentage of maximal aggregation and compared with controls using Kruskal-Wallis one way analysis of variance test. RESULTS: The tests with ADP as aggregating agent revealed that the percentage of maximal aggregation was a mean of 72.66+/-3.51% for ADP only, 58.66+/-3.05% for silicone oil of 1000 cs, 62.66+/-2.08% for silicone oil of 5700 cs, 56.00+/-7.00% for perfluoroperhydrophenantren, and 52.3+/-3.1 % for perfluorodecaline. With EPI, aggregation was induced in all control samples with a mean of 76+/-9.54%. The mean percentage of maximal aggregation was 66.7+/-3.06 for silicone oil of 1000 cs, 72.33+/-5.5% for silicone oil of 5700 cs, 71.67+/-3.79% for perfluoroperhydrophenantren, and 70.33+/-2.52% for perfluorodecaline. With collagen, it was 86.67+/-1.53% for controls, 83.67+/-3.51% for silicone oil of 1000 cs, 85.33+/-4.51% for silicone oil of 5700 cs, 83.33+/-4.93% for perfluoroperhydrophenantren, and 81.33+/-4.16% for perfluorodecaline. Statistical analysis revealed no significant change in the percentage of maximal aggregation for all tested substances in the experiments. CONCLUSIONS: Silicone oil of different viscosities and perfluoroperhydrophenantren and perfluorodecaline have minimal antiaggregating effect on platelets. The level of effect is not statistically significant.
PURPOSE: To study the effect of Healon, Healon GV, Healon 5, Viscoat, and OcuCoat on platelet aggregation under in vitro conditions. METHODS: Ocular viscoelastic devices including Healon, Healon GV, Healon 5, Viscoat, and OcuCoat were studied to investigate the effect of these agents on platelet aggregation under in vitro conditions. The experiments were performed by using platelet-rich plasma with an aggregometer. Aggregation was induced with three different agonists including 5''-adeno-sinediphosphate (ADP), epinephrine (EPI), and collagen (Col ). The results were obtained as a percentage of maximal aggregation and compared with controls using one-way analysis of variance (ANOVA) test. RESULTS: The tests with ADP as aggregating agent revealed that the percentages of maximal aggregation were a mean of 75 +/- 4.35% for ADP only, 67 +/- 4.35% for Healon, 59.33 +/- 3.51% for Healon GV, 70 +/- 3% for Healon 5, 58 +/- 3.46% for Viscoat, and 64 +/- 2% for OcuCoat. Kruskal-Wallis one-way ANOVA test revealed no significant decrease in the percentage of maximal aggregation for all tested substances. With EPI, aggregation was induced in all control samples with a mean of 80.66 +/- 2.08%. The mean percentage of maximal aggregation was 67 +/- 3% for Healon, 77.66 +/- 4.04% for Healon GV, 77 +/- 4% for Healon 5, 80.6 +/- 4.04% for Viscoat, and 65 +/- 5% for OcuCoat. Statistical analysis showed no significant difference. With collagen, maximum aggregation was 74 +/- 5.29% for controls, 65 +/- 4.35% for Healon, 54 +/- 2% for Healon GV, 51 +/- 2.64% for Healon 5, 59 +/- 2% for Viscoat, and 72.66 +/- 1.52% for OcuCoat. Kruskal -Wallis one-way ANOVA test revealed no significant change in the percentage of maximal aggregation for all tested substances in the experiments. CONCLUSIONS: Ophthalmic viscosurgical devices like Healon, Healon GV, Healon 5, and Viscoat that contain glycosaminoglycans and OcuCoat that contains hydroxypropyl methylcellulose have inhibitory effects on platelet aggregation but the effect is not statistically significant and there is no difference among the ocular viscoelastic devices in regard to inhibitory effect on platelet aggregation.
PURPOSE: A pilot study was carried out to evaluate the practicality, reliability, and validity of an objective structured clinical examination (OSCE) for assessing the clinical skills and abilities of specialists in ophthalmology. METHODS: Ten unfolded OSCE style, criterion referenced questions were asked to nine candidates to assess their clinical skills and abilities, as opposed to subject knowledge. Candidate and assessor reactions to the examination process were monitored and analyzed using participant observation and questionnaires administered immediately after the event. Relevant statistical techniques were applied to the results. RESULTS: A total of 89% of candidates passed the examination, with the pass boundary set at 70%. Candidates revealed themselves more successful in meeting clinical skill criteria (mean 77%) than clinical ability criteria (mean 72%). Candidates, assessors, and observers all expressed the view that the OSCE pilot had been a successful way of assessing clinical skills and abilities. CONCLUSIONS: OSCE style assessment is an effective and efficient means of assessing skills and abilities in clinical ophthalmology education.
BACKGROUND AND OBJECTIVE: To evaluate fluorescence properties of mono-L-aspartyl chlorin e6 (NPe6; Meija Seika Kaisha, Ltd., Tokyo, Japan) photodynamic therapy, which allows real-time simultaneous imaging of choroidal and retinal vasculature during treatment without the addition of another dye. MATERIALS AND METHODS: Four pigmented rabbits, 4 pigmented rats, and 2 African green monkeys were administered intravenous injections of the NPe6 dye. The animals were immediately placed in front of the scanning laser ophthalmoscope and the fundus was viewed with the helium-neon laser. The resulting fluorescence was viewed and recorded on super-VHS videotape. RESULTS: Fluorescence demonstrated clearly that NPe6 entered the retinal and choroidal circulation within seconds of intravenous injection. The concentration of NPe6 was diminished over a period of 1.5 hours in the monkey and 5 hours in the rat, as evidenced by considerable diminution of the intensity of fluorescence. CONCLUSION: NPe6 fluorescence allows evaluation of drug availability within the retinal and choroidal circulation and visualization of pathological lesions before commencement of photodynamic therapy.
OBJECTIVE: To determine the threshold power levels for producing retinal and choroidal vascular occlusion using mono-L-aspartyl chlorin e6 (NPe6) photodynamic therapy; to evaluate its efficacy with longer intervals between photosensitizer injection and laser application; to determine the elapsed time between light application and appearance of angiographic changes. METHODS: Pigmented and nonpigmented rabbits were injected intravenously with 2 mg/kg of NPe6 before laser irradiation of the retina-choroid. Group 1 was treated at increasing power levels; fluorescein angiograms were obtained at each fluence. Group 2 animals were exposed to laser irradiation at 5 minutes, and 1 and 3 hours postinjection to determine (by fluorescein angiography 24 hours post-treatment) if increasing the interval affected outcome. Group 3 animals underwent fluorescein angiography at 30 minutes, 1 hour, 2 hours, and 24 hours posttreatment to document the time between laser application and subsequent vessel closure. RESULTS: Choroidal vessel occlusion was angiographically evident in all lesions at fluences of > or = 2.65 J/cm2 in pigmented rabbits and at > or = 0.88 J/cm2 in nonpigmented rabbits. Lesion diameter decreased as the time between injection and treatment increased. Vessel occlusion was documented at least 2 hours after treatment. CONCLUSION: Choroidal vessel occlusion can occur at very low fluence.
BACKGROUND AND OBJECTIVE: To determine the threshold fluence for producing choroidal and retinal vascular occlusion with mono-L-aspartyl chlorin e6 (NPe6) photodynamic therapy (PDT) during primary treatment and the effect of retreatment. METHODS: Primary treatment: Rats, rabbits, and monkeys underwent NPe6 PDT to determine the threshold fluences for choroidal and retinal vessel occlusion. The threshold was determined by analyzing fluorescein angiograms for areas of nonperfusion. Retreatment: Dutch-belted rabbits underwent NPe6 PDT followed by fluorescein angiography. Rabbits were retreated one week later at the same parameters. RESULTS: Fluence levels and vascular damage thresholds were always higher for retinal than for choroidal vascular occlusion. Retreatment caused choroidal vessel closure at all tested fluences but retinal capillaries closed only at a fluence > 17.7 J/cm2. CONCLUSION: NPe6 PDT has a lower threshold to occlude choroidal vessels than retinal vessels. The cumulative effect of retreatment does not damage retinal vessels unless the threshold is exceeded during a single retreatment session.