Diameter Changes of Retinal Vessels During Hypoxia

Study Overview
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Brief Summary
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The primary objective is to study if an inhibition of nitric oxide and/or prostaglandins affect the diameter changes of retinal vessels observed during hypoxia. Diameter changes are studied using the Dynamic Vessel Analyzer.

Official Title
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Diameter Changes of Retinal Vessels During Hypoxia

Conditions
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Diabetes Mellitus Type 1, Diabetic Maculopathy

Intervention / Treatment
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* Other: COX inhibitor
* Other: L-NG-monomethyl arginine citrate
* Other: COX inhibitor + L-NG-monomethyl arginine citrate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diabetes type 1 without retinopathy Diabetic retinopathy Exclusion Criteria: Cardio-vascular disease Lung disease Pregnancy Previous ocular disease other than retinal branch vein occlusion Previous treatment with medications influencing on the intraocular pressure or the metabolism of nitric oxide or prostaglandins

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Hypoxia<br>Inhaling hypoxic gas mixture to induce hypoxemia during recordings of diameter changes of retinal vessels. Recording are performed during hypoxia alone and in combination with the associated interventions at two examination days. | Other: COX inhibitor<br>* Administration of 1 drop voltaren 45 minutes before recordings of diameter changes of retinal vessels are initiated<br>* Other names: Eye drops voltaren 1 mg/ml;Other: L-NG-monomethyl arginine citrate<br>* Intravenous administration of L-NMMA during recordings of diameter changes of retinal vessels<br>* Other names: L-NMMA;Other: COX inhibitor + L-NG-monomethyl arginine citrate<br>* Combination of interventions. Administration of an eye drop voltaren and 45 minutes later infusion with L-NMMA is started and recording of diameter changes of retinal vessels is performed<br>|
| Experimental: Normoxia<br>Breathing atmospheric air during recordings of diameter changes of retinal vessels. Recording are performed during normoxia alone and in combination with the associated interventions at two examination days. | Other: COX inhibitor<br>* Administration of 1 drop voltaren 45 minutes before recordings of diameter changes of retinal vessels are initiated<br>* Other names: Eye drops voltaren 1 mg/ml;Other: L-NG-monomethyl arginine citrate<br>* Intravenous administration of L-NMMA during recordings of diameter changes of retinal vessels<br>* Other names: L-NMMA;Other: COX inhibitor + L-NG-monomethyl arginine citrate<br>* Combination of interventions. Administration of an eye drop voltaren and 45 minutes later infusion with L-NMMA is started and recording of diameter changes of retinal vessels is performed<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diameter changes of retinal vessels | Comparing the differences of diameter changes occuring during each of the interventions. | Examination day 1 and 2 |