PubMed Health⌕ Search

Biomedical subjects

J Ben-nun

Publications and source records attributed to J Ben-nun.

5 recordsLinked to original sources
PubMed2002

In search of better control for diabetes.

Diabetes mellitus is by far the most ubiquitous microvasculopathy. The pathogenesis is reflected by reduced capillary perfusion, tissue ischemia (according to the pattern of capillary damage) and the consequential structural and functional damage. The current treatment is based on blood sugar control within accepted 'normal' levels. Adjustments to the treatment are made by clinical assessment of the accumulated damage to the patient's various organs, related to his last check-up. This strategy of 'damage-assessment' has been the cornerstone of medical practice in this field since the discovery of insulin. Modern imaging technology enabled real-time quantitative assessment of the blood cell flow in individual retinal capillaries in animals. Using such technologies in diabetic patients, the capillary blood flow disturbances, prior to the development of irreversible damage, might be recognized and understood. Such knowledge will enable the design of more sensible 'damage-preventing' treatment strategies for these patients.

Animals↗
PubMed2001

Cornea sparing by endoscopically guided vitreoretinal surgery.

PURPOSE: To report a series of eyes with acute severe corneal edema and vitreoretinal complications treated with endoscopic vitreous surgery without a keratoprosthesis to the cornea. DESIGN: Retrospective, small, noncomparative case series. PARTICIPANTS: Seven patients with unilateral acute severe corneal edema, poor view of the fundus, and vitreoretinal complications were reviewed. Five eyes were postcataract surgery, one eye was postpenetrating intraocular blunt trauma by a ferrous foreign body, and one eye had endophthalmitis. INTERVENTION: Vitreous surgery was performed on each eye under the guidance of endoscopy. Topical steroid treatment was administered to the cornea for several weeks after the vitreoretinal surgery, until the corneal edema had been completely resolved. MAIN OUTCOME MEASURES AND RESULTS: The edematous corneas recovered within an average of 9 weeks (range, 6-13 weeks). The preoperative visual acuity ranged from 6/90 to hand motion at 0.5 m, and the final postoperative visual acuity was 6/30 or better after an average follow-up of 14 months (range, 3-23 months). CONCLUSIONS: (1) Endoscopic surgery for vitreoretinal complications in eyes with acute severe corneal edema can obviate keratoprosthesis and keratoplasty. (2) By minimizing further damage to the corneal endothelium, endoscopic vitreoretinal surgery might benefit corneal recovery.

Acute Disease↗
PubMed1996

Comparative flow velocity of erythrocytes and leukocytes in feline retinal capillaries.

PURPOSE: To study the flow velocity of erythrocytes and leukocytes in the same retinal capillaries in cat eyes. METHODS: Blood cells from cats were stained with fluorescent label and reinjected into the animals. An electro-optical device combined with a highly sensitive CCD camera detected the fluorescent signal from the labeled blood cells. The signal was stored on a videotape (VHS-PAL, 25 frames per second) and later analyzed digitally. Twenty leukocytes were identified, each flowing through a separate retinal capillary pathway. The capillary pathways were categorized as simple and complex according to their morphologic complexity. Observations were made on 10 simple and 10 complex capillary pathways. The passages of one leukocyte and 20 erythrocytes in each capillary path were recorded and analyzed. The blood cell velocity ratio was calculated from the number of frames needed for each cell to complete a passage through the capillary pathway (higher velocity = fewer frames). RESULTS: The erythrocytes traveled faster than the leukocytes in both the short and long capillary pathways. The frames ratio (mean percent +/- standard deviation) of erythrocyte-leukocyte passage in the same capillary pathway was 84.55% +/- 2.0% in the short ones and 66.21% +/- 7.1% in the complex ones. The main deceleration in leukocytes flow was noted in the looping parts of the complex capillary pathways. CONCLUSIONS: The velocity of leukocytes is slower than that of erythrocytes in a given retinal capillary pathway. The structural complexity of a capillary pathway has a greater effect on leukocytic velocity than on erythrocytic velocity.

Animals↗
PubMed1992

Flow patterns of blood cells in the retinal capillaries. Retinal capillary flow patterns.

We present a new technique for retinal blood cell angiography which was used to investigate flow patterns of blood cells in the retinal capillary net of normal cats. Capillary paths were defined to be the path taken by the labelled blood cells from the terminal arteriole to the entry point into a collecting venule. We were able to define two types of capillary paths. The 'simple' paths were minimally coiled and had a high blood cell flux. The 'complex' paths were coiled, structurally complex and had a low blood cell flux in comparison to the simple paths of the same eye. A simultaneous fluorescein angiogram was performed to reveal the complete anatomy of the capillary net in which the functional paths exist. The possibility that such flow patterns exist in the human retina should be considered.

Animals↗