Medical Hypothesis, Discovery & Innovation (MEHDI) Ophthalmology Journal
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Diabetic Retinopathy and Ehrlichia: the Possible Relationship
Full text linkIn the United States, 20,000 patients each year lose their sight from diabetic retinopathy. The cause has been attributed to a failure of control of glucose levels. Recent studies have challenged this, and have suggested that there is no evidence for a consistent glycemic threshold in various populations relating to the incidence of retinopathy. The Ehrlichia have been recently suggested as having a role in diabetes. The action of this obligate parasitic bacterium which often affects the cells involved in immunity has the potential of affecting various tissues randomly.   This includes self-reactive T or B cells which may be erroneously altered or released from the marrow because of infection of marrow precursors by an Ehrlichia. The discovery of a gene obtained by molecular methodology from a leukemia patient, has given us a tool to identify by molecular methods, the presence of this gene and assumed bacterium in the blood of patients with various syndromes that includes diabetes. Because of the inconsistent evidence of a uniform glycemic threshold in retinopathy and the failure of its control, this hypothesis raises the question of something else that might be causing this damage. The suspected bacterium in diabetes may have as a significant side effect of its infection of the immune system, specifically the site of action of damage to the small vessels of the retina which could lead to what is regularly described in retinopathy; further, and that may include damage to other vessels seen in peripheral and coronary arteries. The availability of a molecular test in whole blood specimens from diabetics suggests a survey for the gene of the bacterium described in diabetic patients and matched controls. Such an investigation could lead to other therapies directed against the bacterium's presence in the marrow if discovered, and strategies to eliminate the harmful self-reactive T or B cells, if found in diabetes
Collagen-Based Bioengineered Substitutes of Donor Corneal Allograft Implantation: Assessment and Hypotheses
Full text linkTo fabricate donor corneal substitutes based on carbodiimide cross-linked porcine collagen, to study their in vitro and in vivo properties, and to elaborate new implantation techniques for the donor corneal collagen-based substitutes, this study had been performed. Bioengineered substitutes of corneal stroma (BSCS) were fabricated by cross-linking porcine type I collagen with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide and N-hydroxysuccinimide, as previously described. Their refractive indices were measured using an Abbe refractometer. The mechanical properties were evaluated by their ability to tolerate interrupted stitches placed during deep lamellar keratoplasty performed on isolated rabbit eyes. BSCS were then implanted into one cornea of 8 rabbits and were followed-up for 12 months. Our BSCS had refractive indices of 1.24-1.3 (human cornea 1.37-1.38), and tolerated the placement of 12 interrupted stitches well. A new technique, the BSCS “stitchless†implantation, was developed. When implanted into rabbit corneas, BSCS remained stably integrated and clear during the 12 month follow-up. Non-intensive opacities within corneal layers (grade 1.5 on a scale of 0 to 4) were observed in 2/8 eyes during the 1st postoperative week, and in one eye the opacity resolved. In the 2nd eye a fine opacity (grade 1) remained. Light microscopy confirmed the integrity of the implants and the absence of inflammation in corneal stroma. The current data suggest that the BSCS fabricated in the Ukraine by cross-linking collagen is a good alternative to human donor corneas if medical grade porcine collagen is used. In addition, the new “stitchless†technique of BSCS implantation may decrease corneal substitute damage and accelerate its epithelialisation
Was Terson's Tersons?
Full text linkTerson’s syndrome has had multiple definitions. The original definition is unlikely to have included Terson’s original case. An updated definition based on mechanism is proposed and related to the original case described by Terson