Biomedical subjects
Publications and source records attributed to D J Doughman.
A culture proven case of bacterial endophthalmitis (alpha streptococci, not Group D, and coagulase-negative staphylococci) occurred in association with a vitreous wick 26 days following uncomplicated intracapsular cataract extraction. Despite intensive antibiotic therapy, the eye was lost to infection. Immediate surgical repair of vitreous wicks which communicate with the external ocular surface is recommended.
Fungal endophthalmitis developed in an elderly woman following penetrating keratoplasty with an organ-cultured cornea. An unsuccessful search was made for the source of the infection. Modification in our sterility checks prior to surgery were made in hopes of preventing future infections.
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We used the clinical specular microscope to examine the endothelium of 14 clear penetrating corneal grafts that ranged from 4 days to 2 1/2 years posttransplantation. All the donor corneas had been preserved in organ culture at 37 C for up to five weeks before grafting. Ten of the transplants were aphakic. The graft endothelial cell density, although less than that of normal corneas of the same age, was similar to that of other transplants done by the same two surgeons using alternate methods of donor preservation. We found a significant inverse correlation between graft endothelial cell density and the age of the corneal donor.
A family of ten individuals aged 18 months to 75 years had biomicroscopic findings consisting of large, amorphous, sheet-like opacifications of the posterior stroma and Descemet's membrane, and alterations of the endothelium. A uniform thinning of the cornea was present. These findings do not conform to previously described corneal dystrophies. The condition appears minimally progressive and the three-generation pedigree indicated an autosomal-dominant inheritance pattern.
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This report summarized the findings in 40 rabbit eyes undergoing extracapsular cataract extraction, 20 of which underwent intraocular lens implantation. The parameters of postoperative evaluation are shown to be limited by the susceptability of the rabbit cornea to corneal edema in the early postoperative phases. The only apparent parameter of statistical importance in this series, however, was the day at which the intraocular lens implanted eye returned to normal compared to the day that the non-implanted eye returned to normal. The fact that there is a 13-day difference in these eyes and the fact that this difference is statistically significant may be important. Pathologic examination of lens implanted eyes has shown that the surgical objectives of intracapsular loop fixation are quite feasible. Microscopic study also showed that there is minimal tissue response to the materials placed in the anterior chamber in this type of surgery.
The fixation of two-loop intraocular plastic lenses has been studied in the laboratory. Twenty rabbit eyes underwent extracapsular lens extraction and placement of plastic lens loops within the capsular remnants. Placement was successful in 25 of 40 (62.5%) attempts. The placement of intracapsular lens loops was studied histologically, and the structural alterations were seen to be minimal. There was virtually no cellular response to the implantation of the plastic lenses, even in the areas of tissue contact.
Circular freeze-thaw endothelial wounds were created on paired human corneas. Ultrastructural and physiological studies were performed after organ culture (OC) incubation at 37 C from 1 to 21 days as well as on fresh noncultured controls. As early as 24 hours after injury, OC corneas demonstrated ultrastructurally intact endothelial cells at the margin of the wound, elongating and sliding toward its center. All OC corneas were completely covered by ultrastructurally intact and physiologically functioning endothelial cells by seven days of OC. These cells were approximately twice normal size. Enlarged endothelial cells that maintained deturgescence function were seen in the wounded area after 14 and 21 days of OC. None of the fresh controls demonstrated deturgescence function and in none could ultrastructurally intact endothelial cells be found in the area of the wound. This confirms our hypothesis that during 37 C OC incubation, human corneal endothelium repairs defects in its layer by cells that are physiologically and ultrastructurally intact.
Macrophage migration inhibition factor (MIF), a soluble mediator of delayed hypersensitivity, was assayed for in the aqueous humor of rabbits undergoing corneal graft rejection. Penetrating and interlamellar xenografts and interlamellar allografts were performed in rabbits, and aqueous humor early in the course of xenograft and allograft rejection, and MIF activity was present during the course of the active rejection. This activity returned to near normal after the active rejection resolved. No significant MIF activity could be measured during the nonspecific inflammations produced by alkali burns, multiple paracenteses, intracorneal clove oil, mechanical debriding of the endothelium.
We examined the glucose metabolism and ultrastructure of human corneas stored for 11 to 37 days in organ culture using a modified Eagle's minimum essential medium. Changing the media twice weekly provided a stable pH of 7.22 to 7.28 but the glucose concentration of the media decreased from 110 mg/100 ml to 30 mg/100 ml, and lactate concentration increased from 7 mg/100 ml to 84 mg/100 ml before media replacement. The initial rate of glucose uptake and lactate release averaged 149 mug/hr and 95 mug/hr, respectively, and the rates decreased approximately 50% by day 12. The glucose uptake rate stabilized between 40 and 60% of the original rate to day 37, but the lactate release rate decreased again at day 25 from 64 to 25%. The lactate/glucose ratio averaged 65 to 82% during the first 25 days of organ culture and 33 to 53% from days 28 to 37. Electron microscopy revealed that the endothelium formed a complete monolayer of normal appearing cells covering Descemet's membrane. Intracytoplasmic deposition of glycogen granules was present in endothelial, stromal, and epithelial cells.
Human, chicken, and guineapig corneas organ cultured (O.C.) from 1 to 4 weeks were transplanted intralamellarly into rabbits. Chicken and guinea pid corneal xenografts O.C 3 to 4 weeks had statistically significant delayed rejection times reject. Histologically, O.C. xenografts with delayed rejection or nonrejection were hypocellular. Chicken xenografts O.C. 4 weeks in which recipient (autochthonous) rabbit serum replaced the calf serum routinely used in the media also had a significant delay in rejection time when compared to fresh controls or chicken xenografts stored in pooled (allogeneic) rabbit serum. The rejection time of human corneal xenografts O.C. FOR PERIODS UP TO 4 WEEKS WAS NOt delayed. These data suggest that in this model, prolonged survival of xenografts after O.C. is species specific and represents a form of immunological modification, possibly reduced antigenicity sedondary to donor hypocellularity.
A case of acrodermatitis enteropathica occurred with corneal changes consisting of linear subepithelial corneal opacities. From the results of histochemical and electronmicrographic studies on a biopsy specimen of the corneal lesion, no definite conclusion may be drawn as to whether the corneal changes are a manifestation of acrodermatitis enterophathica or a result of iodochlorhydroxyquin therapy.
The stroma and epithelium of human corneas that had been stored in organ culture medium for 10 to 22 days at 37 C were examined by light and electron microscopy. Total corneal thickness was found to be doubled at ten days and there was no further increase even at 22 days. The posterior portion of the stroma was more hydrated than the anterior region. Stromal cells were reduced in number and normal-appearing cells were present only in superficial stroma. The epithelial basement membrane was irregular and thickened. Although the epithelium was reduced to three or four cells in thickness and the intercellular spaces were dilated, the epithelial cells contained normal subcellular organelles and appeared to be viable.
Of 278 consecutive therapeutic soft lens wearers, 19 (6.8%) developed discrete lens opacities on the anterior (air) surface of the lens. The incidence rose to 16.6% in patients fitted for dry eye syndromes, to 19% in bullous keratopathy and to 20% in exposure keratitis and trichiasis, if worn for longer than 2 weeks. These opacities were not associated with medications. Scanning electron microscopy demonstrated cracks on the anterior lens surface associated with these opacities. Transmission electron microscopy demonstrated the opacities to be amorphous material with extensions of the contact lens polymer into the substance of these opacities. Lipid, as demonstrated by histochemical methods, was found in these opacities. It is likely that the combination of dryness, stress on the lens surface, and lipid deposition act to alter the structure of the plastic and cause these opacities.
Several immunologic tests were used to compare the soluble antigens of cultured and normal bovine corneas. Results of fluorescent-antibody tests on normal corneas confirmed our earlier observation that the epithelium contained little serum protein, and that stroma and epithelium shared an antigen not found in bovine serum. Immunoelectrophoresis, immunodiffusion, and fluorescent-antibody tests preformed on extracts prepared from normal and cultured corneas indicated that corneas absorbed serum proteins during the incubation period. We also noted that very little intact epithelium remained on corneas cultured in the presence of calf serum. The extract prepared from cultured corneas did not contain the strongly antigenic protein present in extracts of normal cornea or epithelium. The implications of these findings are discussed.
Sixty-three penetrating keratoplasties were performed in 63 patients using donor corneas stored by 37 C organ culture incubation for an average of 13 days (range 2 to 35 days). No grafts failed before four weeks, except one which was stored at 4 C for 48 hours prior to transplantation, indicating that endothelial viability is maintained when proper storage conditions are maintained. Sixteen grafts have failed as a result of factors other than the storage method. This clinical study confirms our previous laboratory conclusions that 37 C OC incubation up to 35 days improves the quality of donor endothelium compared with other methods of storage, and it represents a significant advance in corneal preservation.