Biomedical subjects
Publications and source records attributed to B Delbosc.
This study used peripheral human corneal epithelium in tissue culture. Cells were observed in cytology, histology and by immunofluorescence staining. This in vitro-system may provide a suitable model to study biocompatibility but also to collect free human corneal cells.
27 consecutive cases of non freeze myopic keratomileusis were performed on 22 patients in a retrospective study. 4 per operative complications were noted. Visual acuity with and without correction, keratometry, astigmatism, pachymetry, esthesiometry before and after surgery were reviewed at 1 week, 1 month, 3 months, 6 months and 1 year post operatively.
This study reports the clinical use of donor corneas stored at +37 degrees C in organ culture medium. Twenty-five penetrating keratoplasties were performed. The mean storage time of organ-cultured donor corneas was 12.3 days (3-21). The follow up of the patients was 12 months. The criteria for the survival of corneal grafts was mean central corneal thickness, clarity of the cornea and mean endothelial cell density. The graft survival was 92% at 12 months. The mean central corneal thicken was 0.54 mm. The mean endothelial cell density was 1625 cells/mm2. The mean decrease in endothelial cell density at 12 months was 40.6%.
A study of 36 penetrating keratoplasties using donor corneas stored at +37 degrees C in organ culture incubation for an average of 12 days prior to transplantation is reported. The criteria for the survival of corneal grafts were mean central corneal thickness, clarity of the cornea and mean endothelial cell density. A total of 86% of the grafts remained clear after 12 months follow-up time. The mean central corneal thickness was 0.47 mm. The mean endothelial cell density was 1452 cells/mm2. Based on the results of this study, organ culture reported here appears to be a safe and efficient method of medium to long-term corneal storage.
Authors have studied the penetration of ciprofloxacin in the aqueous humor of 30 patients (30 eyes). The concentration in the anterior chamber was on average 0.73 mg/l (33% of serum level), from 1.30 hours after a single oral dose (1000 mg) till the 5th hour after this dose. The samples were assessed by a microbiological method. These results are over the minimal inhibitory concentration for many bacterial agents found in endophthalmitis. So this antibiotic may be proposed in the treatment of endophthalmitis, with further investigations assessing the safety of this procedure.
A corneal endothelium staining technique is described which can be performed in a few minutes. The first step of this in vitro staining is atraumatic for the endothelium. The cell density and the number of dead cells are thus determined. The second step is a staining of nuclear and intercellular spaces with a fixation by ethanol. Which then permits an histological analysis. This method of the endothelium, as described, thus allows for the control of corneal button either before grafts or after preservation, as well as the analysis of corneal pathologies.
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Prospective evaluation of radial keratotomy was conducted on 300 surgeries. Group A recovered low myopia within -0.75 to -3.00 diopters (D) and group B extended from -3.25 to -9.00 D. Before surgery the mean spherical equivalent in the first group was -2.29 D and in the second -4.81 D. After 12 months, the average change in spherical equivalent was 2.19 D in the A group and 4.08 in the B group. After one year, the mean uncorrected visual acuity was above 20/25 in all cases of the first group and ranged from 20/30 to 20/25 in the second one. A discussion of the different predictive factors is presented as well as a statistical approach to each parameter.
The Opacity Lensmeter is a new instrument permitting the measurement of lens opacity. This preliminary report was performed on 98 patients (195 phakic eyes). Age, sex, lens opacity and retinal sensibility (using automated perimetry with the Octopus 2000 R) were assessed. A correlation between age and lens opacity was found in a simple linear regression model on 186 eyes (available data): opacity = 0.00423 square (age) + 5.18. An another more precise correlation was found in 138 eyes, excluding those with anterior segment abnormalities and corneal opacity: opacity = 0.0035 square (age) + 5.17. No statistical differences were observed between lens opacity and sex nor were left/right differences significant. No conclusion was possible concerning retinal sensibility and measured lens opacity because of the small sample (25 eyes). This easily handled instrument may be helpful in daily practice to evaluate opacity in lens pathology. Furthermore, it should be useful for the interpretation of the respective role of cataract and retinal damage in P.O.A.G. loss of retinal sensibility.
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The Octopus global analysis Program G1 was developed as a glaucoma program. It is the combination in a single program of: examination procedures, visual field assessment methods. The whole examination is carried out in three phases: the first phase measures 59 test locations in the central 30 degrees field. All locations are measured with the normal strategy. The local threshold is precisely determined to +/- 1 dB by the proven bracketing method. At the end of the first phase, the system automatically calculates the key values (visual field indices) for mean defect and loss variance. the second phase, which retests the same central field, starts from the threshold values measured during phase one. The additional indices corrected loss variance and short term fluctuation, are calculated. in the last phase 14 selected peripheral points between 30 and 60 degrees excentricity with particular emphasis on the superior and inferior nasal step are determined in a qualitative test. Visual field changes can be detected and categorized in three major groups: (Flammer and coll., 1985). 1. local defects or scotomas in varying depths and sizes. 2. diffused depression of the whole field. 3. Increased short-term. The original index called Corrected Loss Variance could determine an early defect before the existence of a light scotoma. Particularly, an increased Corrected Loss Variance indicates that the deviations are due to real scotomas and not just to scattering effects. The therapeutic decision could be more rational.
Using the methods of Doughman, Sperling and Pels 66 human corneas were preserved up to five weeks in a modified tissue culture medium at +37 degrees C. The organ culture medium consisted of the following ingredients: Dulbecco Iscov's medium, 2% fetal calf serum, penicillin 100 IU/ml, Streptomycin 0.5 mg/ml, and fungizone 5 mg/ml. After culture the corneal endothelium was examined by light microscopy after staining with trypan blue 0.3% and alizarin red 1%. The number of dead cells was counted and the morphological alterations were described at 7, 14, 21 and 35 days. Biochemical analysis of the medium (pH, lactate, glucose) during storage has allowed the comparison of three kinds of storage: 50 ml, 20 ml, and 20 ml with 10 ml substitution weekly. After culture the number of dead cells did not exceed 1% at each period indicating that no dead cell was present at that time. Alteration of the cell shape and formation of rosette and joint meetings of 5 to 8 cells were the dominating morphological changes of the endothelial cells. The endothelial layer was intact and coherent on to 35 days culture. Endothelial cells loses during culture were not determined. The biochemical studies have shown the better quality (pH stability, anaerobic ratio) of storage in 50 ml medium or 20 ml 50% weekly substitution medium. This last kind of storage has given the best metabolic conditions for the preserved corneas. However for long period of storage up to 3-4 weeks, renewing 50% of the medium is found appropriate. At the end of this study a clinical trial is proposed.
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