[Will refractive surgery replace glasses?].
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Eyeglasses↗
Biomedical subjects
G Renard
Publications and source records attributed to G Renard.
A novel variant of granular corneal dystrophy caused by association of 2 mutations in the TGFBI gene-R124L and DeltaT125-DeltaE126.
OBJECTIVE: To characterize the molecular defect in the TGFBI gene in a French family affected with an atypical granular corneal dystrophy. PATIENTS: This family comprises 9 affected individuals across 3 generations without consanguineous marriage. METHODS: Light and electron microscopy were used to examine corneal buttons from patients. Exons of the TGFBI gene were amplified by polymerase chain reaction and sequenced directly using an automated method. Restriction digestion analysis and heteroduplex screening were performed to confirm that the mutations identified were not polymorphisms. RESULTS: Round or snow-flakes-like deposits that stained red with Masson trichrome and appeared as dense, rod-shaped structures were observed in the most anterior layers of the central stroma. All patients were heterozygous for the R124L mutation and a novel mutation predicting the deletion of 2 amino acid residues-threonine (T) and glutamic acid (E)-at codons 125 and 126. CONCLUSIONS: This French family is affected with a novel variant of granular dystrophy that is caused by a molecular defect in the TGFBI gene, reported here for the first time. CLINICAL RELEVANCE: These 2 mutations cause a novel variant of granular dystrophy that is intermediate in severity between the classical and superficial variant forms. Arch Ophthalmol. 2000;118:814-818
Adult↗
Inhibition of lens epithelial cell proliferation by substituted PMMA intraocular lenses.
BACKGROUND: Migration and proliferation of lens epithelial cells (LECs) are based on interactions between cellular integrins and extracellular matrix proteins (ECMs). We were able to design polymers substituted with COO- and SO3- groups that counteract LEC proliferation through modification of the integrin/ECM interaction. The objective of this study was to compare the cell proliferation-inhibiting properties of differently substituted copolymers with those of a homopolymer. METHODS: Polymers were synthesized by radical polymerization and characterized by nuclear resonance spectroscopy. Second-passage rabbit LECs were cultured either on PMMA homopolymers (control) or on substituted PMMA copolymers. Cells were counted on days 2, 7, and 17. Cell vitality was evaluated by trypan blue staining. Experiments were run in quadruplicate. Statistical analysis was performed using the Wilcoxon test and the Mann-Whitney U-test. RESULTS: Compared with control, cells cultured on copolymers grew to significantly lower cell numbers. The inhibitory effect became evident at day 2 after seeding and persisted throughout the experiment. Different ratios of COO-/SO3- substitutions yielded different grades of inhibition. No toxic effect was seen on rabbit LECs. CONCLUSIONS: The tested copolymers inhibit cell proliferation and are nontoxic. Further evaluation could lead to the development of new intraocular lens materials that prevent secondary cataract.
Animals↗
The intrastromal corneal ring in clinical refractive surgery: reference to results in rabbit eyes.
BACKGROUND: The intrastromal corneal ring (ISR) is a refractive device recently introduced for clinical application that is implanted in the mid-peripheral corneal stroma in order to correct myopia without invasion of the central optical zone. First clinical results of intracorneal ring segment implantation were published recently. These results reveal striking similarities to our own experimental data, only briefly published up to now. The aim of this study is to present the refractive and histopathological data of ISR implants in rabbits and to compare these results with the clinical data actually available. METHODS: Expansion/constriction effects were evaluated with a ring of constant size (7.5 x 0.5 x 0.2 mm) in channels of 7.0, 7.5, or 8.0 mm in diameter, volume effects by implantation of 7.5-mm rings with varying thickness (0.2, 0.3, 0.4 mm) into a channel of 7.5 mm, respectively. Refractive power was measured preoperatively and at day (D) 7, D14, D30 for the first and the second experiment, plus D60, D90 for the second experiment. Histological evaluations of the induced morphological changes were additionally performed at all time intervals. RESULTS: Significant (P<0.05) flattening of the cornea was obtained in all but the first (constant ring, 7.0-mm channel) implants postoperatively at D7 and/or D14, with mean dioptric changes up to -5.03+/-2.92 compared with controls. However, from D30 on, there was no statistically significant difference between operated and control eyes. Biomicroscopy and histology of the implanted eyes revealed good biocompatibility, with only rare major complications such as stromal abscess or massive neovascularization. CONCLUSIONS: Although our implantation technique differs slightly from that employed in the recent FDA studies, our results tend to confirm the maximal achievable refractive change of about -5 dpt with this procedure. Furthermore, this study is the first to demonstrate that in rabbits, ISR implantation has only a shortterm effect on refractive power. Our results indicate that long-term refractive follow-up may be necessary in human eyes prior to the introduction of ISRs as a routine procedure in refractive surgery.
Animals↗
A new mutation (A546T) of the betaig-h3 gene responsible for a French lattice corneal dystrophy type IIIA.
PURPOSE: To characterize the betaig-h3 gene defect in a French family affected with lattice corneal dystrophy type IIIA (LCDIIIA). METHODS: Histologic examination was performed from corneal buttons of two patients. Genomic DNA was extracted from leukocytes, and exons of the betaig-h3 gene were amplified by polymerase chain reaction to be directly sequenced. RESULTS: Numerous deposits were evident in the stroma and beneath the Bowman membrane, which had all the features of amyloid deposits. Analysis of exon 12 revealed a heterozygous G to A transition on codon 546. CONCLUSION: In contrast to Japanese patients, these French patients affected with LCDIIIA carry a distinct mutation of the betaig-h3 gene (A546T instead of P501T). Therefore, it is unclear whether different mutations could result in the same dystrophy or whether we are dealing with clinical heterogeneity of LCDIIIA.
Adult↗
Clinical, histologic, and ultrastructural features of the corneal dystrophy caused by the R124L mutation of the BIGH3 gene.
OBJECTIVE: This study was designed to describe the clinical, histologic, and ultrastructural features of the corneal dystrophy associated with the R124L mutation of the BIGH3 gene. DESIGN: Retrospective clinical and histologic review of a new genetic mutation. PARTICIPANTS: Thirty-four patients from five unrelated French families with corneal dystrophy caused by the R124L mutation of the BIGH3 gene were studied at the clinical, histologic, and ultrastructural levels. Records of patients carrying this mutation were compared with those from three unrelated patients with corneal dystrophy of Bowman's layer (CDB) type 2 (R555Q mutation) and from three unrelated patients with classic corneal granular dystrophy (R555W mutation). INTERVENTION: The mutational genetic status of the BIGH3 gene was determined for each patient, and the histologic and ultrastructural data available after corneal graft were analyzed. MAIN OUTCOMES MEASURES: Genomic DNA was extracted from peripheral blood leukocytes. Exons 4 and 12 of the BIGH3 gene were amplified by the polymerase chain reaction (PCR), and the PCR products were directly sequenced. RESULTS: All 34 patients with the R124L mutation displayed the clinical, histologic, and electron microscopic features of the dystrophy previously described as a superficial variant of corneal granular dystrophy. Combining molecular genetics with clinical and histologic findings established a clear distinction between the R555Q and R555W dystrophies. CONCLUSIONS: The R124L mutation of the BIGH3 gene is associated with specific clinical and morphologic criteria. This indicates that molecular studies are needed for an adequate classification of corneal dystrophies. All criteria are presently available to segregate the dystrophy caused by the R124L mutation (known as CDB1) from the dystrophy caused by the R555Q mutation (known as CDB2).
Adult↗
Cloning and functional expression of a Boophilus microplus cathepsin L-like enzyme.
A cysteine proteinase gene homologous to cathepsins L genes was isolated from a B. microplus cDNA library. The precursor protein deduced from the nucleotide sequence contains 332 amino acid residues consisting of a signal sequence (pre-region), a pro-region and a mature proteinase. The DNA fragment coding for the proenzyme was cloned and expressed using the E. coli expression vector pMAL-p. The recombinant protein (MBP+PROCP) once activated is able to hydrolyze synthetic substrates as well as protein substrates like hemoglobin, vitellin and gelatin. Its optimal enzymatic activity on both fluorogenic and protein substrates was found to occur at an acidic pH. Expression of the proteinase gene was tested by RT-PCR with tick larvae RNA. Detection of amplified sequences indicates that the gene is expressed at this stage of the tick life cycle and the molecule is therefore potentially a target for chemotherapy or an immunogen in a vaccine.
Animals↗
Salzmann's corneal degeneration associated with epithelial basement membrane dystrophy.
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Adult↗
Persistent corneal opacity after oral isotretinoin therapy for acne.
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Acne Vulgaris↗
[Fragmentation of hydrogel episcleral implants: a series of 4 cases].
A histopathologic study was performed on 4 capsule specimens obtained after surgical removal of hydrogel episcleral implant previously sutured to the scleral surface aiming to reattach the retina. Fragments of hydrogel were found on the inner surface of the capsular fragments, each of them parts of the capsule, which coated the hydrogel implant on the scleral surface. Some fragments were surrounded with a foreign body giant cell granulomatous reaction. Changes in scleral curvature and scleral thinning were consequences of the buckling procedure. The hydrogel fragmentation previously observed in experimental and human specimens gave histologic evidence of degradation of this material after its implantation on the eye surface. This characteristic demonstrates the instability of the material after implantation.
Adult↗
[Lyell's syndrome and its ophthalmologic manifestations in Cameroon].
BACKGROUND: To study basic epidemiological datas and ocular involvment during toxic epidermal necrolysis (T.E.N.) in Cameroonian patients. METHODS: Ten consecutive patients in the Central Hospital of Yaounde were included during a 4 years period. Anamnesis, clinical features, dermatological, ophthalmological and pathological examinations were done. Minimal follow up of 3 months. RESULTS: Mean age: 20.1 +/- 11.4 yrs (SD); culprit drugs: sulfadoxin (5/10), sulfamethoxazol (3/10); phenytoin (1/10). Mean of skin detachment: 41 +/- 17%. 2 patients died with sulfadoxin as culprit drug. Early ocular findings: conjunctivitis (all patients), symblepharon (1/8), ankyloblepharon (3 patients over 8 with sulfadoxin as culprit drug). All cases with ankyloblepharon (3) evoluated toward formation of a fibrovascular precorneal membrane with blindness. Two of the patients received a kerothoprosthesis on one eye. The 3 patients had a severe dry eye syndrome. CONCLUSION: TEN appears to be uncommon in Cameroon. Use of sulfonamides for treatment and prevention of malaria and AID'S opportunistic infections may increase the incidence of disease in tropical african areas. Ophthalmologists should be aware of early management of ocular manifestations in Lyell syndrome to avoid severe sequelae. That sequelae may be due to usual intensive healing in African patients. Severe corneal damages can be corrected only by keratoprosthesis.
Adolescent↗
[Endonasal dacryocystorhinostomy (DCR) with protected drill].
PURPOSE: To analyze the interest of protected drills to perform endoscopic endonasal DCR. MATERIAL AND METHODS: [corrected] Fifty patients suffering from chronic epiphora were operated successively. None of those patients had had prior nasal surgery. The same surgeons (BF and ER) did the surgical procedure for all the cases. The technical steps were: endoscopic visualization of the middle meatus and evaluation of the anatomic variations of the nose; identification of the lacrymal bag with a 1 mm light in the canaliculus; unciformectomy; the maxillary bone was drilled with a 3.2 mm bit (straightshot Xomed), protected and irrigated; the lacrymal bag was opened by cissors and the flap was pushed in the ethmoid and coagulated. RESULTS: The suction-irrigation system was efficient to clean the surgical site, with a good endoscopic control. The protected bit didn't damage the 4-mm optics and the septal wall mucosa, even in narrow noses. The staightshot bit (Xomed) was tough enough to drill the maxillary bone in only 68 % of the surgical cases. In 28 % the drilling was unsatisfactory and in 4 % it was inefficient. The functional results at 6 month were good in 85 %. There was no difference between normal and narrow noses. CONCLUSION: The concept of protected bits perfectly matches the endoscopic endonasal DCR. The visual comfort and security of the surgical procedure are increased. Short term results are equivalent to external DCR, but are rather inefficient and expensive.
Chronic Disease↗
[Therapeutic photokeratectomy for the treatment of band keratopathy].
PURPOSE: This retrospective study was designed to investigate the therapeutic potential of phototherapeutic keratectomy (PTK) for the treatment of band keratopathy. PATIENTS AND METHODS: PTK was performed with the Excimed UV 200, (Summit Technology, Inc) on 27 eyes of 22 patients and with the Nidek EC5000 on 11 eyes of 10 patients with band keratopathy. Mean patient age was 57 years. The mean follow-up period was 19 months (ranged from 4 to 54 months). When possible, the change in best corrected visual acuity and spherical equivalent was evaluated at 6, 12, 18 and 24 months. RESULTS: Almost 90% of patients with smooth bands achieved visual improvement and 85% of patients with rough bands improved ocular discomfort. The mean hyperopic shift caused by tissue ablation was less than +2.0D after one year, for smooth bands. CONCLUSION: Excimer laser PTK is a safe and effective outpatient treatment and should be used as initial treatment for band keratopathy.
Corneal Diseases↗
[Xeroderma pigmentosum and its ocular manifestations. The first case in Cameroon].
We report a case of xeroderma pigmentosum in a 9-year-old back Cameroonian boy. The diagnosis was based on typical clinical presentation of the disease: cutaneous atrophy, hypepigmented macules, and areas of depigmentation on sun exposed regions of the skin. Multiple tumoral lesions were localized on the head. Ocular findings were also present: conjunctival hyperemia, peripheral corneal opacification. Excision of the tumors and potoprotection was proposed for this patient. The role of tribal black African marriage traditions in disease transmission is discussed.
Atrophy↗
[Choroidal melanoma. An anatomic-clinical case report].
A 78-year-old-male-patient had his left eye affected by a 10 mm thick choroidal malignant melanoma. The size of the tumor did not allowed to keep the eye, and no conservative treatment was used for therapy. Enucleation was performed and histopathological study of the eye showed a mushroom-shaped and mixed-cell choroidal melanoma, devoid of transcleral extension, but harboring intrascleral infiltration. A period of 2 year-follow-up without metastasis was observed since the removal of the tumoral eye.
Aged↗
[Residual left orbital phlebolith. An anatomic-clinical observation].
A 29-year-old female patient displayed a dense and hard left orbital mass, inferiorly, 3 years after she was treated through a neurosurgical approach for a left orbital varix. The lesion was hyperdense on CT-scan and was removed through a trans-conjunctival approach, with an excellent result. The histological diagnosis was a phlebolith.
Adult↗
[Giant basal cell carcinoma of the eyelid in a black patient from Cameroon].
Basal cell carcinoma of the skin is the most common human cancer. It is also the most frequent malignant tumor of the eyelid. In Europe, its most common clinical presentation is a hard indurated, and sometimes ulcerated nodule. The authors report a giant palpebral basal cell carcinoma in a black non albinos Cameroonian patient. The ethnic origin, localization and macroscopic aspect are discussed. The problems connected with diagnosis and treatment of malignant tumors in Africa are noted.
Cameroon↗
[Unusual preseptal location of an orbital cavernous hemangioma in African patient].
Cavernous hemangioma is the most common primary vascular orbital tumor in adults. Generally the benign tumor arises within the muscle cone, revealed by proptosis with choroidal folds, and more rarely develops in other orbital localizations. We report the case of a 42-year-old female African patient who had a cavernous hemangioma in an unusual anterior localization. Clinically, a small superficial tumor was palpated in the right superior nasal orbital angle. After complete surgical excision, the histopathological study established the diagnosis of cavernous hemangioma
Adult↗