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Biomedical subjects

P Dureau

Publications and source records attributed to P Dureau.

34 records · Page 2Linked to original sources

[Characteristics of retinal detachment in children].

INTRODUCTION: Pediatric retinal detachments differ from adult retinal detachments in their etiologies, prognosis and treatment. The aims of this study were the analysis and long-term follow-up of a group of pediatric retinal detachment patients. PATIENTS AND METHODS: All the cases of juvenile retinal detachments treated in our department between 1987 and 1999 were retrospectively studied. The age at the time of diagnosis, etiology, initial topography of the detachment, treatments undertaken, follow-up, and final results were recorded. RESULTS: The study investigated 64 eyes of 53 children. The follow-up was longer than 6 months for 31 eyes, with a mean follow-up of 39.5 months. The main etiologies were traumatism, high myopia, and affections leading to an exudative retinal detachment such as retinoblastoma and Coats disease. Circular scleral buckling was often used because of the vitreous cohesiveness in children. A vitrectomy was frequently associated to treat severe proliferative vitreoretinopathy. The final visual acuity was higher than 0.05 in 32% of the cases. DISCUSSION: The etiological features, late diagnosis and frequency of proliferative vitreoretinopathy are responsible for the greater severity of retinal detachments in children. These factors associated with amblyopia lead to poor visual prognosis. CONCLUSION: Retinal detachment in children remains a severe pathology. However the prognosis seems to be improving with progress in examination techniques and surgery methods.

Adolescent↗

Quantitative analysis of subretinal injections in the rat.

BACKGROUND: Experimental therapeutic approaches to retinal degenerations often require the subretinal injection of a therapeutic agent. The injected volume and the age of the animal can influence the proportion of the retinal surface affected by the subretinal injection. We have investigated the quantitative effect of a single injection in the subretinal space. METHODS: Normal and Royal College of Surgeons rats aged 1 week, 3 weeks or 2 months received subretinal transscleral injections of 1, 3, 5 or 10 microl China ink. After 24 h, animals were killed, injected eyes were enucleated and fixated, and the retinas flattened. An image analyzing program was used to measure the total retinal surface and the retinal surface affected by the dye. RESULTS: The mean retinal surface affected by the injection ranged from 5.24+/-2.76 mm2 to 14.8+/-2.3 mm2, depending on animal age and injected volume. The injection affected 8.79+/-0.89 to 36.9+/-8.13% of total retinal surface. There was no statistically significant difference between normal and Royal College of Surgeons rats. Intravitreal leakage of the dye was more frequent with increasing injection volumes. CONCLUSION: The retinal surface affected by a single subretinal injection increases with the injected volume, but this increase is not proportional. Higher volumes lead to a loss of injected solution, either in the vitreous body or through the sclerotomy. In 2-month-old rats, a 3-microl subretinal injection appears to have the best reproducibility, with 20-30% of retinal surface covered by the injected dye.

Animals↗

PAX2 mutations in renal-coloboma syndrome: mutational hotspot and germline mosaicism.

The renal-coloboma syndrome (RCS, MIM 120330) is an autosomal dominant disorder caused by PAX2 gene mutations. We screened the entire coding sequence of the PAX2 gene for mutations in nine patients with RCS. We found five heterozygous PAX2 gene mutations: a dinucleotide insertion (2G) at position 619 in one sporadic RCS case, a single nucleotide insertion (619 + G) in three unrelated cases, and a single nucleotide deletion in a familial case. In this familial case, three affected sibs showed a striking ocular phenotypic variability. Each of the sibs carried a 619insG mutation, whilst unaffected parents did not, suggesting the presence of germline mosaicism. Interestingly, the 619insG mutation has been previously reported in several patients and is also responsible for the Pax21Neu mouse mutant, an animal model of human RCS. This study confirms the critical role of the PAX2 gene in human renal and ocular development. In addition, it emphasises the high variability of ocular defects associated with PAX2 mutations ranging from subtle optic disc anomalies to microphthalmia. Finally, the presence of PAX2 germline mosaicism highlights the difficulties associated with genetic counselling for PAX2 mutations.

Base Sequence↗

[Clinical features of gliomas of the chiasma. A retrospective study of a series of 18 patients].

Eighteen patients with a glioma of the chiasma were managed between 1980 and 1994. A retrospective analysis of this series showed that the most frequent functional ophthalmological signs were visual loss, nystagmus, or strabismus. Funduscopic examination was abnormal in 65%, mostly with optic atrophy. Other exams (visual field and electrophysiology) were inadequate for diagnosis. Our series demonstrated that early diagnosis of involvement of the chiasma could improve functional prognosis as rapid management can improve prognosis.

Adolescent↗

SHORT syndrome: a case with high hyperopia and astigmatism.

We describe a case of the SHORT syndrome and compare it with previously published cases. This six-year-old girl shows nearly all the typical manifestations reported in patients with the SHORT syndrome, including lipoatrophy, minor facial anomalies, Rieger anomaly, and short stature. However, she also suffers from high hyperopia and astigmatism associated with poor visual acuity.

Abnormalities, Multiple↗

[Persistence of the pupillary membrane. Apropos of 3 cases].

Persistent pupillary membrane has in most cases no functional consequence. Nevertheless, a thick membrane involving visual axis sometimes requires surgical removal. We describe three cases of this surgery with pathologic examination and functional results.

Child↗

[Deep sclerectomy in congenital glaucoma. Preliminary results].

PURPOSE: Trabeculectomy is an efficient procedure for congenital glaucoma, but can lead to postoperative complications. These complications seem to be less frequent with deep sclerectomy. The aim of this study is to evaluate results of this surgical technique for congenital glaucoma. MATERIALS AND METHODS: Twelve eyes from eight patients (age 2 to 84 months) with congenital glaucoma underwent sclerectomy and were followed-up for 10 months postoperatively. Success criteria was intraocular pressure inferior to 16 mm Hg under general anaesthesia. RESULTS: No per or immediate postoperative complication was observed. For nine eyes (75%), intraocular pressure was controlled at final examination. For three eyes, postoperative intraocular pressure was elevated and one of them underwent re-operation. CONCLUSIONS: Success rate of sclerectomy for congenital glaucoma is equivalent to trabeculectomy. Absence of anterior chamber opening diminishes postoperative complications risk. Further study with longer follow-up is currently under evaluation.

Anesthesia, General↗

Choroidal neovascularization complicating epiretinal membrane removal.

PURPOSE: Surgical removal of epiretinal membranes generally leads to anatomic and functional improvement. Main complications include cataract, retinal breaks and detachment. We describe the onset of a juxtafoveal choroidal neovascularization 2 years after surgery of an epiretinal membrane. METHODS: The neovascular membrane was treated by argon laser photocoagulation. RESULTS: Complete obliteration of the neovascularization was obtained resulting in functional improvement. CONCLUSIONS: Although rare, choroidal neovascularization as a complication of epiretinal membrane surgery must be suspected in case of poor visual outcome or relapse of symptoms.

Adult↗

[Extracapsular extraction and posterior chamber implantation in diabetics. Prospective study of 198 eyes].

PURPOSE: Visual results and retinal changes in diabetic patients who underwent cataract surgery. METHODS: In a prospective study we followed up 198 eyes of diabetic patients who underwent cataract surgery for at least six months postoperatively. Pre and postoperative retinal status were assessed by clinical examination and fluorescein angiography. Per and postoperative complications and the evolution of visual acuity were noted. RESULTS: In 83.3% of eyes, visual acuity improved by two or more lines. In 59.6% of patients, visual acuity at six months was more than 6/15. The quality of visual outcome diminished with the severity of retinopathy, but in the most serious cases, lens extraction allowed fundus observation and treatment. Inflammatory complications, posterior capsule opacification and cystoid macular oedema were significantly more frequent in cases of preoperative diabetic retinopathy than in normal fundus. We observed few aggravations of the diabetic retinopathy, but underline the high frequency of cystoid macular edema in diabetic patients. CONCLUSION: Visual results are good in diabetic patients with mild retinopathy and, in severe cases, surgery allows retinal examination and treatment.

Adult↗

Long term light-induced retinal degeneration in the miniature pig.

In developing a model of slow light-induced retinal degeneration, ten miniature pigs were submitted to constant lighting for a period ranging from one to three months. Post-lighting survival time ranged from zero to two months. Control and illuminated animals were examined for pupillary reflex, underwent fundus examination and an electroretinogram. After euthanasia, retinas were processed for histology with measure of outer nuclear layer thickness. All animals illuminated one or more months had pupillar reflex alteration. Mean outer nuclear thickness was 24.12 microns in the control and ranged from 18.36 to 21.45 microns in illuminated animals (mean reduction 20%). Despite the pigmentation of miniature pigs, consistent results were obtained in the absence of pharmacologic pupil dilation.

Animals↗

Fluid-regulating and sympathoadrenal hormonal responses to peak exercise following cardiac transplantation.

Orthotopic heart transplantation results in cardiac denervation that can disrupt the normal regulation of hydromineral balance. This study compared the exercise-induced variations in plasma osmolality; atrial natriuretic peptide (ANP), arginine vasopressin (AVP), norepinephrine (NE), epinephrine (E), and dopamine (DA) concentrations; and plasma renin activity (PRA) of six cardiac transplant recipients (HTX) and six healthy age-matched controls (C) submitted to graded upright maximal cycling. Venous blood samples were obtained at rest, at submaximal (70% O2 uptake) and peak exercise, and after 10 and 30 min of sitting recovery. Peak O2 uptake was not different between groups despite lower maximal heart rate in HTX (136 +/- 6 vs. 183 +/- 9 beats/min). Baseline plasma ANP and PRA were higher in HTX (203 +/- 55 pg/ml and 29.9 +/- 7.4 ng.ml-1 x h-1) than in C (71 +/- 17 pg/ml and 5.4 +/- 0.96 ng.ml-1 x h-1); AVP was lower in HTX than in C (1.1 +/- 0.3 vs. 3.2 +/- 0.8 pg/ml; P < 0.05); and circulating E, NE, and DA were not different between groups. Exercise resulted in more marked increases in HTX than in C for ANP (300 vs. 100%), AVP (2,000 vs. 300%), NE (860 vs. 500%), and DA (611 vs. 187%) but not for PRA and a higher E response in C than in HTX (455 vs. 1,258%). These observations confirm that the potential for ANP release to central volume loading is independent of intact cardiac innervation. The exaggerated AVP response in HTX could, however, reflect the absence of inhibitory influences consecutive to denervation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗

Long-term results of trabeculectomy for congenital glaucoma.

BACKGROUND: To evaluate long-term results of intraocular pressure after trabeculectomy for congenital glaucoma. METHODS: Data concerning 55 eyes (30 patients) who underwent trabeculectomy for congenital glaucoma were recorded. Mean age at diagnosis was 3.4 months (range: 2 days to 10 months). Mean follow up was 56.8 months. Associated anterior segment abnormalities, need for one or more new trabeculectomy procedures during follow up, and intraocular pressure at the last examination were noted. RESULTS: Of the 55 eyes, 48 met the success criteria (87.3%). A second and sometimes third or fourth trabeculectomy were necessary during follow up in 17 eyes (31%). Of the seven failures at final examination, six (85%) had been diagnosed and operated on before the age of 1 month, whereas 15 of the 48 eyes with good results (31.2%) were in this group (p < 0.02). Of the seven failures at final examination, six (85%) were operated on two to four times, whereas 10 of the 48 eyes with good results (20.1%) were in this group (p < 0.01). An associated anterior segment abnormality was present in 13 eyes (23%), and did not seem to influence the final outcome. CONCLUSION: Trabeculectomy is an effective procedure for long-term control of intraocular pressure in congenital glaucoma. The early diagnosis and surgical treatment correspond to a poor long-term prognosis, probably related to initially severe cases. In these cases, intraocular pressure is difficult to control despite repeated surgical procedures.

Chi-Square Distribution↗