Biomedical subjects

J L Dufier

Publications and source records attributed to J L Dufier.

At least 19 recordsLinked to original sources

PubMed2006

[Congenital cataract: general review].

Cataract is a loss of lens transparency because of a protein alteration. Etiopathogenesis is poorly understood but new mutations of different developmental genes involved are found in 25% of cases. Frequency of onset, particularly when different ocular development anomalies occur, is related to the lens induction phenomena on the eye's anterior segment structure during embryologic development. Genetic transmission is often found on the dominant autosomal mode. Diagnosis is based on a complete and detailed examination of the eye, often with general anaesthesia. This condition predisposes children to later, sometimes serious amblyopia. Different clinical aspects can be observed: from cataract with ocular and/or systemic anomalies to polymalformative syndrome, skeletal, dermatological, neurological, metabolic, and genetic or chromosomal diseases. A general systematic pediatric examination is necessary. Congenital cataract requires first and foremost early diagnosis and a search for all etiologies. Surgical treatment is adapted case by case but it has progressed with the quality of today's intraocular lenses even if systematic implantation continues to be debated. Life-long monitoring is absolutely necessary.

Cataract↗

PubMed2002

Use of denaturing HPLC and automated sequencing to screen the VMD2 gene for mutations associated with Best's vitelliform macular dystrophy.

We identified three novel VMD2 mutations in patients with Best's macular dystrophy. DHPLC analysis of the 11 VMD2 exons revealed abnormal profiles in exon 8. Direct sequencing showed that these abnormal profiles were due to monoallelic transitions and transversions. We also found three polymorphic sequence changes that have been reported previously and annotated to an online database (http://www.uni-wuerzburg.de/humangenetics/vmd2.html).

Bestrophins↗

PubMed2002

[Congenital megalocornea].

Congenital megalocornea is a bilateral enlargement of the cornea's diameter that can be associated with trabecula and/or iris dysgenesis. This condition predisposes the patient to glaucoma. The physiopathology is poorly understood and may be related to lens induction during embryological development of the anterior of the eye. X-linked genetic transmission is found in 50% of cases, autosomal transmission in 40%, and sporadic transmission in the remaining 10%. Diagnosis is based on a thorough examination of the child's eye, often with general anesthesia. Different clinical aspects can be observed: simple megalocornea without ocular or systemic anomalies, megalocornea with ocular and/or systemic anomalies as well as multiple malformation syndromes, dermatological diseases, skeletal diseases, and genetic or chromosomic diseases. A systematic general pediatric examination is therefore necessary. Congenital megalocornea must be considered, first of all, as a differential diagnosis of primary congenital glaucoma and all of its etiologies. Treatment of associated ocular diseases, the search for an association with systemic diseases, and follow-up for the rest of the patient's life are indispensable.

Child, Preschool↗

PubMed2001

[Leber's optic neuropathy].

Leber hereditary optic neuropathy is associated to mutations of the mitochondrial DNA that seem to be pathogenic of this disease. However, other genetic or environmental factors must play a role in the development of this optic atrophy. Leber hereditary optic neuropathy is usually isolated. Its typical clinical feature includes in a young man a sudden and severe decrease of vision of one eye. The second eye is affected few weeks later. But, atypical feature can be observed. Thus, this diagnosis must be suspected as soon as there is no evident aetiology for an optic neuropathy, whatever the clinical feature, the age or the sex of the patient can be. There is no treatment. But visual recovery can spontaneously occurred even years after the disease appearance.

Adult↗

PubMed2001

Mutation analysis of the tyrosinase gene in oculocutaneous albinism.

Type I oculocutaneous albinism (OCA) is an autosomal recessive disorder caused by the reduction or the absence of tyrosinase (TYR) activity in melanocytes of the skin, hair and eyes. Here we report an analysis of 45 patients with OCA. We found five novel mutations in the tyrosinase gene involved in the pathogenesis of oculocutaneous albinism type IA or type IB (OCA-1A/B) in five unrelated patients. Three mutations are missense mutations (G109R, P205T and H256Y) and two are nucleotide deletions (336-337delCA and 678-680delAGG). One patient is homozygous for the previously known V275F mutation but has an extremely mild OCA phenotype and has no eye features typical of OCA. In several patients we discovered only one or even no mutation in the coding sequence of the TYR gene. Thus, this disease may also result from mutations in non coding regions of the gene or in another gene involved in the biosynthesis of melanin. Hum Mutat 17:352, 2001.

Albinism↗

PubMed2001

Identification of novel VMD2 gene mutations in patients with best vitelliform macular dystrophy.

ABSTRACT We report five novel VMD2 mutations in Best's macular dystrophy patients (S16F, I73N, R92H, V235L, and N296S). An SSCP analysis of the VMD2 11 exons revealed electrophoretic mobility shifts exclusively in exons 2, 3, 4, 6 and 8. Direct sequencing indicated that these shifts are caused by mono-allelic transition in exons 2, 4, 6, 8 and transversion in exons 3 and 6. Five novel "silent" polymorphisms are also reported: 213T>C, 323C>A, 1514A>G, 1661C>T, and 1712T>C. Hum Mutat 17:235, 2001.

Base Sequence↗

PubMed2001

Renal coloboma syndrome.

OBJECTIVE: To characterize the ocular features of renal coloboma syndrome. DESIGN: Prospective, observational case series. PARTICIPANTS: Twelve patients referred by the pediatric nephrology clinic and the ophthalmic records of five additional patients. METHODS: For each patient, age at the time of examination, gender, renal function, and presence of a mutation in the PAX2 gene were noted. All patients underwent measurement of visual acuity and anterior and posterior segment examination with fundus photography. Goldmann visual fields were tested in four cases. MAIN OUTCOME MEASURES: Visual acuity, optic disc abnormalities, and mutation in the PAX2 gene. RESULTS: Mean age was 21.5 years. Renal failure was mild in 6 patients and severe in 11 patients. A mutation in the PAX2 gene was identified in nine patients, without correlation to the ocular phenotype. Ocular features could be divided into five groups: optic disc dysplasia limited to an unusual pattern of retinal vessels without functional consequence; optic disc pit with normal visual acuity and blind spot enlargement; large optic disc coloboma; large coloboma of the optic disc and adjacent retina; morning glory anomaly (these last three conditions were accompanied by poor visual acuity). Fundus abnormalities were symmetrical in most cases and unrelated to renal status. CONCLUSIONS: Ophthalmic and renal characteristics of the renal coloboma syndrome are highly variable. The need for dialysis or renal transplantation can occur early in life or several years later. A wide range of ocular abnormalities located in the posterior segment can be observed. Mild optic disc dysplasia or pit have no functional consequence and can be underdiagnosed. More severe colobomas or related abnormalities, such as morning glory anomaly, often lead to poor visual acuity. Molecular biology allows detection of the mutations in the PAX2 gene, but can be negative in approximately 50% of cases. The observation of an optic disc coloboma or related abnormality stimulates the ophthalmologist to propose simple nephrologic investigations to check for renal hypoplasia, a potentially life-threatening disease. Conversely, renal hypoplasia stimulates the nephrologist to ask for a fundus examination to confirm the diagnosis and check for complications such as retinal detachment.

Abnormalities, Multiple↗

PubMed2001

Complete exon-intron structure of the RPGR-interacting protein (RPGRIP1) gene allows the identification of mutations underlying Leber congenital amaurosis.

Leber congenital amaurosis (LCA) is a genetically heterogeneous autosomal recessive condition responsible for congenital blindness or greatly impaired vision since birth. So far, six LCA loci have been mapped but only 4 out of 6 genes have been identified. A genome-wide screen for homozygosity was conducted in seven consanguineous families unlinked to any of the six LCA loci. Evidence for homozygosity was found in two of these seven families at the 14q11 chromosomal region. Two retinal specific candidate genes were known to map to this region, namely the neural retina leucine zipper (NRL) and the retinitis pigmentosa GTPase regulator interacting protein (RPGRIP1). No mutation of the NRL gene was found in any of the two families. Thus, we determined the complete exon-intron structure of the RPGRIP1 gene. RPGRIP1 encompasses 24 coding exons, nine of which are first described here with their corresponding exon-intron boundaries. The screening of the gene in the two families consistent with linkage to chromosome 14q11 allowed the identification of a homozygous null mutation and a homozygous missense mutation, respectively. Further screening of LCA patients unlinked to any of the four already identified LCA genes (n=86) identified seven additional mutations in six of them. In total, eight distinct mutations (5 out of 8 truncating) in 8/93 patients were found. So far this gene accounts for eight out of 142 LCA cases in our series (5.6%).

Amino Acid Sequence↗

PubMed2001

Quantitative analysis of intravitreal injections in the rat.

Intravitreal injections are currently used in the rat to introduce a therapeutic factor in the eye, especially for experimental treatments of retinal degenerations. The injected volume and its location can influence the quantification of results. We have investigated the quantitative effect of a single intravitreal injection in rats at different ages and for different volumes. Albinos rats aged three weeks or two months received intravitreal injections of 1, 3, 5 or 10 microl China ink. Animals were sacrificed immediately after injection, eyes were enucleated, fixated, embedded in paraffin and microtomy was performed in a sagittal plane. Regularly spaced sections were analyzed to reconstruct the vitreous and injected dye volumes. The measured vitreous volume was 6.76 +/- 0.37 mm(3) in three weeks old rats and 13.36 +/- 0.64 mm(3) in two months old rats. Mean intravitreal ink volumes immediately after injection were 0.8 mm(3) for 1 ml injections, 2 mm( 3) for 3 ml, 2.3 to 2.6 mm(3) for 5 microl and 3.2 mm(3 ) for 10 microl. The percentage of vitreous volume involved by the injection ranged from 4.4% to 33.2%. The injected volume is limited by the large lens size of the rat. Extraocular loss of injected solution increases for higher injected volumes, with larger standard deviations. In this model, the dye tends to localize behind the lens. A 3 or 5 microl volume appears to have the best reproducibility with minimum loss of solution.

Aging↗

PubMed2001

Prominent beta-5 gene expression in the cardiovascular system and in the cartilaginous primordiae of the skeleton during mouse development.

The alpha v beta (alpha(v)beta5) heterodimer has been implicated in many biological functions, including angiogenesis. We report the beta5 gene expression pattern in embryonic and foetal mouse tissues as determined by Northern blotting and in situ hybridization. During the earliest stages, beta5 mRNA is widespread in the mesoderm. During later developmental stages, it remains mostly confined to tissues of mesodermal origin, although probable inductive effects trigger shifts of beta5 gene expression from some mesenchymatous to epithelial structures. This was observed in the teeth, skin, kidneys, and gut. Of physiological importance is the beta5 labeling in the developing cardiovascular and respiratory systems and cartilages. Furthermore, early beta5 gene expression was observed within the intra- and extraembryonic sites of hematopoiesis. This suggests a major role for beta5 in the hematopoietic and angiogenic stem cells and thus in the development of the vascular system. Later, the beta5 gene was expressed in endothelial cells of the vessels developing both by angiogenesis and vasculogenesis in the lung, heart, and kidneys. Moreover, the beta5 hybridization signal was detected in developing cartilages but not in ossified or ossifying bones. beta5-Integrin is a key integrin involved in angiogenesis, vasculogenesis, hematopoiesis, and bone formation.

Animals↗

PubMed2001

[Benign childhood intracranial hypertension].

INTRODUCTION: Infrequent in children, benign intracranial hypertension (or pseudotumor cerebri) is most often observed in adults. Careful diagnosis requires eliminating all the other etiologies of intracranial hypertension. Most often medical, its treatment must be rapid to avoid permanent visual loss. However, a surgical procedure is necessary when vision is threatened. We present our experience with this pathology and discuss its clinical aspects, its etiologies, and the physiopathological mechanisms. PATIENTS AND METHODS: We conducted a retrospective study on children who presented benign intracranial hypertension confirmed by neuroradiological and neurosurgical examinations. These examinations also served to specify the responsible etiologies. The ophthalmologic examinations, adapted to the child's age and clinical status, included visual acuity testing, optic disc evaluation, ocular motility testing, and visual field evaluation. Progression of visual acuity and the topic disc was analyzed after treatment. RESULTS: The diagnosis of benign intracranial hypertension was confirmed in 22 children (12 boys and 10 girls). Clinical presentation included headache and visual disturbance such as visual loss and oculomotor nerve palsy. Papilledema was present in nearly all cases. Medical treatment was successful in 7 children; however, the remaining 15 patients required a lumboperitoneal shunt because of elevated intracranial pressure, no response to the medical therapy, or threatened vision. DISCUSSION: The physiopathological mechanisms of benign intracranial hypertension, an uncommon condition in children, are still unclear. It can be associated with severe visual loss. All other intracranial or medullary expansive lesions should be eliminated before diagnosis. The causes of this syndrome are not the same for pediatric and adult patients. Although medical therapy is usually sufficient to normalize the intracranial pressure, a lumboperitoneal shunt is at times required. The role of the ophthalmologist is important in detecting a possible visual loss or papilla abnormality and in ensuring proper treatment follow-up. CONCLUSION: Ophtalmologists are involved in the detection of pseudotumor cerebri and the monitoring of visual function, an important element in evaluating treatment efficacy.

Adolescent↗

PubMed2001

[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↗

PubMed2000

Ocular cell transfection with the human basic fibroblast growth factor gene delays photoreceptor cell degeneration in RCS rats.

Based on the K8/JTS-1-mediated transfection technique, we developed an in vivo protocol for an efficient transfer of plasmid DNA to ocular cells. As determined with condensed plasmids containing reporter genes for either beta-galactosidase (pcDNA-lacZ) or enhanced green fluorescent protein (pREP-EGFP), the immortalized human retinal epithelial cells RPE D407 and human embryonic kidney 293 cells can be transfected with typical efficiencies of 11 and 19%, respectively. Unlike 293 cells, RPE D407 cells had a reduced viability on transfection with both plasmids. In vivo, subretinal injections of DNA-K8/JTS-1 complexes revealed reporter gene expression in choroidal and RPE cells of normal pink-eyed Royal College of Surgeons (RCS) rats. The validity of this transfection technique in terms of retinal cell survival in RCS rats was then examined by using pREP-hFGF2 plasmid, which encodes the human basic fibroblast growth factor isoforms (hFGF2). Subretinal injection of pREP-hFGF2-K8/JTS-1 complexes into 3-week-old dystrophic RCS rat eyes reveals a delayed photoreceptor cell degeneration 60 days postinjection. In this case, the average analyzed field points with delayed cell dystrophy represent 14 to 17% of the retinal surface as compared with 2.6 and 4% in pREP5beta and vehicle-injected eyes, respectively. Peptide-mediated in oculo transfection thus appears to be a promising technique for the treatment of retinal cell and photoreceptor degenerations.

Animals↗

PubMed2000

Chronic infantile neurological cutaneous and articular/neonatal onset multisystem inflammatory disease syndrome: ocular manifestations in a recently recognized chronic inflammatory disease of childhood.

OBJECTIVE: To report on the ocular manifestations of the Chronic Infantile Neurological Cutaneous and Articular/Neonatal Onset Multisystem Inflammatory Disease (CINCA/NOMID) syndrome, a rare, recently identified, pediatric multisystem inflammatory disease with chronic cutaneous, neurological, and articular manifestations. DESIGN: Descriptive case-report study. SETTING: International collaborative study based on a questionnaire. RESULTS: We included 31 patients. The mean age at onset of eye manifestations was 4.5 years. Optic disc changes were the most common feature, occurring in 26 patients (83%), including optic disc edema, pseudopapilledema, and optic atrophy. Anterior segment manifestations varying from mild to severe were seen in 13 patients (42%); chronic anterior uveitis, in 17 patients (55%). Moderate to severe visual acuity loss in at least 1 eye was seen in 8 patients (26%) as a consequence of the disease. Posterior synechia, glaucoma, and white iritis were not observed in any patient. CONCLUSION: Ocular manifestations with potentially sight-threatening complications occur commonly in the CINCA/NOMID syndrome. The distinctive nature of these complications may assist the ophthalmologist in recognizing this rare disorder and distinguishing it from juvenile rheumatoid arthritis.

Abnormalities, Multiple↗

PubMed2000

Homozygous deletion in the coding sequence of the c-mer gene in RCS rats unravels general mechanisms of physiological cell adhesion and apoptosis.

The RCS rat presents an autosomal recessive retinal pigment epithelium dystrophy characterized by the outer segments of photoreceptors being phagocytosis-deficient. A systematic genetic study allowed us to restrict the interval containing the rdy locus to that between the markers D3Mit13 and D3Rat256. We report the chromosomal localization of the rat c-mer gene in the cytogenetic bands 3q35-36, based on genetic analysis and radiation hybrid mapping. Using a systematic biocomputing analysis, we identified two strong related candidate genes encoding protein tyrosine kinase receptors of the AXL subfamily. The comparison of their expression patterns in human and mice tissues suggested that the c-mer gene was the best gene to screen for mutations. RCS rdy- and RCS rdy+ cDNAs were sequenced. The RCS rdy- cDNAs carried a significant deletion in the 5' part of the coding sequence of the c-mer gene resulting in a shortened aberrant transcript encoding a 20 amino acid peptide. The c-mer gene contains characteristic motifs of neural cell adhesion. A ligand of the c-mer receptor, Gas6, exhibits antiapoptotic properties.

Amino Acid Sequence↗

PubMed2000

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↗

PubMed2000

Spectrum of retGC1 mutations in Leber's congenital amaurosis.

Leber's congenital amaurosis (LCA) is the earliest and most severe form of all inherited retinal dystrophies responsible for congenital blindness. Genetic heterogeneity of LCA has been suspected since the report by Waardenburg of normal children born to affected parents. In 1995 we localised the first disease causing gene, LCA1, to chromosome 17p13 and confirmed the genetic heterogeneity. In 1996 we ascribed LCA1 to mutations in the photoreceptor-specific guanylate cyclase gene (retGC1). Here, we report on the screening of the whole coding sequence of the retGC1 gene in 118 patients affected with LCA. We found 22 different mutations in 24 unrelated families originating from various countries of the world. It is worth noting that all retGC1 mutations consistently caused congenital cone-rod dystrophy in our series, confirming the previous genotype-phenotype correlations we were able to establish. RetGC1 is an essential protein implicated in the phototransduction cascade, especially in the recovery of the dark state after the excitation process of photoreceptor cells by light stimulation. We postulate that the retGC1 mutations hinder the restoration of the basal level of cGMP of cone and rod photoreceptor cells, leading to a situation equivalent to consistent light exposure during photoreceptor development, explaining the severity of the visual disorder at birth.

Blindness↗

PubMed2000

[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↗