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Biomedical subjects

B Arnaud

Publications and source records attributed to B Arnaud.

At least 37 records · Page 2Linked to original sources
PubMed1999

Molecular analysis of the rhodopsin gene in southern France: identification of the first duplication responsible for retinitis pigmentosa, c.998999ins4.

PURPOSE: Mutations in the gene encoding rhodopsin, the visual pigment in rod photoreceptors, were shown to be the most common cause of autosomal retinitis pigmentosa (RP). In order to determine the prevalence of rhodopsin alterations in southern French populations, we examined 52 unrelated patients/families with autosomal dominant RP (adRP=29), RP simplex (6), or unclassified RP (17). METHODS: The full coding and flanking sequences of the rhodopsin (RHO) gene were scanned using an improved DGGE (denaturing gradient gel electrophoresis) assay, followed by sequencing of abnormal fragments. RESULTS: This study revealed three RHO mutations in patients with adRP (G106R, R135W, and c.998999ins4) and a number of frequent or rare polymorphisms. No disease-causing sequence variation was found in simplex and unclassified RP pedigrees. Mutation c.998999ins4 has not been previously reported, and appears as the first duplication identified so far in the RHO gene. This frameshift mutation, which is associated with a severe RP, alters the carboxy terminus and predicts a 353-amino acid mutant rhodopsin instead of 348. DISCUSSION: Our study demonstrates that rhodopsin mutations are responsible for only 10.3% of adRP in French populations living in the Mediterranean area in contrast to the 25-35% reported in other populations.

Adult↗
PubMed1999

[Intra-orbital decompression of the optic nerve by opening the peri-optic meninges in the treatment of severe optic neuropathies complicating benign intracranial hypertension].

Papilledema from benign intracranial hypertension can cause severe loss of visual acuity and visual field, with an optic neuropathy. We report a study of 5 patients with benign intracranial hypertension, and severe visual loss (visual field loss and visual acuity reduced to 1/10 or less) not improved by medical therapy (acetazolamide). We performed unilateral orbital decompression of the optic nerve sheath. No major operative complication was noted. Follow-up ranged from 11 months to 23 months, with an average of sixteen months. Visual function improvement was noted within 3 months after operation in 4 patients (for 2 eyes on the surgical side improvement of 2/10 and 5/10, for 3 eyes on the opposite surgical side average improvement of 4.6/10). The other patient showed improvement, but no significant. Optic nerve sheath decompression in benign intracranial hypertension seems to be a safe procedure and a therapeutic option in the management of raised intracranial pressure complicated by optic neuropathy with severe visual loss.

Acetazolamide↗
PubMed1998

Rod and cone function in the Nougaret form of stationary night blindness.

BACKGROUND: Recently, a mutation (Gly38Asp) was identified in the alpha subunit of rod transducin in members of the Nougaret pedigree affected with dominantly inherited stationary night blindness. OBJECTIVE: To evaluate retinal function in patients with the Gly38Asp gene defect. DESIGN: Ocular examinations, including specialized measures of rod and cone function. SETTING: A clinical research facility in Boston, Mass. PATIENTS: A father (aged 48 years) and son (aged 25 years) with the Gly38Asp mutation. MAIN OUTCOME MEASURES: Psychophysical thresholds to white and narrowband lights and full-field electroretinographic (ERG) responses. RESULTS: Both patients showed dark-adapted thresholds to white light that were elevated approximately 2 log-units across the retina. Spectral sensitivity testing revealed thresholds that seemed to be governed mostly by rods. Although both patients' dark-adapted ERG responses to a dim blue flash were nondetectable, their dark-adapted ERGs to a white flash showed an a-wave with cone and rod components and a b-wave amplitude larger than what could have been generated by cone function alone. Rod ERGs to bright blue flashes had subnormal, but detectable, amplitudes that seemed to result from a profound reduction in sensitivity. The patients also showed loss of a cone subcomponent in the dark-adapted response to a red flash. The abnormal dark-adapted ERG responses of the patients could be simulated in the ERG responses of normal subjects tested with blue, white, and red flashes presented in the presence of a mesopic background. CONCLUSIONS: Although the Nougaret form of stationary night blindness has been cited as a prototype of absent rod function with normal cone function, our findings, based on the genealogically and genotypically documented descendants of Jean Nougaret, show that rod function is present, although subnormal, and that there is slight impairment of cone function. The data also suggest that these abnormalities can be simulated by light-adapting the normal retina, compatible with the proposal that the rod transducin encoded by the mutant gene is constitutively active and that the night blindness results from partial desensitization of rods caused by the constitutive activity.

Adult↗
PubMed1998

[Ocular trauma and caustic burns by air bags].

We report two cases of ocular injuries caused by airbag inflation. These cases illustrate two main types of airbag-induced eye injuries: chemical and traumatic. In the first case, chemical keratitis was caused by the aerosol spray of alkaline particles produced by the airbag deployment system. In the second case, the high-speed deployment system caused mechanical injury to the anterior and posterior segments demonstrating the effect of the sudden deceleration when the individual hits the airbag. These two cases as well as others reported in the literature suggest that ocular injury should always be suspected because of the inherent traumatic effect of the airbag protection system.

Acceleration↗
PubMed1998

[Clinical features and genetic analysis in a family with X-linked incomplete congenital stationary night blindness (CSNBi)].

PURPOSE: We describe particular clinical features in a three-generation family with X-linked CSNBi and present the genetic analysis. METHOD: The diagnosis of CSNBi was established on clinical and electrophysiological criteria. Polymorphic DNA markers of the Xp region were analyzed by fluorescent polymerase chain reaction. RESULTS: Clinical findings evidenced an atypical association of both myopia and hyperopia in the same brotherhood. The most interesting feature in this family was the observation of major worsening of the clinical shape between the first and the third generation of affected individuals. DNA analysis did not show significant linkage between the disease and markers of the Xp11-p21 region. Southern analysis did not show expansion of trinucleotide repeat CAG/CTG and CCG/CGG over the three generation. CONCLUSION: Haplotypic analysis together with clinical observations allow to exclude the existence of a myopia gene closely linked to the CSNB2 locus. The clinical anticipation observed in this family does not seem to be linked with trinucleotide repeat expansion CAG/CTG or CCG/CGG.

Adolescent↗
PubMed1998

[Update on a diagnostic test for choroideremia: the protein truncation test (PTT)].

PURPOSE: The aim of this study was to define the RT-PCR-PTT parameters for CHM gene analysis and to evaluate its interest as a method for CHM mutation screening. METHODS: The entire CHM coding region was reversed-transcribed in three overlapping cDNA segments (RT-PCR) which were amplified and further analyzed by PTT after in vitro transcription/translation. RESULTS: This strategy enabled us to detect a truncated peptide in each of the 6 unrelated patients from southern France who were investigated. The mutation was further characterized by direct sequencing of the RT-PCR product. CONCLUSION: In CHM gene, all conditions are present to make the RT-PCR-PTT strategy the method of choice for mutation screening. As a result of the simplified protocol described in this study, the families of the patients could benefit from accurate carrier-status assessment.

Adaptor Proteins, Signal Transducing↗
PubMed1998

[Value of the conjunctival provocation test in evaluating the activity of 2 concentrations of anti-allergy eyedrops, mequitazine].

PURPOSE: To compare the activity of topical 0.05% and 0.01% mequitazine versus vehicle in the prevention of allergic conjunctivitis induced by a conjunctival provocation test with allergens. METHODS: Forty subjects with a history of grass pollen allergic conjunctivitis were enrolled in this comparative, randomized, double-masked study. Fifteen minutes before the conjunctival provocation test, subjects received one instillation alone of 0.05% mequitazine eyedrops in one eye and in the fellow eye either one drop of 0.01% dose or vehicle, at the same dosage. Then a specific conjunctival provocation test (CPT) was performed with the allergen threshold concentration previously defined. The therapeutic efficacy was assessed by the decrease in a symptomatic composite score representing the allergic reaction. RESULTS: Topical mequitazine at the dose of 0.05% significantly decreases the intensity of the allergic reaction compared to vehicle. Moreover, the group treated with this dose needed a higher allergen concentration to trigger ocular signs. The 0.01% dose appears efficient only on itching, compared to vehicle. CONCLUSION: The results of this study support the efficacy and the onset of action of 0.05% mequitazine eyedrops versus 0.01% or vehicle in the prevention of allergic conjunctivitis induced by a conjunctival provocation test.

Adult↗
PubMed1997

The protein truncation test (PTT) as a method of detection for choroideremia mutations.

The predominance of truncative mutations responsible for choroideremia (CHM) led us to investigate the use of the protein truncation test (PTT) applied to lymphocyte RNA derived from affected males as a scanning method. The entire CHM coding region was reversed-transcribed in three overlapping cDNA segments (RT-PCR) which were amplified and further analysed by PTT after in vitro transcription/ translation. This strategy enabled us to detect the CHM-causative alteration in each of the four unrelated patients from southern France who were investigated. We describe three novel mutations (E177X, 323delT, 1313delTC), and report one recurrent mutation (R267X) in CHM. We believe this to be the first attempt at applying RT-PCR-PTT to CHM mutation detection.

Choroideremia↗
PubMed1997

Trauma after radial keratotomy and photorefractive keratectomy.

A 25-year-old man sustained bilateral ocular trauma from an explosion, which resulted in ocular injuries from the blast, mineral projections, and heat. Before the accident, the patient had eight-incision radial keratotomy in the left eye followed 1 week later by photorefractive keratectomy in the right eye. After the accident, the left cornea had a full-thickness rupture of four incisions; the fellow cornea had a full-thickness laceration from a mineral projection. Five months after the accident, the left eye had an uncorrected visual acuity of 20/25; the right eye did not achieve an acuity of 20/200 until 20 months after the accident.

Adult↗
PubMed1997

Efficacy of mequitazine in comparison with placebo assessed by ocular challenge with allergen in allergic conjunctivitis.

Pharmacologic intervention in the management of allergic conjunctivitis was evaluated with different topical ocular agents in man. Their effect can be precisely assessed with the conjunctival provocation test (CPT). A potent specific H1-receptor antagonist, 0.05% mequitazine eye-drops, was tested in a double-blind randomized, placebo-controlled study using CPT with grass pollen allergens. Twenty healthy subjects allergic to grass pollen were included outside the pollen season after a positive CPT screening. They received one drop of 0.05% mequitazine in one eye and the vehicle in the contralateral eye in a random order, four times daily for 5 days. CPT was performed 15 min after the last instillation, and the threshold dose inducing a positive reaction was determined. Results were given by Abelson's composite score including redness, chemosis, tearing, and itching. Topical 0.05% mequitazine significantly reduced the composite score compared to placebo. The allergen threshold concentration which induced the positive conjunctival reaction was higher in mequitazine pretreated eyes. No side-effect was reported. These data clearly suggest that mequitazine has potential to treat allergic conjunctivitis.

Adult↗
PubMed1997

A complex allele (1064delTC and IVS2 + 22ins7) in the peripherin/RDS gene in retinitis pigmentosa with macular dystrophy.

Because mutations in the peripherin/RDS gene have been found in retinal dystrophies involving the macula, we examined various types of macular dystrophies from southern France to characterize sequence variations that may be associated with these conditions. DNA sequence analysis of the full coding and flanking regions of the peripherin/RDS gene was performed in fifteen unrelated patients with different types of macular dystrophy, including nine with retinitis pigmentosa (RP). Of the 15 probands with macular disease, two (13.3%) were found to carry a mutation in the peripherin/RDS gene. The recurrent mutation P216S was identified in a pedigree with autosomal dominant RP. A previously unreported complex allele (1064delTC associated with IVS2 + 22ins7) that is predicted to result in the premature termination of peripherin/RDS synthesis was identified in a sporadic case of macular atrophy with RP. We also report eight novel neutral sequence variations in the peripherin/RDS gene, most of them found in the 3' untranslated part of the gene.

Adult↗
PubMed1997

[Double-blind study on 3 parallel groups of 2 formulations of 0.1% indomethacin and 0.1% diclofenac in preventing and controlling inflammation after cataract surgery].

PURPOSE: To evaluate the efficiency and safety of LCM 1110 eyedrops, a new 0.1% indomethacin formulation, compared with the registered 0.1% indomethacin solution and with 0.1% diclofenac, in the management of post cataract surgery inflammation. METHODS: A total of 352 patients randomly assigned to LCM 1110 (n = 116), to indomethacin (n = 121) or to diclofenac (n = 115) were included in this three-arm, prospective, multicenter and double-masked trial, after giving written informed consent. They were given preoperatively 1 drop QID the day before surgery, 5 drops within 2 hours prior to operation then 1 drop QID for 1 month. Cataracts were extracted by either extracapsular or phacoemulsification methods, with PC-IOL implantation. The main efficacy evaluation was based on the assessments of anterior chamber cells and flare at days 1, 7 and 30 following surgery. Symptoms, other objective signs and IOP were recorded. RESULTS: Cellular and proteinic Tyndall phenomenon did not significantly differ in the 3 groups, at any of the post surgical assessments. Clinical symptoms and visual acuity improved similarly. IOP was not adversely affected by any drug. Compared with subjects having received LCM 1110, diclofenac-treated patients experienced a superficial punctuate keratitis more frequently. Tolerance of instillation, measured by a visual analogic scale, was best improved by LCM 1110 followed by the indomethacin solution and by diclofenac (LCM 1110-diclofenac; p = 0.004). CONCLUSION: These data suggest that LCM 1110, a new 0.1% indomethacin ophthalmic solution, appears to be a safe promising agent for the control of postoperative inflammation.

Aged↗
PubMed1997

An exonic polymorphism (381A/G) in the choroideremia gene.

By using the single strand conformational analysis (SSCA) to search for point mutations in the choroideremia gene, we have identified a previously undescribed polymorphism within exon 5a (381A/G). We have studied the frequency of this polymorphism in a population from Southern France. The sequence variation creates a new restriction site for HhaI, allowing a convenient DNA-based genetic counseling in families in which the causal disease mutation is unknown.

Choroideremia↗
PubMed1997

[Rapid genetic diagnosis of females carriers related to patients with choroideremia].

PURPOSE: By using the single strand conformation analysis to search for point mutations in the choroideremia gene, we had previously identified the first truncative mutation responsible for CHM in France. The aim of the present study was to perform a simple and nonisotopic routine test to identify carriers and non carriers in the relevant family. METHODS: We used a PCR-based restriction analysis to detect the presence or absence of the mutation in the family members, as the mutation creates a restriction site in the coding sequence of the CHM gene. RESULTS: We could follow the segregation of the mutation in the pedigree, and unambiguously determine the genetic status of the females. CONCLUSION: When a mutation responsible for choroideremia modifies a restriction site, the PCR-restriction provides an efficient and unexpensive one-day test to detect heterozygosity in the family.

Carrier State↗