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Biomedical subjects

P Y Robert

Publications and source records attributed to P Y Robert.

At least 19 recordsLinked to original sources

[Ophthalmic arteries originating from external carotid arteries].

The ophthalmic artery arises from the internal carotid at the level of the carotid siphon; in 3.5-5% of the population, it arises from the middle meningeal artery, a branch of the internal maxillary artery, terminal of the external carotid artery. We report a rare case of bilateral malformation in a 28-year-old patient. Our study covers the possible dual origin of orbital blood vascularization. This variation in the anatomic distribution is important to know, particularly if embolization is intended as inadvertent occlusion of the ophthalmic artery, because it may lead to permanent loss of vision.

Abnormalities, Multiple↗

[New ceramic materials for use in anophthalmia surgery].

Over the last 20 years eyeball replacement surgery has improved, especially with the widely accepted use of biocolonisable implants. These implants allow long-lasting biointegration, thus improving prosthesis motility and reducing the rate of postoperative exposure. In this article, we review the chemical structure, toxicity data and manufacturing procedures of the three main commercially available materials: aluminium, hydroxyapatite and porous polyethylene.

Aluminum Oxide↗

Bone formation in hydroxyapatite tricalcium phosphate ceramic implants used in the treatment of the postenucleation socket syndrome.

PURPOSE: To determine the histopathologic changes in coralline hydroxyapatite tricalcium phosphate (HA-TCP) blocks used in the treatment of the postenucleation socket syndrome (PESS). METHODS: Twenty-four patients were treated with HA-TCP blocks placed directly into the orbital fat to correct the PESS. Eight of these patients required partial removal of the material for various reasons between 32 and 371 days after the initial operation. The orbital implants were decalcified and processed for light and electron microscopic examination. RESULTS: Light microscopy demonstrated fibrovascular ingrowth into the pores of the implant in all cases. Osteogenesis was observed in three cases in the periphery of the implant. Ossification occurred in the implants after a mean implantation duration of 276 days versus 67 days in cases without ossification. CONCLUSION: Implants of HA-TCP, a new material used in ophthalmology, demonstrate the presence of fibrovascular ingrowth, reflecting the excellent biointegration of this material.

Adolescent↗

[Dependence for daily life activities in the prison population in Western France].

OBJECTIVE: As the mean age of the penitential population rises and the duration of imprisonment grows longer, health services are confronted with the problem of prisoners dependent for daily life activities. The purpose of this study was to determine the number of prisoners dependent for daily life activities and quantify their dependency on human and material support. METHODS: A survey was conducted in the summer of 2,000 in the western region of France (19 prisons in the following regions: Pays-de-Loire, Brittany, Lower Normandy). RESULTS: Among the 4,168 persons incarcerated in these regions, 32 dependent prisoners were identified: 21 men (mean age 57 years) and 11 women (mean age 48 years). Among these persons, 19 suffered from major or moderate dependence (GIR 1-4). The main problems involved toilet facilities, dressing, transfers, and moving about. When human support was available, it was generally provided by other prisoners. Material help was scarce. DISCUSSION: The questions of prisoner's rights, human assistance, the status of caregivers, and the need for adapted architectural, material, and medical facilities are discussed. The information collected here provides a better knowledge of prisoners' needs for support and for changes which would be necessary in the prison environment.

Activities of Daily Living↗

Risk factors for visual loss in giant cell (temporal) arteritis: a prospective study of 174 patients.

OBJECTIVE: To determine the risk factors--especially the effects of thrombocytosis--for permanent visual loss in patients with temporal arteritis. METHODS: One hundred seventy-four patients with temporal arteritis (147 biopsy proven) were prospectively observed for the development of permanent visual loss. We used multivariate logistic regression analysis to determine which of 17 pretreatment characteristics were associated with visual loss. RESULTS: Visual ischemic manifestations occurred in 48 (28%) patients, including permanent visual loss in 23 (13%) patients. The independent predictors associated with an increased risk of permanent visual loss were a history of transient visual ischemic symptoms (odds ratio [OR] = 6.3; 95% confidence interval [CI]: 1.4 to 29; P = 0.02) and a higher platelet count (OR = 3.7 per SD; 95% CI: 1.8 to 7.9; P = 0.001). The presence of constitutional symptoms (OR = 0.14; 95% CI: 0.02 to 0.77, P = 0.01), polymyalgia rheumatica (OR = 0.04; 95% CI: 0.01 to 0.48, P = 0.02), and C-reactive protein level (OR = 0.35 per SD; 95% CI: 0.13 to 0.92, P = 0.03) were associated with a reduced risk. Upper limb artery involvement was excluded from the multivariate model, as no patients with that problem developed permanent visual loss. Of the 87 patients who presented with thrombocytosis (platelet count >400 x 10(9)/L), 32 (37%) developed ischemic visual symptoms, compared with 16 (18%) of those without thrombocytosis. CONCLUSIONS: An elevated platelet count is a risk factor for permanent visual loss in temporal arteritis. The finding of thrombocytosis in a patient with suspected temporal arteritis should emphasize the need for urgent treatment, with consideration of using inhibitors of platelet aggregation or anticoagulation therapy.

Aged↗

CT appearances of chronically retained wooden intraorbital foreign bodies.

Identification of wooden intraorbital foreign bodies (WIOFB) is crucial for avoiding severe orbital infection. Despite careful clinical examination, WIOFB are often not recognised. We report the CT findings in chronically retained WIOFB. When not initially diagnosed, WIOFB create a granulomatous inflammatory foreign-body reaction. CT demonstrates the WIOFB as a linear dense structure surrounded by a soft-tissue mass with density similar to that of muscle, corresponding to the foreign-body reaction.

Adult↗

[Analysis of the aqueous humor in keratoplasty patients with keratitis. Initial results].

OBJECTIVE: Herpetic keratitis is a common indication for corneal transplantation. In this patient group especially, there is a relatively high risk of graft failure, partly because of viral recurrence. It can be difficult to clinically distinguish stromal herpetic recurrence from early endothelial allograft rejection. Also a perioperative observation of viral activity seems advisable because of therapeutic consequences. For these reasons we use aqueous humor analysis in certain corneal transplant patients to determine intraocular antibody production. The aim of this study was to evaluate the diagnostic value of such an analysis of aqueous humor. MATERIAL AND METHODS: A total of 28 samples of aqueous humor were obtained from 24 eyes and all samples were tested for antibodies against herpes simplex virus (HSV), most samples (26/28) were tested for antibodies against varizella zoster virus (VZV) and some samples (6/28) for antibodies against cytomegalovirus. We used a modified micro-ELISA technique to detect intraocular IgG production. RESULTS: In 14 samples (50%) we found antibodies against HSV, in 7 samples (25%) against HSV and VZV, in 1 sample (3.6%) against VZV and 6 samples (21.4%) were negative for all antibodies tested. CONCLUSION: The results of aqueous humor analysis led to a specific local or systemic antiviral therapy perioperatively or in the case of postoperative recurrence of herpetic keratitis in most patients. Some patients could be spared long-term treatment with antiviral agents because of negative results in the aqueous humor analysis.

Adult↗

[Risk factors for irreversible cerebral ischemia complications from Horton's disease: prospective study of 178 patients].

PURPOSE: To search for risk factors of developing irreversible cranial ischemic complications (ICIC) in patients with giant cell arteritis (GCA) and to explore whether two subsets of patients (high risk and low risk of developing ICIC) can be defined. METHODS: One-hundred seventy-eight consecutive patients with temporal arteritis (149 biopsy-proven) were diagnosed and followed up in a department of Internal Medicine between 1976 and 1999. The patients were separated into two groups, according to the presence or absence of ICIC, with comparison of 17 clinical and biological parameters prospectively recorded for each patient using a pre-established comprehensive questionnaire. RESULTS: ICIC occurred in 25 patients (14%), with amaurosis in 22 cases. Suggestive symptoms and/or signs of temporal arteritis were present in 92% of the patients, lasting 50 days (median) before the onset of ICIC. Forty-three patients (24%) complained of transient visual ischemic symptoms (TVIS), which preceded acute blindness in 11 cases. A multivariate logistic regression, from which 28 cases with upper limb artery involvement were excluded for technical reasons (no CCII in any case, thus predicting perfectly the lack of ischemic risk, P = 0.02), indicated that the only independent variables associated with the ischemic risk were: a history of TVIS (P = 0.05), the lack of signs of polymyalgia rheumatica (PMR; P = 0.02), lower blood levels of fibrinogen (P = 0.024) and higher mean blood platelets levels (P = 0.006). However, these five variables predicted only 30% of the variability of the model. Sensitivity, specificity, positive and negative predictive values of the model reached respectively 36, 96, 64 and 88%. Overall, 86% of the cases were correctly classified with respect to the ischemic risk. CONCLUSION: The rate of ICIC should be reduced by an earlier recognition of the usual signs of temporal arteritis. Several independent risk factors of ICIC have been identified. However, the logistic model failed to predict accurately the ischemic risk in 14% of the cases, indicating that as yet unrecognised factors probably exist that play a role in the occurrence of ICIC. Nevertheless, regarding the strong association between platelet levels and ICIC, patients with thrombocytosis should receive initially both corticosteroids and antiplatelet agents.

Aged↗

Comparative review of topical ophthalmic antibacterial preparations.

The choice of an antibacterial is based on considerations of pharmacodynamic, pharmacokinetic and bacteriological characteristics, risk of selecting resistant mutants, and cost. In this article we review 16 commercially available ophthalmic antibacterial preparations. Fusidic acid and bacitracin are selective for gram-positive bacteria whereas polymyxin B targets gram-negative species. Aminoglycosides and quinolones are broad spectrum antibacterials. The widespread use of an antibacterial increases risks of selecting resistance to it. Acquired resistance is well documented for fusidic acid and rifamycin, and newly described for quinolones. The bioavailability of an antibacterial agent depends on the target bacterial species, the site of infection and the integrity of the haemato-aqueous barrier. Some agents (fusidic acid, quinolones) penetrate the cornea, passing into the anterior chamber of normal eyes at therapeutic concentrations, whereas others (polymixin B, bacitracin) have no penetrating powers and remain at the surface of the eye. Toxicity is mostly manifested by allergic reactions to excipients or active ingredients in topical antibacterial preparations. A few cases of haematological toxicity have brought suspicion on topical chloramphenicol, but the link has yet to be proven. Erythromycin and polymyxin B are probably okay to use as topical applications in pregnant women and nursing mothers. Costs of treatment must be evaluated as a whole (regimen, drug associations). Prices for a bottle of eyedrops may vary 3-fold. The cheapest drugs include chloramphenicol, polymyxin B and gentamicin, the most expensive being fusidic acid and the quinolones.

Administration, Topical↗

[Cyclosporin A eyedrops: manufacturing, toxicity, pharmacokinetics and indications in 2000].

INTRODUCTION: Cyclosporin eye-drops allow local immunoregulation without systemic side effects and is an alternate to local steroids. In this article we review specific problems of product setup and clinical studies published over the past 20 years. PRODUCT SETUP: The main problems in eye-drop preparation are sterility, pH, particles, and its lipophilic properties. Numerous excipients have been tested including oil solvents, alphacyclodextrin, collagen shields, liposomes, polyester nanocapsules, but documentation on stability of the molecule is inadequate. TOXICITY: Epithelial toxicity is well known and is probably mainly due to the excipient. No endothelial toxicity has been described in vivo. Repeated doses lead to uveal reactions in animals, which could limit the indications for intraocular diseases. PHARMACOKINETICS: Bioavailability is mainly limited by the lipophilic properties. Oil excipients, the most widely used, lead to good corneal penetration but low intraocular concentrations. Cyclosporin bioavailability is improved when using hydrophilic excipients. INDICATIONS: Every ocular surface disease that involves cytokines is a potential indication for cyclosporine eyedrops: keratoconjunctivitis sicca, vernal keratitis, adjuvant therapy of filtering surgery, stromal herpes keratitis, immunity limbal keratitis, and Thygeson's keratitis. There is biological evidence of efficacy, and encouraging results from many studies, yet few have tested a large number of patients. A large multicenter study on dry eye is currently in progress.

Biological Availability↗

[Evisceration using the Russian doll or the parachute technique].

The authors describe two new techniques of evisceration after resection of the corneal epithelium and limbus with a conservative approach of the posterior lamella of the cornea and anterior sclera after a 360 degrees dissection of the sclera behind the insertion of the oculomotor recti muscles, and with a conservative approach of the recti oculomotor muscles. The technique is called "Parachute" when the posterior sclera is removed and "Russian Doll" when the posterior sclera is not removed and placed behind the orbital implant. The implant is then introduced with "bird cage" forceps. The indications of the technique are those of evisceration when the size of the remaining globe is at least one-third of the volume of a normal eye. The main advantage is to provide safely a large volume for the implant in order to prevent post enucleation socket syndrome.

Eye Evisceration↗

[Bioavailability of antibiotics].

To be effective, an antibiotic must achieve therapeutic concentrations at the site of infection. This article is a review on the bioavailability of local and systemic antibiotics. Amongst topical antibiotics, fluoroquinolones and fusidic acid have the best intra-corneal and intra-cameral penetration. Chloramphenicol penetrates the anterior chamber but not always at therepeutic levels. Serum levels are low from topical administration, and haematological toxicity of chloramphenicol eyedrops is still not proven. Amongst systemic antibiotics, the molecules capable of penetrating the eye at therapeutic levels are fosfomycin, imipenem, some of third generation cephalosporins, fluoroquinolones and ureidopenicillins. Intra-ocular penetration of antibiotics is increased by infection, corneal epithelium abrasion, increasing dose frequency or delivery using a biomaterial reservoir (soft contact lenses or collagen schields). Antibiotic-antiinflammatory associations can make infected sites more accessible to antibiotics. The choice of a treatment must take in consideration molecules, dosing and route, and be adapted to the germ to kill and the infected site to treat.

Animals↗

HLA-G and classical HLA class I transcripts in various components of the adult human eye.

HLA-G transcripts have previously been detected in the ocular cell line HS738, in foetal eyes and in global ocular extract. Using RT-PCR and hybridization, we searched for HLA-G and classical HLA class I transcripts in the corneas of eye donors (n = 6) and in various components of eyes collected at time of surgery: lens (n = 3), iris (n = 2), vitreous body (n = 2) and retina (n = 2). Whereas HLA class I mRNA was abundant in the ocular tissues of all donors, we could not find HLA-G transcript in any ocular tissues obtained from subjects in vivo. The absence of HLA-G in adult eye cornea limits its interest as a possible target in corneal transplantation. Classical HLA class I transcripts were abundant in the cornea and other components of the eye. These results highlight the role of classical HLA class I antigen in eye immunity and corneal transplantation.

Cornea↗

Treatment of the postenucleation socket syndrome with a new hydroxyapatite tricalcium phosphate ceramic implant.

PURPOSE: Surgical correction of the postenucleation socket syndrome (PESS) is challenging. Various biomaterials are used for reconstruction of the anophthalmic orbit, often with unsatisfactory long-term results. Implants have been placed between the periorbital and the orbital floor. The authors describe a new material composed of hydroxyapatite tricalcium phosphate (HA-TCP) in the form of ceramic blocks, to be placed into the orbital fat as a new surgical site. METHODS: Ten patients with PESS underwent surgery to compensate the volume deficit of the anophthalmic orbit. Blocks of HA-TCP were created by fragmentation of a larger piece, tailored as needed, and implanted in the orbital fat. The patients were monitored regularly with clinical and radiologic examinations to evaluate the behavior of the implants. RESULTS: The volume of the HA-TCP was measured in 5 cases (mean, 2.95 +/- 1.08 ml). A significant reduction of enophthalmos was obtained: mean Hertel exophthalmometry measured 12.7 +/- 2.5 mm preoperatively and 14 +/- 2.4 mm postoperatively (p < 0.05). The average prosthesis volume was significantly reduced in the cases measured: 2.7 ml +/- 0.94 ml preoperatively and 1.8 +/- 0.7 ml postoperatively (p < 0.02). There was a negative correlation between the HA-TCP implant volume and postoperative prosthesis volume (correlation coefficient = -0.925; p < 0.05). According to photographic evaluation, correction of the enophthalmos and of the superior sulcus depression were obtained in 70% and 90% of cases, respectively. Magnetic resonance imaging seems to demonstrate that the blocks become well integrated into the surrounding orbital tissue. CONCLUSION: The HA-TCP blocks correct some anomalies of PESS. Placement of the blocks directly into the orbital fat is a promising alternative to the traditional subperiosteal location.

Adolescent↗

Local antimicrobial prophylaxis in cataract surgery: recent controversies and clinical guidelines.

The best prevention of endophthamitis is the use of strict surgical hygiene. Supplementing the irrigating solution with aminoglycosides and/or vancomycin is a rational, convenient and cost effective method of antimicrobial prophylaxis. However emerging resistance to vancomycin entails restrictions to its daily use. In conclusion, two options are possible: limit the use of prophylaxis in the irrigating solution to only those patients at high risk of injection, or use topical and general antibioprophylaxis with low cost drugs.

Anti-Bacterial Agents↗