PubMed Health⌕ Search

Biomedical subjects

A Mathis

Publications and source records attributed to A Mathis.

At least 19 recordsLinked to original sources
PubMed1992

Giant retinal tears. Surgical techniques and results using perfluorodecalin and silicone oil tamponade.

Intraoperative use of perfluorocarbon liquids in the management of giant retinal tears was introduced about 4 years ago. Twenty-four patients were operated on for giant retinal tears using perfluorodecalin and silicone oil tamponade. All patients underwent pars plana vitrectomy, unfolding of the giant retinal tears by perfluorodecalin, perfluorodecalin-silicone oil exchange, and endophotocoagulation. The lens was removed in 10 of 14 phakic patients, and encircling scleral buckle was placed in 18 cases. Twenty-three of 24 retinas remained successfully attached with a minimum of 6 months of follow-up. Short-term results of intraoperative use of perfluorodecalin and silicone oil tamponade in the management of giant retinal tears are encouraging. Perfluorodecalin offers the advantage of low cost compared with other perfluoro-carbon liquids like perfluoro-n-octane. The exchange with silicone oil offers the advantages of easy removal of perfluorodecalin and absence of posterior slippage of the retinal tear.

Adolescent↗
PubMed1992

Case report: top hearing performances of a postlingually deaf cochlear implant user.

On the occasion of the Cochlear Implant Symposium in Geneva in October 1991, top hearing results attained by a young postlingually deaf woman with cochlear implant systems were presented in video recordings. These data are centered on demanding hearing performances in test situations and in a telephone conversation. For various reasons, two reimplantations were necessary in this deaf patient. Initially, she was provided with a single-channel extra-cochlear electrode of the Vienna type, which she found to improve her lipreading substantially, and she attained an unexpectedly good understanding of speech on a purely auditory basis. Today, this postlingually deaf women uses a multichannel intracochlear electrode of the Nucleus type. The excellent results with the first extracochlear system are clearly surpassed with the intracochlear system. Not least because of her above-average speech competence, the cochlear implant user attains a high degree of open speech understanding. Her verbal hearing efficiency is comparable to that of a person with mild to moderately severe hearing loss.

Adolescent↗
PubMed1992

[Surgery of retinal detachment of patients with pseudophakia using the panfunduscope].

Examination of the extreme periphery of the fundus of patients with pseudophakic retinal detachment is difficult due to poor pupil dilatation, optical aberrations from the intraocular lens, opacification of the posterior capsule or peripheral capsular remnants. Fifty-one patients with pseudophakic retinal detachment were operated on with using the wide angle panfunduscope of Rodenstock. It allows a very satisfactory pre- or intraoperative view of the extreme periphery of the fundus using the slit-lamp of the operative microscope combined with a scleral indentation. In only 3 cases no break was found in spite of pre- and intraoperative examination of the fundus periphery with the panfunduscope. Anatomic success was achieved in 47 out of 48 patients with a minimum of 6 months of follow-up; 3 patients were lost to follow-up. The mean postoperative visual acuity was 0.5. Unlike other methods of fundus examination, such the 3 mirror Goldmann lens or the indirect binocular ophthalmoscope, the panfunduscope allows good visualization of the peripheral retina of patients with pseudophakic retinal detachment using the slit-lamp of the operative microscope combined with a scleral indentation. Thus, small peripheral retinal breaks, often associated with pseudophakic retinal detachment, can be identified.

Adult↗
PubMed1992

[Peribulbar anesthesia in surgery of the vitreous body and retina].

Peribulbar anaesthesia was used in 40 patients undergoing vitreoretinal surgery; two injections of a mixture of bupivacaine 0.5% and hyaluronidase were performed in the lower and the upper eyelid. Results were judged very satisfactory in 38 of these 40 cases, for anaesthesia as well as for akinesia; no local or systemic complications were observed. Peribulbar anaesthesia is one of the methods of choice, because of its safety; it seems well appropriate for vitreoretinal surgery, provided that its indications are judicious.

Aged↗
PubMed1992

[Leber's optic neuropathy: new diagnostic prospects].

The diagnosis of Leber's hereditary optic neuropathy, essentially based on a family history of a similar illness, becomes difficult in sporadic cases. In this disease, mitochondrial DNA mutations have been recently discovered and detected by digestion with restriction enzyme after amplification by the Polymerase Chain Reaction. We present two patients in whom these molecular biological techniques confirmed the diagnosis of Leber's hereditary optic neuropathy in the absence of a convincing family history. These new molecular biological methods, providing a precious diagnostic test, would certainly play a greater part in genetic counselling and would probably be a prerequisite for the development of new forms of therapy.

Adult↗
PubMed1991

A child with an unusually high-level spontaneous otoacoustic emission.

We describe a child who emitted a continuous audible sound from his left ear. A high-level spontaneous otoacoustic emission was measured at the frequency of 5.64 kHz with an amplitude of 55 dB sound pressure level. A high-frequency hearing loss was measured in both ears; however, it was more pronounced in the emitting ear. The emission failed to synchronize to external click stimuli. This spontaneous emission is probably related to a cochlear defect, but it should not contribute additionally to the child's existing auditory impairment.

Acoustics↗
PubMed1991

Localization of acidic fibroblast growth factor in proliferative vitreoretinopathy membranes.

The pathogenesis of proliferative vitreoretinopathy (PVR) membranes remains poorly understood. We have studied the presence of acidic fibroblast growth factor (aFGF), a potent mitogen for many cells, within these membranes. We have used affinity purified monospecific anti-aFGF polyclonal antibodies, in conjunction with highly sensitive immunofluorescence techniques. The labelling was exclusively localized to cell bodies and was absent from the extracellular matrix. Double labelling techniques revealed that all cytokeratin positive cells (probably pigmented epithelial cells) and macrophages contained aFGF-like immunoreactivity, whilst glial cells were unlabelled. Appropriate controls indicated the specificity of the antibodies. Hence, the presence of this mitogenic molecule within certain cell types constituting PVR membranes may contribute to the pathogenesis.

Animals↗
PubMed1991

[Extracapsular cataract extraction and implantation in the capsular sac during vitrectomy in diabetics].

Removal of the lens is often performed during pars plana vitrectomy for complications of proliferative diabetic retinopathy, but correction of aphakia often remains unsatisfactory. Some authors have reported posterior chamber intraocular lens implantation during pars plana vitrectomy in diabetic patients who presented with coexisting cataract and vitreoretinal complications from proliferative diabetic retinopathy. Some patients were operated by pars plana lensectomy and vitrectomy followed by posterior chamber intraocular lens implantation in the ciliary sulcus, others by extracapsular extraction, posterior chamber intraocular lens implantation in the ciliary sulcus, and pars plana vitrectomy. Other authors have described phacoemulsification through the limbus, pars plana vitrectomy and implantation in the capsular bag in one operation in various indications, including complications of proliferative diabetic retinopathy. We inserted a posterior chamber intraocular lens into the capsular bag in 18 eyes of 16 patients with complications of proliferative diabetic retinopathy after extracapsular cataract extraction and pars plana vitrectomy in a single session. A standard extracapsular cataract extraction was performed before pars plana vitrectomy. Sufficient anterior capsule was left in place in order to facilitate implantation in the capsular bag after pars plana vitrectomy. The anterior chamber was filled with sodium hyaluronate in order to maintain anterior chamber depth, corneal clarity, and good mydriasis during the continuation of the procedure. A standard three port pars plana vitrectomy was performed in all cases. After closure of superior sclerotomies, superior corneal incision was partially reopened, an intraocular lens specifically designed for the capsular bag with an optic size of 7 mm was inserted, and the corneal incision was closed with interrupted 10/0 sutures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The use of perfluorodecalin in diabetic vitrectomy.

Nine patients were operated on for severe proliferative diabetic retinopathy using a perfluorocarbon liquid, purified perfluorodecalin; 7 patients were operated on for traction-rhegmatogenous retinal detachment, 2 for severe fibrovascular proliferation complicated intraoperatively by iatrogenic holes with surrounding retinal detachment. The intraoperative use of perfluorodecalin allowed flattening of the retina and endophotocoagulation to be carried out easily. Perfluorodecalin was removed at the end of the procedure, and intraocular tamponade was provided by silicone oil in 5 eyes and by a long-acting gas in 4 eyes. Anatomic success was obtained in 8/9 cases with a minimum follow-up of six months; 4 eyes had improved vision, 2 had the same vision, and 3 had decreased vision. The main advantage of intraoperative use of perfluordecalin is to allow easy flattening of the retina and effective endophotocoagulation under optimal visual conditions.

Adult↗
PubMed1991

[Transitory evoked otoacoustic emissions in isolated high frequency, low frequency and middle frequency hearing].

Transient evoked otoacoustic emissions (TEOAE) of 153 patients of various ages with normal or nearly normal hearing in the low, high or middle frequency ranges (different aetiologies) have been recorded. We found that the rate of detection of otoacoustic emissions depends on the width of the frequency range of preserved hearing. Single cases of narrow bands of hearing in the middle frequency region showed this region's significance for the high detectability of TEOAE. Although the investigated population consists mainly of adults, conclusions for the use of the TEOAE method for infant screening are drawn.

Audiometry, Pure-Tone↗
PubMed1989

[Culture of retinal capillary endothelial cells].

The culture of retinal capillary endothelial cells involves certain problems concerning contamination by pericytes, the maintenance of differentiation and the duration of culture viability. A procedure for the isolation and culture of capillary endothelial cells from bovine retina which overcomes these difficulties, is described. Microvessel fragments isolated by mechanical dispersion and filtration techniques adhere strongly to dishes coated with extracellular matrix produced by bovine corneal endothelial cells. The first migrating cells emerge from the original microvessel fragments two days after plating. This technique and subsequent cloning provides migrating and proliferating cells derived only from the retinal capillaries and uncontaminated by other cell types such as pericytes. Endothelial cells were grown on gelatin coated dishes in a serum supplemented medium (10% calf serum). Cell proliferation was significantly enhanced by the addition of basic fibroblast growth factor (1 ng/ml) to the culture medium. In these culture conditions, retinal capillary endothelial cells can be repeatedly passing without the loss of their principal morphological characteristics and some of the differentiated properties of endothelial cells. Primary cultures and subcultures, at least up to the 8th passage, formed a monolayer of small, elongated, tightly-packed, contact inhibited cells which expressed Factor VIII-related antigen. Ultrastructural examination by transmission electron microscopy of confluent bovine retinal capillary endothelial cells showed many tight junctions and Webel Palade granules. These studies provide new means for the isolation and culture of retinal capillary endothelial cells and presents evidence for growth factor requirements for the ability of cells to be repeatedly passing.

Animals↗
PubMed1989

[Auditory and communication learning in patients with cochlear implants].

Nowadays the cochlear implant (CI) offers a new method of hearing, especially for deaf patients who do not benefit from conventional hearing aids. However, it may be difficult to get used to this kind of hearing advice. CI users have special problems in interpreting strange acoustic sensations and relating them to auditory features of language and noise they knew before the onset of deafness. An interdisciplinary approach is very important for rehabilitation. Beside otological examination and the surgical implantation, audiological assessment is needed for the correct adjustment of the speech processor and for measurement of performance. Also auditory management and counselling of deaf patients is an important part of CI rehabilitation. A learning programme in hearing and communicating ("hearing training") is offered to CI users that takes account of different linguistic levels. Auditory learning by the use of CI is based on different abilities of the deaf patient, of which the most important are speech skills and learning capacity. Although success rates vary, it certainly improves speech intelligibility during lip reading, communication behaviour, and recognition of environmental noise. The latter ability improves orientation in the acoustic surroundings. CI rehabilitation may improve the psychosocial attitude of the deaf.

Cochlear Implants↗
PubMed1988

Immunological analysis of the aqueous humour in candida endophthalmitis. II: Clinical study.

An anterior chamber paracentesis was carried out on six patients with candida endophthalmitis and on control subjects. We endeavoured to find out if there was local production of antibodies by evaluating the anti-candida antibody titres, the immunoglobulin G, and the albumin levels in the aqueous humour and in the serum. A significant difference in the level of specific antibodies between patients and controls was found. Local synthesis of anti-candida antibodies was discovered in five out of six patients with candida endophthalmitis. There would seem to be a correlation between the severity of uveitis and antibody titres.

Adult↗