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Biomedical subjects

M Portmann

Publications and source records attributed to M Portmann.

At least 19 recordsLinked to original sources
PubMed1992

Laser micromanipulation in the mouse embryo: a novel approach to zona drilling.

OBJECTIVE: To introduce the use of excimer lasers for penetration of the zona pellucida for micromanipulation purposes. DESIGN: Cryopreserved two-cell mouse embryos were thawed and exposed to the 248-nm line of a krypton fluoride excimer laser (Lambda Physik EMG 202, Goettingen, Germany) creating a 2 to 4-micron opening in the zona pellucida. SETTING: The Laser Ablation Laboratory at DuPont and the in Vitro Fertilization Laboratory at The Medical Center. INTERVENTIONS: The embryos were exposed in either phosphate-buffered solution (PBS) or modified human tubal fluid (HTF) with the laser power varying from 1 to 2 J/cm2 and cultured in Ham's F-10 medium (GIBCO, Grand Island, NY) with 0.4% bovine serum albumin. MAIN OUTCOME MEASURES: The outcome of each experiment was measured by blastocyst formation of laser-exposed embryos as compared with a set of unexposed control embryos handled in a similar fashion. RESULTS: Successful laser penetration of the zona pellucida was achieved using the 248-nm line of a krypton fluoride excimer laser. A higher blastocyst formation was found for embryos exposed in PBS. The higher optical absorption of the modified HTF partially inhibited embryo development. The blastocyst statistics increased 2.5-fold times by reducing the exposure of the embryos to ablation by-products. CONCLUSIONS: The use of a krypton fluoride excimer laser was introduced as a new method to open the zona pellucida of two-cell mouse embryos without interrupting blastocyst formation.

Animals↗
PubMed1992

Problems in alloplastic middle ear reconstruction.

Alloplastic materials have been used in middle ear reconstruction since 1952. Biologically, biomaterials and specifically ceramics can be defined as being bioinert, bioactive or biodegradable; these terms being descriptive of the biochemical response provoked by the material in the host tissue. Various ceramics, carbons and polymers and their reactions have been studied by the author and his colleagues over the past 5 years utilising animal implantation and fibroblast culture studies aligned with experience from clinical usage. The qualities of the ideal alloplastic implant namely: biocompatibility, stabilisation and incorporation, the consistency of the implant and bioactive bonding and the biofunctionality or mechanics, are applied to the materials currently available. No single alloplastic material fulfills all criteria, the problems encountered in relation to the biomaterials are reported. A better understanding of the microstresses, fatigue and microfractures is necessary, before the ideal alloplastic biomaterial becomes available.

Animals↗
PubMed1992

[Congenital cholesteatoma of the middle ear and mastoid. Apropos of 5 cases].

Five cases of congenital cholesteatoma of the middle ear and mastoid as defined by Derlacki's criteria were encountered over a 14 month period. They make up 5% of all cases of cholesteatoma managed over the same period of time. Three were young children and all presented with unilateral hearing loss. One had associated multiple congenital abnormalities of the external and middle ear. Only in one patient was the diagnosis made on initial otoscopic examination and the remainder diagnosed on CTscan, myringotomy and tympanotomy. All were operated on; three by the intact canal wall technique, one by the canal down technique with mastoid cavity obliteration and one by atticotomy with lateral attic wall reconstruction. One patient required a second stage operation for excision of an extension of disease deep to the superior semicircular canal via the middle cranial fossa approach in order to preserve cochlear function. These five cases illustrate the diagnostic pitfalls of this condition in which silent danger lurks behind an intact tympanic membrane.

Adult↗
PubMed1992

[Apropos of the infratemporal pre-auricular approach (its value in the approach to the midline skull base].

The role of the infratemporal pre-auricular pathway to the median base of the skull resides in the fact that it enables very wide access to this region while sparing the facial and auditory nerves. Among the operations performed on the approaches of the base of the skull by their teams, the authors chose a particularly typical observation dealing with the indication of this pathway: a 34-year old male with a giant cholesteatoma of the tip of the petrous bone totally surrounding the internal carotid artery along its entire (intrapetrous) length, from the cervical region to the cavernous sinus, having invaded the clivus and pushed back the brainstem. This lesion is located on the side of the only healthy ear. The patient is completely deaf in the ear on the other side. The operation enabled its complete exeresis while respecting the facial, auditive and vestibular functions.

Adult↗
PubMed1991

[Biomaterials in otology].

Biomaterial may be biological or non-biological in origin. Only the latter will be considered here. Their possible use in otology is threefold: ossiculoplasty: the author recalls the different materials used during the past 30 years. Today, it seems that only certain ceramics are able to compete with auto and homografts. Hydroxylapatite ossicles are a perfectly good alternative; canal wall reconstruction in radical operations: in this context their role appears to be less satisfactory than that of autografts; cavity obliteration: very useful and effective when performed in the correct situation and under certain well-defined technical conditions. After outlining the different materials used in the past 30 years, the author draws upon the experience of his own school to give his personal opinion.

Biocompatible Materials↗
PubMed1991

Results of middle ear reconstruction surgery.

Reconstructive surgery of the middle ear comprises two types of operations, i.e. reconstruction of the surroundings of the middle ear (external auditory canal) and reconstruction of the tympano ossicular contents of the middle ear (tympano-ossiculoplasty). Reconstruction of the external auditory canal may be total after certain open techniques, or partial after certain closed techniques. The results are markedly better when cortical bone autografts are used rather than materials such as Ceravital or Hydroxylapatite. Furthermore, cavity obliteration gives excellent results in 90% of cases (using bone powder, biomaterial powder, fibrin glue and covering muscular flaps). Tympano-ossiculoplasty gives on the whole, good results. Based on statistics of over 2200 cases, the author dwells in particular on the use of ossicular homografts, the results of which are generally superior to those of the best biomaterial (Ceravital and Hydroxylapatite).

Ear Diseases↗
PubMed1991

[Post-traumatic facial paralysis without any fracture of the petrous bone].

Post-traumatic facial palsies are generally observed after a transverse, longitudinal or comminuted fracture of the pars petrosa. Occasionally, the fracture does not involve the Fallopian aqueduct and another mechanism must be sought. The authors present a case of facial palsy that occurred after a Le Fort's fracture of the base of the skull, not involving the Fallopian aqueduct on the CT scan. This was confirmed by surgical exploration. The authors recall the possibility of a facial palsy through the stretching of the nerve by the petrosal nerve.

Adult↗
PubMed1991

[Exostosis of the external auditory canal: clinical and therapeutic aspects].

Based on the study of 25 cases, the authors recall the frequency and pathogeny of these lesions, specifying the surgical technique and presenting their results. The risks of this surgery lie in the ever possible impairment of the facial nerve and labyrinthization on treble frequencies (2 cases). The incidents are tympanic perforation (1 case) and the opening of the temporomandibular joint. It is not always possible to preserve the skin of the external auditory canal. It can be reconstructed by a free (3 cases) or pedicle (3 cases) graft of more simply in case of small loss of substance by a temporal fascia graft.

Adolescent↗
PubMed1991

[Bulbar auditory nuclei: morphological study, consequences for implantation of electrodes].

Many bilaterally profoundly deaf individuals cannot benefit from a cochlear implant because the eight nerve is not intact from the cochlea to the brain stem. For these individuals, electrical stimulation of the cochlear nuclear complex (CNC) may partially restore the sensation of hearing. Histological studies were done on 12 brain stems containing the region of the CNC and findings of this study seems important to accurate implantation of the prosthesis on the CNC for chronic electrical stimulation. Apparently the spheroid cells of the inferior ventral cochlear nucleus (IVCN) represents the site of the CNC for such stimulation.

Adult↗
PubMed1990

[Synergism between noise and ototoxic drugs: new experimental data].

Results of experiments investigating, in the guinea pig, the effects of combinations of gentamicin (GM), ethacrynic acid (EA) and acoustic stimulations are reported. They indicate that functional and morphological alterations develop only after GM has penetrated specifically into the sensory cells, that this penetration is indirectly facilitated by EA, since it is known to increase GM concentration in endolymph, and directly by functional depolarization of the cell, as it occurs during normal acoustic stimulation.

Animals↗
PubMed1990

[Ménière's disease].

Ménière's disease is based upon a clinical definition: the traditional Ménière's triad, a physiopathological definition, and the presence of hydrops. If all cases of Ménière's disease suffer from hydrops, not all cases of hydrops suffer from Ménière's disease. Recent progress thanks to electrocochleography, determination of the summating potential and its possible reversability under the effect of glycerol, enables a more reliable diagnostic approach, which furthermore includes the usual clinical and para-clinical examinations. Medical treatment has several objectives: the action of water on the metabolism, action on the behaviour of the labyrinthine capillaries and the biology of neurosensorial cells, action on vestibular information and the receptivity of the nerve centres and finally on the patients' lifestyle. There are two predominant surgical techniques: decompression of the endolymphatic sac and transcranial neurectomy. Two other techniques are employed in more exceptional circumstances, and only in cases of very severe deafness: transoval destruction and translabyrinthine neurectomy. The ideal clinical profile corresponding to the indications for these four surgical methods is explained.

Audiometry, Evoked Response↗
PubMed1990

[Efficacy and tolerability of morniflumate in acute otitis in infants: results of a randomized study versus placebos].

In a randomized double-blind placebo-controlled, parallel group study, 79 infants with acute otitis media received treatment with suppositories containing either Nifluril (400 mg daily, morniflumate) or placebo for five days. Both groups of patients also received amoxicilline (50 mg/kg daily) for eight days. The combination of Nifluril with antibiotic therapy gave significantly greater relief from abnormalities of the tympanic membrane (after two days treatment), inflammation of the throat and nasal congestion than did antibiotic therapy alone. Overall clinical assessment confirmed a significantly greater recover rate in the Nifluril group compared with the placebo group. Very few side effects were recorded, limited to diarrhoea, without any drug interruption. Nifluril may be recommended as an effective safe adjuvant to the antibiotic treatment of acute otitis media in infants.

Acute Disease↗
PubMed1990

[Use of the Musco NT3 tympanic isopressor in tubal dysfunction. Apropos of 30 cases].

We have studied the tolerance and efficacy of tubal insufflations with the MUSCO NT3 isopressor (Bexen) in a sample of 30 patients suffering from chronic tubal pathology. The apparatus was modified for use with an Itar Catheter. We recorded a favourable evolution of serous otitis (9 cases of normalization), with little modification of the retraction pockets. The paraclinical study revealed a major and significant overall, audiometric and tympanometric improvement.

Adolescent↗
PubMed1990

[Management of open and closed cavities in otology].

Surgery of chronic otitis follows a few basic principles, some of which are long-standing but still topical. In the majority of cases, opening of the cavities of the middle ear uses one of the following two techniques: the open technique (radical mastoidectomy), or the closed technique (transmastoid approach or canal up technique). Whatever the technique used, a readjustment of the cavity is often indispensable to avoid any recurrence of the pathology (cholesteatoma) or the appearance of a new pathology (chronic otorrhea) and facilitates a functional step if required. Open techniques must therefore always follow the rule of the ratio V/S (where V = the volume of circulating air coming from outside, and S = the surface area of the skin of the cavity). This ratio is specific to each individual. The readjustment must enable either an increase of V (meatoconchaplasty) or a decrease of S (reconstruction of the posterior auditory canal, obliteration of the cavity), or a combination of the two. Closed techniques must also be adjusted to avoid any retraction towards the posterior or upper cavities. Depending on the clinical background and on the aggressivity of the pathology, the posterior tympanotomy can be closed, and the attic and aditus cavities of the middle ear separated by a bony fragment leaving the protympanum open upwards to enable normal ventilation towards the attic, the aditus and the antrum, or much more rarely, these cavities can be completely closed.

Chronic Disease↗
PubMed1975

[Acoustic neuroma. Apropos of a series of 40 cases].

The authors present statistics of 40 acoustic neuromas operated upon by micro-surgical technique in co-operation with oto-neuro-surgery. As regards clinical picture, all persons presenting with unilateral progressive sensoryneural deafness should be subjected to cochlear vestibular and radiologic examination. They advocated essentially two routes:--translabyrinthine approach for the tumours within the internal auditory meatus, --posterior fossa approach for the other tumours. They reported their results and analysed the major advantages of the microsurgical technique which diminish considerably the risk of this surgery, so that the functional result should be of first importance.

Adult↗