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Biomedical subjects

L Feenstra

Publications and source records attributed to L Feenstra.

At least 109 records · Page 6Linked to original sources
PubMed1988

Serous otitis media (S.O.M.). A bacteriological study of the ear canal and the middle ear.

A bacteriological study of the middle-ear effusions and the ear canals in children with chronic serous otitis media (S.O.M.) was performed. Sixty-eight children (127 ears) were investigated. From this study it appeared that cleansing of the ear canal with 0.5% chlorhexidine in 70% ethanol for 30 s is partially effective; micro-organisms (diptheroids, Staphylococcus epidermidis) could still be isolated in 29%. Cleansing of the ear canal decreases the incidence of middle-ear fluid contamination by non-pathogenic ear canal organisms (diptheroids, Staphylococcus epidermidis, Aerococcus), but after cleansing, 'non-pathogenic' micro-organisms could still be isolated in 33% of the effusions (diptheroids, Staphylococcus epidermidis). From 12% of the middle-ear effusions pathogenic micro-organisms (Hemophilus influenzae, Staphylococcus pneumoniae) were isolated; cleansing of the ear canal did not influence this percentage. Anaerobics were not isolated from the middle-ear effusions.

Adolescent↗
PubMed1987

Primary ciliary dyskinesia and nasal mucociliary clearance.

In this study, nasal mucociliary clearance is investigated in patients with primary ciliary dyskinesia, patients with other respiratory tract infections and healthy persons. Mucociliary clearance is established with a drop of albumen labelled with 99m-Tc. From this study it appears that measurement of mucociliary clearance in the nose can serve as a reliable screening method. If a patient with respiratory tract infections shows a normal mucociliary clearance rate there is no primary ciliary dyskinesia, and a biopsy of ciliated epithelium is not necessary. If, after repeated examinations, a normal clearance rate cannot be demonstrated, a biopsy of ciliated epithelium should be taken for studying ciliary activity and ciliary ultrastructure.

Cilia↗
PubMed1986

Studies on the mechanics of the normal human middle ear.

The middle ear was studied in temporal bone preparations using a laser-Doppler interferometer. For measurements at a sound level of 80 dB SPL this method proved to be very reliable, as was shown by good reproducibility of results in experiments over more than 6 hours. The vibrations of the tympanic membrane and stapes footplate were studied from 200 Hz to 10 KHz and the results demonstrate a piston-like movement of the stapes footplate up to 120 dB SPL. The damping effect of the normal ear is located mainly at the footplate/cochlea level and the middle ear cavity per se does not contribute significantly to the stiffness of the middle ear system.

Acoustic Stimulation↗
PubMed1986

Studies on the mechanics of the reconstructed human middle ear.

Using a laser-Doppler interferometer the influence of different positions of an incus prosthesis on hearing performance was examined in human temporal bone preparations. The influence of position and tension of a malleus to footplate prosthesis (columella) was studied in the same way. It is concluded that an incus prosthesis should be placed along an imaginary line through the centre of the footplate and the head of the stapes. With a malleus to footplate prosthesis the position on the footplate is relatively unimportant. Tension between the malleus, prosthesis and footplate, however, is quite important and should be as low as possible, and compatible with a stable situation. The malleus to footplate prosthesis provides a columella type of prosthesis which for lower frequencies works better than an incus prosthesis, and occasionally even better than the normal ear.

Biomechanical Phenomena↗
PubMed1985

Mollaret's meningitis responding to phenylbutazonum. A case report.

A patient with Mollaret's meningitis is presented, with some unusual features. Criteria for the diagnosis are discussed. Many therapies for this recurrent aseptic meningitis have been suggested. In our patient there was a good response to phenylbutazonum, which to our knowledge has not been reported before.

Body Temperature↗
PubMed1985

Patients with an acoustic neurinoma examined with a tilting room.

Patients with acoustic neurinomas do not usually show vertigo or spontaneous nystagmus, suggesting a gradual decrease of vestibular function with adequate compensation. Seventeen patients with acoustic neurinoma were examined to test their postural control. Examination in the tilting room showed a visual dominance in postural control with these patients irrespective of involvement of the central vestibular system. The subjective horizon was determined in addition to routine audiovestibular examination, to be informed about the compensation process. When routine audiovestibular examination points to an acoustic neurinoma, a pathological subjective horizon favours the diagnosis, although this is not mandatory. The combination of tilting room and stabilometry is superior in detecting visual dominance to the standard Romberg test.

Humans↗
PubMed1985

Verification of the air-bone gap using cancellation and evoked responses.

Using the cancellation method as well as evoked responses, we investigated their application in the estimation of the air-bone gap in patients undergoing operation on middle ear structures. The cancellation method had a closer relationship with pure-tone audiometry than evoked responses in predicting the air-bone gap. This was caused by recruitment, by which the cancellation method was not affected. The results of brainstem-evoked responses to bone and air conduction signals showed therefore an underestimation in the prediction of the air-bone gap. Combining the cancellation method with evoked responses elicited to air conduction signals permitted the estimation of the cochlear reserve without the need of threshold measurement by bone conduction.

Adult↗
PubMed1985

Surgical treatment of brain herniation into the middle ear and mastoid.

A series of thirty-five patients operated on for brain herniation into the middle ear and mastoid is presented. The etiologic factor was felt to be previous surgery in twenty-six cases, head trauma in four cases, chronic otomastoiditis in four cases, congenital dehiscence of the tegmen in one case, and subdural empyema in one case. Diagnosis and treatment of brain herniation are discussed. The mastoid approach for repair of tegmen defects from below with the use of homologous cartilage or autologous cortical bone is advocated. A combined procedure using the transmastoid approach plus a mini-craniotomy of the temporalis squama is suggested as an alternative treatment to middle cranial fossa repair for larger cerebral hernias.

Adolescent↗
PubMed1984

The concept of an artificial tympanic membrane.

A review is given of the development of the concept of an artificial tympanic membrane. Starting with homologous tympanic membranes we compared biodegradable collagen materials (homologous and heterologous) and biodegradable synthetic materials, poly-glycolic acid, poly-lactic acid and poly-alpha-amino acids. As a non-degradable material microporous PTFE and bisphenol-A poly (carbonate) were investigated. It is concluded that either poly-alpha-amino acid or PTFE with poly-alpha-amino acid maybe a suitable material for an artificial tympanic membrane.

Animals↗