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Biomedical subjects

L Feenstra

Publications and source records attributed to L Feenstra.

At least 127 records · Page 7Linked to original sources
PubMed1984

New perspectives in myringoplasty.

Until 1950 the treatment of a perforated eardrum consisted of covering the drum permanently with artificial material. Since then a surgical technique to establish a functional reconstruction of the eardrum was developed (myringoplasty). A survey of the biological grafting materials used in this technique is given. Biodegradable and non-degradable synthetic materials may prove to be a valuable supplement of the existing biological grafting materials. Artificial eardrums made from several biodegradable poly(alpha-hydroxy acids) and poly(alpha-amino acids) and made from a number of microporous poly(tetrafluorethylene) membranes and from a microporous bisphenol-A poly(carbonate) membrane were implanted into the ears of rats and dogs and as a reference subcutaneously. The implants were histologically examined for periods up to one year. From the biodegradable polymers studied poly(beta-benzyl-L-aspartate-co-L-leucine) 50/50 evoked the least tissue reaction and the newly formed eardrums were the best in terms of thickness and overall integrity. The formation of a reinforced eardrum may be accomplished by the support of an inert, very thin, highly porous poly(tetrafluoroethylene membrane) preferably implanted as a composite graft with a biodegradable polymer.

Animals↗
PubMed1983

The mastoid approach for brain herniation into the middle ear.

A mastoid approach to replace middle ear brain tissue herniation is advocated. Ten patients have been successfully treated without complication over a period of 7 yr with our method which basically makes use of temporalis fascia and pieces of mastoid bone.

Adolescent↗
PubMed1983

Kartagener's syndrome: clinical symptoms and laboratory studies.

The purpose of this study was to develop a research program for the detection of congenital malfunction of cilia in the respiratory tract of selected patients with chronic respiratory infection. A clear difference was found between patients with Kartagener's syndrome and patients with respiratory tract infections of unknown etiology by studying patients employing this program, including examination of mucociliary clearance, ciliary motility and ciliary ultrastructure. The name "primary ciliary dyskinesia" is appropriate for emcompassing several ciliary abnormalities.

Adolescent↗
PubMed1980

Experimental myringoplasty.

Artificial eardrums made from biodegradable poly(D,L-lactic acid), poly(glycolic acid) and poly(beta-benzyl-L-aspartate-co-L-leucine) 50/50, and made from the microporous poly(tetrafluoroethylene) and bisphenol-A poly(carbonate) membranes were implanted into the ear and as a reference subcutaneously in rats. The implants were histologically examined for periods up to one year. From the biodegradable polymers studied the poly(beta-benzyl-L-aspartate-co-L-leucine) 50/50 evoked the least tissue reaction and the newly formed tympanic membranes are the best in terms of thickness and overall integrity. The microporous poly(tetrafluoroethylene) membrane can be considered as a valuable support for the formation of a reinforced tympanic membrane.

Animals↗
PubMed1980

The immotile cilia syndrome: phase contrast light microscopy, scanning and transmission electron microscopy.

In the immotile cilia syndrome, transmission electron microscopy of the cilia shows abnormalities in the arrangement of the central pairs of tubules and in the dynein arms of the peripheral tubules, or in the radial spokes, We studied four nonrelated children, 9/12, 5, 6, and 6 years old, with situs inversus and a history of chronic sinusitis and bronchitis (Kartagener's syndrome) and four children in the same age group and with the same history, but without situs inversus. Under the phase contrast microscope no motile cilia were seen in the four patients with Kartagener's syndrome and in two of the four other children. Transmission electron microscopy showed aberrations in the cilia (absence of dyneim arms, random orientation of central tubules) in the patients with Kartagener's syndrome. Scanning electron microscopy revealed differences in morphology and arrangement of cilia between patients and controls. In the patients much more mucus was present on the mucosal surface. Furthermore, the cilia were in a state of disorder, with a multidirectional orientation instead of the parallel orientation seen in controls.

Child↗
PubMed1979

Surgical management of brain tissue herniation into the middle ear and mastoid.

In the well pneumatized temporal bone, the temporal lobe of the brain is separated from the middle ear and mastoid process by a thin layer of bone known as the tegmen. Congenital defects, infection, and trauma can alter this structure in such a way that cerebral tissue herniates into the ear. This unusual condition may precipitate numerous otologic problems such as hearing loss, trapped squamous epithelium, and the potential for meningitis or encephalitis. The purpose of this paper is to define the problem as well as discuss the diagnosis and surgical management. The authors feel this should be a team effort, in many cases employing the assistance of a neurosurgeon, as the repair must often be intradural. Case histories and an extensive review of the literature are to be included.

Adult↗
PubMed1977

Comparison of homograft preservation techniques.

Much practical experience with homograft materials has been gained in cardiac surgery, vascular surgery, orthopedics, plastic surgery, ophthalmology, and otology; and a fair amount is known about the morphological and histological consequences of the use of these materials. There are still arrears in chemical engineering in otology, but construction of better bioprostheses may become possible in the long run. Empirical data indicate that until that time the use of mercury salts and 70 per cent alcohol will remain the preservation techniques of choice in otology.

Alcohols↗
PubMed1977

Response of the nasal mucosa to allergen challenge measured by two different methods of rhinomanometry.

Nasal provocation tests with allergen (House Dust 5.0 mg/ml or Grass-Pollen 10000 Noon Units/ml) were performed on patients suffering from perennial rhinitis or pollinosis. The changes of the nasal passages before and after allergen challenge were measured by two different methods, (1) the rhinomanometry anterior (Balloon Method) and (2) the rhinomanometry posterior (V-P Method). No distinct differences were observed between results obtained by the two methods. Both are therefore considered suitable and applicable for nasal provocation tests. For a satisfactory result using both techniques, the measurements should be made within at least 30 minutes but preferably 60 minutes after the allergen challenge.

Adult↗