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The cytokeratin expression of cholesteatoma matrix, meatal epidermis and middle ear epithelium was investigated with six anticytokeratin monoclonal antibodies. One of these was broad specific and the other antibodies were directed against cytokeratins 4, 8, 10, 18 and 19 respectively. Immunoperoxidase staining of cryosections revealed the presence of cytokeratin 10 in cholesteatoma matrix and meatal epidermis. In contrast, middle ear epithelium was characterized by cytokeratins 4, 8, 18 and 19 and not by cytokeratin 10. An infrequent focal presence of cytokeratins 4, 18 and 19 was found in cholesteatoma. In general, the divergence between the cytokeratin expression of middle ear epithelium versus that of cholesteatoma and meatal epidermis suggests an epidermal origin of cholesteatoma. However, a metaplastic origin of cholesteatoma cannot be excluded because of the infrequent focal presence of cytokeratins 4, 18 and 19 in cholesteatoma.

This paper describes the clinical results of the application of dense hydroxyapatite assembly prostheses. A study of 60 patients with hydroxyapatite incus prostheses revealed an air-bone gap closure within 20 dB in 86.6% of the cases, and an air-bone gap closure of less than 10 dB in 60.6%. No improvement was seen in 5% of the patients. The follow-up period varied from 1 to 4 years with an average of 2 years, and the hearing gain remained constant during this period. Hydroxyapatite may be considered a useful material for reconstructive middle ear surgery.

In vascular smooth muscle of canine carotid artery segments the decrease in oxygen tension from approximately 550 mmHg to approximately 30 mmHg leads to a dose-dependent hyperpolarization and relaxation of the vessel strip. At PO2 values below approximately 15-20 mmHg depolarization and subsequent contraction were found. All changes of the parameters investigated were reversible. Indomethacin (10(-5) M) had no significant effect on the hypoxia-dependent potential and tension changes. The hyperpolarized part of the activation curve was obtained by plotting tension versus membrane potential values.

The present study deals with the behaviour of the erectile tissue of the nasal mucosa in the normal rat and after selective transection of the autonomic nerve supply, measured with physiological and histometrical techniques. In the normal animal cyclic changes in the patency of the nasal lumen occurs with a cyclus time of 61 min, disturbances being observed in this rhythm a few weeks after transection of the various autonomic nerves. Selective transection of the main route of the sympathetic or the parasympathetic systems results in a dominance of the antagonist (congestion or decongestion). Transection of both systems does not result in a significant change in the dilated state of the nasal cavity from normal, although the cyclic activity disappears. A tendency towards a normal nasal cycle was observed several months after transection.

In 35 patients, with an average follow-up period of 2 1/2 years, the middle ear was reconstructed with prostheses of hydroxyapatite, which is the main substance of living bone tissue. In case of a missing incus, an interposition prosthesis of dense hydroxyapatite was used. Defects in the bony posterior canal wall were reconstructed with a canal wall prosthesis of porous hydroxyapatite and cavities with a barefoot plate were reconstructed with a total alloplastic middle-ear implant, consisting of a canal wall of porous hydroxyapatite and a chain of wire and dense hydroxyapatite. With these prostheses, radical surgery of the middle ear can be combined with a physiological reconstruction.

Specimens of cholesteatoma matrix, meatal epidermis, and middle ear epithelium were removed during surgery, and immunohistochemical techniques were used to investigate cytokeratin expression. The use of five chain-specific anticytokeratin monoclonal antibodies and one broad specific anticytokeratin monoclonal antibody showed the divergent behavior of middle ear epithelium compared with the cytokeratin expression of the other two types of epithelium. Middle ear epithelium was characterized by the presence of cytokeratins 4, 8, 18, and 19, whereas in both cholesteatoma and meatal epidermis cytokeratin 10 predominated. Furthermore, cholesteatoma showed an infrequent focal presence of cytokeratins 4, 18, and 19. The similarity between cholesteatoma and meatal epidermis with respect to morphology, and the presence of cytokeratin 10 support an epidermal origin of cholesteatoma. However, a metaplastic origin cannot be excluded, because of the infrequent occurrence of a small amount of cytokeratins 4, 18, and 19 in cholesteatoma matrix that was not found in meatal epidermis but was a component of the cytokeratin pattern of middle ear epithelium.

In arterial smooth muscle with normal tone or predepolarized and precontracted by noradrenaline, prostacyclin (10(-9) to 10(-6) M) effects a dose-dependent hyperpolarization and relaxation. The hyperpolarization is due to K+ channel opening. In hypoxic vasodilatation, which is likewise induced by membrane hyperpolarization, a share of 20% falls to prostacyclin and 80% to an endothelium derived hyperpolarizing factor.

In the present study 141 children aged between 3 and 10 years and suffering from chronic maxillary sinusitis were treated non-selectively in one of 4 ways: amoxicillin combined with decongestive nose drops, drainage of the maxillary sinus, a combination of the two, or a placebo. The duration of the follow-up period was 6 months. The therapeutic effects of the 4 forms of treatment did not differ significantly. Haemophilus influenzae and streptococcus pneumoniae were the micro-organisms encountered most often in these children. The results are discussed.

In the present study the biological performance of macroporous and dense hydroxyapatite after implantation in the rat middle ear was evaluated during an induced Staphylococcus aureus middle ear infection. The course of the infection was similar to that in the absence of an implant. Hydroxyapatite was frequently integrated with fibrous ingrowths in the middle ear lumen, originating solely from the infection. Good epithelial covering of the implant with all types of epithelial cells of importance for middle ear defence, was found. Increase of the exudate in the pores due to the infection was relatively small, and most of the exudate was restricted to pores on the implant surface. The bony tissue in the pores was not influenced significantly by the induced infection. Degradation of hydroxyapatite was consistent with earlier results obtained in the non-infected middle ear. The results obtained so far suggest that hydroxyapatite is highly suitable for middle ear implantation.

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The present investigation comprises a retrospective and a prospective study on children with middle ear effusion (MEE). It is shown that, in the majority of patients, middle ear effusion was found in combination with an infective disease of other parts of the upper respiratory system, especially in the maxillary sinuses. Lavage of the infected sinuses resulted in resolution of the middle ear effusion in about 85 per cent of the cases, while adenoidectomy, in patients in whom adenoid enlargement was found together with middle ear effusion, had only a minor effect.

The autonomic innervation of the nasal mucosa has been studied in normal rats and in rats in which the supplying nerves had seen selectively transected; postoperative survival times varied from 2 weeks up to 18 months. The vascular structures appeared to be innervated both by acetylcholinesterase- and noradrenalin-containing fibres. Furthermore a nerve plexus consisting of both types of fibres was observed in the subepithelial region. The nasal glands however showed only a cholinergic innervation. The pattern of the autonomic nerve supply deduced from these selective denervation experiments does not differ fundamentally from the generally accepted scheme of this system in the nose of other mammals. Denervation occurred within 2 weeks after transection of the supplying nerves, but after longer survival times reinnervation was observed.

The intention of this study was to investigate the epithelial reactions to hydroxyapatite ceramic in vivo and in vitro. Shortly after implantation in the rat middle ear, hydroxyapatite was found covered by a mucosal layer. In the early postoperative period the implant was almost completely covered by epithelial cells, which were found to proliferate and also showed migratory activity. After longer intervals the implant was completely covered by epithelium, which was composed predominantly of flat polygonal cells and a relatively small number of ciliated epithelium and goblet cells. All cells showed normal morphology. In vitro experiments showed preservation of the morphology of rat middle-ear mucosa explants with good outgrowth of epithelial cells. In these outgrows, the majority of the cells were flat polygonal, but ciliated epithelium was also seen. No difference was found between the absence and presence of hydroxyapatite. Serially cultured cells displayed normal polygonal morphology, but no ciliated cells were found. Ciliated cells were also absent in control experiments without hydroxyapatite. Growth curves obtained in the absence and presence of hydroxyapatite did not differ significantly from each other.

The biological performance of macroporous beta-whitlockite implanted in the rat middle ear was evaluated. The material was studied in the non-infected middle ear and in middle ears infected by Staphylococcus aureus. beta-whitlockite was quickly covered by a normal mucosa. One week post-operatively the macropores were filled with exudate, fibrous tissue, and a small quantity of bone. Six months after the operation the greater part of the macropore area was filled with bone (74%); fibrous tissue accounted for 20%, and exudate for 5%. In histological sections, the macropore area of beta-whitlockite had increased by 68% after six months, indicating biodegradation. Macrophages and multinucleated cells were present in the vicinity of the implant and played a role in this biodegradation. Besides cytoplasmic vacuoles containing calcium phosphate, the cells showed smaller granules containing trace elements originally present in the implant material, such as silicon, titanium, aluminum, iron, and magnesium.

Bacteriologic and clinical features of 28 cases of traumatic marine injuries are described. The most common bacterial isolates were normal skin bacteria, Staphylococcus aureus and, in 11% of cases, Vibrio alginolyticus. All injuries responded to local wound care, and only half received antibiotic therapy.

To achieve a lasting result in reconstruction of the ossicular chain, strict material and surgical criteria must be combined. The best biomaterial, apart from bone, is hydroxyapatite, the mineral matrix of living bone tissue. For the reconstruction, the assembly technique is used instead of a columella. Direct contact with the drum membrane is not reliable if a columella is used, and extrusion or lateralization may influence postoperative results. In the case of a missing incus, an assembly prosthesis of dense hydroxyapatite is placed on top of the stapes head and the handle of the malleus, in a pocket between drum membrane and the neck of the malleus. Long postoperative follow-up of 120 patients showed an air-bone gap closure within 20 dB for 83.3% of the patients, no extrusion was observed, and the hearing gain stayed constant. Reconstruction of a tympanic membrane perforation and posterior canal wall was performed in the same stage in sixty patients. In the case of a missing incus and stapes superstructure, an incus/stapes prosthesis of dense hydroxyapatite, as assembly between footplate and handle of the malleus, was used. Long postoperative follow-up of twenty-five patients showed an air-bone gap closure within 20 dB for 68% of the patients. Reconstruction of a tympanic membrane perforation and posterior canal wall was performed in sixteen patients. No extrusion was observed and the hearing gain stayed constant. Hydroxyapatite prostheses have proven to be a good alternative for autologous and homologous ossicles.

Implants of Silastic, Estane, polypropylene oxide and an HPOE/PBT segmented polyether polyester copolymer were qualitatively and quantitatively evaluated, with respect to interaction with mononuclear and multinucleated phagocytes as well as fibrous capsule formation, after implantation at three sites in the rat middle ear. The volume of the phagocyte exudate surrounding the implants, the degree of implant degradation and fragmentation and the thickness of the fibrous capsules were found to be correlated with the implantation site. From these findings, it can be concluded that it is important to assess the biological performance of a biomaterial at carefully chosen implantation sites.

The aim of this study was to obtain more information about macropore tissue ingrowth into the pores of sintered hydroxyapatite implanted in the rat middle ear, for the assessment of the usefulness of this material in reconstructive middle-ear surgery. The exudate filing the pores during the early post-operative period was gradually replaced by equal amounts of fibrous tissue and bone. The percentage of the macropore area occupied by bone was directly correlated with the macropore size. Bone was deposited not only from the pore wall towards the pore centre, but also in the opposite direction. Bonding osteogenesis was demonstrated. At sites of mechanical irritation, the presence of multinucleated cells and proliferatively active mononuclear phagocytes persisted for as long as a year. Under appropriate conditions hydroxyapatite seems to be a promising material for bone substitution in reconstructive middle-ear surgery.