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Biomedical subjects

M Anniko

Publications and source records attributed to M Anniko.

At least 19 recordsLinked to original sources
PubMed1992

Age-dependent disruption of basal lamina and extracellular matrix formation in L-proline analog treated otic explants.

L-azetidine-2-carboxylic acid, LACA, a naturally occurring vegetable imino acid, can be incorporated into mammal proteins instead of proline. This incorporation has an especially inhibitive effect on collagen secretion. Exposure of embryonic mouse inner ear explants to LACA causes dysmorphogenesis and retarded differentiation, reduces the number of collagen fibrils in the perilymphatic spaces and capsules, and gives rise to a dose-dependent derangement of the basal lamina. In control specimens, both in vivo and in vitro, the inner ear epithelia had a dense contiguous basal lamina overlying a well-developed network of collagen fibrils. When the inner ears were exposed to LACA at a concentration of 150 micrograms per ml of medium, there was a loss of the collagen network and gaps appeared in the basal lamina. At exposure to 300 micrograms LACA/ml, scarcely any collagen fibrils were present and the basal lamina was disrupted in many areas, especially beneath the sensory epithelia.

Animals↗
PubMed1992

Cochlear structure and function in a recessive type of genetically induced inner ear degeneration.

An age-related consecutive morphological analysis of the cochlea has been performed in homozygote (je/je) and heterozygote (je/+) jerker mouse mutants. A difference in the time of onset of hair cell pathology was evident between the two, but, when taking place, it showed a similar morphological type of degeneration. The cuticular plate and the stereocilia are particularly vulnerable structures and are the primary sites of damage. The suprastructures on both outer and inner hair cells disintegrate at the same time, irrespective of the level along the basilar membrane. During aging, the je/+ animals showed a progressive age-related impairment of auditory brainstem response thresholds which was correlated semiquantitatively to hair cell pathology.

Age Factors↗
PubMed1992

Characteristic ionic composition of endolymph is maintained in cultured inner ear.

Inner ear anlagen from mouse were explanted on the 16th gestational day (gd) and cultured for 5 days, i.e. corresponding to the time of birth. By using energy dispersive X-ray technique an elemental composition characteristic for endolymph was found within the membranous labyrinth of the explants. The sodium to potassium ratio in the endolymphatic space of the cultured inner ears corresponded to endolymph of the 16th gd fetus in vivo. There was no difference in the endolymph compartment between the cochlear and vestibular halves of the in vitro specimens. Differences in Na to K ratio between endolymph of the inner ears and the surrounding medium were statistically significant. Thus, endolymph-regulating mechanisms are active also under organ culture conditions, although not fully optimal.

Animals↗
PubMed1992

Genetically induced inner ear degeneration. A structural and functional study.

The jerker mouse mutant has an autosomal recessive mutation, which in homozygotes results in early postnatal degeneration of the sensory epithelia in both the cochlea and vestibulum. An age-related consecutive functional and morphological analysis of the cochlea has been performed in homozygote (je/je) and heterozygote (je/+) jerker mice. Cochlear function was determined with auditory brainstem response (ABR) technique. Heterozygotes were regularly tested to a final age of 12 months. With increasing age they displayed ABR threshold shifts which were of about the same magnitude in the whole frequency range tested (2-31.5 kHz) but extremely variable in individual animals. From homozygote jerker mice no ABR could be elicited. There was a similar morphologic pattern of cochlear degeneration in both homozygote and heterozygote jerker mice affecting primarily the stereocilia and cuticular plate in both outer and inner hair cells. In homozygotes these changes were found in very young animals but in heterozygotes they did not become evident until later in life. All parts of the cochlea became simultaneously affected, that means there was no topographical gradient in the pathological course. The ABR thresholds in 12 months old heterozygotes were correlated semiquantitatively to hair cell pathology in the cochlea. The functional and morphological changes in heterozygotes probably reflect a random influence of the jerker gene vis-à-vis the wild type of gene.

Animals↗
PubMed1992

Cochlear effects of hyaluronan applied on ruptured round window membrane.

The purpose of the present experimental study was to determine whether hyaluronan (hyaluronic acid, HYA) exerts any functional or morphologic ototoxic effects on the cochlea when in contact with a ruptured round window membrane (RWM). HYA in 1% solution was applied in the round window (RW) niche of rats (n = 6) prior to perforating the RWM. In a control group (n = 6) the RWM was perforated alone. Cochlear functioning and structure were monitored by recording auditory brainstem responses (ABRs) at 2-31.5 kHz and by scanning electron microscopy. Perforation of the RWM alone resulted in immediate loss of ABR thresholds between 6 and 31.5 kHz in 2 of 6 animals. Similar results were obtained after application of HYA into the RW niche and subsequent RWM perforation. In both treatment groups the mean ABR thresholds and mean latencies for wave II at the ABR threshold returned to the pre-surgical (normal) range after 2 months. Also with respect to the cochlear morphology the results in both treatment groups were alike including minor structural changes in hair cell stereociliae but no loss of hair cells. It is concluded that HYA, when instilled into the middle ear with the inner ear opened, is free from cochlear ototoxic effects. Our present findings enhance the potential usefulness of HYA in otosurgery, even in cases when the inner ear has been opened and/or when one wishes to protect the inner ear.

Animals↗
PubMed1991

Repair of chronic tympanic membrane perforations using applications of hyaluronan or rice paper prostheses.

A controlled randomized study was performed in 60 patients with 64 chronic, dry tympanic membrane (TM) perforations. The perforations were randomly allocated to either resection of the perforation rim and instillation of 1% hyaluronan (Healon; HYA) in the perforation gap once daily for 7 days (33 ears) or resection of the perforation margin and application of a sterile rice paper prosthesis (31 ears). The treatment effect was documented by TM photography and morphometric measurements of the perforation area. The hearing was assessed with puretone and high-frequency audiometry. After 2 months, 5 of the HYA-treated perforations (15%) and 4 of the rice-paper-treated TMs (13%) were healed. After 1 year, 18 perforations (9 in each treatment group) were healed. In neither group were there any persistent adverse effects on hearing. It is noteworthy that 28% (18/64) of the chronic, long-standing TM perforations could be repaired by these technically simple and time-saving methods. Both procedures should be considered as easy first-choice alternatives to myringoplasty in selected cases.

Adolescent↗
PubMed1991

Acetylcholine receptor localization in human adult cochlear and vestibular hair cells.

The FITC technique using alpha-bungarotoxin visualized the staining pattern of acetylcholine (ACh) receptors in adult human cochlear and vestibular hair cells (HCs) in normal labyrinths and in cochleae with sensorineural hearing loss. Flourescence staining occurred in the cuticular plates of all HCs, indicating that the micromechanics of their suprastructures can act under cholinergic control. Quantitative differences of the fluorescence of ACh receptors occurred between the three rows of outer HCs at the same level in the cochlea and decreasing along a base-to-apex directed gradient. There is strong evidence that the subsurface cisterns are integrated in the efferent nerve system. In the degenerating organ of Corti an uncoupling of the efferent system takes places adjacent to disintegrating HCs, though the staining in the cuticular plates remains until a very late stage in HC disintegration. In vestibular HCs type I, fluorescence is emitted in the supranuclear area of the cytoplasm below the cuticular plate probably indicating an efferent guidance on the afferent nerve transmission directly via the HC itself.

Adult↗
PubMed1991

Hyaluronan applied to lesioned round window membrane is free from cochlear ototoxicity.

Hyaluronan (HYA) in 1% solution was instilled into the round window (RW) niche of rats (n = 6) prior to perforating the round window membrane (RWM). Cochlear functioning and structure were then monitored by recording auditory brainstem responses (ABRs) at 2-31.5 kHz and by scanning electron microscopy. Perforation of the RWM alone (n = 6) resulted in immediate loss of ABR thresholds between 6 and 31.5 kHz in 2 of 6 animals. Similar results were obtained after instilling HYA into the RW niche and subsequent RWM perforation (n = 6). After 2 months, ABR thresholds were recorded at all frequencies in the HYA-treated animals, whereas in 2 of the controls no ABR thresholds could be elicited at 20 and 31.5 kHz. However, in both treatment groups the mean ABR thresholds and mean latencies for wave II at the ABR threshold returned to the pre-surgical (normal) range after 2 months. With respect to the cochlear morphology the results in both treatment groups were also alike including minor structural changes in hair cell stereociliae but no loss of hair cells. It is concluded that HYA, when instilled into the middle ear with the inner ear opened, is free from cochlear otoxicity.

Animals↗
PubMed1990

Freeze-fracture and immunomorphological analysis of spiral ganglion cells.

Freeze-fracture analysis of adult spiral ganglion cells of CBA/CBA mice revealed two types of membrane specializations. Most cells (type I) had a smooth surface and were surrounded by Schwann cells. Type II spiral ganglion cells showed numerous membrane specializations with well-delineated indentations similar to those previously found on hair cells adjacent to afferent and efferent nerve endings. Immunomorphological analysis (using well-defined monoclonal antibodies directed against different subclasses of intermediate filament proteins) revealed a unique co-expression of neurofilaments, vimentin and cytokeratins in spiral ganglion cells of 8- to 22-week human fetuses.

Animals↗
PubMed1990

Regional variations in the expression of cytokeratin proteins in the adult human cochlea.

In the adult human cochlea, a cytokeratin (Ck) network exists along the entire surface of the organ of Corti, enclosing it like a shell. Only the surfaces of the outer and inner hair cells are not integrated in this network. In temporal bone specimens, Ck filaments in Hensen's cells were found to be arranged parallel with and closely apposed to the plasma membrane. In the stria vascularis, Cks were identified only in the marginal cells. Cells in Reissner's membrane and spiral prominence showed varying degrees of immunoreactivity to different monoclonal antibodies directed against Cks. A distinct positivity for Cks was found in most spiral ganglion cells, indicating their presence in all cells. The principal pattern of immunoreactivity was the same in the organ of Corti of the entire cochlea. However, a quantitative gradient in the expression of Cks was observed, with more Cks at the apex than at the base. This was correlated to a difference in the number of Hensen's cells between the two regions. The distinct shell configuration of the Ck network in Corti's organ gives it a tonotopically related difference in rigidity which must be of considerable importance for the perception of sound in the cochlea. The absence of Cks in inner and outer sulcus cells gives them cytoskeletal characteristics of mesenchymal cells with a possible regenerative potential.

Adult↗
PubMed1990

Electrophysiological effects of the clinically used local anesthetics lidocaine, lidocaine-prilocaine and phenol on the rat's inner ear.

Local anesthetics, even if applied to the outer ear canal, may still enter the middle ear, running the risk of penetrating the round window. To elucidate the effect of certain topical anesthetics on the inner ear, the round window niche in the laboratory rat's middle ear was exposed separately to lidocaine, lidocaine-prilocaine and phenol. Auditory brain-stem responses (ABR) were recorded at 2, 4, 6, 8, 12, 16, 20, and 31.5 kHz before the application, and 24 h, 3 weeks, 2 months and 6 months after exposure. After terminating the 6-month ABR measurements, the animal were sacrificed and the temporal bones fixed and decalcified for light microscopic analysis. All three drugs affected the ABR thresholds and the cochlear morphology with a pattern characteristic for each drug. At 24 h, all three substances caused severe impairment of ABR thresholds, followed by a period of restitution lasting up to 2 months. Even 6 months after exposure, the ABR thresholds at and above 12 kHz were impaired, as compared with the pretreatment level, for all substances tested. In the lower frequencies the original ABR threshold was reached in the order: (1) lidocaine, (2) lidocaine-prilocaine, (3) phenol. The cochlear structures were unaffected by lidocaine, whereas lidocaine-prilocaine and phenol caused morphological damage which was most pronounced after exposure to phenol. The heterogeneity of the changes in the ABR thresholds suggests differences in the mechanism of action of each type of local anesthetic investigated. The effects following lidocaine were transient. However, clinicians must be aware of the ototoxic potential of both lidocaine and phenol.

Anesthetics, Local↗
PubMed1990

Morphologically specific vestibular hair cell degeneration in the jerker mouse mutant.

The vestibular organs in homozygote (je/je) and heterozygote (je/+) 1- to 12-month-old jerker mouse mutants were analyzed morphologically using light microscopy and transmission and scanning electron microscopy. The pathological changes were initially confined to the surface structure of predominantly type I hair cells. The latter cells showed disintegration of the cuticular plate, disarray of stereocilia and finally fusion of sensory hairs. The hair cells were then expelled into the endolymphatic space. A notable finding was that most expelled hair cells still showed a rather normal ultrastructure of their cytoplasm and nuclei. The morphological type of pathology was the same in je/je and je/+ mutants. However, in je/je animals the degeneration occurred within 1-3 months after birth, whereas in je/+ mutants a slowly progressive degeneration lasted for up to 1 year of age or even more. The degeneration was more extensive in the two maculae than in the three cristae ampullares.

Aging↗
PubMed1990

[The cytokeratin skeleton of the human organ of Corti and its functional significance].

In the adult human organ of Corti cytokeratin (CK) is expressed by all supporting cells enclosing it like a shell. The pattern of immunoreactivity clearly demonstrates a quantitative gradient in the expression of CK, with more CK at the apex than at the base of the cochlea. Predominantly in the apical cochlear turns, the CK-shell separates the compartment of the inner hair cells from that of the outer hair cells. Ultrastructurally, the supporting cells contain a loose fibrillary network which apically is oriented toward the desmosome chain and which can be clearly distinguished from the well-known tubular filaments (microtubuli). Some supporting cells show centrioles. Both the expression of CK and the presence of centrioles indicate a possible potential for cell regeneration. Ultrastructurally, outer hair cells and Deiters' cells show features of a specialized contact zone which might be of functional significance regarding the contractile abilities of the outer hair cells. In the human organ of Corti, vimentin is expressed only by the inner and outer pillar cells. These cells thus express CK together with vimentin. The distinct shell configuration of the CK network in the organ of Corti gives it a tonotopically related difference in rigidity which not only must be of importance for cochlear perception of sound but also could explain the reduced vulnerability of the ear to low frequencies.

Cytoskeleton↗
PubMed1990

[Functional morphology of the outer hair cells of the human: new aspects].

Serial sections through the outer hair cells of the human organ of Corti were investigated using high-resolution electron microscopy. Delicate monostratified tubular structures of differing lengths are located on the cytoplasmic side of the hair-cell membrane. They are connected to the cell membrane via short fibers (pillars) arranged in pairs. The tubular structures, which are also termed subsurface cisterns (SSC), constitute an extensive network. This network lines the entire inner surface of the outer hair-cell membrane, and in contrast to the mammals investigated so far, also lines the base of the cell. The postsynaptic cisterns of the efferent synapses are integrated into this system. At the surface of the inner lamina of the cisterns, pores 8.5 nm in diameter are to be found. These are surrounded by protein complexes with a stellate arrangement. Similar protein complexes are located on the inner lamina of the postsynaptic cisterns. Pores 8.5 nm in diameter are also present in the outer lamina of the SSC. These constitute the base for the pillar filaments. At high magnification, the pillars are seen to have a lumen about 6 nm in diameter. Pores about 8 nm in diameter are again to be found where the pillars are anchored in the outer cell membrane. The pillars, consisting of actin, are probably ionic channels, and the pores of the inner lamina of the SSC surrounded by protein complexes are thought to be acetylcholine receptors. Since the postsynaptic cisterns of the efferent innervation of the outer hair cells are part of the overall system of the SSC, and acetylcholine is regarded as the neurotransmitter of efferent innervation, it would seem possible to regulate the subsurface cisterns, as a wall-stabilizing, contractile system, via the efferent innervation. On the basis of serial sections, a three-dimensional, true-to-scale model of the contractile wall system of the human outer hair cell was reconstructed.

Adult↗
PubMed1990

Sealing of the round window reversibly affects auditory brainstem response latencies.

The round window (RW) niche was sealed in 12 adult female albino Sprague-Dawley rats. Electrophysiological auditory function was measured with a computerized auditory brainstem response (ABR) recording technique, using 1- and 6 kHz stimuli. ABR measurements were performed prior to closure of the niche, immediately after the sealing, and 4 h, 24 h and 7 days later. After sealing, the latencies elicited by a 6 kHz stimulus increased, but returned to normal between 24 h and 7 days after closure. Stimulation with 1 kHz did not influence the latencies in such a clear-cut manner as when using 6 kHz. It is conceivable that sealing of the RW deprives a minor fraction of oxygen supplied to the basal part of the cochlea through the RW membrane, a procedure which by us is monitored as transient electrophysiological changes.

Animals↗
PubMed1990

Long-term survival of patients with paranasal sinus carcinoma.

The survival rate for all patients with a squamous cell carcinoma of the paranasal sinuses (n = 77) diagnosed in 1960-1985 in a population of approximately 1 million inhabitants was analysed without any selection of cases. This population is geographically restricted to the most northern part of Sweden. The 5-year survival rates of patients with T3 and T4 carcinomas were 42 and 14%, respectively (corrected survival), and the 10-year survival rates were 40 and 14%, respectively. In patients with tumours which initially were considered as resectable, the optimal treatment modality was a combination of radiotherapy and surgery.

Carcinoma, Squamous Cell↗