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Biomedical subjects

H Rask-Andersen

Publications and source records attributed to H Rask-Andersen.

At least 37 records · Page 2Linked to original sources
PubMed1997

Evaluation of quality of life and symptoms after translabyrinthine acoustic neuroma surgery.

OBJECTIVE: This study aimed to describe the consequences of acoustic neuroma surgery in terms of symptoms and quality of life. STUDY DESIGN: This study was a retrospective case review. SETTING: The surgery was conducted in Uppsala, Sweden. PATIENTS: A consecutive sample of acoustic neuroma patients operated on between 1988 and 1994. INTERVENTION: All patients had been operated on with the translabyrinthine technique. MAIN OUTCOME MEASURES: A questionnaire was constructed including questions about the surgery and symptoms. The House and Brackmann scale was used for grading facial function and the Brackmann and Bars scale was used for self-assessment of facial function. RESULTS: Follow-up data were collected by a postal questionnaire sent out and returned by 141 patients, which yielded a 90% response rate. Normal to moderately impaired facial function (House I-III) was evident in 85.2% of patients, although residual facial problems were reported. Most considered hearing to be worse after surgery (80%), and tinnitus was found in 60% of the sample. Balance problems (45%), dizziness (19%), and headache/pain (22%) were also reported. Work ability was affected in 23%, and 37% reported a continued need for medical consultations, mainly because of facial problems and pain. Most (89%) were pleased with the preoperative information. CONCLUSIONS: This study showed that few patients with acoustic neuroma had experienced negative social consequences after surgery. Although not linked to the operation, residual symptoms were reported that may necessitate further rehabilitation.

Adult↗
PubMed1996

Erythrocyte removal and blood clearance in the endolymphatic sac. An experimental and TEM study.

The endolymphatic sac (ES) appears to serve as an immunologic/phagocytic defence organ. This may involve both specific and unspecific cell reactions for removal of both endogenous waste products and debris and foreign material. The present study was carried out in order to investigate whether the ES is involved in the removal of blood from the inner ear. The round window was exposed and the stapedial artery experimentally lesioned to cause bleeding. The ES was taken out after various time intervals and analyzed by TEM and LM, care being taken to maintain the structural integrity at all levels. This was done in order to see if the endolymphatic sac is involved in the removal of blood from the inner ear. The results indicate that the ES possesses hitherto unknown specific cellular properties for the disposal of blood and blood corpuscles. It is believed that this system may represent an important physiological function for regulation of homeostatic equilibrium around the inner ear sensory structures. The results also offer further support for the existence of a longitudinal "flow" of endolymph from the cochlea into the ES. Judging from the time it takes for erythrocytes to appear in the duct and sac, this flow would seem to take about 1-2 h in the mouse.

Animals↗
PubMed1995

Natural killer cell response in the inner ear.

Heterologous tumor cells (human chronic myelogenous leukemia K-562 cells) were injected into the perilymph and skin in guinea pigs in order to study the induction of NK cell activity in the inner ear. An in vitro transmission electron microscopic and immunohistochemical study showed that K-562 cells were attacked by guinea pig large granular lymphocytes. K-562 cells injected through the round window membrane were found to be targeted by NK cells emerging from surrounding venules after 7 to 9 days. During this time morhological changes occurred in the organ of Corti and stria vacularis. These findings suggest that the inner ear response to foreign cells induces activation and invasion of NK cells which occur relatively late compared with those in other organs such as skin.

Animals↗
PubMed1994

Localization of hyaluronan in the human endolymphatic sac. A study using the affinity hyaluronan binding protein.

This study was undertaken with the aim of localizing hyaluronan (hyaluronic acid, HYA) in tissue sections of the human endolymphatic sac by use of a hyaluronan-binding affinity protein and the avidin-biotin/peroxidase staining procedure. Five human endolymphatic sacs were removed during surgery for acoustic neuroma. After microwave-aided fixation and decalcification, paraffin-embedded sections were prepared by routine histological methods. HYA was detected in some of the intraluminal substance as well as in parts of the epithelial lining, mainly in the rugose portions of the endolymphatic sac. HYA was observed intracellularly in epithelial cells. It was also found in the subepithelial tissue near the epithelia and close to the bony aqueduct. The distribution of HYA was uneven at all locations. The finding of HYA within the human endolymphatic sac may imply that this substance has important functions in the control of inner ear fluid homeostasis.

Affinity Labels↗
PubMed1994

Adrenergic innervation of the human endolymphatic sac.

Adrenergic innervation of the human endolymphatic sac (ES) has not been verified previously. To investigate this question a sensitive histofluorescence method for visualization of catecholamines and serotonin, using a solution composed of sucrose-potassium phosphate-glyoxylic acid (SPG) in cryostat sections, was employed. Three human ES specimens were obtained during surgery for acoustic neuroma. Distinct fluorescence in the subepithelial tissue, indicating the presence of monoaminergic neurones and their axonal varicosities, was observed. SPG-positive terminal nerve fibres around small ES capillaries and subendothelially were also seen. Like the effects of sympathetic stimulation elsewhere in the human body, the ES might respond to such stimulation with, for example, vasoconstriction and increased transepithelial water transport. Since the ES is thought to be responsible for maintaining inner ear fluid homeostasis, adrenergic influence could be important for it to function properly.

Adrenergic Fibers↗
PubMed1994

Identification of substances in the endolymphatic sac.

The composition of the contents of the endolymphatic sac (ES) has yet to be fully defined. Carbohydrates have been found in the ES of human fetuses and animals but not identified in the adult human ES. In the present study, celloidin was removed from previously prepared human temporal bone sections and a histochemical method was used to detect carbohydrates and protein in the ES. Six biotinylated lectins were used to identify specific carbohydrates in 15 ears: beta-D-N-acetylglucosamine, beta-D-galactose, D-galactose, alpha-D-mannose, D-N-acetylgalactosamine and alpha-L-fucose. The intensity of staining was graded qualitatively. A substance in the ES tubules that did not stain with any lectin was identified by the Millon reaction as containing protein. The carbohydrates and protein may exist in the different tubules or in the same tubule without mixing. This finding seems to support the idea that at least some of these substances are produced locally in the ES. Our observations support the hypothesis of the existence of a secretion and degradation system in the endolymphatic sac.

Carbohydrates↗
PubMed1994

Ultrasound treatment of Ménière's disease.

This article reviews the technical data about ultrasonography devices, the mode of action of ultrasound waves on vestibular structures, when to use this technique, and the surgical procedure. It also presents the results of this treatment obtained during the last 10 years in the authors' various institutions.

Adolescent↗
PubMed1993

Endolymphatic sac morphology after instillation of hyperosmolar hyaluronan in the round window niche.

One hundred and sixty-eight mice were injected with hyaluronan (HA) of varying tonicity in the middle ear and compared with 81 control animals to study the effects of hypertonic solutions in the middle ear on inner ear fluid homeostasis and endolymphatic sac (ES) response. Six hours after 1.9% HA and 4, 6 and 8 h after 4% HA deposition there was a significant increase in the proportion of granule-containing light epithelial cells in the ES as compared with controls indicating an enhanced secretory activity from the epithelial lining. Six, 8 and 10 h after deposition of 4% HA, the ES volume was significantly reduced. The secretory activity and the ability of the ES to vary its volume could be specific responses to dehydration of the inner ear resulting from the high colloid osmotic pressure exerted by concentrated HA. The secretion of high-molecular substances into the ES may serve to keep the ES lumen patent and thus ensure a proper ES function and/or to regulate the intralabyrinthine volume and fluid pressure. Whether the findings may have clinical relevance for Ménière's patients remains to be elucidated.

Animals↗
PubMed1992

Origin of sympathetic and sensory innervation of the endolymphatic sac. A retrograde axonal tracing study in the guinea pig.

Lectin-conjugated horseradish peroxidase (WGA-HRP) was used as a retrograde axonal tracer to determine endolymphatic sac (ES) innervation and the nature of such a nervous supply. WGA-HRP placed into the ES of the guinea pig resulted in labelling of neurons in the ipsilateral sympathetic superior cervical ganglion and the sensory trigeminal ganglion. The number of labelled neurons in the cervical superior ganglion varied according to the survival time with peak labelling occurring after 48 h. Sparse labelling of the sensory trigeminal ganglion was also present after 48 h. The results indicate that sympathetic neurons from the superior cervical ganglion and to a certain extent trigeminal somatosensory neurons innervate the ES or perisaccular tissue. If these findings reflect the existence of a sympathetic functional reflex unit remains to be elucidated.

Animals↗
PubMed1992

Osmotically induced macrophage activity in the endolymphatic sac. On the possible interaction between periaqueductal bone marrow cells and the endolymphatic sac.

This study aimed to investigate the origin of the free cells in the lumen of the endolymphatic sac (ES). Activation of the cells was accomplished through osmotic induction using glycerol. The ES and the perisaccular tissue were analyzed with special reference to the activity of periaqueductal bone marrow cells after different time intervals following the injection of hyperosmotic agents. The results show that the perisaccular or periaqueductal bone marrow space may constitute a source of some of the free cells occurring in the ES. Osmotic challenging of the inner ear may cause activation of the periaqueductal bone marrow, initiating the locomotion and migration of cells (mostly monocytes, neutrophils and eosinophilic leukocytes) along bone marrow sinusoids that frequently anastomose with the ES vessels. The free cells show signs of transepithelial diapedesis and, in the lumen of the ES, cells may develop into phagocytes which initiate the ingestion and degradation of secreted macromolecular aggregates. It is thought that osmotic alterations in the inner ear may give rise to local changes in or around the ES, leading to the chemotactic attraction of bone marrow cells. The results verify the existence of a complex sugar/protein aggregate metabolism over the wall of the ES, which is linked to the turnover of free cells. The findings may indicate that ES macrophages are important in the regulation of inner ear fluid homeostasis.

Animals↗
PubMed1992

Effects of glycerol on the endolymphatic sac. A time sequence study.

A time sequence study was performed on experimental animals to investigate long-term effects of intravenously administered glycerol on the epithelial cell activity in the endolymphatic sac (ES) and on the ES volume. Fifteen to 60 min after systemic glycerol administration, the ES volume decreased. During this time, the ES lumen was often obliterated. Subsequently, the lumen dilated. Meanwhile, many light epithelial cells showed granules with floccular and/or lamellar contents. Concomitant deposition of floccular material into the luminal space suggested secretion of macromolecular substances, presumably from these transformed light cells. The number of granule-containing cells was significantly increased 2 h (p < 0.01) and 4 h (p < 0.01) after glycerol administration. The ES was significantly dilated after 4 h (p < 0.01) and 6 h (p < 0.05). Thus systemic alterations in osmotic pressure led to a reversible change in ES volume, with initial collapse followed by dilation and normalization after 8 h. The secretory response of the ES preceded the volume increase. A great variability in ES volume indicated high compliance of this organ system. A secretion/degradation system or turnover of osmotically active macromolecular complexes in the epithelial lining and ES lumen seems to be linked to the ability of the ES to hold fluid volumes within a wide range. This may serve as a micromechanical pressure-volume-regulating device for monitoring endolymph fluid homeostasis.

Animals↗
PubMed1992

Microorganism transport in the human endolymphatic duct.

There are indications that endolymphatic sac (ES) may be an immunologically active part of the inner ear. So far, no microorganisms or foreign substances have been localized in this area under 'normal' conditions. Only a limited number of human specimens, including the entire endolymphatic duct (ED) and ES, have been collected and analyzed from cadavers or surgical biopsy specimens. In this study, 6 human ED and ES collected from cadavers and at surgery were analyzed by light and electron microscopy. This was done in order to investigate if microorganisms may normally be drained at this route into the ES. Some microorganisms (Mycoplasma pneumoniae) were found in the lumen and subepithelial tissue of 1 human ED. These observations suggest that microorganisms may also be locally processed and disposed at the level of the ED. These results add further evidence as to the immunodefensive role of the human ES.

Endolymphatic Duct↗
PubMed1992

A technique to obtain and process surgical specimens of the human vestibular aqueduct for histopathological studies of the endolymphatic duct and sac.

The endolymphatic sac (ES) may play a crucial role in the pathophysiology of Ménière's disease. This paper presents a technique to obtain and process fresh human specimens of the endolymphatic duct (ED) and the presumably more active intraosseous portion of the ES obtained at surgery. The specimens are preserved with an intact bony shell around the ED and the intraosseous ES. This allows ultrastructural histopathological evaluation of the intraluminal contents, the epithelium and the subepithelial tissue as well as the mutual relationships of these structures. Various factors influencing ES ultrastructure are discussed. The results obtained from this method may increase our understanding of the possible role of the ES in the etiology of different inner ear disorders.

Endolymphatic Duct↗
PubMed1992

Multicentre evaluation of the temporal bones obtained from a patient with suspected Menière's disease.

A multicentre study of the inner ears of an 88-year-old patient with vertiginous spells and severe hearing loss in the left ear was performed, employing regular and block surface preparations, light and electron microscopy with qualitative and quantitative evaluation of the cochlear and vestibular nerves. There was severe hydrops of the left cochlea and saccule. Reissner's membrane extended into the vestibule and herniated into the perilymphatic space of the non-ampullated end of the horizontal canal. Furthermore, the short canal connecting the posterior ampulla with the utricle had a small, exceedingly thin balloon-like expansion. Only slight hydrops limited to the cochlea was found in the right ear. Sensorineural degeneration was much more pronounced in the left cochlea than in the right. The number of cochlear and vestibular nerve fibres was greatly reduced in the left ear where more fibres with degenerative changes were present. In both specimens the number of myelinated nerve fibres in osseous spiral lamina was smaller than that in the cochlear nerve in the internal auditory canal. Changes occurred in the endolymphatic sacs but were considered non-specific. In this case severe, apparently progressive hydrops and sensorineural degeneration, characteristic of Menière's disease, were associated with atypical onset of clinical symptoms at a late age.

Aged↗
PubMed1991

Structure of the endolymphatic sac after instillation of hyaluronan in the middle ear.

Hyaluronan (HA) 0.5, 1, 1.9 and 4% was instilled into the round window niche in mice. Six hours after the 1.9% HA and 4, 6 and 8 h after the 4% HA deposition there was a significant increase in the proportion of granule-containing light epithelial cells in the endolymphatic sac. This indicated an increase in secretory activity. This activity could be a response to lowered intralabyrinthine pressure due to the osmotic capacity of HA. Secretion of high molecular substances can serve to keep the sac lumen patent and/or to regulate labyrinthine volume and pressure.

Animals↗
PubMed1991

Ultrastructural evidence of a merocrine secretion in the human endolymphatic sac.

The results of a light and transmission electron microscopic analysis of an endolymphatic sac (ES) from a patient suffering from episodic vertigo, tinnitus, and hearing loss are presented. A biopsy of the intraosseous portion of the ES was obtained during a translabyrinthine approach to section the vestibular nerve in the internal acoustic meatus. The material consisted mainly of tubular epithelial structures filled with heavily stained material. Pathologically dilated and degranulated rough endoplasmic reticuli and disaggregation of polyribosomes with accumulation of solitary ribosomes in the cytosol and endoplasmic reticulum suggested a disturbed epithelial cell protein synthesis. Ultrastructural evidence of an increased merocrine secretion of glycoprotein conjugates into the ES was noted. This made it possible to analyze the presumed intracellular secretory pathways. An increased number of intraepithelial lymphocytes and monocytes was observed. Since the inner ear had been subjected to surgical intervention before the vestibular nerve section, no conclusions can be drawn as to whether the patient's symptoms were related to the disturbed protein metabolism and hypersecretion of glycoprotein conjugates into the ES. The findings support earlier experimental results that indicate that the ES has not only a resorptive function but also a secretory one.

Adult↗