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K Helling

Publications and source records attributed to K Helling.

At least 19 recordsLinked to original sources
PubMed2006

Testing utricular function by means of on-axis rotation.

CONCLUSIONS: Subjective visual vertical (SVV) estimation during on-axis rotation provides an efficient screening test of utricle function. The survey demonstrates that isolated disorders of peripheral utricular function can occur while SCC function appears normal. OBJECTIVE: The present study aimed to investigate estimation of SVV during constant velocity yaw rotation (with the head held on-axis--to enhance any asymmetry between right and left utricular responses), as a useful screening test. MATERIALS AND METHODS: In all, 230 patients were recruited from the dizziness clinic. For each patient, the SVV was estimated (a) while held stationary, and (b) during constant angular velocity (240 degrees/s), with the head centred on-axis. Bithermal caloric testing was also performed in 201 of the patients. RESULTS: Of those patients with normal SVV results during stationary testing, 18.3% were pathological during rotation testing. In those cases with pathological SVV during stationary testing, a significantly greater deviation from the norm was observed during rotation (p<0.001). Of those patients with normal caloric responses, 44.4% showed pathological SVV estimates; this increased to 54.3% for cases with unilateral weakness, and 56.5% for unilateral loss. No clear correlation was found between reports of tilt illusion and pathological SVV, respectively, between rotatory vertigo and pathological caloric responses.

Adult↗
PubMed2005

Morphological aspects of potassium flow in the semicircular canal ampulla of the pigeon.

Potassium ions are a prerequisite for the development and regulation of sensory cell stimulation in the inner ear. From the potassium-rich endolymph the ions flow into the sensory cells apically and are released basolaterally. After transport pathways of various lengths potassium is released again into the endolymph - in the cochlea by marginal cells of the stria vascularis, in the vestibular labyrinth by dark cells. While this long recycling pathway is relatively well-known in the cochlea, few studies have been conducted on the semicircular canal ampullae (SCCA) where its morphological basis is largely unknown. According to the present electron microscopic findings, potassium ions are initially released into the extracellular space during stimulation of the sensory cells and then absorbed by supporting and light cells. Finally they are transported transcellularly over numerous very long gap junctions into the region of the dark cells. From here they move to an extracellular compartment, which is more or less completely sealed off basally by basal plates of the light cells. Apically the intercellular space between light and dark cells is sealed by junctional complexes. This newly identified space in the SCCA corresponds to the extracellular compartment between the marginal and intermediate cells in the stria vascularis. At both sites, the cochlea and the SCCA, this probably serves as a regulatory valve, reservoir or storage space, particularly for potassium ions. It is likely that the different morphology of the ion transport pathways is related to the different flow levels of potassium ions expressed by the different levels of the so-called endocochlear potential and concomitant movement of other ions in the cochlea and SCCA.

Animals↗
PubMed2003

[Therapeutic and histological features of basaloid squamous cell carcinoma].

BACKGROUND AND OBJECTIVE: Basaloid squamous cell carcinoma s a rare, highly malignant carcinoma variant typically situated in the tongue base, supraglottis and pyriform sinus. It is usually only diagnosed at a very advanced stage due to its tendency towards submucosal growth, deep infiltration and early local and distant metastases. PATIENTS/METHODS: The case described involves a 39-year-old man with the clinical and histopathological findings typical for this neoplasm. RESULTS: In contrast to simple squamous cell carcinomas, the basaloid variant with its very poor prognosis calls for therapeutic decisions that give particular consideration to quality of life. It should be stressed that highly invasive surgery is justified only in exceptional cases because of the high local recurrence rate and early distant metastases. CONCLUSIONS: The case presented shows that radio- and chemotherapeutic approaches are just as important as surgery.

Adult↗
PubMed2003

Unilateral examination of utricle and saccule function.

Attention is directed towards the recently developed unilateral tests of saccular and utricular function. Together with the now widely used head-thrust test and the standard caloric test for semicircular canal function, these provide for a more comprehensive unilateral examination of labyrinth function. The efficacy of vestibular evoked myogenic potentials (VEMP) as a direct unilateral test of saccular function is currently being demonstrated in an increasing number of reports. Furthermore, the relevant neuronal pathways have been delineated in animal studies, so that all evidence points to the validity of the VEMP as a saccule-mediated response. Concerning utricular function, considerable headway has been made using the unilateral centrifugation paradigm. Testing is performed with a variable radius rotary chair with constant velocity rotation about the earth-vertical axis. Displacing the head by 3.5-4 cm from the rotation axis, the eccentrically positioned utricle is stimulated unilaterally by the resultant centrifugal force. This paradigm can be employed to elicit a utriculo-ocular response (UOR) or to permit measurement of the subjective visual vertical (SVV). More recently, it has also been demonstrated that testing during normal, on-centre yaw axis rotation is often sufficient to localise peripheral otolith dysfunction by means of SVV estimation. This test mode can be easily integrated into routine clinical testing. To illustrate the efficacy of such differential testing, the findings from two patients are presented that demonstrate for the first time an isolated unilateral utricular dysfunction.

Animals↗
PubMed2002

[Laser tonsillectomy in tonsillar hyperplasia of early childhood].

Tonsillotomy, the partial resection of hyperplastic tonsils, is generally rejected in Germany as a treatment option for obstructions of the isthmus faucium in early childhood. We think this approach merits consideration. The favorable results obtained with tonsillotomy in the University Hospital Benjamin Franklin (n = 637), a private clinic, and an ENT practice with surgical facilities (n = 189) showed that there is no justification for adhering to literature reports of severe late complications with scarred tonsillar crypts and peritonsillar abscesses. No patient has developed any of these complications thus far. Following tonsillotomy, preoperative complaints (snoring, respiratory obstruction, dysphagia, and failure to grow) decreased considerably. Thus, tonsillotomy proved to be a suitable modality for treating tonsillar hyperplasia in early childhood. The prerequisite for long-term success is strict limitation of this intervention to the diagnosis of tonsillar hyperplasia.

Airway Obstruction↗
PubMed2002

Preoperative evaluation of chronic alcoholics assessed for surgery of the upper digestive tract.

BACKGROUND: Alcoholics are at risk of developing major complications in the postoperative period. Adequate prophylactic treatment, as well as preoperative abstinence, can significantly decrease the rate of complications. However, the preoperative diagnosis of alcoholism is difficult to establish. The purpose of this study was to assess whether three preoperative visits, an alcohol-related questionnaire (CAGE), and the laboratory markers carbohydrate-deficient transferrin (CDT) and gamma-glutamyltransferase (GGT) would increase the rate of detection of chronic alcoholics. METHODS: The study included the Departments of ENT, Facial and Maxillofacial Surgery, and General Surgery of a university hospital; 705 male patients were assessed for tumor surgery of the upper digestive tract and were allocated to 5 different groups. All patients were seen three times, and five different strategies were used to detect chronic alcoholics. The gold standard was the diagnosis of alcohol misuse made by an experienced (blinded) investigator according to the DSM-III-R. The main outcome measurements were the detection rates of the different test strategies. RESULTS: By clinical routine alone, only 16% were detected during the first visit and 34% after three visits. If the CAGE questionnaire was added, sensitivity increased to 64%. The further addition of GGT or CDT led to 80 and 85% detections, respectively. A combination of all tests had a sensitivity of 91%. CONCLUSIONS: To detect more alcoholic patients at risk for major complications, patients should be seen more often, and additional diagnostic tools such as the CAGE, CDT, and GGT should be used before surgery.

Adult↗
PubMed2001

Electron microscopic studies of ion- and H2O-transporting epithelial cells in the horizontal ampulla of the pigeon.

Earlier morphological studies of the epithelial structure in the semicircular canals of mammals have focused on the sensory cells of the crista ampullaris. This report draws attention to the fact that there exist at least seven further cell types in the horizontal ampulla walls of pigeon with various functions; the role of ion- and H2O-transporting epithelial cells is dealt with here in detail. While the dark cells appear to play a decisive role in the regulation of ionic composition, the cells in the planum semilunatum may transport H2O and assist in the regulation of endolymph volume. In addition, protein-secreting structures are located in the apical region of the cells of the planum semilunatum. The question whether the proteins are dispersed in the endolymph or contribute to cupula formation remains unclear. The morphology and possible functions of these two cell types are discussed on the basis of electron microscopic results.

Animals↗
PubMed2001

Passage of dextran magnetite nanoparticles through the subcupular space of the pigeon.

We examined the permeability of the subcupular space for endolymph flow in the pigeon. A new technique was developed in which nanoparticles consisting of dextran magnetite were attracted by use of a magnet, instead of injecting a dye solution. The method was revealed to prevent an excess pressure application by the injection of dye solution. The Berlin blue color resulting from the dextran magnetite nanoparticles was found mainly within the subcupular space contacting with the sensory hairs. Further formation of the Berlin blue was found within the sensory cells. The result supports the idea that the fluid passes through the subcupular space.

Animals↗
PubMed2001

Cupular response and functional anatomy to pressure application in the pigeon.

In this study, horizontal semicircular canal of the pigeon was inserted with a microfill, 164 micrometers in outer diameter, to gauge the pressure change in the canal and to clarify two things. One is whether the endolymph passes through the crista ampullaris or not. The other is as to the space where the endolymph passes through in the crista ampullaris if the endolymph goes through the crista. The pressure applications were performed by using Evans blue solution and as a result three pressure groups, i.e., 1) high, 2) moderate and 3) low were discriminated. Our results suggest that the endolymphatic fluid passes through the subcupular space or the top of the crista ampullaris when the pressure is enough small like the head rotates in daily life. Accordingly we present a new hypothesis as to the functional anatomy of the cupula in contrast to current hypotheses e.g. drum membrane or revolving door.

Animals↗
PubMed2001

Motion sickness and otolith asymmetry.

There is a highly scattered inter-individual susceptibility in man to motion sickness. It is discussed whether different masses of otoconias between right and left sides are responsible for a high susceptibility. In order to proof this theory, we measured the otoliths of fish (salmons, trouts, Xiphophorus Helleri; Sumatra barbes) and found big differences in the utricular stones up to 140%. The mass differences of the saccular stones were much smaller. In fish, showing abnormal swimming behavior during off-vertical axis rotation we found big mass differences compared to that of normal swimmers. This difference was only seen in the utricular and not in the saccular stones. We therefore assume, that a big mass difference is one of the factors to trigger motion sickness especially for the high susceptibility to it. The macula utriculi seem to be much more integrated in the vestibular sense than the macula sacculi.

Animals↗
PubMed2000

[Morphological studies of the form of the cupula in the semicircular canal ampulla].

BACKGROUND AND OBJECTIVE: The cupula in the ampulla of the semicircular canal, like the tectorial membrane in the cochlea, forms the essential link in transferring endolymph fluid movement stimuli to the hair cells. Clear understanding of physiological cupula movement only started evolving towards the end of the 1970s. Currently, the cupula is assumed to adhere firmly to the ampulla wall, with diaphragm-like displacement in the central section and at the base. PATIENTS/METHODS: In contrast to detailed functional descriptions, there have been very few investigations on cupula morphology. These have proved difficult due to the extremely hydrous structure, which inevitably results in shape distortion during fixation. This difficulty applies particularly to electron microscopy. RESULTS: The present morphological investigations were performed in artificial endolymph on fresh preparations in the salmon (Salmo salar). After staining and isolating the cupula from the ampulla, a precise morphological investigation was performed. A relatively uniform basic structure was observed, with considerable interindividual variability in cupula shape. CONCLUSIONS: Such variability suggests that impairment of cupular form can occur and could be associated with altered peripheral vestibular function.

Animals↗
PubMed2000

Primary tracheal leiomyosarcoma.

We present the clinical course of a 56-year-old female patient with a primary tracheal leiomyosarcoma. The diagnostic approach and pathological classification of this seldom described tumour remains extremely difficult. We discuss the symptoms as well as the diagnostic and therapeutic procedures, including multimodal chemotherapy with organ-preserving surgery leading to complete remission.

Chemotherapy, Adjuvant↗
PubMed1999

[Highly differentiated liposarcoma of the larynx].

Liposarcomas are very rare malignancies in the larynx. At present only a few case reports have been described in the available literature. These cases have been highly differentiated liposarcomas, just like our case. The unremarkable clinical picture of these tumors is that of a soft, lipomatous, smooth limited tumor. Findings first appear to be consistent with a lipoma and not a malignancy. Our case of a 23-year-old man is the youngest patient with a laryngeal liposarcoma described thus far. We discuss the surgical procedure used, especially in view of a local recurrence rate of approximately 60%, as well as additional radiotherapy. The treatment of choice is extensive local tumor resection. Chemotherapy is presently not useful for highly differentiated liposarcomas.

Adult↗
PubMed1997

[Individual differences in susceptibility to motion sickness].

Several different theories exist about the origin of kinetosis and the space adaptation syndrome, with individual sensitivities differing significantly. One explanation involves the hypothesis of a different otolith mass between the right and left statolith organ and especially a difference in the utricles. A difference in mass results in a different sensitivity to acceleration. For this reason we measured interindividual variances in saccular and utricular otolith mass. Since the anatomy of the vestibular organ in vertebrates is based as similar principles, we selected fish (salmon and trout) as our study model to facilitation preparations. The maximum difference in mass in the saccule was 17% and was generally smaller in the utricle, although in individual cases was much higher. We assume that a misbalanced sensitivity of the statolith organs occurs but is totally compensated for by the vestibular system as long as physiological motion patterns take place. Decompensation leads to kinetosis under non-physiological motion patterns. When the vestibular system is better balanced and has an equally distributed otolith mass to both sides, the possibility for developing kinetosis or space adaptation syndrome is much less likely.

Animals↗
PubMed1997

On the origin of interindividual susceptibility to motion sickness.

According to the otolith asymmetry hypothesis for susceptibility to motion sickness, the interlabyrinthine asymmetry in the otoconial mass, which is normally compensated in the circuity of the vestibular system by appropriate neuronal weighting, becomes disrupted as a result of unfamiliar movement patterns or force environments. Measurements in various species have demonstrated a large scatter in the otoconial mass. As the utricle and saccule have distinct functions in the vestibular system it seems appropriate to deal with these organs separately. Results are presented on mass distribution and lateral preponderance of the otoconial mass in the utricles and saccules of the salmon (Salmo salar) and trout (Salmo irideus). The measurements revealed considerably larger dimensions of the saccular otoconia in these species, amounting to twenty-fold. This substantial difference indicates that different regulatory principles underlie the otoconial generation of each of the organs and is presumably related to their specific functions. The lateral preponderance was found to be normally distributed for both organs in both species, with standard deviations of approx. 4% except for the utricular otoconia of the salmon (13%). In a second set of experiments, fish were exposed to a Coriolis force environment. Their sealed aquarium was subjected to constant vertical axis rotation combined with pendular oscillation around the horizontal axis. The aquarium was illuminated by a light source fixed to project through the top, and a video camera recorded the movements of the fish. During combined rotation and pendular oscillation, one group of fish maintained an active compensatory swimming behaviour, whereas the movements of a second group became uncoordinated and often led to passive behaviour. Analysis of the otoconia of these two groups of fish promises to yield further evidence relevant to the otolith asymmetry hypothesis.

Animals↗