Critical behavior and scaling functions of the three-dimensional O(6) model.

We numerically investigate the three-dimensional O(6) model on 12(3) to 120(3) lattices within the critical region at zero magnetic field, as well as at finite magnetic field on the critical isotherm and for several fixed couplings in the broken and the symmetric phase. We obtain from the Binder cumulant at vanishing magnetic field the critical coupling J(c)=1.42865(3). The universal value of the Binder cumulant at this point is g(r)(J(c))=-1.94456(10). At the critical coupling, the critical exponents gamma=1.604(6), beta=0.425(2), and nu=0.818(5) are determined from a finite-size-scaling analysis. Furthermore, we verify predicted effects induced by massless Goldstone modes in the broken phase. The results are well described by the perturbative form of the model's equation of state. Our O(6) result is compared to the corresponding Ising, O(2) and O(4) scaling functions. Finally, we study the finite-size-scaling behavior of the magnetization on the pseudocritical line.

[Ear thermometry from the otologic viewpoint]. / Die Ohr-Thermometrie aus otologischer Sicht.

Tympanic thermometry (TT) detects infrared emissions reaching a probe placed in the ear canal directed toward the tympanic membrane. This has been reported to be an ideal site for clinical temperature measurements. TT provides results rapidly, taking only one second. It is clean, safe, and there is no mucous membrane contact. Studies have primarily focused on the use of TT in pediatric office and emergency room settings. In the literature published to date, the otological viewpoint has not played an important role. Specially there is no systematic investigation of the influence of cerumen on TT. Twenty patients were examined. All of them had a complete obstruction of the auditory canal by cerumen. TT was performed before and after the removal of cerumen. It was found to have a significant impact on the ear temperature reading. After the removal, the temperature was higher by 0.5 degree C. In conclusion, one should consider that there can be a systematic error when using TT to determine body temperature. Nevertheless there are some important advantages compared to other methods of temperature measurements. Especially in the hands of physicians and nurses TT is accurate and can be recommended. However, at home in the hand of non-professionals there are some limitations and restrictions, particular when used in children. Further studies will have to be performed with a focus on otological problems and to determine the accuracy of TT in the non-professional user.

[A new method for measuring internal ear circulation using colored microspheres]. / Eine neue Methode zur Messung der Innenohrdurchblutung mit Hilfe farbiger Mikrosphären.

The pathogenesis of sudden hearing loss is as yet unknown. Vascular disturbances are thought to play a major role, but they cannot be diagnosed clinically. We have therefore developed an animal model which allows measurements of the cochlear blood flow (CBF) and function. For CBF measurements a new technique based on coloured microspheres was developed. New Zealand rabbits were anaesthetised, ventilated and blood pressure and heart frequency were continuously monitored. 6 x 10(6) microspheres of one colour were injected in the left ventricle; different colours are available and allow multiple measurements. The amount of microspheres trapped in the capillary bed of the cochlea depends on the regional blood flow. An arterial reference blood sample makes it possible to calculate absolute values of the regional blood flow in the cochlea. The amount of microspheres trapped in the cochlea was determined microscopically after dissecting, dissolving and filtrating the cochlea. Measurements of the CBF in a control group (5 rabbits, 10 inner ears) at the beginning and after 120 minutes were performed. Mean CBF was 3.8 +/- 1.1 microliters/min and 4.3 +/- 1.3 microliters/min. The coloured microsphere technique allows repeated measurements of the CBF with good reproducibility and an acceptable standard deviation. CBF can be measured in absolute values, which is of advantage for determining a lower limit of the CBF for the cochlea function.

[Endoscopic, 3-dimensional measurement of neoplasms and stenoses of the larynx and trachea]. / Endoskopische, dreidimensionale Vermessung von Neubildungen und Stenosen des Larynx und der Trachea.

Calculating the exact measures of laryngeal tumours will be crucial for the next generation of the TNM System. Furthermore, cross-sectional area and length of a laryngotracheal stenosis are of major interest for clinical management. It is the aim of this study to assess these parameters endoscopically in a more detailed and exact manner. For this purpose a Hopkins Endoscope (Karl Storz, Tuttlingen, Germany) and a slide caliper are combined. This new instrument is called laryngometer (Fig. 1a u. b). It helps to measure the lengths of a stenosis or neoplasm. In addition it defines the level of a given object and provides a standard in a two-dimensional video sequence. Thus the laryngometer allows to digitally analyse cross-sectional areas and distances as well as to evaluate craniocaudal parameters.

[Surgical treatment of pediatric laryngeal stenosis in the area of the ring cartilage]. / Die chirurgische Behandlung der kindlichen Larynxstenose im Ringknorpelbereich.

In the past 15 years, infants and children with laryngeal stenosis have also been successfully treated with laryngotracheoplasty. From 1991 to 1993 we performed a surgical treatment in 20 pediatric patients with subglottic stenosis. The anterior cricoid split procedure should always be considered in children who cannot be extubated before undergoing tracheotomy, especially because in case of failure there are no disadvantages for any further operative measurements. By modifying the technique described by Cotton and Seid (1980), we performed an endoscopically controlled anterior cricoid split in 5 children via an endolaryngeal approach. 4 of these patients were extubated within 10 days after using a nasotracheal tube for splinting the cricoid level. In 14 patients with a tracheostoma we used a modification of Réthi's division of the posterior lamina of the cricoid by the placement of a autogenous costal cartilage graft. A 6-week-period of stenting is required for sufficient healing and stability of the reconstructed airway.

[Clinical significance of cervico-ocular reactions]. / Zur klinischen Bedeutung zerviko-okulärer Reaktionen.

Cervically induced eye movements consist of a nystagmus and a deviation of the mean eye position (shift). They show in relation to different neck torsion velocities maximum reactions at slow velocities. The clinical significance of these cervico-ocular reactions is discussed controversially. Therefore we investigated 40 healthy subjects without any neurootological findings, who, in addition, underwent a manual examination. The neck torsion test was performed automatically with quantifiable stimulus parameters and a complete head fixation by means of individual dental casts. It could be shown that at a constant chair velocity of 5 degrees/s every healthy subject exhibits cervical nystagmus and/or shift deviations. In comparison a group of 30 patients with an upper cervical spine syndrome also showed similar cervico-ocular reactions without significant difference. It can be concluded that a muscle hypertonus in the deep neck region does not lead to pathological, cervically induced eye movements and that the cervical nystagmus itself is not a pathognomonic sign for cervical, proprioceptive vertigo.

[Reconstruction of a malformed external ear by an endoprosthesis of porous polyethylene with an integrated suction system]. / Der Aufbau einer missgebildeten Ohrmuschel durch eine Endoprothese aus porösem Polyäthylen mit integriertem Sogsystem.

Complete reconstruction of the external ear is one of the most difficult tasks in plastic and reconstructive surgery. The risk of frame protrusion inherent in all alloplastic materials is reduced by using a new premoulded endoprosthesis with an integrated suction system. It consists of tissue-compatible porous polyethylene. A conventional suction drainage can be attached to a hollow canal system within the endoprosthesis that empties from defined spaces corresponding to the natural concavities of the external ear. In combination with a preceding expansion the overlying skin is then adapted evenly and completely to the frame by suction. As a result of this vacuum seromas and haematomas can be prevented. Furthermore, infections and pressure necroses due to matress sutures cannot develop. The use of this endoprosthesis obviates the removal of autogenous cartilage and all the complications and scars that are connected with this procedure. The frame itself is stable and has a relief that is largely similar to the natural form of the auricle. Thus, an aesthetically satisfying result can be achieved also in the hand of the surgeon who is not often engaged in this field of plastic surgery.

[Leiomyosarcoma of the external ear canal]. / Leiomyosarkom des äusseren Gehörganges.

We report on a 45-year-old male patient with the signs of exophytic, obstructive and painless tumour of the right external auditory canal developed within a period of about 3 months. The tumour was completely removed in local anaesthesia and histologically found to be a leiomyosarcoma. The only possible origin of this lesion might be the smooth muscle cells of the local blood vessels or the mm. arrectores pilorum.

The anti-motion sickness mechanism of ginger. A comparative study with placebo and dimenhydrinate.

A controlled, double-blind study was carried out to determine whether nystagmus response to optokinetic or vestibular stimuli might be altered by some agent contained in powdered ginger root (Zingiber officinale). For comparative purposes, the test subjects were examined after medication with ginger root, placebo and with dimenhydrinate. Eye movements were recorded using standard ENG equipment and evaluation was performed by automatic nystagmus analysis. It could be demonstrated that the effect of ginger root did not differ from that found at baseline, or with placebo, i.e. it had no influence on the experimentally induced nystagmus. Dimenhydrinate, on the other hand, was found to cause a reduction in the nystagmus response to caloric, rotatory and optokinetic stimuli. From the present study it can be concluded that neither the vestibular nor the oculomotor system, both of which are of decisive importance in the occurrence of motion sickness, are influenced by ginger. A CNS mechanism, which is characteristic of the conventional anti-motion sickness drugs, can thus be excluded as regards ginger root. It is more likely that any reduction of motion-sickness symptoms derives from the influence of the ginger root agents on the gastric system.

31P-spectroscopy of head and neck tumors--surface coil technique.

Comparative phosphorus-31 magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) of 15 patients with superficial masses such as sarcoma, carcinoma, lymphoma, adenoma, and tuberculosis revealed significant increased concentrations of phosphomonoester, phosphodiester, and inorganic phosphorus in the lesion, whereas the concentration of the phosphocreatine was lower in comparison to muscle tissue. In nearly all masses, pH showed a slight alkaline shift. Existence of necrotic regions detected by MRI was marked by an increase of inorganic phosphorous in the spectra. Tumor growth was characterized by raised concentrations of phosphomonoester. Follow-up studies in a case of lymphoma showed a six-fold decrease of the tumor, while the spectra indicated a gradual transition of tumor values to muscle values. A follow-up study during irradiation of a squamous cell carcinoma revealed a considerable decrease of inorganic phosphate and a subsequent increase of phosphodiester.

[Lyme borreliosis and its significance for the ENT physician]. / Die Lyme-Borreliose und ihre Bedeutung für den HNO-Arzt.

Lyme disease is a tick-borne multisystemic Borrelia infection to which the following diseases belong: erythema migrans, lymphadenosis benigna cutis, lymphocytic meningoradiculitis (Bannwarth's syndrome), Lyme-arthritis and acrodermitis chronica atrophicans. The infection rate of ticks with Borrelia Burgdorferi in Germany amounts to 13.6% compared to the infection with the European spring summer meningoencephalitis virus with 1.1%. Recent investigations show that lipopolysaccharides and interleukin-1 play an important role in the pathogenesis of Lyme disease. Lipopolysaccharides (LPS) are a constitutive part of the outer wall of gram negative bacteria. Its biological activities include pyrogenicity, mitogenicity for lymphocytes and the induction of interleukin-1 (IL-1). IL-1 is the major macrophage-derived immunoregulatory protein. Lyme disease is characterized by a variety of symptoms which could be explained by the effects of IL-1 on host systems. These symptoms include: fever, malaise, erythema migrans and arthritis. The clinical course can be divided into three stages. Erythema migrans, lymphadenosis benigna cutis and general symptoms characterize the first stage. In the second stage disorders of the heart and the neurological system may follow including Bannwarth's syndrome. 60% of the patients develop facial palsy and 30% of these patients bilateral palsy. In 40% of all cases the facial palsy is the only motor disorder. Other cranial nerves can also be affected. The third stage consists of the Lyme-arthritis, acrodermitis chronica atrophicans and encephalomyelitis. The determination of specific spirochetal antibodies in serum and cerebrospinal fluid (CSF) is the most valuable diagnostic aid for this borreliosis. The CSF examination may also be helpful.(ABSTRACT TRUNCATED AT 250 WORDS)

[In vivo 31P magnetic resonance spectroscopy and MRI in patients with superficial tumors]. / In vivo 31P Magnetresonanz Spektroskopie und MRI bei Patienten mit oberflächlich gelegenen Tumoren.

Simultaneous 31P-MR spectroscopy (MRS) and MR imaging (MRI) of 10 patients suffering from superficial tumours like carcinoma, lymphoma and adenoma, revealed significantly enhanced concentrations of phosphomonoester, phosphodiester and inorganic phosphorus in the tumour, whereas the concentration of phosphocreatine was lower in comparison to muscle tissue. In all tumours the pH showed a slight alkaline shift. The existing of necrotic regions detected by MRI was accompanied by an increase of inorganic phosphorus in the spectra. A follow-up study of a patient with a lymphoma during chemotherapy showed a tumour regression, whereas the spectra indicated a continuous approach of tumour values to the muscle values.

[Cervical afferent fibers and their relation to the regulation of equilibrium]. / Zervikale Afferenzen und ihre Einbindung in die Gleichgewichtsregulation.

Experiments with stimulation or denervation of cervical dorsal roots in animals have shown that input of the deep neck region is important for orientation, upright posture and the control of eye movements. Muscle spindles seem to play a dominant role as receptors for neck movements. Different ascending pathways project to the central nervous system and the signals interact with visual and vestibular stimuli. Cervical afferences provide a stabilization of the trunk during head movements because neck reflexes cancel labyrinthine reflexes. Posturographic measurements with head extension manoeuvres however did not turn out to be helpful in dizzy patients. Cervically induced eye movements are part of the complex head-eye coordination. The characteristics of cervico-ocular reactions are described. They show in relation to different neck torsion velocities a tuning curve with maximum reactions at slow velocities. Therefore the velocity of trunk rotation is, among others, an important factor when stimulating cervical afferences. The results from literature as well as own experiments show that there exists no method as yet that could yield positive evidence of cervical dizziness.

Cervico-ocular eye movements in relation to different neck torsion velocities.

Rotation of the trunk with a fixed head causes isolated stimulation of cervical afferent input. Eleven patients with marked cervico-ocular reactions (COR) were selected. A neck torsion test (NTT) was performed with the help of a special apparatus. The resulting cervically induced eye movements consisted of two components. In addition to a cervical nystagmus, with its slow, compensatory phase, a deviation of the mean eye position (shift) in an anticompensatory direction, opposite to trunk rotation was observed. The COR in relation to different neck torsion velocities distinctly showed a tuning curve with maximum reactions between 4 degrees/s and 9 degrees/s. Above these values, a strong decrease in COR resulted. The optimal working range vastly differs from that of the vestibulo-ocular reflex (VOR).