Biomedical subjects

A Keilmann

Publications and source records attributed to A Keilmann.

35 records · Page 2Linked to original sources

PubMed1999

Functional results after CO2 laser surgery compared with conventional phonosurgery.

Treatment of benign vocal fold lesions by the use of the CO2 laser is discussed critically. The aim of the present prospective randomized study was to examine the post-operative functional results after laser phonosurgery in comparison to those after cold phonosurgery. In total, 44 patients with benign vocal fold lesions underwent surgery. Conventional cold phonosurgery was performed in 23 patients, and 21 patients were treated by laser phonosurgery. To determine vocal function, examinations were performed pre-operatively, on the second post-operative day, and one and four months post-operatively. The examinations included direct videolaryngoscopy, determination of maximal phonation, speech voice field as well as singing voice field. The results four months after surgery showed an improvement of vocal function in both treatment groups in comparison to the pre-operative findings. The improvement is only statistically significant after cold surgery.

Adult↗

PubMed1997

The c-Fos transcription factor in the auditory pathway of the juvenile rat: effects of acoustic deprivation and repetitive stimulation.

The expression of the inducible transcription factors (ITF) c-Fos and JunB was investigated in the dorsal cochlear nucleus (DCN), ventral cochlear nucleus (VCN) and inferior colliculus (IC) of juvenile and adult rats following deprivation and repetitive stimulation paradigms using 8 kHz tone bursts at 5 min duration and 70 dB, 90 dB or 120 dB sound pressure level (SPL). (1) During postnatal development without stimulation, c-Fos is absent in DCN and VCN from postnatal day (P) 12 to adulthood, but shows a strong expression in the IC which declines during maturation. A similar decrease was also seen in the pons. (2) Between P15 and P35 stimulation of rats with 8 kHz for 5 min at 70 dB SPL evoked expression of c-Fos in a moderate number of cells of DCN, VCN and IC. Higher sound pressure levels increased the number of c-Fos immunoreactive neurons as studied at P21. (3) Deprivation of acoustic stimulation up to P21 reduced the expression of c-Fos when rats were stimulated with 90 dB immediately after the restoration of acoustic input. In contrast to 90 dB SPL, c-Fos immunoreactivity (IR) did not significantly differ between deprived and normal rats following application of 120 dB SPL at P21. Stimulation at P28, i.e., 7 days after the end of the deprivation, evoked an increase of c-Fos only in the IC compared to otherwise normally stimulated rats. At P35, effects of the former deprivation on the c-Fos expression were not longer detectable. (4) In a repetitive stimulation paradigm, 8 kHz tone bursts 5 min in duration were applied each second day between P23 and P35 or each day between P29 and P35. When compared with acutely stimulated rats at P35, both repetitive acoustic stimulation protocols reduced the c-Fos immunoreactivity by 50%-75% in the DCN, VCN and IC. In adult 4-month-old rats, repetitive stimulation did not reduce the c-Fos immunoreactivity from its moderate levels as compared with acute stimulation. (5) In some experiments, we studied also the expression of the JunB protein. JunB paralleled the expression of c-Fos following single acoustic stimulation, but was expressed in a substantially lower number of cells. In contrast to c-Fos, however, repetitive stimulation as described in section 4 did not evoke a decrease of JunB in the lower acoustic pathway.

Acoustic Stimulation↗

PubMed1997

[CO2 laser versus conventional microlaryngoscopy in benign changes of the vocal cords].

BACKGROUND: Microsurgical treatment of benign vocal fold lesions as nodules, polyps, and Reinke's edema is a routine intervention in phonosurgery. After laser treatment of malignant neoplasms of the larynx has been accepted as a technical advance by most laryngologists, use of the laser has been also proposed for benign lesions. PATIENTS: Forty-four patients with a benign lesion of the vocal fold were randomized and operated conventionally or with the CO2-laser. Preoperatively, two days, one month, and four months postoperatively, the patients were queried about vocal problems and their subjective rating of their voice quality. Videolaryngostroboscopy was performed, the maximal phonation time was determined, and a phonetogram of the speaking and of the singing voice was registered. A phonetically balanced text and sustained vowels were registered on a DAT recorder and used for subjective rating by experienced listeners and electroacoustic analysis. RESULTS: All parameters showed worsening immediately postoperatively and an improvement later compared to the preoperative value. There was no statistical difference between conventional treatment and CO2 laser treatment. CONCLUSIONS: Microsurgical treatment of benign lesions of the glottis either by CO2 laser or by conventional surgery leeds to comparable results as seen in the final result.

Adult↗

PubMed1996

Vocal function following laser and conventional surgery of small malignant vocal fold tumours.

In the described study, 26 patients after conventional cordectomy, and 27 patients after laser cordectomy were examined six months or more after the operation. Videolaryngostroboscopy revealed that patients after laser cordectomy more often phonate on purely glottic level (81 per cent) in comparison to patients after conventional cordectomy (19 per cent). Webs were more frequent and more extended after conventional cordectomy compared to endoscopic laser surgery. The maximal phonation time showed a very wide range with a mean value of 9 to 10 sec; there was no statistical difference between the groups of patients. Using Yanagihara's classification of sonograms, a better voice quality was measured after laser cordectomy than conventional cordectomy. The patients' estimation of their voice quality did not correlate with objective parameters.

Adult↗

PubMed1995

Expression of the c-fos transcription factor in the rat auditory pathway following postnatal auditory deprivation.

As an animal model for inborn hearing loss rat pups were reared in a sound-proof chamber from birth until age 21 days. In addition, pinnae were bilaterally sutured closed to reduce any influence of ambient sound. At the end of the sound deprivation, outer ear channels were reopened. Since previous studies failed to show any difference in the number or morphology of neurons in the auditory pathway in bilaterally sound-deprived animals, expression of c-fos protein was used as a functional marker to map trans-synaptic information transfer in the auditory pathway with cellular resolution. At day 21 sound-deprived rats and untreated controls were stimulated with pure tones of 8kHz for 5min at different sound pressure levels. Acoustic stimulation induced c-fos in both parts of the cochlear nucleus, superior olivary complex and inferior colliculus. Compared to untreated rats, deprivation reduced the number of c-fos labeled neurons in the dorsal and ventral part of the cochlear nucleus and inferior colliculus by 58% and 30%, respectively, following low sound pressure levels (90dB). In contrast, high sound pressure levels (120dB) increased the number of c-fos labeled neurons in these areas and evoked only minor differences in the number of labeled neurons in both untreated and sound deprived rats.

Acoustic Stimulation↗

PubMed1995

Development of aerodynamic aspects in children's voice.

To determine the changes with increasing age in children this study measured the air flow and the acoustic signal in children aged 4-15 years. The subglottal pressure was estimated from the intraoral pressure during the phonation of the word 'ipipi'. From these parameters the glottal resistance and the glottal efficiency were calculated. Since these parameters depend on the sound pressure level, a linear regression of the parameters versus the sound pressure level was done, and the values for 75 dB SPL were taken for statistical analysis. The study found a subglottal pressure in younger children between 6 and 10 cm water column, which seemed to diminish with age. The phonatory flow rate was between 50 and 150 ml/s in younger children, which seemed to increase with age. The glottal resistance did not depend on age, values of 20-250 Ns/m5 at a sound pressure level of 75 dB exceed those for adults given in the literature. The measurements for the glottal efficiency showed a broad variability between 20 ppm and 400 ppm.

Adolescent↗

PubMed1995

[Effects of surgical therapy of obstructive snoring on swallowing and voice quality].

The efficacy of uvulopharyngopalatoplasty (UPPP) in treating obstructive snoring has been reported from many centers. The reduction of uvula and soft palate may result in palatal incompetence. We examined 23 patients undergoing UPPP pre- and postoperatively and found a slight preoperative hypernasality in three patients. None of our patients had problems with swallowing. During the first week postoperatively, most of the patient had hypernasality and noted a nasal escape of liquids. Three to four months after surgery, three patients still had problems swallowing. All 21 patients seen during the last follow-up examination had a nasal escape of air detected by auscultation in at least one of the tests. Two patients had an audible hypernasality. Two patients could not pronounce the letters any more. More than one year after surgery, palatal incompetence was no longer detectable.

Deglutition Disorders↗

PubMed1995

The influence of an insecticide on the function of the eustachian tube.

Organophosphorus compounds in the form of insecticides are in widespread use and have recently attracted considerable interest as environmentally toxic agents. As little is known about the effect of environmental toxins on the tubal function in the ear, we studied the middle ear pressure necessary to force the eustachian tube to open (POL = pressure opening level) under physiological conditions in laboratory mini pigs and under the influence of an i.v. organophosphorus compound (Paraoxon). The median POL in the untreated animals was 6.4 kPa (n = 8). After intoxication with Paraoxon the median POL increased to 12.0 kPa (n = 8). Tubal instillation of surfactant in intoxicated pigs reduced the POL to a median of 7.3 kPa (n = 8), while in non-intoxicated animals (n = 4) it also lowered the POL, though not significantly. These results suggest that organophosphorus compound interferes with the surfactant-dependent tubal patency.

Animals↗

PubMed1993

[Effect of auditory deprivation on maturation of auditory pathways in the rat].

To examine the influence of an auditory deprivation on the maturation of the central auditory pathways we reared newborn rats until the age of 21 days in a sound-proof chamber and additionally sutured their pinnae. At the age of 21 days we reopened the outer ear channels and placed the young rats into a normal environment. Every three days we recorded brain stem auditory evoked potentials with clicks, 1-, 8- and 16 kHz tone pulses until the age of 45 days, at the age of 60 days for the last time. Additionally all animals underwent middle latency response audiometry. Only directly after reopening the ear channels the thresholds for 8 and 16 kHz were worse in the deprived animals than in the normal ones. For clicks and 1 kHz and all testings on the other days the mean threshold response of the deprived rats did not differ from that of the normal animals. Testing with clicks, the interpeak latencies (I-IV), that is the brain stem transmission time, were prolonged significantly between the 24th and the 36th day of life. Measuring with 1 kHz tone pulses we found a difference from the 30th to the 36th day. Testing with 8 and 16 kHz tone pulses the brainstem transmission time was significantly prolonged between the 21st and 33rd day of life. The middle latency responses showed large variances, there was no significant difference. After the 36th day of life all latencies had normalised.

Aging↗

PubMed1993

[Physiology and acoustic analysis of whistle voice of the woman].

Only a few singers are able to use to whistle voice, normally to produce extremely high pitches at the upper limit of their range. The laryngeal mechanism of the whistle voice is not completely understood. Stroboscopy shows only a horizontal vibration, the entire length of the vocal cords vibrating. The vocal cords are stretched to their maximal length. The spectral analysis of the whistle voice shows that the first two partials are much more pronounced than the higher ones. The 3D-PAN of the modal register is more complex than that of the whistle register.

Computer Graphics↗

PubMed1992

[Dysphonia following strumectomy with normal respiratory movement of the vocal cords].

Voice function was phoniatrically investigated pre- and postoperatively in 66 patients undergoing thyroidectomy. Postoperatively we found a disturbance of the voice in 25 patients (43%), though there was a normal function of the recurrent laryngeal nerve. Typical symptoms were a reduced average pitch of the speaking voice, a lowering of the upper and the lower limit of the range of pitch, a lower volume and a fast fatigue of the voice. Eight times the voice remained reduced, even 6 months postoperatively. The cause is not seen in a neural lesion but in a disturbance of the prelaryngeal musculature. The frequency of the voice changes emphasizes the importance of the phoniatric examination, especially in patients who need their voice professionally.

Adult↗

PubMed1991

[Hearing ability after dissection of the vertebral nerve. A long-term study].

To prove the influence of the vertebral nerve on hearing in rabbits, the vertebral artery, together with its sympathetic plexus (n. vertebralis Frank), was unilaterally cut at the height of the first vertebral body, the atlas. Both preoperatively and several times after dissection, auditory and vestibular functions were investigated using BERA and electronystagmography. The hearing threshold was not influenced, neither in the first days after the operation nor as much as six months later. The latencies between wave I and V did not change. Similar results were to be found for the vestibular system. There was no imbalance clinically and it was not possible to detect any electronystagmographic difference between the two vestibular organs. These results indicate, that there is still no experimental proof of hearing loss, as a result of disturbance of the sympathetic vertebral nerve.

Animals↗

PubMed1990

[Reduction of reactivity to allergic rhinitis with intravenous administration of calcium. Clinical-experimental study on the effect of changes of local airway resistance after nasal allergen provocation].

The antiallergic activity of calcium was investigated in 25 patients with allergic rhinitis by nasal provocation with increasing doses of phleum pratense during a symptom free interval. Prior to that provocation, the patients received 9 mmol calcium (Calcium-Sandoz) i.v. or placebo respectively (double blind cross-over design). The concentration of serum calcium increased after calcium injection by 0.45 +/- 0.055 mmol/l. Calcium exerted a significant protective effect as compared to placebo: higher allergen doses, (p = 0.021) i.e. 20433 biological units/ml vs. 7494 biological units/ml, were required in order to induce a defined allergic reaction (50% decrease of nasal air flow). The data thus furnish evidence that intravenous calcium reduces the allergic response in type I allergy.

Adult↗

PubMed1989

[Middle ear effusion and allergy in childhood].

Besides mechanical or infectious factors in the genesis of secretory otitis media IgE-mediated hypersensitivity has often been discussed. In order to estimate the importance of an allergic reaction in the development of middle ear disease, we examined 27 children having adenoids and a secretory otitis media. We documented the patients' history of allergy and determined the IgE-levels in the serum, the middle ear effusions and the adenoid tissue. 5 out of 27 children suffered from an allergy of the upper respiratory tract, but only in one child we found an elevated level of IgE in middle ear effusion. On the basis of our investigations and recent literature, we suggest that an allergic rhinitis might cause an Eustachian tube dysfunction in a few patients. There is no evidence of a local allergic reaction of the middle ear mucosa.

Adenoidectomy↗

PubMed1988

[Sensitivity and specificity of intranasal provocation].

As a result of the development of a number of modern biochemical and immunological in-vitro techniques together with in-vivo skin tests, it has been possible to purify, characterise and standardise allergen extracts for diagnosis and therapy. Despite the diagnostic value of the NPT for daily clinical practice, no standardisation has been achieved to establish the correct allergen concentration for that test. In 43 patients allergic to grass we determined the nasal threshold by means of allergen titrations with increasing concentrations from 1000 BE/ml to 170,000 BE/ml (1000 BE/ml = 1 HEP). For evaluation we used rhinomanometry and symptom scores. 10 normal subjects served as control. In order to achieve the best sensitivity and specificity of the NPT, allergen concentrations of 100,000-150,000 BE/ml had to be used. For research purposes an allergen titration is recommended as standard. Much work remains to be done in respect of technique and evaluation criteria to establish a standardised and reliable NPT.

Airway Resistance↗

PubMed1988

[Treatment of zoster oticus].

On the basis of aetiology and pathophysiology a rational concept for the treatment of zoster oticus is attempted. The current literature and own experiences favour the simultaneous application of the virostatic acyclovir and glucocorticosteroids.

Acyclovir↗

PubMedDate not supplied

Decreased expression of the c-Fos, but not Jun B, transcription factor in the auditory pathway of the rat after repetitive acoustic stimulation.

Between the 21st and 34th postnatal days, male rats received an acoustic stimulus every second day, and the expression of c-Fos and Jun B proteins was compared with rats that received only a single acoustic stimulus at postnatal day 34. For acoustic stimulation, 8-kHz pure-tone bursts (100 ms duration at a rate of 6.3 Hz) were applied for 5 min. The numbers of neurons immunoreactive to c-Fos and Jun B were studied 2 h after the last or acute stimulus, respectively, in the ventral cochlear nucleus (VCN), dorsal cochlear nucleus (DCN) and inferior colliculus (IC). Compared with the single stimulus, repetitive stimulation significantly reduced the number of c-Fos labeled neurons in the VCN by 51%, in the DCN by 75% and in the IC by 48%. In contrast to c-Fos, repetitive stimulation did not significantly lower the number of Jun-B-expressing neurons. These findings indicate that independent intraneuronal pathways terminate on the induction of c-Fos- and Jun-B-expressing genes during the juvenile maturation of the acoustic pathway and that chronic exposure of acoustic events alters the program of intraneuronal gene expression by reducing transcriptional activities with subsequent stabilization at the genetic level.

Acoustic Stimulation↗