Search PubMed⌕ Search

Biomedical subjects

H W Pau

Publications and source records attributed to H W Pau.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Diagnostic difficulties in benign hypopharyngeal tumors. Demonstrated by a case example of pedicled angiolipoma].

Benign intraluminar tumours of the hypopharynx or upper esophagus are often pedunculate. In cases of very soft tumours such as the present case (angiolipoma), the patient's symptoms may be so uncharacteristic that one might think of a "globus nervosus". If the peduncle is very thin, X-ray esophagograms or even endoscopic examinations may be negative. Those tumours may become very dangerous if, as a result of a vomiting reflex, they obstruct the upper airways. The present paper points out diagnostic problems. Diagnosis may be facilitated if anamnesis is considered carefully.

Female↗
PubMed1991

[Interventional angiography in the ENT field].

Development of new micro catheters and digital technique of angiography today allows a superselective angiography of small vessels of the external carotid artery. Therapeutical and diagnostical possibilities for ENT will be discussed.

Adolescent↗
PubMed1990

[Air temperature in the outer ear canal--experimental studies in relation to radical cavity surgery].

By means of special probes, air temperatures were determined in external auditory meatus and in "radical" mastoid cavities. Under normal conditions, there was no difference between the two groups, the temperature next to the drum head being in the same range as the body temperature. Exposure to simulated wind only lowered the temperature significantly in cases with very wide external meatus; e.g., after surgery. Suction--as is used in the daily practice of cleaning ears in the ENT surgery--caused a very abrupt decrease in temperature. In cases with open mastoid cavities, there was vertigo with nystagmus, due to the caloric vestibular stimulus. -Operative techniques such as the obliteration of such cavities or the reconstruction of the posterior wall of the meatus can considerably reduce this phenomenon.

Air Movements↗
PubMed1990

[Electron microscopy studies of the collagen fiber structure of the human tympanic membrane in an adhesive process].

In an EM study, the collagen fiber arrangement of the lamina propria in adhesive otitis media was investigated. Nine biopsies of the tympanic membrane were taken intraoperatively, and compared with two normal ones. The physiological specimens showed a regular arrangement of collagen fibrils and fibers, the typical network of the lamina propria. This confirmed results reported previously. In all adhesive otitis media samples the regular structure of the fiber arrangement was disturbed. Degenerative processes were to be found in the form of hyaline changes, with the network character of the fibers no longer in evidence. In one specimen a mass of microfibrils was observed, which was possibly a sign of reparative processes. The pathohistological findings in adhesive otitis media may be due to mechanical stresses (tubal function). Aside from that, they may also be caused by the biochemical influence of specific collagenases, which have been found by several authors in secretory otitis was well as in cholesteatoma.

Biopsy↗
PubMed1990

[Changes in blood flow velocity in the basal cerebral arteries following neck dissection].

Cerebral blood-flow velocities (cm/s) and pulse index (PI) were studied pre- and postoperatively in a total of 15 male patients following bilateral radical/functional (group A; n = 10) or unilateral radical neck dissection (group B; n = 5) using a 2 MHz-pulsed transcranial Doppler ultrasonographical system (TCD), with a transtemporal approach to the middle cerebral artery. Systolic and mean flow velocities were significant reduced with subsequent increases in PI during the first postoperative sonography in group A-patients while no significant differences in TCD date developed in group B. Blood-flow velocities and PI reached control values within three days. General hemodynamic and respiratory parameters did not influence the changes in TCD flow profiles with the exception of moderate increases in arterial CO2 during the early postoperative period. It is concluded that the reductions in blood-flow velocities and concomitant increases in PI reflect a heightened resistance to flow in the arterial cerebral vasculature. The decrease in cerebral vascular compliance suggests increases in the cerebral venous outflow following the resection of essential drainage pathways. However, TCD does not provide any information about the adequacy of cerebral blood flow.

Adult↗
PubMed1990

[Epithelial migration following surgical obliteration of radical cavities].

We investigated whether the self-cleansing mechanism of the normal ear can be restored in operatively reconstructed open cavities. Dots of Indian ink placed on the drumhead were followed for up to 10 weeks. The epithelium migrates outwards, acting as a self-cleansing mechanism. Partial obliteration of open cavities is recommended in the light of other factors (acoustic phenomena, temperature protection of the inner ear).

Carbon↗
PubMed1989

[Flow kinetics of the endolymph in caloric stimulation].

From our experiment in fluid mechanics there is strong evidence that caloric nystagmus is caused by streaming endolymph in weightlessness as well as by gravity. Two different mechanisms are postulated: thermoconvection (dependent on gravity and head position) and thermo-induced change in volume (independent of those two factors). Our results indicate that tangential endolymph flow in the ampulla directed from crista to cupula leads to a nystagmus towards the examined ear, whereas the adverse flow leads to a nystagmus to the other side. Depending on the head position the flow due to thermoconvection is increased or decreased by the flow due to extension. In mathematical approaches we found the flow due to the thermoconvection to be somewhat higher than that due to fluid extension, but still in the range of micron/s.

Caloric Tests↗
PubMed1989

[Flow kinetics of endolymph in rotational stimulation].

In this paper, experimental and mathematical results are presented, indicating rotatory nystagmus to be caused by endolymph flow in the ampulla of the horizontal semicircular canal. During positive or negative acceleration circular flows may develop within the endolymph system, especially in the ampulla of the horizontal semicircular canal. While being independent of the position of the axis of the horizontally rotating system, the velocity of the flow depends on the radius of the establishing "whirl" in the ampulla. It is demonstrated that, close to the corresponding angular acceleration threshold, the velocity of the tangential flow along the cupula is in the same range as that calculated for a caloric stimulus. Like in our model of calorisation also in rotation there is strong evidence that an endolymph flow directed from crista to cupula in the lateral part of the ampulla causes a nystagmus towards the corresponding side, whereas a flow from cupula to crista causes a nystagmus in the opposite direction. Our results suggest that endolymph flows, evoked either by calorisation or rotation, represent adequate stimuli for vestibular excitability.

Acceleration↗
PubMed1989

[Personal experiences with audiometric detection of perilymph fistulas].

Rupture of the round window membrane is thought to be important in the pathogenesis of sudden hearing loss. In 1982 Fraser and Flood proposed an audiometric test to improve the indication for tympanoscopy which, in their experience, verified the diagnosis of perilymph fistulae in a high percentage of cases. Between 1 January 1986 and 30 June 1988 the above test was carried out on 74 patients at the ENT Department of the University of Hamburg. In 41 cases a tympanoscopy was performed. In 13 cases with a positive test result not a single perilymphatic fistula could be found intra-operatively, while in 3 cases of rupture the test was negative. In our experience this test is not helpful for the pre-operative assessment of tympanotomy in sudden hearing loss.

Audiometry↗
PubMed1988

[Experimental studies of static stress on the footplate in the reconstruction of the sound conduction system].

If a destroyed ossicular chain is substituted by a drum-to-footplate prosthesis (TORP), not only sound pressures but also static pressures are conducted via this new connection. To measure these effects in the area of the oval window, in isolated temporal bones the stapes was removed and substituted by a piece of plastipore, attached to the incus. This piece was connected by a very fine needle to a foil strain gauge, in order to registrate the effects of experimentally changed pressures in the external ear canal towards the inner ear. The incus was then also removed too and a TORP was introduced. Under the same measuring condition we found the conducted pressures ten times higher than in the previous situation. This can only be explained by movements in the incudo-malleal joint, if this is intact. Consequently patients with TORPs should avoid all situations of rapid changes of surrounding pressure, such as diving etc., especially if the tube function is impaired. These situations may be dangerous for the footplate and the inner ear. In fortunately rare cases perforations of the footplate were reported by some ear surgeons.

Biomechanical Phenomena↗
PubMed1988

[The significance of slow flows for the caloric excitability of the vestibular organs in weightlessness].

Bárány's theory of caloric nystagmus is based on the assumption of fluid convection in the perilymph. It was a great surprise that caloric nystagmus could be demonstrated in weightlessness as well, i.e. under conditions in which thermoconvection cannot occur because of loss of gravity. This phenomenon was explained by different theories, each of which is bound to certain assumptions. Experimental investigations and mathematical approaches concerning fluid mechanics of the endolymph under calorisation, indicate that creeping flow must be an important factor. This flow--not taken into consideration so far--may explain caloric nystagmus in weightlessness as well as some difficult problems in caloric excitability on farth.

Caloric Tests↗
PubMed1985

[Yeast fungus flora in tumor irradiation of the upper aerodigestive tract].

The microflora of the oral cavity and pharynx were examined in 28 patients undergoing radiotherapy for cancer of the upper aerodigestive tract. We found no correlation between yeast flora and mucositis: early mucositis occurred between 10 and 20 gy. independent of the concentration of yeast. During radiotherapy the number of patients with detectable yeasts rose from 12 to 22 of the 28. There was a tenfold increase of mean values for yeasts during irradiation, whereas the normal flora (eg. streptococci) remained unchanged. The value of an antifungal local therapy for the prevention of yeast-induced complications is discussed.

Adult↗
PubMed1985

[Vascular architecture of the vocal cord surfaces. A fluorescence angiography study].

The study reported in this paper was devoted to investigating whether there are differences in the superficial vascularisation of the vocal cords compared with surrounding respiratory mucosa (e.g. false cords). The in-vivo technique employed was fluoresceine angiography. In full agreement with findings in anatomic preparations there was a fine vascular network, consisting of straight vessels running parallel to the surface of the vocal cords in dorsal-ventral direction. In contrast, the superficial vascular pattern of the false cords or other areas of the upper respiratory tract did not follow a linear pattern. Our findings may form the basis for further in-vivo studies of blood vessels in pathological alterations of the vocal cords.

Adult↗
PubMed1984

[Involvement of the tympanic membrane and ear ossicle system in ochronotic alkaptonuria].

Ochronotic alcaptonuria is a rare hereditary disease in which the metabolism of phenylalanine and tyrosine is disturbed, leading to accumulation and urinary excretion of homogentisic acid. Its affinity towards bradytroph tissues makes e.g. cartilage, tendons, sclera etc. become stained dark, hard and inflexible, leading to early arthrosis or ruptures of tendons. In the ENT literature mostly signs like darkening of the conchas, the septum or the larynx are mentioned, whereas involvements of the middle ear are rarely described. Such changes were seen in a 60-year old patient, who showed dark discolourations of his thickened tympanic membranes. He had a combined high-frequency hearing loss, the conductive component of which we explain as an increase of mass and changed elasticity. It may also be due to alterations of the ossicular chain. The case was demonstrated to direct the ENT specialist's attention to findings suspicious of ochronotic alcaptonuria and - on the other hand - to present photos of involved tympanic membranes, which in this kind we did not see in the literature.

Alkaptonuria↗
PubMed1983

[Photodocumentation of intra-arterial infusions using fluorescein].

Intra-arterial chemotherapy was given to 12 patients with Head and Neck tumours with the aim of selective perfusion of the tumour area, usually located in the area of supply of the lingual and/or facial artery. A catheter was inserted retrograde into the external carotid artery. The skin or mucous membrane area thus selectively infused by the antineoplastic drug and fluorescein solution could be controlled and documented using an excitation- and barrier filter. Serial photographs were used to demonstrate the higher fluorescence in the perfused area during the intra-arterial infusion lasting 60 or 90 minutes. The use of a balloon catheter increased the selectivity of the fluorescent region. At the end of the infusion the fluorescence disappeared rapidly. From our findings we conclude that it is possible to produce a selective higher concentration of a substance in the tumour during the intra-arterial infusion.

Catheterization↗