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Biomedical subjects

U Koch

Publications and source records attributed to U Koch.

At least 127 records · Page 7Linked to original sources
PubMed1988

[Therapeutic success following endolymphatic sac surgery-- postoperative course of vestibular compensation].

In recent years the benefit of endolymphatic sac surgery has been controversial. Earlier investigations were restricted to the patient's postoperative symptoms, but detailed analysis of postoperative vestibular function was not reported. Nineteen patients who had undergone endolymphatic sac surgery were followed-up for 6 months on up to 16 occasions. Twelve of the 19 patients showed continuous improvement of canal function beginning no earlier than 2 weeks after the operation. No vestibular compensation was observed after simple mastoidectomy. The postoperative symptoms were not proper indicators for successful therapy.

Ear, Inner↗
PubMed1988

[Dentin ossicle prostheses (DOP)--a new concept in replacing the ear ossicles].

The variety of materials used for replacement of the ossicles is proof enough that no single material can satisfy all criteria: availability, mouldability, stability and biocompatibility. The trouble-free availability as well as the excellent mouldability enable the development of a principle of preparation of ossicular replacement prosthesis from homologous dentine. The moulding of the dentine ossicular prosthesis is simple and can be performed with an equipment available at any otologic department.

Bioprosthesis↗
PubMed1987

Chlorogenic acid biosynthesis: characterization of a light-induced microsomal 5-O-(4-coumaroyl)-D-quinate/shikimate 3'-hydroxylase from carrot (Daucus carota L.) cell suspension cultures.

Microsomal preparations from carrot (Daucus carota L.) cell suspension cultures catalyze the formation of trans-5-O-caffeoyl-D-quinate (chlorogenate) from trans-5-O-(4-coumaroyl)-D-quinate. trans-5-O-(4-Coumaroyl)shikimate is converted to about the same extent to trans-5-O-caffeoylshikimate. trans-4-O-(4-Coumaroyl)-D-quinate, trans-3-O-(4-coumaroyl)-D-quinate, trans-4-coumarate, and cis-5-O-(4-coumaroyl)-D-quinate do not act as substrates. The reaction is strictly dependent on molecular oxygen and on NADPH as reducing cofactor. NADH and ascorbic acid cannot substitute for NADPH. Cytochrome c, Tetcyclacis, and carbon monoxide inhibit the reaction suggesting a cytochrome P-450-dependent mixed-function monooxygenase. Competition experiments as well as induction and inhibition phenomena indicate that there is only one enzyme species which is responsibl for the hydroxylation of the 5-O-(4-coumaric) esters of both D-quinate and shikimate. The activity of this enzyme is greatly increased by in vivo irradiation of the cells with blue/uv light. We conclude that the biosynthesis of the predominant caffeic acid conjugates in carrot cells occurs via the corresponding 4-coumaric acid esters. Thus, in this system, 5-O-(4-coumaroyl)-D-quinate can be seen as the final intermediate in the chlorogenic acid pathway.

Carbon Monoxide↗
PubMed1987

[Therapy of advanced hypopharyngeal carcinoma].

Patients with hypopharynx carcinoma underwent planned irradiation and surgical treatment (pharyngo-laryngectomy with uni- or bilateral neck dissection) with postoperative planned irradiation. One group of these patients was treated with intraarterial chemotherapy with Methotrexat prior to any other therapy. The group with intraarterial therapy followed by irradiation seems to give the best results.

Combined Modality Therapy↗
PubMed1987

[Histopathology of collagen fibers of the tympanic membrane].

The lamina propria of the human tympanic membrane consists mainly of collagen fibres, but vessels and nerves can also be found as solitary elastic fibres. The pathologic alterations of the collagen fibres were examined by 47 biopsies of the tympanic membrane. These biopsies were taken in various middle ear diseases, and pathological changes were found in every case, ranging from clotting to chondral metaplasia; in one case a metaplasia into osseous tissue was found. No relationship was seen between the otoscopic findings and the severity of the pathological changes.

Biopsy↗
PubMed1986

Fengycin--a novel antifungal lipopeptide antibiotic produced by Bacillus subtilis F-29-3.

Fengycin is an antifungal lipopeptide complex produced by Bacillus subtilis strain F-29-3. It inhibits filamentous fungi but is ineffective against yeast and bacteria. The inhibition is antagonized by sterols, phospholipids and oleic acid, whereas two other unsaturated fatty acids increase the antifungal effect. Fengycin consists of two main components differing by one amino acid exchange. Fengycin A is composed of 1 D-Ala, 1 L-Ile, 1 L-Pro, 1 D-allo-Thr, 3 L-Glx, 1 D-Tyr, 1 L-Tyr, 1 D-Orn, whereas in fengycin B the D-Ala is replaced by D-Val. The lipid moiety of both analogs is more variable, as fatty acids have been identified as anteiso-pentadecanoic acid (ai-C15), iso-hexadecanoic acid (i-C16), n-hexadecanoic acid (n-C16), and there is evidence for further saturated and unsaturated residues up to C18.

Antifungal Agents↗
PubMed1986

Activity of an identified histaminergic neuron, and its possible role in arousal of feeding behavior in semi-intact Aplysia.

The possible functions of histaminergic neuron C2 were studied in an isolated head preparation from which it was possible to obtain intracellular recordings while the buccal mass exhibited feeding-like responses. Application of food to the lips of the isolated head preparation elicited rhythmic buccal movements that appeared to be ingestion responses, since they moved seaweed into the buccal cavity and towards the esophagus, and their frequency and regularity was similar to the ingestion responses studied in a group of intact animals. The ingestion responses of the buccal mass consisted of 2 main phases of movement of the radula from a middle rest position: forward and return to rest, and backward and return to rest. The relative magnitudes and timing of these 2 phases were variable. Intracellular recordings from C2 in the isolated head revealed that C2 is silent when the buccal mass is quiescent, but that it can be excited into spike activity, either by mechanical stimulation of the perioral zone or by chemostimulation that results in rhythmic movement. C2 fires a burst of spikes in phase with each protraction-retraction cycle, and, if the movements continue, C2 fires even when the eliciting stimulus has been removed. Activity of the cell was usually preceded by fast depolarizing responses that appeared to be blocked axon spikes. The evidence suggests that C2 is part of a positive feedback loop that may help maintain the persistence of arousal of feeding behavior beyond the time that food stimuli are removed.

Animals↗
PubMed1986

[Long-term results following tympanoplasty in complete atelectasis of the tympanum].

24 patients with complete tympanal atelectasis were followed up for at least 7 years after tympanoplasty. The operation was done by the intact canal technique, the eardrum and ossicles were reconstructed. In 10 of the 24 patients the tympanic membrane remained intact and the tympanUM was aerated for over 7 years; in 8 patients postoperative retraction of the tympanic membrane was prevented by grommets. Atelectasis recurred in the remaining 6 patients. Even in normal tube function and normal middle ear pressure these recurrences may develop. In these cases histological studies have shown a change in eardrum elasticity. In most of the cases followed up, social hearing was sufficient for more than 7 years. Even though the long-term results of the operation are satisfactory, when tympanoplasty is indicated it must be kept in mind that there is a high percentage of recurrence in all patients, even in those with normal tube function. A prerequisite for long-term success is that the patient accepts follow-up observation for a matter of years. Otherwise therapeutic alternatives to tympanoplasty (e.g. tympanoplasty of Type IV) must be considered.

Audiometry, Pure-Tone↗
PubMed1985

[Operation indications of blow-out and midface fractures].

89 patients with fractures of the orbital floor - both in isolation (blow-out fractures) and combined with a complex fracture of the midregion of the face - were followed up for an average of 5 years. Particular attention was paid to the quantitative evaluation of binocular fusion, diplopia and enophthalmos. Comparison of operated and conservatively treated patients with blow-out fractures led to the following conclusions with regard to indications for surgery: 1. It is not justified to regard either surgery or its postponement pending developments as obligatory in all cases. 2. Surgery is indicated by clinical, orthoptic and roentgenological findings as follows: a) In case of enophthalmos or roentgenological demonstration of prolapse, surgery is indicated independent of diplopia. b) Diplopia outside the main field of view does not, in general, necessitate surgery. c) If there is diplopia within the main field of view, surgery is indicated. It is generally accepted that orbital-floor fractures associated with complex mid-face fractures require early surgical treatment. The present investigation confirms this view.

Convergence, Ocular↗
PubMed1984

Spontaneous flow measurements of laryngotracheal resistance in 30 tracheostoma patients.

The airway resistance of 30 patients with stenosis in the region of the larynx and upper trachea was assessed by means of the spontaneous flow method. For this purpose, the measuring head of a spontaneous flow rhinomanometer (A 440 rhinomanometer, Allergopharma, Reinbek, FRG) was adapted to the new conditions. Laryngotracheal airway resistance between 1.8 and 30 mbar/l/s was registered. This method proved to be suitable for measuring the airway resistance of the larynx and upper trachea in tracheostoma patients with varying degrees of stenosis. Thus, a further objective parameter has been added to those of inspection and X-rays for reviewing the indications for tracheostoma closure.

Adolescent↗
PubMed1984

[Mondini-type petrous bone dysplasia as a cause of spontaneous otoliquorrhea].

A case of fistula formation in a congenitally deformed petrous bone is described. This case demonstrates the diagnostic problem of deafness with spontaneous cerebrospinal fluid otorrhoea causing recurrent meningitis. Methods of diagnosis and therapy are discussed and the value of hypocycloidal polytomography is stressed.

Bone Diseases, Developmental↗
PubMed1984

[High resolution computer tomography of the middle and inner ear].

High-resolution CT enables exact visualisation of the bony structures of the petrous bone; at the same time, all relevant nerval, vascular and muscular elements of the middle and inner ear are visualised. A wider range of findings can be attained in this region of wide differences in density than via conventional pluridirectional tomography. The normal anatomy of the petrous bone is demonstrated via CT series of slices in axial and coronal projection.

Ear Diseases↗
PubMed1984

[Measurements of airway resistance in stenosis of the laryngo-tracheal region].

The airway resistance of 32 patients with tracheostomies due to tracheal or laryngeal stenoses was measured using the autoflow and the oscillation method. The resistance to flow between the mouth and tracheostomy was determined with the autoflow method. While measuring with the oscillation method the tracheostoma was blocked with stomahaesive . The comparison of both methods resulted in a good correlation (r2 = 0.83). Hence, the oscillation method can be used to determine airway resistance in patients with stenosis of the larynx or trachea, irrespective of whether or not they have a tracheostome .

Airway Resistance↗