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Biomedical subjects

F Wallner

Publications and source records attributed to F Wallner.

At least 19 recordsLinked to original sources
PubMed2005

[Evaluation of aspiration protective-covered tracheal cannulas].

BACKGROUND: The aim of the study was to evaluate leakage of liquids in terms of water and artificially produced saliva past low-pressure cuffs of tracheal tubes. METHODS: Three different types of tracheal tubes, TRACOE vario, Rüsch Ultra-Tracheoflex, and Portex Blue Line Ultra, were tested in isolated pig tracheas by infusing 6 ml of water or artificially produced saliva over the cuff and measuring the volume of fluid leaking past the cuff after 5, 10, and 15 min. RESULTS: The leakage in the saliva experiments was significantly lower than in the water experiments (p < 0.05). The amount of leakage between the three different types of tubes showed statistically significant (p < 0.05) results. There was no statistically significant difference between tracheal tubes of 7 and 8 mm internal diameter. CONCLUSION: The present laboratory findings suggest that the three tracheal tubes studied will not guard against aspiration of water but they will prevent the leakage of artificial saliva to a great extent.

Equipment Failure Analysis↗
PubMed2004

[Health aspects of diving in ENT medicine. Part I: Diving associated diseases].

There has been a steady increase in the number of recreational scuba divers in the last years, with a growing number of diving associated diseases involving ENT medicine. Disorders of the ears, sinuses and pharynx are those most common in divers. In particular, external otitis and barotrauma of the middle ear are commonly treated by every ENT specialist. They usually do not lead to any permanent complaints. Incidents involving the cochleovestibular system are less common, but can result in deafness, vertigo and tinnitus, and therefore have to be treated appropriately. To treat diving medical disorders, the physician has to have some basic understanding of the physical laws that lead to diving incidents. This article will inform the reader of the forces that are encountered by divers, and then give details of the treatment of acute ENT diseases which result from diving incidents.

Barotrauma↗
PubMed2004

[Health aspects of diving in ENT medicine. Part II: Diving fitness].

Diving has become increasingly popular. With the growing number of patients who want to dive, there is an increasing number of divers who require their regular medical examination. As ENT problems are the most common disorders in divers, otorhinolaryngologists regularly have to assess the diver's fitness. It should be noted that an ENT examination does not certify complete fitness to dive! Diving can be resumed 3 months after middle ear surgery, especially after tympanoplastic type I, II and III with insertion of a PORP, when there is regular middle ear ventilation without atrophic scars of the tympanic membrane. Even after stapes surgery, diving can be resumed when there are no signs of vestibular irritation during a provocation test. By 3 months after sinus surgery, the diver should perform a test dive under supervision before fitness to dive can be certified. After inner ear barotrauma, the diver remains fit to dive depending on his hearing ability in the involved ear. After inner ear decompression illness, one should look for a vascular right-to-left shunt before diving can be resumed. These and many more aspects are discussed in this article on how to determine whether a diver with ENT problems is fit to dive.

Certification↗
PubMed2004

Prognostic impact of EBV-related LMP-1, histologic type, and environmental factors in nasopharyngeal carcinoma in a German population.

INTRODUCTION: This retrospective study addressed the possible involvement of latent Epstein-Barr virus (EBV) infection, in particular LMP-1 expression, and further exogenous factors, i.e. tobacco, alcohol and occupational hazardous substances, in nasopharyngeal carcinoma (NPC) in a German population. PATIENTS AND METHODS: From 1980 to 2000, 44 patients suffering from histologically confirmed NPC were entered into the study. 33 specimens were available for immunostaining (IHC) to analyze LMP-1 expression. Information about environmental exposures were obtained employing a detailed standardized questionnaire. RESULTS: Outcome of patients with squamous cell NPC (SC-NPC) was significant worse than that of those with non-keratinizing NPC (NK-NPC). Age and tumor size correlated with response to therapy. The group with negative conventional LMP-1 staining showed better overall survival after 5 years compared to the group with positive or marginally positive LMP-1 detection (not significant). Nevertheless, after staining by tyramid-augmented IHC (TSA-IHC), nearly all specimens with negative LMP-1-staining in conventional IHC were found to be clearly positive. All patients with SC-NPC were smokers. The distribution of smokers and non-smokers in the group of NK-NPC was balanced. Comparable to the tobacco observation, there was also a correlation between high alcohol consumption and SC-NPC. CONCLUSION: Prognosis of NPC is mainly dependent on histologic type. Prognostic impact of LMP-1 is still unclear since LMP-1 was detected in all specimens using TSA-IHC. Therefore, TSA-IHC-LMP-1 detection might be interesting for diagnostic specification and development of new therapeutic strategies in NPC.

Adaptor Proteins, Signal Transducing↗
PubMed2000

[Antibiotic impregnation of cartilage implants: diffusion kinetics of fluoroquinolones].

BACKGROUND: Antibiotic impregnation of cartilage implants may reduce the risk of bacterial infection and subsequent absorption. The aim of this study was to investigate the penetration kinetics of two quinolone antibiotics into fresh cartilage and the concentrations in the core of lyophilized cartilage after rehydration. METHODS: Fresh human costal cartilage was impregnated with ofloxacin and ciprofloxacin (2 mg/ml) for 2, 15 and 90 min. Concentrations were measured in 6 levels (0.5 mm each) from the surface to 3 mm beneath the surface with high performance liquid chromatography (HPLC). Lyophilized human costal cartilage was rehydrated in ofloxacine and ciprofloxacine solutions (2 mg/ml, 0.2 mg/ml and 0.02 mg/ml) for 18 hours and concentrations in the core of the rib segment were measured. RESULTS: Quinolone antibiotics penetrate into cartilage by free diffusion. We found no evidence of significant binding to cartilage. After 2 and 15 min of impregnation, concentrations above the minimal inhibitory concentration (MIC90) for pseudomonas species are found from 0-0.5 mm below the surface of fresh cartilage. After 90 min concentrations above the MIC90 were found 1.0-1.5 mm below surface of the implant. In lyophilized rib grafts which were rehydrated in 1/10 diluted intravenous solutions (0.2 mg/ml), concentrations in the core of the specimen were above MIC90. Differences between the penetration characteristics of ofloxacine and ciprofloxacine were minor. CONCLUSION: Intraoperative impregnation of cartilage implants with ofloxacin or ciprofloxacin probably offers only short-term protection against bacterial infection. Rehydrated rib grafts, however, contain high quinolone concentrations which may be effective even in infected implant beds for several hours.

Anti-Infective Agents↗
PubMed1999

[The potential uses and limitations of the flexible laryngoscopy under local anesthesia in clinical practice].

Microsurgery of the larynx is commonly performed as direct laryngoscopy (DL) under general anesthesia. An alternative in selected cases is flexible laryngoscopy (FSL) under local anesthesia. We used a flexible laryngoscope that contained an additional working tunnel (Olympus ENF Type T3). Local anaesthesia of the larynx was achieved with 1% oxybuprocaine-HCl. Tissue samples were taken under endoscopic view and control. Twenty-five patients were studied and had benign lesions of the larynx or were being followed after treatment for cancer. The examination was tolerated well by all patients. The handling of the endoscope allowed precise targeting and sample taking. Due to the 2.2 mm diameter of the forceps the sizes of the biopsies were also limited. However, nearly all of the biopsies taken allowed sufficient histological examination. The advantage of the FSL was its simplicity and the minor inconvenience for patients. Although true histological results of suspect findings are possible, limitations in examining the hypopharynx prevent true staging of cancer patients. In general, FCL is a worth-while complement to DL.

Anesthesia, Local↗
PubMed1999

[An aberrant course of the internal carotid artery through the middle ear].

The presence of the internal carotid artery in the middle ear is a rare but known vascular anomaly. A blue-reddish mass behind the tympanic membrane, hearing loss and a tinnitus that is synchronous with the pulse are the typical symptoms and should lead to a correct diagnosis. The diagnostic procedure includes high resolution CT scans with or without contrast or MRI. Possible methods of therapy include embolization, stent implantation or balloon occlusion of the internal carotid artery but are seldom indicated clinically because of the high rate of side-effects. However, regular followup examinations must be performed.

Adult↗
PubMed1998

[Exophytic papillomatous space-occupying lesions of the larynx as a rare manifestation of candidiasis. Diagnostic and therapeutic consequences].

Laryngeal candidiasis is very rare in the absence of other more proximal diseases in the aerodigestive tract. The lesion shows pseudoepitheliomatous hyperplasia or acanthosis and, given its rarity, may be confused with cancer. In the present paper we report on a 56-year-old male patient who presented with hoarseness. Physical examination of the larynx revealed a hyperplastic lesion involving both vocal cords. The clinical aspect and the risk factor profile of the patient (ten bottles of beer and 40 cigarettes per day) generated the clinical diagnosis of laryngeal cancer. A biopsy was taken. The histopathological examination of the specimen excluded a squamous cell carcinoma; however, it could not provide a clear diagnosis. Laryngeal papillomatosis and tuberculosis, which had been suspected, could be excluded. As the lesion progressed, further biopsies led to the diagnosis of candidiasis. Systemic antimycotic treatment with fluconazol and amphotericin caused a complete remission.

Amphotericin B↗
PubMed1996

[Detection of rapid eye movement with rapidly adapting neuronal fuzzy systems in imprecise REM syntax].

Both living beings and artificial neuronal networks are capable of 'learning' and behavioural adaptation. But also the fuzzy program designed to detect rapid eye movements (REM) during sleep and described here, can be provided with a self-learning option that provides important information about REM sleep. The algorithm computes REM on the basis of horizontal and vertical EOG. EEG, EMG and actiography signals are employed to optimize the method and eliminate artefacts. In a second step, the fuzzy system learns to detect REM with the aid of a sample data set and a minimal set of syntax rules. From sample data and the actions and reactions of visual scorers, the program extracts additional rules and information, which are then used to build a complete fuzzy structure. Thereafter, the REM detection program optimizes the fuzzy logic structure, independently of visual monitoring, on its own. A direct comparison of the results of the algorithm in a 10-night analysis with those of two experienced visual scorers revealed a better than 95% agreement. Re-analysis with the algorithm showed a 100% concurrence. Complete visual measurement of the eye movements occurring in a single night requires several hours; this compares with only 15 minutes required by the algorithm.

Algorithms↗
PubMed1996

[Rest-activity cycle in man].

An actigraph (ZAK company) is a small device that can be worn on the wrist like a watch. We carried out a study to compare sleep efficiency and total sleep time as determined by actigraphy and polysomnography. The number of body movements per minute is a density function. The integrated function shows a virtually constant gradient in the wake state and a different constant gradient during sleep. The body movement density function per hour provides a useful threshold for correctly differentiating between wake and sleep states. This threshold is defined as the minimum between the two maxima of the bimodal logarithmic body movement density distribution. In the second step we computed a rank scale of the different gradients and approximated the integrated function for every scale element using linear graphs. The points of intersection of the straight lines define the time points for sleep onset and end of sleep. Sleep efficiency is given by SE = 100 (TST-sleep interruption time)/TST. Total sleep time is the interval between sleep onset and end of sleep. Actigraphy is a suitable semi-objective method for estimating sleep efficiency and total sleep time, and--for cost reasons--should be used for screening before approaching a sleep laboratory. Actigraphy carried out over several days shows only small differences in comparison with polysomnography. The estimation of parameters is more accurate the longer the patient wears the actigraph, and a minimum of five days is recommended. Spectral analysis of the intregrated body movement density provides important information for detecting subclinical sleep disorders.

Circadian Rhythm↗
PubMed1996

[How good is spatial orientation with rigid endoscopic optics? Study of micromanipulation in the nasal cavity].

Rigid endoscopes are used as an alternative to the operating microscope for visual control during paranasal sinus surgery. Since the view through the endoscope is monocular, perception of depth (stereopsis) through the operating microscope must be expected to be superior due to the binocular view afforded. To investigate whether monocular visualization through an endoscope is a disadvantage in paranasal sinus surgery, we compared stereoacuity in a model of the nasal cavity, using a head lamp, an operating microscope and a 0 degree Hopkin's endoscope. Twenty volunteers had to touch defined points in a spatial model of the nasal cavity. Under binocular vision with a head lamp, performance was significantly better than with the microscope or the endoscope. Manipulations were performed with the same speed under microscopic and endoscopic control, although under microscopic guidance more faults in point sequence were made than with the endoscope. Various monocular phenomena seem to allow sufficient spatial orientation through the endoscope, so that monocular visualization does not appear to be a disadvantage for quick and safe manipulations during functional endoscopic sinus surgery.

Depth Perception↗
PubMed1995

[Approximation of sleep duration and sleep efficiency using actography].

The actography is a cost-effective semiobjective method to measure sleep/wake-cycles. This is the reason why the actography should be used first. The actography is after the cost-intensive polysomnography the best method in diagnosis of sleep disorders and monitoring of sleep disorder therapy. Actography over several days allows a precise estimation of total sleep time and sleep efficiency and makes possible an analysis of sleep/wake in natural conditions. The estimation is better if the patient is in high wake body activity and the recording time is longer. The mean values of total sleep time and sleep efficiency from polysomnography and actography are congruent.

Adult↗
PubMed1990

[The coexpression of keratin and vimentin in untreated squamous cell carcinoma of the ENT tract].

Forty-four untreated squamous-cell carcinomas of the upper aerodigestive tract were examined immunohistochemically with antibodies against keratin and vimentin. Surprisingly, in 18% of cases, a coexpression of both intermediate filaments was found both in undifferentiated carcinomas and in highly differentiated carcinomas, where it was only possible to observe this phenomenon in the basal cell layer. The tumor-biological relevance of these findings must be the subject of further investigations.

Antibodies, Monoclonal↗
PubMed1989

Coexpression of intermediate filaments in squamous cell carcinomas of upper aerodigestive tract before and after radiation and chemotherapy.

Frozen sections of 48 squamous cell carcinomas and seven undifferentiated carcinomas of the upper aerodigestive tract were investigated immunohistochemically with monoclonal antibodies specific for keratin, vimentin, desmin, neurofilaments, and glial fibrillary acidic proteins. In nine squamous cell carcinomas (19%) and six undifferentiated carcinomas (86%) obtained before treatment coexpression of keratin and vimentin was detected in some tumor cells by double immunofluorescence studies. Nine squamous cell carcinomas expressed neurofilaments in scattered tumor cells. Coexpression of vimentin or neurofilaments was seen especially in the peripheral cell layer of the tumor nests and did not seem to correlate with the degree of differentiation. Three undifferentiated carcinomas additionally expressed desmin, and one tumor contained neurofilaments. Glial fibrillary acidic proteins were not detected. Increased coexpression of keratin with vimentin, desmin, or neurofilaments was seen in some tumors that were studied before and after radiation/chemotherapy, suggesting that the intermediate filament profile of tumor cells can be altered by external influences.

Carcinoma, Squamous Cell↗
PubMed1983

Coronary rheothermia: a quasi non-invasive method for controlling bypass patency.

A method based on the principle of thermodilution was developed for a quasi non-invasive permeability control of aortocoronary bypass. An epivascularly-attached thermistor records the cooling of the bypass wall when, following the intravenous injection of 5 to 10 ml of a NaCl solution at 4 degrees C, a bolus of cooled blood passes through the bypass. During cardiosurgical intervention, the thermistor is attached to the venous bridge by one or 2 sutures. The efferent cable goes through the thorax wall and is coupled to a subcutaneously implanted telemetric amplifier unit. The influence of the vessel wall on the perivascular temperature signal, as compared to the intravascular one, was studied in acute and chronic animal experiments. In acute experiments the perivascular peak of temperature was found to be lower than the intravascular one. Continuous measurements over 9 days showed variations in the perivascular signals which must have been due to changes in the thermal capacity of the tissue coupled to the thermistor as well as to changes in resistance caused by a variable extent of scarred area and by the varying water content of the wound bed. These variables will continue to keep rheothermia within the limitations of a method with primarily binary results (= bypass: open or closed). Given stable coupling conditions after full development of the scar around the thermistor, the signal falsification by the then constantly coupled tissue capacity becomes calculable such as to obtain semiquantitative results which, theoretically should vary predominantly with cardiac output.

Animals↗