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R Hagen

Publications and source records attributed to R Hagen.

At least 19 recordsLinked to original sources
PubMed2007

Skin conductance or entropy for detection of non-noxious stimulation during different clinical levels of sedation.

BACKGROUND: State entropy (SE) measures electroencephalographic signals, whereas response entropy (RE) also includes frontal electromyographic activity. In the presence of electromyographic activity, the RE index is larger than the SE index, the difference being denoted as RE-Delta (RE-Delta= RE - SE). Skin conductance (SC) may be expressed by a slow reacting variable, the mean SC level, the derivate of the mean SC level (D-SC), the number of SC fluctuations (NSCF) or the amplitude of the SC fluctuations (ASCF), which directly shows skin sympathetic nerve activity. The goal of this study was to evaluate whether these SC and entropy variables could differentiate between the responses obtained to load sound stimuli at different sedation levels before the induction of general anaesthesia. METHODS: Twenty women scheduled for gynaecological laparotomy were studied. The modified observer's assessment of alertness sedation (OAAS) was used to classify the patients' hypnotic levels. White sounds (98 dB) were given at OAAS level 5 without propofol, at OAAS levels 4-3 and 3-2 with propofol and at OAAS levels 3-2 and < 2 with propofol and remifentanil. RESULTS: RE and SE showed a steady decline from OAAS level 5 to level < 2 (P < 0.01). RE-Delta did not discriminate between any of the OAAS levels (P= NS). The mean SC level discriminated between OAAS levels 4-3 to < 2 (P < 0.01). D-SC discriminated between all the different OAAS levels (P < 0.01). NSCF discriminated between OAAS levels 5 to 3-2 (P < 0.05), but did not discriminate at OAAS level 3-2 between propofol alone or combined with remifentanil, or between OAAS level 3-2 and < 2. ASCF differentiated between OAAS levels 5 and 4 (P < 0.001) and OAAS levels 3-2 and < 2 (P < 0.05) only. CONCLUSION: RE, SE and D-SC showed a similar discrimination between sound responses at the different sedation levels.

Acoustic Stimulation↗
PubMed2007

Comparison of skin conductance with entropy during intubation, tetanic stimulation and emergence from general anaesthesia.

BACKGROUND: The number of skin conductance fluctuations (NSCF) expresses sympathetic skin nerve activity. The response entropy (RE) measures electromyographic and electroencephalographic activity in the forehead. The state entropy (SE) measures mainly electroencephalographic activity. When the suppression of frontal muscular activity is complete, RE is equal to SE. RE-Delta is defined as SE minus RE. The purposes of this study were to examine whether NSCF and RE-Delta correlate with signs of clinical stress during intubation and tetanic noxious stimulation and to elucidate how rapidly and accurately entropy and NSCF react during emergence from general anaesthesia. METHODS: Twenty women scheduled for gynaecological laparotomy were studied. During intubation in remifentanil and propofol general anaesthesia, NSCF and RE-Delta were correlated with the clinical stress score. After a wash-out period, two series of tetanic stimuli were given, the first with (R+) and the second without (R-) remifentanil infusion. The tetanic pre-stimuli periods were compared with the tetanic post-stimuli periods, and R+ was compared with R-. During emergence, the responses of entropy and skin conductance were related to the time of extubation. RESULTS: NSCF correlated well with the clinical stress score during intubation (r(2)= 0.73, P < 0.0005). RE-Delta showed a weaker correlation (r(2)= 0.33, P= 0.007). During tetanic stimuli, the NSCF pre-stimuli level was lower than the post-stimuli level (P < 0.001), and the NSCF R+ response was lower than the NSCF R- response (P= 0.002). RE-Delta did not show similar differences. During emergence, RE reacted before NSCF and SE (P= 0.003). CONCLUSION: NSCF was better than RE-Delta for the measurement of clinical stress during intubation, and was sensitive to tetanic stimuli at different opioid analgesic levels, by contrast with RE-Delta. Both modalities were able to predict emergence at the end of anaesthesia, but RE was more rapid.

Adult↗
PubMed2006

[Significance of PET and integrated PET/CT in the diagnostics of occult primary tumors].

BACKGROUND: In the last years (18)F-FDG-positron-emission-tomography (PET) worked satisfactorily as helpful auxiliary method in order to verify recurrency of head and neck tumors and to detect primary tumors in case of CUP syndrome especially when CT and MR imaging failed to identify the tumor accurately. Fusion of FDG hypermetabolism in PET scan and anatomical structures is achieved by integrating positron emission tomography with CT and provides improvement also in case of CUP syndrome. This retrospective study shows 47 patients with neck metastases where PET or PET/CT helped to detect primary tumor site. PATIENTS: In a retrospective investigation 49 PET studies of 47 patients with CUP syndrome were analyzed. RESULTS: 9 cases had positive PET findings, 1 case false-positive. 5 cases were false-negative. In 40 PET studies there couldn't be found any sign of suspicious FDG hypermetabolism. CONCLUSION: PET and PET/CT deliver a certain improvement in localization of primary tumor site and therapeutical strategy.

Adult↗
PubMed2006

[The integrated PET/CT: technological advance in diagnostics of head and neck recurrencies and CUP?].

BACKGROUND: In the last years (18)F-Fluoro-deoxy-glucose (FDG)-positron emission tomography (PET) worked satisfactorily as auxiliary method in order to show recurrency of head and neck tumors and to detect primary tumors in case of CUP especially when CT and MR imaging failed to identify the tumor accurately. The correlation of FDG hypermetabolism and anatomical structures is now provided by a new technology which is integrating PET and CT: Integrated PET/CT represents a new technical development, which combines the advantages of CT and PET. PATIENTS: In a retrospective investigation 84 non selected PET/CT studies of 83 patients with recurrent head and neck disease and CUP were critically analyzed. RESULTS: 33 cases had positive PET findings. 5 of these 33 cases showed false-positive findings. In 51 PET studies there was not found any sign of suspicious FDG hypermetabolism. CONCLUSION: Integrated PET/CT delivers substantial progress in detecting tumor localization. False positive findings have to be considered and therefore indications should be strictly limited to special cases of head and neck tumor recurrency, cases with complex anatomical sites and CUP.

Adult↗
PubMed2005

[Surgical voice restoration following total laryngectomy].

In spite of the progress made in organ-preserving therapy modalities, including endoscopic or external partial laryngectomies, radiotherapy or chemoradiation in many patients with advanced laryngeal and hypopharyngeal carcinomas, total laryngectomy remains the only safe possibility for long lasting local tumour control. The existing strategies for a sufficient restoration of voice following total laryngectomy are still controversial. Besides the strictly conservative methods of esophageal voice and electronic devices, different surgical procedures are carried out worldwide. At present, the exclusively surgical voice shunt techniques are only offered in a few very specialized centres. In Germany, three surgical methods are in use: (1) microvascular laryngoplasty according to Hagen (> 300 cases), (2) the "jejunal speaking siphon" according to Ehrenberger modified by Remmert (> 60 cases), and (3) the modified Asai-technique according to Maier and Weidauer (> 80 cases).

Adult↗
PubMed2005

Difficulties in the fixation of prostheses for voice rehabilitation after laryngectomy.

In most patients with advanced or recurrent laryngeal or hypopharyngeal cancer, total laryngectomy is indicated. This means the loss of three main functions: phonation; respiration; and the prevention of aspiration during deglutition. Laryngectomy patients have various options to restore phonation: an oesophageal voice; an electrolaryngeal voice; or a tracheo-oesophageal voice. In the last case a silicone rubber shunt valve is placed in the tracheo-oesophageal wall and phonation is generated when exhaled air is forced through the oesophagus and neopharynx. This method is widely applied in Western Europe. In this paper we review the literature on fixation problems with shunt valves, tracheostoma valves and heat and moisture exchange (HME) filters. Tracheo-oesophageal speech without a valve is not considered. Despite 22 years of experience with the implantation of tracheo-esophageal shunt valves and many improvements in the design, problems still remain, such as biofilm formation with subsequent leakage through the valve, the need for frequent and inconvenient replacements, fistula enlargement leading to leakage around the device and reduced fixation, and infections. The high cost of shunt valves is a drawback to their use worldwide. To enable hands-free speech, different types of tracheostoma valve have been developed. These valves are fixed to the skin or to the tracheostoma by means of an intra-tracheal device. An HME filter is used to protect the airway and maintain physiological balance. Such devices are only suitable for a selected group of patients as fixation to the skin or trachea can be a major problem. Speaking and coughing cause pressure increases, which often result in mucous leakage and disconnection of the valve and/or HME filter. Recommendations are made for future improvements in fixation techniques.

Humans↗
PubMed2004

Conformational kinetics of disaccharides in aqueous solutions.

Between 100 kHz and 2 GHz ultrasonic attenuation spectra of disaccharides in water have been measured at 25 degrees C. Some additional measurements have been performed at different temperatures between 10 and 35 degrees C and as a function of saccharide concentration c (0.5 mol/l</=c</=1.8 mol/l). The analytical description of the spectra in terms of relaxation spectral functions revealed four relaxation regimes. Three relaxation regions correspond to such revealed by monosaccharides in solution. These relaxations reflect a pseudorotation, an exocyclic hydroxymethyl group rotation, and probably a saccharide-saccharide association. The relaxation term with relaxation time between 3.6 and 19 ns (25 degrees C) is characteristic for the disaccharide solutions. It has been assigned to a rotation of the disaccharide rings relative to one another.

Disaccharides↗
PubMed2004

Kinetics of Ca2+ complexation with some carbohydrates in aqueous solutions.

For solutions of four saccharides in water with alkaline-earth chlorides added ultrasonic attenuation spectra between 100 kHz and 2 GHz are reported and compared to those for carbohydrate solutions without salt. Calcium chloride does not alter the relaxation times in the spectra of D-glucose and D+-maltose solutions, reflecting the exocyclic hydroxymethyl group rotation, a saccharide-saccharide association, and, with the disaccharide, also motions of both rings of a molecule relative to one another. The spectra of D-xylose and D-fructose solutions are substantially changed by the salts. With both saccharides an additional term with relaxation time around some nanoseconds exists which is assigned to a rearrangement of a carbohydrate-cation complex. Other relaxation terms of these saccharide solutions are also subject to noticeable changes by the salt, indicating specific carbohydrate-cation interactions. The ultrasonic spectra show that such interactions may exist also with carbohydrates which do not display the particular hydroxyl group sequences that are considered to promote complexation with cations.

Journal Article↗
PubMed2004

[Tracheostoma valve with integrated cough lid for improvement of hands-free speech in laryngectomees - long term results].

BACKGROUND: Tracheostoma valves for laryngectomized patients were introduced to enable the laryngectomee after successful surgical voice restoration either by a voice prosthesis, a surgical shunt or microvascular laryngoplasty, to speak without using his fingers to close the tracheostoma. The basic principle of these aids is a mobile valve, which closes automatically at a certain air flow, directing the expired air of the lungs into the pharynx. In spite of the clear advantage of enabling a hands-free speech, the long term acceptance rate is still rather low, which is mainly caused by problems of an airtight fixation within or at the tracheostoma. Another important disadvantage of these tracheostoma valves is the necessity of removing the valve during coughing. The new tracheostoma valve "Window" (ADEVA Company, Lübeck, Germany) offers a clear improvement regarding this point. It is constructed with an additional coughing lid, which opens at a certain airflow and closes automatically after the coughing attack. After successful development and clinical testing of the new aid in 1999 and 2000, it was now the question, if the previously low acceptance rate of tracheostoma valves could be improved in the long term use by this new type of valve. PATIENTS: Within the last 4 years 70 patients were provided with the "Window" tracheostoma valve. Patients were followed up at regular intervals in order to evaluate the function, the acceptance and the durability of the new device. Additional to the clinical examination patients had to fill in a questionnaire in order to investigate the subjective estimation by each patient himself. 15 patients did not send back their questionnaire or did not fill it in correctly, 5 patients refused clinical supervision after adjustment of the device, so finally the long term use in 50 patients could be analysed. RESULTS: 82 % of the patients reported, that the coughing lid worked safely and opened immediately during the coughing attack. Most of the patients were satisfied with their device, but had nevertheless some proposals for a further improvement: although they cover the tracheostoma either with their clothes or a protection scarf, most of the patients would prefer a device which is smaller than the current model. Some patients reported on an insufficient stability of the plastic material, which led to a defect at the sliding mechanism of the coughing lid. The greatest problem regarding the regular use of the valve was - comparable to conventional tracheostoma valves - the occurrence of an air leakage around the tracheostoma. Although there are three different models of the "Window" tracheostoma valve available, only patients being fitted with the "standard-T-type" version could wear the device 10 hours a day or longer without any problems of air leakage. CONCLUSIONS: The "Window" tracheostoma valve with an integrated coughing lid provides further improvement in speech rehabilitation of laryngectomees. The actual rate of acceptance of 62 % for all "Window" patients (1 month daily use for at least 2 hours) is superior to other reports on the use of tracheostoma valves and probably caused by the additional comfort provided by the coughing lid. Another important factor for the long term use of tracheostoma valves is however the safe fixation of the device in or around the tracheostoma. In this point further improvement is necessary, as only the model with the fixation within the trachea (T-type) led to a satisfactory long term airtight fixation.

Cough↗
PubMed2003

[Are titanium implants superior to gold implants in the tympanic cavity?].

BACKGROUND: Gold implants in reconstructive surgery of the middle ear have proved to work sufficiently: That applies to tympanic cavity conditions without signs of chronic inflammation as also to the bacterially infected middle ear. For some years titanium implants are also in the use and established as well. The biocompatibility of titanium, the clinical and the audiological results are satisfactory. When using gold-prostheses in stapes surgery however, the still unsolved problem of occasional deafness has to be considered. PATIENTS: The clinical and functional results of middle ear surgery were examined retrospectively. There was no preselection of patients. 53 patients underwent middle ear surgery with titanium prostheses, 42 patients with gold prostheses. RESULTS: Due to their material properties and due to their delicate shape titanium prostheses (PORP, TORP) can be inserted into the tympanic cavity more simply and with better fit. The audiological results of gold and titanium prostheses are comparable. The extruding rate of the gold prostheses is substantial, whereas the extruding rate of titanium is negligible. CONCLUSION: The functional results of both materials are comparable. Due to the high extruding rates of gold prostheses titanium is clearly superior.

Auditory Threshold↗
PubMed2002

[Functional long-term results following hemipharyngo-hemilaryngectomy and microvascular reconstruction using the radial forearm flap].

BACKGROUND: The surgical treatment of advanced hypopharyngeal carcinomas with infiltration of the laryngeal skeleton often includes total laryngectomy for functional reasons, although tumor infiltration is limited to only one half of the larynx. When not only the infiltrated half of the thyroid cartilage but also the cricoid cartilage of the involved side has to be removed, in spite of adequate reconstruction using local or pedicled flaps (f. e. pectoralis major flap) persistent dysphagia and aspiration prevent oral food intake and closure of the tracheostoma. These functional disturbances are increased by the negative effects of postoperative radiotherapy, which has to be applied in most of the cases for oncological reasons. The routine use of free, microvascularly anastomosed flaps for reconstruction of defects following removal of extended carcinomas of the mouth, the tongue or the oropharynx as well as in total pharyngolaryngectomy led to considerable improvements in functional rehabilitation of swallowing and speech. An improved functional outcome is also reported following partial resections of the hypopharynx and reconstruction by means of these thin and pliable transplants (f. e. replacement of the entire posterior hypopharyngeal wall). METHOD: Since 1991 in 30 patients with a T3 or T4 squamous cell carcinoma of the piriform sinus a complete hemipharyngo-hemilaryngectomy including resection of the involved thyroid and cricoid cartilage was carried out. For reconstruction a radial forearm flap was dissected with two separate epithelial islands: The smaller island was used to create an epithelialized endolarynx, which allows complete closure of the glottis by the healthy vocal chord. With the bigger second island the hypopharynx was replaced, creating a highly mobile, adaptable neo-piriform-sinus, which was suspended to the ipsilateral half of the hyoid bone. Parts of the both islands were sutured together to create a new aryepiglottic fold. The laryngeal skeleton intentionally was not reconstructed. RESULTS: One year evaluation revealed 25 of the 30 patients swallowing normal diet and being decannulated. 4 patients could take up a soft diet, 1 patient with a severe stricture at the entrance to the esophagus however had to be laryngectomized for functional reasons. Most of the patients judged their postoperative voice as satisfactory, although there was a different impairment of the voice (quite normal up to a marked hoarseness). During follow-up (up to 10 years) 4 patients developed a local recurrence, in 3 cases a secondary metastasis after neck dissection occurred. In 3 patients a second primary was detected (oropharynx 2, esophagus 1), 3 patients died with lung metastases. CONCLUSION: Rehabilitation of normal swallowing and a satisfying voice restoration without a permanent tracheostoma following complete hemipharyngo-hemilaryngectomy can obviously be improved by the use of microvascular transplants (here radial forearm flap) in comparison to other surgical techniques. The necessary radical extirpation of these extended carcinomas also is guaranteed like in total laryngectomy, so that in spite of the advanced tumor stage an organ preserving surgery can be offered. A prolonged course of swallowing rehabilitation however has to be taken into consideration.

Adult↗
PubMed2002

[Mechanical ileus caused by a Provox voice prosthesis -- an "iatrogenic" enteral complication in voice prosthesis rehabilitation of laryngectomees].

BACKGROUND: During the exchange of a defect Provox-I voice prosthesis followed by an insertion of a Provox-II voice prosthesis the esophageal part of the prosthesis often is pushed into the esophagus, as the enteral passage of the prosthesis was thought to be less traumatic for the voice shunt in comparison to a complete extraction of the stiff esophageal flange through the tracheostoma. This procedure is also recommended in the users video of the ATOS company. CASE: A laryngectomized patient, in whom the change of the voice prosthesis was carried out pushing the esophageal flange of the prosthesis into the esophagus, developed a mechanical ileus, as the voice prosthesis got stuck in Bauhin's valve. This resulted in the necessity of a laparatomy for removal of the voice prosthesis. CONCLUSION: During the replacement of the Provox voice prosthesis it is necessary in all cases that the esophageal remnant of the voice prosthesis either is pulled out of the tracheoesophageal shunt via the tracheostoma or removed with a guide-wire transorally.

Aged↗
PubMed2001

[Tracheostomy valve with integrated cough flap for improving hands-free speech in laryngectomized patients--development and clinical applications].

BACKGROUND: Following successful voice restoration after laryngectomy either by a voice prosthesis, a surgical shunt or microvascular laryngoplasty, a further goal in rehabilitation is the insertion of a tracheostoma valve, which enables the patient to speak without using his fingers for closure of the tracheostoma. One important disadvantage of the tracheostoma valves, which are available today, is the necessity of removal of the valve in case of coughing, because the valve could be thrown from the stoma by the strong air flow during coughing. As many laryngectomies suffer from chronic bronchitis, this coughing problem is one of the reasons why only few patients could be provided with this useful aid. METHOD: At the department of biomedical engineering of the faculty of medicine at the university of Groningen, the Netherlands, 1994 two prototypes of a tracheostoma valve with an integrated cough lid were developed. These devices contain two separate valve systems: the normal speaking valve and a special coughing valve, which opens at a certain air flow and closes automatically after the coughing attack. Thus no manipulations are necessary during coughing, the patient can speak undisturbed. The ADEVA company (Lübeck, Germany) undertook the industrial production of this new type of tracheostoma valve creating different modifications of the prototype #2. PATIENTS: In four series with 6-8 patients per group the modified tracheostoma valves were tested clinically and the occurring faults or lack of correct function eliminated by small changes in the production. RESULTS: Meanwhile a suitable model for routine use is available, which was tested in 30 patients so far. This suitability was achieved by improvements in the valve mechanism, the valve seal and the adjustment mechanisms for the individual pressure level of the speaking and the coughing valve. CONCLUSION: The newly developed tracheostoma valve with integrated coughing lid (Window, ADEVA-medical Company, Lübeck, Germany) provides further improvement in speech rehabilitation of laryngectomies. The low acceptance of tracheostoma valves, which enable the patient to speak without using his fingers for closure of the tracheostoma, possibly may be raised by this new aid.

Bronchitis↗
PubMed2001

A highly specific one-step PCR - assay for the rapid discrimination of enteropathogenic Yersinia enterocolitica from pathogenic Yersinia pseudotuberculosis and Yersinia pestis.

Based on differences within the yopT-coding region of Yersinia. enterocolitica, Y pseudotuberculosis and Y pestis, a rapid and sensitive one-step polymerase chain reaction assay with high specificity for pathogenic Y enterocolitica was developed. By this method pathogenic isolates of Y enterocolitica can be easily identified and discriminated from other members of this genus. The entire coding sequence of the yopT effector gene of Y. pseudotuberculosis Y36 was determined.

Animals↗
PubMed2000

[Thrombosis of the basilar artery--a rare differential sudden deafness diagnosis and vestibular failure].

BACKGROUND: Occlusion of basilar artery is a rare and life-threatening event. A quick and safe diagnosis and initiation of adequate therapy are decisive. For the ENT-specialist it is important to know that this thrombosis, which runs a lethal course in many cases, can develop with a disturbance of hearing and/or vestibular function as initial symptoms. PATIENTS: Reported are four cases of thrombosis of the basilar or vertebral artery. Two out of four patients contacted the ENT emergency unit because of symptoms of acute vestibular neuritis, one patient was previously diagnosed with sudden deafness by a local ENT-specialist, one patient was treated for hypertension induced epistaxis in one of our wards. Only one patient initially presented additional neurological symptoms, causing suspicion for a brainstem lesion as well. However these symptoms were only noticed on close examination. By immediate anticoagulation therapy (with Heparin) progress of thrombosis could be avoided. The patient showed a complete recovery and was free of any symptoms two years after thrombosis. Two of the other two patients developed a delayed onset of neurological symptoms next to the initial symptoms of vestibular and cochlear affection (within 24 hours), therefore diagnosis of thrombosis was late and despite of immediate anticoagulation therapy (with Heparin) both patients died. The one patient treated for hypertension induced epistaxis developed only discrete symptoms of basilar artery thrombosis, nevertheless he was diagnosed and treated immediately. He made a complete recovery and was dismissed two weeks later. CONCLUSIONS: It is therefore necessary to carefully control and sometimes correct diagnosis in cases of sudden deafness and acute vestibular neuritis. Especially additional neurological symptoms indicate the necessity of a MRI-angiogram or CT-(angiography)scan to exclude thrombosis of the basilar artery.

Adult↗
PubMed2000

Aflatoxin B1-induced mitotic recombination in L5178Y mouse lymphoma cells.

Aflatoxin B1 is a human hepatocarcinogen. It is also a known point mutagen in bacteria and mammalian cells. This mutagenic activity may be at least partly responsible for its carcinogenic activity. However, recent studies show that aflatoxin B1 induces mitotic recombination in the yeast Saccharomyces cerevisiae. Because numerous reports have implicated mitotic recombination in mechanisms leading to carcinogenesis and because no one has shown that aflatoxin B1 induces recombination in mammalian cells, we decided to examine the ability of aflatoxin B1 to induce recombination in a mammalian cell line. We used a combination of methods, analysis for loss of heterozygosity and whole chromosome in situ hybridization, to identify mechanisms of chromosome mutation, including mitotic recombination in the mammalian L5178Y mouse lymphoma cell system. Our experiments revealed that mitotic recombination caused approximately 60% or more of the aflatoxin B1-induced mutagenic lesions in this cell system. Thus, mitotic recombination plays an important role in aflatoxin B1-induced mutagenesis in mammalian cells and possibly in chemically induced mutagenesis and carcinogenesis. This work suggests that multiple genetic lesions may be involved in aflatoxin B1-induced pathology.

Aflatoxin B1↗