Biomedical subjects

W J Mann

Publications and source records attributed to W J Mann.

At least 37 records · Page 2Linked to original sources

PubMed2004

Expression and localization of cyclooxigenases (Cox-1 and Cox-2) in nasal respiratory mucosa. Does Cox-2 play a key role in the immunology of nasal polyps?

INTRODUCTION: Cyclooxygenases 1 (Cox-1) and 2 (Cox-2) play a key role in arachidonic acid metabolism and in the regulation of eicosanoid production. The balance of prostaglandin and leukotrien release in respiratory mucosa is a crucial factor in the development of Sampter's triad in NSAID (aspirin-) intolerant patients and possibly also relevant in the pathophysiology and immunology of chronic rhinosinusitis (CRS) and nasal polyposis in NSAID tolerant patients. METHODS: 36 surgical specimens were immunohistochemically labeled for Cox-1 and Cox-2. Specimens were taken from chronically inflamed mucosa (n=13) and from nasal polyps (n=10) during endonasal sinus surgery. Controls were obtained from healthy nasal respiratory mucosa (n=13), harvested during turbinate surgery in patients with nasal obstruction without inflammatory disease. RESULTS: Analysis revealed that Cox-1 and Cox-2 were labeled in all 23 inflamed / polypoid tissue specimens and in all 13 controls. In chronically inflamed tissue the expression of Cox-1 and Cox-2 was strongly labeled in the respiratory epithelial lining and in mucosal glandular ducts. In nasal polyps the expression pattern of Cox-1 was similar, but Cox-2 was much less intensely labeled in the superficial epithelial cellular lining. Controls showed homogenious labeling of Cox-1 and Cox-2 in both tissues with little intensity. CONCLUSIONS: These data suggest that Cox-2 is downregulated in epithelial cells of nasal polyps. Cox-1 and 2 are present in high concentrations in ductal structures of mucosal glands. The significance of these findings has to be discussed with regard to the regulatory function of Cox-2 in eicosanoid release and the role of the latter in the immunology and pathophysiology of nasal polyps.

Adult↗

PubMed2003

Chromosomal aberrations in premalignant and malignant squamous epithelium.

Biopsies of oropharyngeal cancer were screened for chromosomal imbalances by comparative genomic hybridization (CGH) performed on 22 primary tumors and morphologically nonmalignant surrounding mucosa. The aim was to determine early chromosomal changes of tumor development and to draw conclusions on the mechanisms leading to multiple tumors. The most prominent chromosomal imbalances observed were over representations of genomic material on 3q, 15q, 8q, and 11q and losses on 9p, 3p, and 11q. In morphologically normal mucosa collected at 1 cm from the primary tumor border (M1), amplifications on 15q and 21q were most frequent. Far fewer gains and losses were found in M1 than in the primary tumor (average 2.2 vs. 6.9). Gains dominated over losses, but a tendency toward an increasing proportion of losses in the primary tumor (PT) was observed (ratio of gains to losses: PT, 4.75; M1, 6.3). Almost all the imbalances in M1 were detected in the primary tumor. No chromosomal alterations were identified with CGH in tissue samples dissected at 2 cm from the primary tumor (M2). In all samples, dysplastic morphologic changes decreased with distance from the primary tumor, which correlates with the observed lower level of genetic changes. We suggest that gains of genetic material on 15q and 21q are early events in malignant progression of squamous cell carcinoma, followed by gains on 3q, 8q, and 11q, and losses on 3p and 9p at later stages. Based on our cytogenetic data, we discuss the monoclonal model followed by lateral epithelial spread as an explanation of multiple head and neck squamous cell carcinomas.

Adult↗

PubMed2003

[Prevalence of obstructive sleep apnea syndrome (OSA) in patients with sudden hearing loss. A pilot study].

BACKGROUND: It is estimated that in patients with sleep-related breathing disorders the probability of a cerebral vascular infarction (CVI) is 3.1 times that in patients without sleep apnea and that 25-50% of all patients who have a stroke suffer from sleep apnea (OSA) and have a respiratory disturbance index (RDI) higher than 10. CVI may be caused by variations in intracranial pressure or in intracranial hemodynamics owing to decreasing pO(2) and increasing pCO(2) during cessation of airflow. It is suspected that the most common causes of sudden deafness are vasospasm, thrombosis, embolism, hypercoagulation and sludging. The present study analyzed the prevalence of sleep apnea in patients with sudden hearing loss. PATIENTS AND METHODS: A 7-channel polygraph was used to test 33 subjects with normal hearing and 27 patients suffering from sudden hearing loss. Statistical analyses were performed with a Chi-square test and the Mann-Whitney test. RESULTS: We found that 29.6% of the patient group and 21.2% of those in the study control group were suffering from OSA and had RDI >10; this difference was not significant ( p=0.554). Sudden hearing loss may also be an indicator of arteriosclerosis secondary to such risk factors as hypertension ( p=0.005), diabetes ( p=0.003), and hyperlipidemia ( p=0.004), which were highly significant for the patient group. CONCLUSION: Patients who develop sudden hearing loss tend to have OSA more frequently than those in the control group owing to the similar risk factors for cerebral infarction and sudden hearing loss.

Adolescent↗

PubMed2003

[The need for 24-h double probe pH monitoring in the diagnosis of laryngo-pharyngeal reflux].

BACKGROUND: Laryngopharyngeal reflux disease (LPRD) can have various causes. Because LPRD differs from gastroesophageal reflux disease (GERD), the pH monitoring has to be performed directly next to the entrance of the larynx. This is now possible using a new system called pH-RESPONSE. METHODS: The ambulatory pH was monitored using the double probe pH-RESPONSE in 20 patients with suspected LPRD. The number of refluxes, the number of long refluxes and the period in which the pH was below 4 were compared at the level of the larynx with the data from the esophageal electrode. The DeMeester score was also determined. RESULTS: The system was well tolerated by 19/20 patients. In 12 patients a GERD could be proved and ten also had LPRD. Surprisingly, these patients had no typical signs such as heart burn. The number of refluxes measured in the esophagus was a third that of the larynx. The average time of pH below 4 was 30 min. CONCLUSION: The pH-RESPONSE easily allows ambulatory 24 -h double probe pH monitoring to diagnose LPRD. Because large differences were found between data form the esophagus from the level of the larynx, 24-h double probe pH monitoring should be a standard procedure before starting any therapy for LPRD.

Esophagus↗

PubMed2003

[Common errors of intraoperative navigation in lateral skull base surgery].

BACKGROUND AND OBJECTIVE: The knowledge of disturbing factors for navigated surgical procedures in lateral skull base surgery will help the user to identify, avoid, and correct these errors. PATIENTS/METHODS: Based on our experiences with 85 patients undergoing surgery of the lateral skull base, errors of hard- and software, of image acquisition and image transfer, of patient registration, user-related errors as well as strategic errors were analyzed. RESULTS: Any impairment of the camera field leads to functional limitation of optical systems to the same extent as electromagnetic systems can be affected by ferromagnetic materials. Standard patient registration procedures as well as the lack of compensation for soft tissue shift may cause problems. CONCLUSIONS: While dealing with navigation devices in lateral skull base surgery, the user must pay critical attention to certain details in order to recognize and interpret possible malfunction.

Computer Systems↗

PubMed2003

[Results in terms of hearing results after surgical closure of labyrinthine fistulas].

OBJECTIVES: We investigated the results achieved in terms of hearing in 36 patients who had each undergone resection of a cholesteatoma and closure of a labyrinthine fistula. PATIENTS AND METHODS: These patients included 28 who had a fistula of the semicircular canal, in 7 of them with an opened perilymphatic space. In 8 cases we found a fistula of the cochlea, with with a perilymphatic leak 7 in of them. We compared the sensorineural threshold before and after surgery and also the results in the two groups. Patients who were deaf preoperatively were excluded from further analysis. RESULTS: Hearing did not improve in any of the patients (n=5) who were deaf preoperatively. There was no significant difference in changes to the hearing threshold between patients with fistula of the cochlear and those with fistula of the semicircular canal with opened perilymphatic space; nor did patients with a fistula of the semicircular canal without perilymphatic leakage have a better outcome than patients with an open membranous labyrinth. CONCLUSIONS: The outcome of cholesteatoma resection and closure of the fistula in a single operation was good. Perilymphatic leakage seems to be predictive of a poorer result in terms of hearing.

Audiometry, Pure-Tone↗

PubMed2003

[The application of an optical navigation system in endonasal sinus surgery].

BACKGROUND: There are several CAS-systems in use in modern endonasal sinus surgery. The VectorVision Compact is the first optoelectrical system especially designed for such surgery. This paper investigates its reliability and practicability. PATIENTS AND METHODS: The system was used for intraoperative navigation in 60 patients suffering from chronic rhinosinusitis. The accuracy was measured by visual estimation and compared with other navigated systems. RESULTS: The accuracy was 1.9 mm which is comparable to other systems on the market. Navigation was successful and reliable in 83.3% of the patients. Problems occurred mainly due to loss of sight of the referencing balls and when using other surgical instruments. CONCLUSION: The VectorVision Compact was adequate for endonasal sinus surgery. Further improvements incorporating various surgical instruments should broaden its clinical usefulness.

Endoscopes↗

PubMed2003

[Epidemiological data of patients with sudden hearing loss -- a retrospective study over a period of three years].

In this retrospective study data of 257 patients (11- 6 years; 52 % male, 48 % female) admitted during the last three years for treatment of sudden unilateral hearing loss are statistically evaluated. No correlation with coexisting disease like hypertension, coronary heart disease, hypercholesteremia, arthropathy of the cervical spine, diabetes, thyroid disorders or nicotine abuse were evident. In 194 patients (75 %) total remission was achieved after rheological therapy. Patients additionally treated with steroids had a significant better outcome. Younger patients had higher remission rates. The best prognosis was found for patients with hearing loss in the lower frequency range. There were no differences in remission rates for patients with preexisting sensorineural hearing loss or chronic otitis media. Also patients suffering from recurrent episodes of sudden hearing loss had a similar outcome also.

Adolescent↗

PubMed2003

[Percutaneous dilatative tracheostomy versus conventional surgical tracheostomy: a retrospective trial].

BACKGROUND: In this retrospective study we compared endoscopically controlled percutaneous dilatative tracheostomies (PDT) with conventional surgical tracheostomies as a bedside procedure and in the operating theatre. PATIENTS: Between 1998 and 2000 we performed 360 tracheostomies electively, 152 in PDT-technique (42 %) and 208 (58 %) with the conventional procedure. Referring to the PDT-technique 74 % (n = 112) were performed at the bedside and 26 % in the operating theatre. The conventional tracheostomies took place at bedside in 53 % (n = 110) and in the operating theatre in 47 % (n = 98) of the cases. The complications were divided in 5 groups with special interest if the operation took place in the operating theatre or as a bedside procedure. RESULTS: In general the rate of complications in the PDT group was 33 % (50/152) versus 22 % (46/208) referring to the conventional group. Referring to the PDT group the rate of complications were 35 % (39/112) at the bed site procedure and 28 % (11/40) in the operating theatre. The complication rate for the conventional group was 27 % (30/110) as a bedside procedure versus 16 % (16/98) in the operating theatre. Significant differences were found for the PDT with an increase of tubal obstructions (p = 0.007). For the conventional tracheostomy we found a significant increase of wound infections (p = 0.006). There was significantly higher postoperative hemorrhage if the procedure was done at bed site. CONCLUSION: PDT and conventional tracheostomies have different complications. The higher risk of postoperative hemorrhage for bed site procedure has to be considered.

Adolescent↗

PubMed2003

[The effects of Streptolysin-O and sodium hyaluronate on the permeability of the round window membrane in guinea pigs--an electrophysiologic study].

BACKGROUND: The round window membrane (RWM) acts like a barrier for topically applied substances into the middle ear preventing diffusion into the perilymphatic fluid compartment. MATERIAL AND METHOD: In an animal model, modulation of the permeability of the RWM was attempted using Streptolysin-O (SLO) in various concentrations and sodium hyaluronate. Thereafter, the effect of intratympanically applied Lidocain 2 % on hearing threshold measured by auditory brainstem response was tested for Lidocain 2 % and Lidocain 2 % in combination with SLO or sodium hyaluronate. RESULTS: The results show that both, SLO and sodium hyaluronate, influence the effect of Lidocain 2 % on hearing thresholds as an indirect sign for changes of the permeability of the RWM. However SLO by itself in low concentrations decreased auditory thresholds in some animals while this was never observed with sodium hyaluronate. CONCLUSIONS: Our findings preclude SLO and favor sodium hyaluronate as a modulator of RWM permeability in therapeutic trials.

Animals↗

PubMed2003

Comparison of Different Computer-Aided Surgery Systems in Skull Base Surgery.

Computer-aided surgery (CAS) based on high-resolution imaging techniques represents an important adjunct to precise intraoperative orientation when anatomical landmarks are distorted or missing. Several commercial systems, mostly based on optical or electromagnetic navigation principles, are on the market. This study investigated the application of EasyGuide(R), VectorVision(R), and InstaTrak(R) CAS systems in ENT surgery under practical and laboratory conditions. System accuracy, time required, handling, individual features, and practicality were examined in 155 patients who underwent endonasal sinus surgery and in 23 patients who underwent anterior or lateral skull base procedures. The VectorVision(R) and InstaTrak(R) CAS systems proved to be suitable for routine application in surgery involving the paranasal sinuses and various regions of the anterior skull base by helping to avoid critical structures and to determine minimally invasive approaches.

Journal Article↗

PubMed2002

[Intraoperative navigation in surgery of paranasal sinus and anterior skull base].

BACKGROUND AND OBJECTIVE: Based on physical laws, stage of technical development and the user's individual skills a number of possible errors have to be considered for the application of CAS in paranasal sinus and anterior skull base surgery. PATIENTS/METHODS: Based on our experiences of 436 navigated cases hard- and software errors, errors of image acquisition and transfer, errors of patient registration, user related errors as well as strategic errors are analyzed. RESULTS: Any hindrance of the camera field leads to a limitation of functionality of optical systems in the same extent as electromagnetic systems can be affected by ferromagnetic materials. The mode of image acquisition is dependent from the CAS-system involved. The reconstruction algorithm requires particular attention. The patient registration based on the headset proved to be reliable for endonasal sinus surgery. CONCLUSIONS: In dealing with navigation devices in paranasal and anterior skull base surgery the user must pay critical attention to possible malfunction in order to guarantee a successful image guided surgical procedure.

Algorithms↗

PubMed2002

Neural conservation in skull base surgery.

Surgical treatment of lesions of the skull base carries significant risk to the functioning of the cerebral hemispheres, the brain stem and the cranial nerves. This risk is due both, to problems associated with maintaining an adequate blood flow while exposing and removing the tumor and to direct or indirect trauma to the brain, perineural tissues and cranial nerves. These risks may be reduced if information about possible implications of surgical maneuvers on the cerebral blood flow and on the function of the patients central nervous system and cranial nerves is available and can be monitored during surgery of the skull base. The use of electromyographic neuromonitoring for the facial nerve and of BERA-monitoring for the auditory nerve have been described and are now standard methods to achieve these goals. In acoustic tumors in the last several years beside preservation of the function of the facial nerve hearing preservation especially in small tumors has been one of the primary goals in acoustic neuroma surgery. Computer assisted surgery and intraoperative imaging for lateral skull base surgery are still in their infancy but promise to allow further improvement of neural conservation.

Brain↗

PubMed2002

[Aspirin sensitivity: long term follow-up after up to 3 years of adaptive desensitization using a maintenance dose of 100 mg of aspirin a day].

BACKGROUND: The full clinical picture of aspirin intolerance, Sampter's triad, is associated with nasal polyposis, clinical sensitivity to most non steroidal antiinflammatory drugs (NSAID) and intrinsic bronchial asthma. But the triad can be incomplete and nasal polyposis can be the first clinical symptom of aspirin sensitivity. Although the exact mechanisms of aspirin intolerance as well as those of desensitization remain obscure, an in vitro assay on eicosanoid metabolism has been proven to be helpful in diagnosis and treatment as it correlates well to the individual severity of clinical symptoms. METHODS: For this investigation 30 patients, who were undergoing adaptive desensitization for aspirin intolerance, were followed-up between 1 and 3 years. They received a maintenance dose of oral aspirin of only 100 mg a day after an initial application of higher doses. Their clinical course as well as their in vitro parameters of eicosanoid release were monitored throughout the individual observation period. RESULTS: Desensitization was successful in 25 of the 30 patients regarding the recurrence rate of nasal polyps, severity of bronchial asthma and sense of smell. There was a clear positive correlation between clinical and in vitro parameters. Discontinuing of aspirin therapy lead to worsening of clinical symptoms, regardless of the prior duration of treatment. CONCLUSIONS: This article reviews the role of the in vitro assay and presents a desensitization protocol that can be maintained as a long term treatment without adverse side effects. Results suggest that the recurrence rate of nasal polyps after surgical therapy can be reduced using this protocol, however, only long term treatment can secure a beneficial outcome over time.

Adolescent↗

PubMed2001

Individual monitoring of aspirin desensitization.

BACKGROUND: Patients with aspirin-sensitive rhinosinusitis, which is frequently associated with intrinsic bronchial asthma, can be desensitized by long-term treatment with oral aspirin. The exact mechanisms of this desensitization remain obscure, but modulations of the eicosanoid pathway occur and can be monitored with the help of a practicable in vitro assay on mixed leukocyte cultures. OBJECTIVE: To monitor the effect of low-dose aspirin desensitization therapy, 100 mg/d, objectively by an in vitro assay. DESIGN: In a prospective study, 30 patients with aspirin intolerance, who were treated following a desensitization protocol with a dose of oral aspirin of only 100 mg/d were followed up for 1 year and reassessed every 3 months clinically and in vitro. RESULTS: Twenty-five patients showed a normalization of in vitro eicosanoid levels during this period, 4 showed some improvement, and 1 showed no therapeutic effect on eicosanoid release. Clinical follow-up revealed a low recurrence rate of nasal polyposis, with recurrent disease only in 4 individuals who also showed no normalization of eicosanoid release levels. Furthermore, a reduction of the average incidence of purulent episodes of sinusitis was seen after 1 year. Of 12 patients with asthma, 9 experienced marked improvement in pulmonary function. Of 16 individuals with a marked impairment of nasal breathing, 14 felt an increase of nasal patency, and 7 of 11 patients with pretreatment hyposmia had an improved sense of smell after 1 year. CONCLUSIONS: Desensitization therapy in patients with aspirin-sensitive rhinosinusitis can be successfully performed with low oral doses of aspirin, and the individual course throughout the desensitization can be monitored with the help of an in vitro analysis of eicosanoid release from mixed leukocyte cultures.

Adult↗

PubMed2001

[Neurofeedback in therapy of tinnitus].

BACKGROUND AND OBJECTIVE: Biofeedback is known as a possibility to control physiologic processes like body temperature or heart frequency. Neurofeedback is a form of biofeedback linked to aspects of the electrical activity of the brain such as frequency, location or amplitude of specific EEG activity. It has been successfully used in patients with closed head injury, hyperactivity disorder or epilepsy. PATIENTS/METHODS: In this study 40 patients with tinnitus were treated with neurofeedback.They trained to upregulate the amplitude of their alpha-activity and downregulate the amplitude of beta-activity during muscle relaxation and acoustic orientation on sounds or music in order to suppress their tinnitus. RESULTS: After 15 sessions of training 24 patients with a duration of their tinnitus for an average of 1 year showed significant increase of alpha-amplitudes while 16 patients with duration of their tinnitus on an average of 7 years showed a decrease of beta-amplitudes without any change in alpha-activity. After the training all patients had a significant reduction of the score in the tin nitusquestionaire of Gobel and Hiller. In a control-group of 15 persons without tinnitus we didn't see any changes of alpha- or beta-amplitudes during the same training. CONCLUSIONS: In conclusion neurofeedback is a new therapy for patients with tinnitus. Patients get the possibility of selfcontrol and therefore of influence on their disease.

Acoustic Stimulation↗

PubMed2001

Prostaglandin E2 activates the ciliary beat frequency of cultured human nasal mucosa via the second messenger cyclic adenosine monophosphate.

Prostaglandins influence the ciliary beat frequency (CBF) of ciliated nasal epithelial cells and a stimulatory effect has been described for prostaglandin E2 (PGE2). Until now, it is not known whether PGE2 has direct ciliostimulatory properties or acts through a second messenger. In this study we investigated whether cyclic adenosine monophosphate (cAMP) is implicated in the signal transduction pathway of PGE2-induced activation of CBF. Ciliated cells of the nasal mucosa were cultured for up to 5 days whereafter the culture medium was removed and the cells were incubated with different concentrations of test solutions. The ciliated cells were recorded under a phase-contrast microscope and viewed in slow motion to count the frequency. PGE2 led to a dose-dependent increase in CBF. This became significant at concentrations of 10(-10) and 10(-5) M (P < 0.01) but not at 10(-13) M (P > 0.05). Addition of cAMP (10(-10) to 10(-5) M) caused a significant (P < 0.01) increase in CBF, whereas depletion of endogenous cAMP after pre-incubation with the adenylate cyclase activator forskolin (10(-5) M) prevented the PGE2-induced increase in CBF (P > 0.05). The ciliostimulatory effect of PGE2 depends on an intact functioning of adenylate cyclase. These results point out that cAMP is directly implicated in the signal transduction pathway of PGE2-induced stimulation of CBF in cultured human ciliated cells of the nasal mucosa.

Adult↗

PubMed2001

[Improved tumor site and contrast resolution in ultrasound diagnosis by using harmonic frequencies].

BACKGROUND: The aim of new techniques in head and neck sonography is to increase the sensitivity and the specificity of the examination. With tissue harmonic imaging (THI) and contrast harmonic imaging (CHI) new techniques are available which allow increased contrast and resolution in head and neck sonography as well as a better detection of small blood vessels. METHODS: We studied whether these techniques improve sonographic detection of head and neck lymph nodes and primary tumours of the upper aerodigestive tract. RESULTS: The results indicate that THI allows a better detection of cervical lymph nodes. Furthermore, intranodal structures and the borders of the lymph node can be better detected. Using CHI, typical patterns of vascularization can be seen, allowing a better interpretation of the node's tumour status. Primary tumours can be detected sufficiently well using conventional B-scan techniques although they are easier to detect with THI. Using CHI, many tumour vessels can be detected, but this does not increase the sensitivity of the sonographic examination. CONCLUSION: THI and CHI may increase the specificity of sonographic diagnostics of cervical lymph nodes but show no clinical benefit regarding the diagnostics of primary tumours of the upper aerodigestive tract.

Contrast Media↗