[Spontaneous course of traumatic tympanic membrane perforations]. / Spontaner Heilungsverlauf traumatischer Trommelfellperforationen.

BACKGROUND: Traumatic eardrum perforation is a common presentation in otorhinolaryngologic practices and emergency clinics. A consistent management strategy (active intervention vs. watchful waiting) is, however, still lacking. OBJECTIVE: In the following study, the outcome of watchful waiting is analyzed and presented. MATERIALS AND METHODS: A collective of 272 patients presenting at two different specialist ENT practices within days of traumatic tympanic membrane perforation from June 2002 to March 2019 were analyzed. Treatment was non-surgical, with prospective monitoring. Whereas antibiotics were not given at all in one practice, they were given only upon signs of infection in the other practice. The outcome was evaluated retrospectively on the basis of patient files. RESULTS: The collective consisted of 185 males and 87 females. Mean age was 30 years (range: 7 months to 82 years). The perforations were most commonly located in the upper anterior and lower posterior quadrants. According to Griffin grading, the size was grade I in 97%. The three most common causes were impact to the ear, barotrauma, and foreign bodies. Under a watchful waiting regimen, 95% of the patients presenting for follow-up checks showed complete closure. CONCLUSION: Watchful waiting can be assessed as appropriate in traumatic eardrum perforation, provided otorhinolaryngologic follow-up is ensured. An exception is blast injury, which is now much less common in Central Europe, as this is associated with a risk of secondary cholesteatomas. In these rare cases, active treatment with surgical exploration of the middle ear including relining the perforation is indicated.

Combined radiotherapy and concurrent tumor treating fields (TTFields) for glioblastoma: Dosimetric consequences on non-coplanar IMRT as initial results from a phase I trial.

BACKGROUND: Glioblastoma is a rapidly proliferating tumor. Patients bear an inferior prognosis with a median survival time of 14-16 months. Proliferation and repopulation are a major resistance promoting factor for conventionally fractionated radiotherapy. Tumor-Treating-Fields (TTFields) are an antimitotic modality applying low-intensity (1-3 V/cm), intermediate-frequency (100-300 kHz) alternating electric-fields. More recently interference of TTFields with DNA-damage-repair and synergistic effects with radiotherapy were reported in the preclinical setting. This study aims at examining the dosimetric consequences of TTFields applied during the course of radiochemotherapy. METHODS: Cone-beam-computed-tomography (CBCT)-data from the first seven patients of the PriCoTTF-phase-I-trial were used in a predefined way for dosimetric verification and dose-accumulation of the non-coplanar-intensity-modulated-radiotherapy (IMRT)-treatment-plans as well as geometric analysis of the transducer-arrays by which TTFields are applied throughout the course of treatment. Transducer-array-position and contours were obtained from the low-dose CBCT's routinely made for image-guidance. Material-composition of the electrodes was determined and a respective Hounsfield-unit was assigned to the electrodes. After 6D-fusion with the planning-CT, the dose-distribution was recalculated using a Boltzmann-equation-solver (Acuros XB) and a Monte-Carlo-dose-calculation-engine. RESULTS: Overdosage in the scalp in comparison to the treatment plan without electrodes stayed below 8.5% of the prescribed dose in the first 2 mm below and also in deeper layers outside 1cm2 at highest dose as obtained from dose-volume-histogram comparisons. In the clinical target volume (CTV), underdosage was limited to 2.0% due to dose attenuation by the electrodes in terms of D95 and the effective-uniform-dose. Principal-component-analysis (PCA) showed that the first principal-position-component of the variation of repeated array-placement in the direction of the largest variations and the perpendicular second-component spanning a tangential plane on the skull had a standard deviation of 1.06 cm, 1.23 cm, 0.96 cm, and 1.11 cm for the frontal, occipital, left and right arrays for the first and 0.70 cm, 0.71 cm, 0.79 cm, and 0.68 cm, respectively for the second-principal-component. The variations did not differ from patient-to-patient (p > 0.8, Kruskal-Wallis-tests). This motion led to a diminution of the dosimetric effects of the electrodes. CONCLUSION: From a dosimetric point of view, dose deviations in the CTV due to transducer-arrays were not clinically significant in the first 7 patients and confirmed feasibility of combined adjuvant radiochemotherapy and concurrent TTFields. PriCoTTF Trial: A phase I/II trial of TTFields prior and concomitant to radiotherapy in newly diagnosed glioblastoma. DRKS-ID: DRKS00016667. Date of Registration in DRKS: 2019/02/26. Investigator Sponsored/Initiated Trial (IST/IIT): yes. Ethics Approval/Approval of the Ethics Committee: Approved. (leading) Ethics Committee Nr.: 18-8316-MF, Ethik-Kommission der Medizinischen. Fakultät der Universität Duisburg-Essen. EUDAMED-No. (for studies acc. to Medical Devices act): CIV-18-08-025247.

Xenografting for disease modeling of intramedullary spinal cord tumors: a systematic review.

STUDY DESIGN: Systematic review. OBJECTIVES: The overall incidence of intramedullary spinal cord tumors (IMSCT) remains low and clinical trials or standardized treatment strategies are missing. Therefore, multiple animal-based xenograft models (AXM) have been developed to foster preclinical research efforts on IMSCT. We constructed a systematic literature review to summarize and compare all AXM for IMSCT, published until April 16, 2018. METHODS: The review was conducted using 4 independent research databases following the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. Studies were included, if they reported on surgical transplantation of tumor cells or tumor tissue to the spinal cord. Methodological study quality was assessed according to the SYRCLE (systematic review center for laboratory animal experimentation) risk of Bias tool. RESULTS: Systematic search yielded 20 publications dealing with AXM for IMSCT. In summary, 4 tumor entities were analyzed in 23 experiments using ~337 animals, mainly investigating glioblastoma or gliosarcoma biology. Studies varied regarding the use of engrafted animals, surgical techniques and tumor burden. Most commonly authors used heterotopic, transdural injection of immortalized brain tumor cell lines (1 × 105 in 5 µl) into the thoracic spinal cord of immunocompromised rats. Quality assessment demonstrated an unclear risk of bias in most cases. CONCLUSION: Although different AXM for IMSCT have been described so far, one rat model is technically feasible, enables robust experiments and demonstrates reproducible results. However, there is a need for new AXM using orthotopic engraftment of patient-derived tumor cells and for genetically engineered animal models.

Sequence-dependent cross-resistance of combined radiotherapy plus BRAFV600E inhibition in melanoma.

INTRODUCTION: Treatment of patients with metastatic melanoma is hampered by drug-resistance and often requires combination with radiotherapy as last-resort option. However, also after radiotherapy, clinical relapses are common. METHODS & RESULTS: Our preclinical models indicated a higher rate of tumour relapse when melanoma cells were first treated with BRAFV600E inhibition (BRAFi) followed by radiotherapy as compared to the reverse sequence. Accordingly, retrospective follow-up data from 65 stage-IV melanoma patients with irradiated melanoma brain metastases confirmed a shortened duration of local response of mitogen-activated protein kinase (MAPK)-inhibitor-pretreated compared with MAPK-inhibitor-naïve intracranial metastases. On the molecular level, we identified JARID1B/KDM5B as a cellular marker for cross-resistance between BRAFi and radiotherapy. JARID1Bhigh cells appeared more frequently under upfront BRAFi as compared with upfront radiation. JARID1B favours cell survival by transcriptional regulation of genes controlling cell cycle, DNA repair and cell death. CONCLUSION: The level of cross-resistance between combined MAPK inhibition and radiotherapy is dependent on the treatment sequence. JARID1B may represent a novel therapy-overarching resistance marker.

Therapy of leptomeningeal metastasis in solid tumors.

Leptomeningeal metastasis (LM), i.e. the seeding of tumor cells to the cerebrospinal fluid (CSF) and the leptomeninges, is a devastating and mostly late-stage complication of various solid tumors. Clinical signs and symptoms may include cranial nerve palsies, radicular symptoms, signs of increased intracranial pressure such as headache, nausea and vomiting, and cognitive dysfunction. In cases of suspected LM, the highest diagnostic sensitivity is provided by the combination of CSF cytology and contrast-enhanced MRI (cranial as well as complete spine). The therapeutic spectrum includes radiotherapy of the clinically involved region as well as systemic and intrathecal chemotherapy. The choice of treatment modalities depends on the type of LM (non-adherent tumor cells in the CSF vs. nodular contrast-enhancing tumor growth), additional systemic involvement (uncontrolled vs. controlled systemic disease) and additional involvement of the CNS parenchyma (LM as the only CNS involvement vs. LM+parenchymal CNS metastases). Larger contrast-enhancing nodular LM or symptomatic lesions of the spine may be treated with radiotherapy. In case of uncontrolled systemic disease, the treatment regimen should include systemic chemotherapy. The choice of systemic treatment should take into account the histology of the primary tumor. Intrathecal chemotherapy is most important in cases of LM of the non-adherent type. There are three substances for routine use for intrathecal chemotherapy: methotrexate, cytarabine, and thiotepa. Liposomal cytarabine shows advantages in terms of longer injection intervals, a sufficient distribution in the entire subarachnoid space after lumbar administration and improved quality-of-life. The role of new agents (e.g. rituximab and trastuzumab) for intrathecal therapy is still unclear.

DNMT-dependent suppression of microRNA regulates the induction of GBM tumor-propagating phenotype by Oct4 and Sox2.

Cancer stem-like cells represent poorly differentiated multipotent tumor-propagating cells that contribute disproportionately to therapeutic resistance and tumor recurrence. Transcriptional mechanisms that control the phenotypic conversion of tumor cells lacking tumor-propagating potential to tumor-propagating stem-like cells remain obscure. Here we show that the reprogramming transcription factors Oct4 and Sox2 induce glioblastoma cells to become stem-like and tumor-propagating via a mechanism involving direct DNA methyl transferase (DNMT) promoter transactivation, resulting in global DNA methylation- and DNMT-dependent downregulation of multiple microRNAs (miRNAs). We show that one such downregulated miRNA, miRNA-148a, inhibits glioblastoma cell stem-like properties and tumor-propagating potential. This study identifies a novel and targetable molecular circuit by which glioma cell stemness and tumor-propagating capacity are regulated.

Effects on specific promoter DNA methylation in zebrafish embryos and larvae following benzo[a]pyrene exposure.

Benzo[a]pyrene (BaP) is an established carcinogen and reproductive and developmental toxicant. BaP exposure in humans and animals has been linked to infertility and multigenerational health consequences. DNA methylation is the most studied epigenetic mechanism that regulates gene expression, and mapping of methylation patterns has become an important tool for understanding pathologic gene expression events. The goal of this study was to investigate aberrant changes in promoter DNA methylation in zebrafish embryos and larvae following a parental and continued embryonic waterborne BaP exposure. A total of 21 genes known for their role in human diseases were selected to measure percent methylation by multiplex deep sequencing. At 96hpf (hours post fertilization) compared to 3.3hpf, dazl, nqo1, sox3, cyp1b1, and gstp1 had higher methylation percentages while c-fos and cdkn1a had decreased CG methylation. BaP exposure significantly reduced egg production and offspring survival. Moreover, BaP decreased global methylation and altered CG, CHH, and CHG methylation both at 3.3 and 96hpf. CG methylation changed by 10% or more due to BaP in six genes (c-fos, cdkn1a, dazl, nqo1, nrf2, and sox3) at 3.3hpf and in ten genes (c-fos, cyp1b1, dazl, gstp1, mlh1, nqo1, pten, p53, sox2, and sox3) at 96hpf. BaP also induced gene expression of cyp1b1 and gstp1 at 96hpf which were found to be hypermethylated. Further studies are needed to link aberrant CG, CHH, and CHG methylation to heritable epigenetic consequences associated with disease in later life.

Ifosfamide, carboplatin and etoposide in recurrent malignant glioma.

After failure of temozolomide, there is no established standard salvage chemotherapy for patients with recurrent glioblastoma (GBM). Two phase II trials combining ifosfamide, carboplatin and etoposide chemotherapy (ICE) showed favorable results. We therefore applied the ICE protocol to 13 patients (10 GBM, 3 anaplastic astrocytomas). Partial or complete remissions were not observed. None of the 13 patients survived progression-free for 6 months. Our retrospective analysis suggests that the ICE regimen is not effective in patients with recurrent high-grade glioma if applied at second or third relapse.

Mapping QTL main and interaction influences on milling quality in elite US rice germplasm.

Rice (Oryza sativa L.) head-rice yield (HR) is a key export and domestic quality trait whose genetic control is poorly understood. With the goal of identifying genomic regions influencing HR, quantitative-trait-locus (QTL) mapping was carried out for quality-related traits in recombinant inbred lines (RILs) derived from crosses of common parent Cypress, a high-HR US japonica cultivar, with RT0034, a low-HR indica line (129 RILs) and LaGrue, a low-HR japonica cultivar (298 RILs), grown in two US locations in 2005-2007. Early heading increased HR in the Louisiana (LA) but not the Arkansas (AR) location. Fitting QTL-mapping models to separate QTL main and QTL × environment interaction (QEI) effects and identify epistatic interactions revealed six main-effect HR QTLs in the two crosses, at four of which Cypress contributed the increasing allele. Multi-QTL models accounted for 0.36 of genetic and 0.21 of genetic × environment interaction of HR in MY1, and corresponding proportions of 0.25 and 0.37 in MY2. The greater HR advantage of Cypress in LA than in AR corresponded to a genomewide pattern of opposition of HR-increasing QTL effects by AR-specific effects, suggesting a selection strategy for improving this cultivar for AR. Treating year-location combinations as independent environments resulted in underestimation of QEI effects, evidently owing to lower variation among years within location than between location. Identification of robust HR QTLs in elite long-grain germplasm is suggested to require more detailed attention to the interaction of plant and grain development parameters with environmental conditions than has been given to date.

Microbial and antibiotic resistant constituents associated with biological aerosols and poultry litter within a commercial poultry house.

Poultry are known to harbor antibiotic resistant and pathogenic bacteria, and as such poultry litter and poultry house air can be contaminated with these bacteria. However, the presence of antibiotic resistant bacteria in biological aerosols and litter is largely not understood. The purpose of this study was to determine the amount of aerosolized bacteria and endotoxin, particularly fecal indicators, staphylococci, and enterococci, associated with poultry house and outdoor air. Aerosol samples were collected at multiple locations on the farm and in the house. Antibiotic resistance was investigated using the Kirby Bauer method on selected isolates using twelve different antibiotics spanning both narrow to broad spectrums of effectiveness. Overall there was a cyclical increase in bacterial concentrations as flocks progressed from pre-flock to late-flock, with >2 orders magnitude lower concentration during pre-flock periods (no chickens), in both the litter and aerosol samples. The house environment provided for significantly concentrated bacterial and endotoxin levels. It was estimated that Staphylococcus bacteria accounted for at least 90% of cultured aerobic bacteria and culture-independent 16S rRNA analyses demonstrated that significant population changes occurred from pre- to late-flock. Rarely was an isolate resistant to more than 4 antibiotic classes; however there was a trend upwards in overall resistance of enterococci as the flock cycle progressed. It appears that although levels of antibiotic resistant bacteria were highly concentrated within the house, levels were much lower outside of the house, and very little house escape occurred.

Analysis of expressed sequence tags from Uromyces appendiculatus hyphae and haustoria and their comparison to sequences from other rust fungi.

Hyphae, 2 to 8 days postinoculation (dpi), and haustoria, 5 dpi, were isolated from Uromyces appendiculatus infected bean leaves (Phaseolus vulgaris cv. Pinto 111) and a separate cDNA library prepared for each fungal preparation. Approximately 10,000 hyphae and 2,700 haustoria clones were sequenced from both the 5' and 3' ends. Assembly of all of the fungal sequences yielded 3,359 contigs and 927 singletons. The U. appendiculatus sequences were compared with sequence data for other rust fungi, Phakopsora pachyrhizi, Uromyces fabae, and Puccinia graminis. The U. appendiculatus haustoria library included a large number of genes with unknown cellular function; however, summation of sequences of known cellular function suggested that haustoria at 5 dpi had fewer transcripts linked to protein synthesis in favor of energy metabolism and nutrient uptake. In addition, open reading frames in the U. appendiculatus data set with an N-terminal signal peptide were identified and compared with other proteins putatively secreted from rust fungi. In this regard, a small family of putatively secreted RTP1-like proteins was identified in U. appendiculatus and P. graminis.

Molecular diversity and association mapping of fiber quality traits in exotic G. hirsutum L. germplasm.

The narrow genetic base of cultivated cotton germplasm is hindering the cotton productivity worldwide. Although potential genetic diversity exists in Gossypium genus, it is largely 'underutilized' due to photoperiodism and the lack of innovative tools to overcome such challenges. The application of linkage disequilibrium (LD)-based association mapping is an alternative powerful molecular tool to dissect and exploit the natural genetic diversity conserved within cotton germplasm collections, greatly accelerating still 'lagging' cotton marker-assisted selection (MAS) programs. However, the extent of genome-wide linkage disequilibrium (LD) has not been determined in cotton. We report the extent of genome-wide LD and association mapping of fiber quality traits by using a 95 core set of microsatellite markers in a total of 285 exotic Gossypium hirsutum accessions, comprising of 208 landrace stocks and 77 photoperiodic variety accessions. We demonstrated the existence of useful genetic diversity within exotic cotton germplasm. In this germplasm set, 11-12% of SSR loci pairs revealed a significant LD. At the significance threshold (r(2)>/=0.1), a genome-wide average of LD declines within the genetic distance at <10 cM in the landrace stocks germplasm and >30 cM in variety germplasm. Genome wide LD at r(2)>/=0.2 was reduced on average to approximately 1-2 cM in the landrace stock germplasm and 6-8 cM in variety germplasm, providing evidence of the potential for association mapping of agronomically important traits in cotton. We observed significant population structure and relatedness in assayed germplasm. Consequently, the application of the mixed liner model (MLM), considering both kinship (K) and population structure (Q) detected between 6% and 13% of SSR markers associated with the main fiber quality traits in cotton. Our results highlight for the first time the feasibility and potential of association mapping, with consideration of the population structure and stratification existing in cotton germplasm resources. The number of SSR markers associated with fiber quality traits in diverse cotton germplasm, which broadly covered many historical meiotic events, should be useful to effectively exploit potentially new genetic variation by using MAS programs.

Aflatoxin formation and gene expression in response to carbon source media shift in Aspergillus parasiticus.

Aflatoxins are toxic and carcinogenic polyketide metabolites produced by fungal species, including Aspergillus flavus and A. parasiticus. The biosynthesis of aflatoxins is modulated by many environmental factors, including the availability of a carbon source. The gene expression profile of A. parasiticus was evaluated during a shift from a medium with low concentration of simple sugars, yeast extract (YE), to a similar medium with sucrose, yeast extract sucrose (YES). Gene expression and aflatoxins (B1, B2, G1, and G2) were quantified from fungal mycelia harvested pre- and post-shifting. When compared with YE media, YES caused temporary reduction of the aflatoxin levels detected at 3-h post-shifting and they remained low well past 12 h post-shift. Aflatoxin levels did not exceed the levels in YE until 24 h post-shift, at which time point a tenfold increase was observed over YE. Microarray analysis comparing the RNA samples from the 48-h YE culture to the YES samples identified a total of 2120 genes that were expressed across all experiments, including most of the aflatoxin biosynthesis genes. One-way analysis of variance (ANOVA) identified 56 genes that were expressed with significant variation across all time points. Three genes responsible for converting norsolorinic acid to averantin were identified among these significantly expressed genes. The potential involvement of these genes in the regulation of aflatoxin biosynthesis is discussed.

Authentication of medicinal plants using molecular biology techniques to compliment conventional methods.

Medicinal plants have become extremely popular in the United States as botanical supplements, herbal medicines and sources of lead compounds for pharmaceutical development. It is estimated that in 1997 Americans used or consumed 5.1 billion US dollars worth of herbal medicines. For the protection of consumers, authentication of medicinal plants is a critical issue. Ideally, authentication should occur from the harvesting of the plant material to the final product. Unfortunately there is no single or superior method to assure 100 percent authentication during the entire process, but the goal can be achieved through the application of a variety of different methodologies. The whole process starts with good voucher specimens that act as reference material and to prove chain of custody. Macroscopic and microscopic examinations can be used as rapid and inexpensive identification techniques. Chemical analysis is by far the best method for the detection of contaminants and can be an excellent method for plant identification. Each of these methodologies has limitations and more analytical methods are needed to assist in the authentication process. Molecular biology offers an assortment of techniques that can be very useful for authentication of medicinal plants. This review covers various aspects of authentication methods, with special emphasis on molecular biology techniques.

Magnetic resonance imaging--guided biopsies of the petrous apex and petroclival region.

OBJECTIVE: To analyze the advantages in safety and precision of biopsies of the petrous apex and petroclival region using open magnetic resonance imaging (MRI). SETTING: The University of Leipzig Medical Center. PATIENTS: Biopsies were taken in 13 patients with tumors of the petrous apex and petroclival region. INTERVENTION: With the patient in the 0.5-T intraoperative MRI system (Signa SP; General Electric Medical Systems, Boston, MA, U.S.A.), biopsies were taken from the petrous apex and the petroclival region under imaging control by transseptal, transsphenoidal access. The region of interest was approached with a virtual pointer (Flashpoint Position Encoder; Image Guided Technologies, U.S.A.) and marked with a gadolinium-filled pointer. RESULTS: In all patients, the authors obtained enough tissue for histologic study, which also proved to be the suspected tumor. One patient had a bone cyst, another had a malignant lymphoma, and another two a cholesterol granuloma originating from the petrous apex. Three other patients had metastases (carcinoma of the breast, bronchial carcinoma, and unknown origin). Three patients had a meningioma, and another three a chordoma. The authors did not see any postoperative complications. CONCLUSIONS: In the authors' experience, the transsphenoidal access is favorable for approaching and sampling lesions of the petrous apex and the petroclival region. This route, however, is disadvantageous because the course of the internal carotid artery and the brainstem narrow the surgical space to the petrous apex. Open MRI in these cases is very useful because it allows a safe approach to the tumor by navigation and by visualizing the anatomic structures in real-time imaging.

Transnasal and transsphenoidal MRI-guided biopsies of petroclival tumors.

Magnetic resonance imaging (MRI) allows excellent tissue characterization in the area of the petroclival region and can depict lesions not visualized with ultrasound or computed tomography (CT). The aim of this study was to demonstrate the clinical feasibility and utility of an interactive MR-guidance system to target and biopsy tumors in the petroclival region. MRI-guided biopsies of 10 patients with tumors in the clivus and petrous apex were performed in an open 0.5-T MR system. Lesions were targeted through a transsphenoidal or transnasal approach. Imaging during biopsies was achieved by a combination of standard and interactive mode. T1-weighted spin-echo, T2-weighted fast spin-echo (FSE), and three-dimensional T1-weighted gradient-echo (GRE) scans (standard mode) were selected to provide optimal tissue characterization for both the lesion and surrounding structures and varied according to the anatomic site. For interactive imaging, T1-weighted GRE and T2-weighted FSE sequences were used. We performed MRI-guided transsphenoidal biopsies in 10 patients who had lesions identified by CT (n = 5) and/or MRI (n = 10). The indications for biopsies were to differentiate between suspected malignant processes (n = 4 ) and benign processes (n = 6). Lesions adjacent to structures like the internal carotid artery were accurately targeted in particular. All biopsies were performed successfully and were the basis for selection of further treatment. No complications occurred during the procedures. An open MR system allows interactive control of biopsies in the area of the petroclival region, providing maximum patient safety and diagnostic accuracy not possible in other systems. The advantages of MRI tissue characterization are combined with an interactive, one-step method of localization and targeting, as well as tissue sampling. J. Magn. Reson. Imaging 2001;13:3-11.

The use of open MRI in otorhinolaryngology: initial experience.

Intraoperative imaging in head and neck surgery is a useful tool in many situations. In addition to being helpful for intraoperative orientation, real-time imaging enables visualization of the progress of surgery and the completeness of tumor resection. Regions in the head and neck to which access is difficult, and which therefore have a high incidence of morbidity and risk for the patient, can be approached more easily and safely in an open MRI than in a conventional way. Interventions in the open MRI (Signa SP, 0.5 Tesla) were performed with nonmagnetic instruments and an MR-safe microscope. For intraoperative navigation, the integrated FlashPoint system is helpful, because it allows targeting of the tumor by a calculated virtual line. T1W spin-echo, T2W fast spin-echo, and 3D T1W gradient-echo sequences were used for high-resolution imaging. Real-time imaging is achieved by fast multiplanar spoiled gradient-echo sequences or T2 single-shot fast spin-echo sequences. From 1996 to the present, we biopsied 17 petroclival tumors, performed paranasal sinus surgery in five cases, biopsied two neck masses, and inserted tubes for brachytherapy in 12 cases. No complications were observed. In all surgical procedures, a good resolution was obtained with MRI, especially for soft-tissue structures. The tumor could be targeted exactly, and all specimens revealed the relevant histology. In paranasal sinus surgery, however, the success rate was lower because it was difficult to distinguish blood from pathologic tissue. The insertion of tubes for brachytherapy was successful in all cases. It was possible to apply the tubes parallel to each other, 1 cm apart. Relevant biopsies could be taken of both neck masses. The indications for the use of open MRI in otorhinolaryngology are biopsies of tumors in regions that are difficult to approach, such as the petrous apex and petroclival region, the parapharyngeal space, and the orbit. Furthermore, the open MRI can be useful in paranasal sinus surgery, in the evaluation of tissue resection, and in the detection of the anatomy of delicate structures such as the internal carotid artery, the skull base, and the orbit. In addition, active navigation in the open MRI is possible with the integrated FlashPoint system. The advantage over conventional navigation systems lies in the possibility of real-time imaging, which allows detection of tissue changes occurring during the procedure.

[Growth of human respiratory epithelium on collagen foil]. / Wachstum humanen respiratorischen Epithels auf Kollagenfolie.

BACKGROUND: Clinical application of bioartificial tracheal prosthesis must still be regarded as an experimental concept because restoration of a functional respiratory epithelium outlining the prosthesis is still not possible. Tissue engineering as a relatively new biotechnological discipline may offer new methods in expanding differentiated respiratory epithelium in vitro. In this study we compare two different cell and tissue culture procedures for growing human nasal mucosa on commercially available collagen foil. MATERIAL AND METHODS: Harvested specimens of human nasal mucosa (n = 6, 4 x 4 cm) were placed on collagen foil and incubated as tissue cultures for 4, 6 and 8 weeks. A suspension of enzymatically dispersed nasal epithelium seeded on collagen foil (5 x 10(5) cells) served as control. Cell growth and ciliary beat were monitored through an inverted microscope with Hoffman's modulation contrast and video set-up. Histological examination was performed after 4, 6 and 8 weeks. RESULTS: In the tissue cultures, the collagen foil was initially covered with fibroblasts growing from the mucosa specimen before epithelial cells spread out. The epithelial layer showed mostly ciliated cells which developed metachronous ciliary beat after 4 weeks in vitro. Ciliary activity was observed until the end of the experiments in 8 weeks. New cells on the suspension cultures were mesenchymal and did not exhibit any ciliary activity. CONCLUSIONS: Mucosa specimens seem to be more appropriate for tissue engineering of respiratory epithelium than cell suspensions from nasal epithelium. Collagen foil as tissue scaffold initiates epithelial-mesenchymal interaction and may play an important role in epithelial differentiation of new respiratory epithelium.

RT-PCR amplification of mRNA from single brain neurospheres.

A method is described that allows cDNA production from individual brain cell clones or 'neurospheres'. These culture-generated spheres of stem, progenitor, and differentiated cells have been the focus of interest because they represent an in vitro model of neurogenesis. However, because neurospheres are somewhat resistant, in part due to their enclosure by a dense extracellular matrix, to methods attempting to disrupt them and isolate nucleic acids, there is a need for new technology that affords the simple and efficient RT-PCR for studies of neural gene expression and discovery. A method is described here that uses sonication and an all-in-one approach for the construction of cDNA from single neurospheres. The generation of cDNA from individual adult brain stem/progenitor cell neurospheres is useful for future studies of neurogenic gene expression.