[Increased report completeness and satisfaction with structured neurotological reporting in the interdisciplinary assessment of vertigo]

BACKGROUND

Results of neurotological function diagnostics in the context of interdisciplinary vertigo assessment are usually formulated as free-text reports (FTR). These are often subject to high variability, which may lead to loss of information. The aim of the present study was to evaluate the completeness of structured reports (SR) and referrer satisfaction in the neurotological assessment of vertigo.

MATERIALS AND METHODS

Neurotological function diagnostics performed as referrals (n = 88) were evaluated retrospectively. On the basis of the available raw data, SRs corresponding to FTRs from clinical routine were created by means of a specific SR template for neurotological function diagnostics. FTRs and SRs were evaluated for completeness and referring physician satisfaction (n = 8) using a visual analog scale (VAS) questionnaire.

RESULTS

Compared to FTRs, SRs showed significantly increased overall completeness (73.7% vs. 51.7%, p < 0.001), especially in terms of patient history (92.5% vs. 66.7%, p < 0.001), description of previous findings (87.5% vs. 38%, p < 0.001), and neurotological (33.5% vs. 26.7%, p < 0.001) and audiometric function diagnostics (58% vs. 32.3%, p < 0.001). In addition, SR showed significantly increased referring physician satisfaction (VAS 8.8 vs. 4.9, p < 0.001).

CONCLUSION

Neurotological SRs enable a significantly increased report completeness with higher referrer satisfaction in the context of interdisciplinary assessment of vertigo. Furthermore, SRs are particularly suitable for scientific data analysis, especially in the context of big data analyses.

Cochlear implantation impairs intracochlear microcirculation and counteracts iNOS induction in guinea pigs

Introduction

Preservation of residual hearing remains a great challenge during cochlear implantation. Cochlear implant (CI) electrode array insertion induces changes in the microvasculature as well as nitric oxide (NO)-dependent vessel dysfunction which have been identified as possible mediators of residual hearing loss after cochlear implantation.

Methods

A total of 24 guinea pigs were randomized to receive either a CI (n = 12) or a sham procedure (sham) by performing a cochleostomy without electrode array insertion (n = 12). The hearing threshold was determined using frequency-specific compound action potentials. To gain visual access to the stria vascularis, a microscopic window was created in the osseous cochlear lateral wall. Cochlear blood flow (CBF) and cochlear microvascular permeability (CMP) were evaluated immediately after treatment, as well as after 1 and 2 h, respectively. Finally, cochleae were resected for subsequent immunohistochemical analysis of the iNOS expression.

Results

The sham control group showed no change in mean CBF after 1 h (104.2 ± 0.7%) and 2 h (100.8 ± 3.6%) compared to baseline. In contrast, cochlear implantation resulted in a significant continuous decrease in CBF after 1 h (78.8 ± 8.1%, p < 0.001) and 2 h (60.6 ± 11.3%, p < 0.001). Additionally, the CI group exhibited a significantly increased CMP (+44.9% compared to baseline, p < 0.0001) and a significant increase in median hearing threshold (20.4 vs. 2.5 dB SPL, p = 0.0009) compared to sham after 2 h. Intriguingly, the CI group showed significantly lower iNOS-expression levels in the organ of Corti (329.5 vs. 54.33 AU, p = 0.0003), stria vascularis (596.7 vs. 48.51 AU, p < 0.0001), interdental cells (564.0 vs. 109.1 AU, p = 0.0003) and limbus fibrocytes (119.4 vs. 18.69 AU, p = 0.0286).

Conclusion

Mechanical and NO-dependent microvascular dysfunction seem to play a pivotal role in residual hearing loss after CI electrode array insertion. This may be facilitated by the implantation associated decrease in iNOS expression. Therefore, stabilization of cochlear microcirculation could be a therapeutic strategy to preserve residual hearing.

[Deforming endonasal mass during pregnancy]

This article presents the case of a 33-year-old woman who consulted the authors' ENT clinic in the 39th week of pregnancy with recurrent epistaxis. A livid endonasal mass was found on the left side, subtotally displacing the nose and leading to deformation of the external nose. External biopsy provided no indications of malignancy. Postpartum CT of the paranasal sinuses revealed a mass destroying the cartilaginous nasal septum. Endoscopic resection of the finding was performed with preservation of the clinically sound nasal septal cartilage. Histopathological examination revealed a capillary hemangioma, which was classified as granuloma gravidarum due to its occurrence during pregnancy.

Development and Integration of DOPS as Formative Tests in Head and Neck Ultrasound Education: Proof of Concept Study for Exploration of Perceptions

In Germany, progress assessments in head and neck ultrasonography training have been carried out mainly theoretically and lack standardisation. Thus, quality assurance and comparisons between certified courses from various course providers are difficult. This study aimed to develop and integrate a direct observation of procedural skills (DOPS) in head and neck ultrasound education and explore the perceptions of both participants and examiners. Five DOPS tests oriented towards assessing basic skills were developed for certified head and neck ultrasound courses on national standards. DOPS tests were completed by 76 participants from basic and advanced ultrasound courses (n = 168 documented DOPS tests) and evaluated using a 7-point Likert scale. Ten examiners performed and evaluated the DOPS after detailed training. The variables of "general aspects" (6.0 Scale Points (SP) vs. 5.9 SP; p = 0.71), "test atmosphere" (6.3 SP vs. 6.4 SP; p = 0.92), and "test task setting" (6.2 SP vs. 5.9 SP; p = 0.12) were positively evaluated by all participants and examiners. There were no significant differences between a basic and advanced course in relation to the overall results of DOPS tests (p = 0.81). Regardless of the courses, there were significant differences in the total number of points achieved between individual DOPS tests. DOPS tests are accepted by participants and examiners as an assessment tool in head and neck ultrasound education. In view of the trend toward "competence-based" teaching, this type of test format should be applied and validated in the future.

Hearing rehabilitation for unilateral deafness using a cochlear implant: the influence of the subjective duration of deafness on speech intelligibility

BACKGROUND

For patients with single sided deafness (SSD) or severe asymmetric sensorineural hearing loss (ASHL), cochlear implantation remains the only solution to restore bilateral hearing capacity. Prognostically, the duration of hearing loss in terms of audiological outcome is not yet clear. Therefore, the aim of this study was to retrospectively investigate the influence of subjective deafness duration on postoperative speech perception after cochlear implantation for SSD as well as its impact on quality of life.

MATERIALS AND METHODS

The present study included a total of 36 adults aged 50.2 ± 15.5 years who underwent CI for SSD/ASHL at our clinic between 2010 and 2015. Patients were audiometrically assessed at 3 and 12-36 months postoperatively. Test results were correlated with self-reported duration of deafness. Quality of life was assessed by questionnaire.

RESULTS

Mean duration of deafness was 193.9 ± 185.7 months. The side-separated hearing threshold showed an averaged target range between 30 and 40 dB HL. Freiburg monosyllable test increased from 0% pre-operatively to 20% after 3 months (p = 0.001) and to 50% after 12-36 months (p = 0.002). There was a significant correlation between audiometric outcome and subjective deafness duration at 12-36 months postoperatively (r = - 0.564; p = 0.02) with a cutoff for open-set monosyllable recognition at a duration of deafness of greater than 408 months. Quality of life was significantly improved by CI.

CONCLUSIONS

CI implantation in unilaterally deafened patients provides objective and subjective benefits. Duration of deafness is unlikely to be an independent negative predictive factor and thus should not generally be considered as contraindication.

The German hearing in noise test with a female talker: development and comparison with German male speech test

PURPOSE

The aim of the study was to develop the German Hearing in Noise Test (HINT) with female speaker by fulfilling the recommendations by International Collegium of Rehabilitative Audiology (ICRA) for using a female speaker to create new multilingual speech tests and to determine norms and to compare these norms with German male speech tests-the male speakers HINT and the Oldenburg Sentence Test (OLSA).

METHODS

The HINT with a female speaker consists of the same speech material as the male speaking HINT. After recording the speech material, 10 normal hearing subjects were included to determine the performance-intensity function (PI function). 24 subjects were part of the measurements to determine the norms and compare them with the norms of male HINT and OLSA. Comparably, adaptive, open-set methods under headphones (HINT) and sound field (OLSA) were used.

RESULTS

Acoustic phonetic analysis demonstrated significant difference in mean fundamental frequency, its range and mean speaking rate between both HINT speakers. The calculated norms by three of the tested four conditions of the HINT with a female speaker are not significantly different from the norms with a male speaker. No significant effect of the speaker's gender of the first HINT measurement and no significant correlation between the threshold results of the HINT and the OLSA were determined.

CONCLUSIONS

The Norms for German HINT with a female speaker are comparable to the norms of the HINT with a male speaker. The speech intelligibility score of the HINT does not depend on the speakers' gender despite significant difference of acoustic-phonetic parameters between the female and male HINT speaker's voice. Instead, the speech intelligibility rating must be seen as a function of the used speech material.

Structured Reporting of Head and Neck Sonography Achieves Substantial Interrater Reliability

Purpose Ultrasound examinations are often criticized for having higher examiner dependency compared to other imaging techniques. Compared to free-text reporting, structured reporting (SR) of head and neck sonography (HNS) achieves superior time efficiency as well as report quality. However, there are no findings concerning the influence of SR on the interrater reliability (IRR) of HNS. Materials and Methods Typical pathologies (n=4) in HNS were documented by video/images by two certified head and neck ultrasound instructors. Consequently, structured reports of these videos/images were created by n=9 senior physicians at departments of otolaryngology or maxillofacial surgery with DEGUM instructors on staff. Reports (n=36) were evaluated regarding overall completeness and IRR. Additionally, user satisfaction was assessed by a visual analog scale (VAS). Results SR yielded very high report completeness (91.8%) in all four cases with a substantial IRR (Fleiss' κ 0.73). Interrater agreement was high at 87.2% with very good user satisfaction (VAS 8.6). Conclusion SR has the potential to ensure high-quality examination reports with substantial comparability and very high user satisfaction. Furthermore, big data collection and analysis are facilitated by SR. Therefore, process quality, workflow, and scientific output are potentially enhanced by SR.

In vivo analysis of noise dependent activation of white blood cells and microvascular dysfunction in mice

This article contains supporting information on data collection for the research article entitled “Aircraft noise exposure drives the activation of white blood cells and induces microvascular dysfunction in mice” by Eckrich et al. We found that noise-induced stress triggered microvascular dysfunction via involvement of innate immune-derived reactive oxygen species. In this article, we present the instrumentation of mice with dorsal skinfold chambers for in vivo microscopic imaging of blood flow, interaction of leukocytes with the vascular wall (also by fluorescent labelling of blood cells) and vessel diameter. In addition, we explain the preparation of cerebral arterioles for measurement of vascular reactivity in vitro.•

visualization of noise-dependent effects in dorsal skinfold chamber.

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in vivo microscopy of noise-dependent activation of white blood cells.

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analysis of noise-dependent microvascular dysfunction in dorsal skinfold chamber and cannulated cerebral arterioles.

Regulation of Endothelial Nitric Oxide Synthase in the Reticular Lamina of the Organ of Corti by a Nitric Oxide Donor

In the vertebrate cochlea, the reticular lamina seals the organ of Corti against the endolymph filled scala media. After noise exposure, fast alterations in the endothelial nitric oxide synthase (eNOS) expression level were identified in this cochlear structure. Minor amounts of nitric oxide (NO) produced by eNOS or applied by NO donors such as S-nitroso-N-acetyl-penicillamine (SNAP) might protect this vulnerable part of the organ of Corti, on the line of gap junctions of supporting cells and cochlear microcirculation. In n=5 anesthetized guinea pigs, SNAP was intravenously applied in two concentrations. Six untreated animals served as controls. The cochleae were removed and prepared for immunoelectron microscopy using specific gold-labeled anti-eNOS antibodies. The density of the gold particles was quantified for seven cellular regions in the reticular lamina at the ultrastructural level. Following SNAP application, a significant increase in eNOS expression (+176%) was detected compared with controls (p=0.012). The increase occurred mainly in actin-rich cuticular structures and the prominent microtubules bundles. Correlation analysis revealed three clear and five moderate cellular associations for controls, whereas only one clear and one moderate after SNAP application. Thus, application of the NO donor SNAP resulted in an increase in eNOS expression in distinct regions of the reticular lamina.

Comparison of Magnetic Resonance Imaging and Contrast-Enhanced Ultrasound as Diagnostic Options for Unclear Cystic Renal Lesions: A Cost-Effectiveness Analysis

PURPOSE

 Correct differentiation between malignant and benign incidentally found cystic renal lesions has critical implications for patient management. In several studies contrast-enhanced ultrasound (CEUS) showed higher sensitivity with respect to the accurate characterization of these lesions compared to MRI, but the cost-effectiveness of CEUS has yet to be investigated. The aim of this study was to analyze the cost-effectiveness of CEUS as an alternative imaging method to MRI for the characterization of incidentally found cystic renal lesions.

MATERIALS AND METHODS

 A decision model including the diagnostic modalities MRI and CEUS was created based on Markov simulations estimating lifetime costs and quality-adjusted life years (QALYs). The recent literature was reviewed to obtain model input parameters. The deterministic sensitivity of diagnostic parameters and costs was determined and probabilistic sensitivity analysis using Monte-Carlo Modelling was applied. Willingness-to-pay (WTP) was assumed to be $ 100 000/QALY.

RESULTS

 In the base-case scenario, the total costs for CEUS were $9654.43, whereas the total costs for MRI were $9675.03. CEUS resulted in an expected effectiveness of 8.06 QALYs versus 8.06 QALYs for MRI. Therefore, from an economic point of view, CEUS was identified as an adequate diagnostic alternative to MRI. Sensitivity analysis showed that results may vary if CEUS costs increase or those of MRI decrease.

CONCLUSION

 Based on the results of the analysis, the use of CEUS was identified as a cost-effective diagnostic strategy for the characterization of incidentally found cystic renal lesions.

Aircraft noise exposure drives the activation of white blood cells and induces microvascular dysfunction in mice

Epidemiological studies showed that traffic noise has a dose-dependent association with increased cardiovascular morbidity and mortality. Whether microvascular dysfunction contributes significantly to the cardiovascular health effects by noise exposure remains to be established. The connection of inflammation and immune cell interaction with microvascular damage and functional impairment is also not well characterized. Male C57BL/6J mice or gp91phox^−/y mice with genetic deletion of the phagocytic NADPH oxidase catalytic subunit (gp91phox or NOX-2) were used at the age of 8 weeks, randomly instrumented with dorsal skinfold chambers and exposed or not exposed to aircraft noise for 4 days. Proteomic analysis (using mass spectrometry) revealed a pro-inflammatory phenotype induced by noise exposure that was less pronounced in noise-exposed gp91phox^−/y mice. Using in vivo fluorescence microscopy, we found a higher number of adhesive leukocytes in noise-exposed wild type mice. Dorsal microvascular diameter (by trend), red blood cell velocity, and segmental blood flow were also decreased by noise exposure indicating microvascular constriction. All adverse effects on functional parameters were normalized or improved at least by trend in noise-exposed gp91phox^−/y mice. Noise exposure also induced endothelial dysfunction in cerebral microvessels, which was associated with higher oxidative stress burden and inflammation, as measured using video microscopy. We here establish a link between a pro-inflammatory phenotype of plasma, activation of circulating leukocytes and microvascular dysfunction in mice exposed to aircraft noise. The phagocytic NADPH oxidase was identified as a central player in the underlying pathophysiological mechanisms.

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Noise exposure induces a pro-thrombo-inflammatory phenotype in mouse plasma.

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Aircraft noise increases leukocyte-endothelium interactions in dorsal microvessels.

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Noise decreases segmental blood flow/red blood cell velocity in dorsal microvessels.

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Noise increases cerebral microvascular dysfunction and oxidative stress.

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Nox2 deficiency (gp91phox^-/y) improves noise-induced adverse effects.

The role of structured reporting and structured operation planning in functional endoscopic sinus surgery

Computed tomography (CT) scans represent the gold standard in the planning of functional endoscopic sinus surgeries (FESS). Yet, radiologists and otolaryngologists have different perspectives on these scans. In general, residents often struggle with aspects involved in both reporting and operation planning. The aim of this study was to compare the completeness of structured reports (SR) of preoperative CT images and structured operation planning (SOP) to conventional reports (CR) and conventional operation planning (COP) to potentially improve future treatment decisions on an individual level. In total, 30 preoperative CT scans obtained for surgical planning of patients scheduled for FESS were evaluated using SR and CR by radiology residents. Subsequently, otolaryngology residents performed a COP using free texts and a SOP using a specific template. All radiology reports and operation plannings were evaluated by two experienced FESS surgeons regarding their completeness for surgical planning. User satisfaction of otolaryngology residents was assessed by using visual analogue scales. Overall radiology report completeness was significantly higher using SRs regarding surgically important structures compared to CRs (84.4 vs. 22.0%, p<0.001). SOPs produced significantly higher completeness ratings (97% vs. 39.4%, p<0.001) regarding pathologies and anatomical variances. Moreover, time efficiency was not significantly impaired by implementation of SR (148 s vs. 160 s, p = 0.61) and user satisfaction was significantly higher for SOP (VAS 8.1 vs. 4.1, p<0.001). Implementation of SR and SOP results in a significantly increased completeness of radiology reports and operation planning for FESS. Consequently, the combination of both facilitates surgical planning and may decrease potential risks during FESS.

Evaluation of optimal education level to implement structured reporting into ultrasound training

AIMS

Reporting of head and neck ultrasound (HNU) has been outlined to be a major obstacle during ultrasound training due to a lack of standardized structure, content and terminology. Consequently, overall report quality differs significantly between various examiners posing a severe risk factor for information loss and miscommunication. Therefore, the present study's purpose is to compare the overall quality of free text reports (FTR) and structured reports (SR) of HNU at various stages of training in order to determine the optimal educational level to implement SR.

MATERIAL AND METHODS

Typical pathologies in HNU were reported upon using SR and FTR by medical students, junior residents and senior residents. The reports were assessed for overall quality, time efficiency and readability. Additionally, user satisfaction was determined using a questionnaire.

RESULTS

SRs exhibited a significantly superior report quality (93.1% vs. 45.6%, p<0.001) at all training levels. Overall time efficiency was significantly better for SRs, especially at the stages of medical school and early residency (89.4 s vs. 160.2 s., p<0.001). Using structured reporting also increased user satisfaction significantly (VAS 8.6 vs. 3.9, p<0.001).

CONCLUSIONS

Implementing structured reporting of HNU results in a superior report quality at all training stages. Greatest benefits for time efficiency are achieved by implementation during medical school. Therefore, structured reporting of HNU should be implemented early on in the training of HNU.

Monitoring of tumor growth and vascularization with repetitive ultrasonography in the chicken chorioallantoic-membrane-assay

The chorioallantoic-membrane (CAM)-assay is an established model for in vivo tumor research. Contrary to rodent-xenograft-models, the CAM-assay does not require breeding of immunodeficient strains due to native immunodeficiency. This allows xenografts to grow on the non-innervated CAM without pain or impairment for the embryo. Considering multidirectional tumor growth, limited monitoring capability of tumor size is the main methodological limitation of the CAM-assay for tumor research. Enclosure of the tumor by the radiopaque eggshell and the small structural size only allows monitoring from above and challenges established imaging techniques. We report the eligibility of ultrasonography for repetitive visualization of tumor growth and vascularization in the CAM-assay. After tumor ingrowth, ultrasonography was repetitively performed in ovo using a commercial ultrasonographic scanner. Finally, the tumor was excised and histologically analyzed. Tumor growth and angiogenesis were successfully monitored and findings in ultrasonographic imaging significantly correlated with results obtained in histological analysis. Ultrasonography is cost efficient and widely available. Tumor imaging in ovo enables the longitudinal monitoring of tumoral development, yet allowing high quantitative output due to the CAM-assays simple and cheap methodology. Thus, this methodological novelty improves reproducibility in the field of in vivo tumor experimentation emphasizing the CAM-assay as an alternative to rodent-xenograft-models.

Association of eIF4E and SPARC Expression with Lymphangiogenesis and Lymph Node Metastasis in Hypopharyngeal Cancer

BACKGROUND/AIM

Head and neck squamous cell carcinomas (HNSCC) are characterized by aggressiveness, early recurrence and lymph node metastasis. Therefore, there is an urgent need to identify new biomarkers and drug targets.

MATERIALS AND METHODS

Neck dissection specimens from 11 patients diagnosed with hypopharyngeal cancer were analyzed for their lymphatic vessel density (LVD) by lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) immunostaining, expression of eukaryotic initiation factor 4E (eIF4E) and levels of secreted protein acidic and rich in cysteine (SPARC) using immunoblot analysis.

RESULTS

Compared to lymph node biopsies of healthy controIs, LVD was significantly increased in metastatic lymph nodes as well as in advanced primary tumors. Overexpression of eIF4E and SPARC was demonstrated in all hypopharyngeal cancer specimens. Notably, we observed that increased LVD significantly correlated with the expression of eIF4E as well as SPARC levels.

CONCLUSION

eIF4E- and SPARC-associated signaling pathways may be associated with lymphangiogenesis and could be exploited to counteract the spread of hypopharyngeal cancer cells.

The "Comprehensive ICF Core Set for Head and Neck Cancer": a Delphi consensus survey among German speaking speech and language therapists

The "Comprehensive ICF Core Set for Head and Neck Cancer" (ICF-HNC) is an application of the "International Classification of Functioning, Disability and Health" (ICF), representing the characteristic spectrum of issues in patients with head and neck cancer (HNC). Our primary aim was to evaluate which categories of the ICF-HNC are dealt with by speech and language therapists (SLTs) in Germany, Austria, and Switzerland. The secondary aim was to identify outcome measures used by SLTs to measure the categories of the ICF-HNC in clinical practice. SLTs experienced in the treatment of HNC patients evaluated the categories of the ICF-HNC in a three-round Delphi survey. They were asked whether the listed categories represented issues treated by SLTs in HNC patients, and what outcome measures were used to assess them. Altogether, 31 SLTs completed the survey. 47 of 108 previously selected categories of the ICF-HNC achieved the cut-off value. Out of these, 40.4% were derived from the component "Body Functions", 36.2% from "Body Structures", 12.8% from "Environmental Factors", and 10.6% from "Activities and Participation". Altogether, 82 of the mentioned outcome measures were considered as reasonable from the perspective of SLTs. Of these, only 37 achieved more than 50% approval. This study emphasises the importance of "Body Structures" and "Body Functions" for SLTs in Germany and Switzerland in treating patients with HNC. Moreover, the results highlighted the need to agree on evidence-based outcome measures in speech and language therapy.

Reduced migration of MLH1 deficient colon cancer cells depends on SPTAN1

Introduction

Defects in the DNA mismatch repair (MMR) protein MLH1 are frequently observed in sporadic and hereditary colorectal cancers (CRC). Affected tumors generate much less metastatic potential than the MLH1 proficient forms. Although MLH1 has been shown to be not only involved in postreplicative MMR but also in several MMR independent processes like cytoskeletal organization, the connection between MLH1 and metastasis remains unclear. We recently identified non-erythroid spectrin αII (SPTAN1), a scaffolding protein involved in cell adhesion and motility, to interact with MLH1. In the current study, the interaction of MLH1 and SPTAN1 and its potential consequences for CRC metastasis was evaluated.

Methods

Nine cancer cell lines as well as fresh and paraffin embedded colon cancer tissue from 12 patients were used in gene expression studies of SPTAN1 and MLH1. Co-expression of SPTAN1 and MLH1 was analyzed by siRNA knock down of MLH1 in HeLa, HEK293, MLH1 positive HCT116, SW480 and LoVo cells. Effects on cellular motility were determined in MLH1 deficient HCT116 and MLH1 deficient HEK293T compared to their MLH1 proficient sister cells, respectively.

Results

MLH1 deficiency is clearly associated with SPTAN1 reduction. Moreover, siRNA knock down of MLH1 decreased the mRNA level of SPTAN1 in HeLa, HEK293 as well as in MLH1 positive HCT116 cells, which indicates a co-expression of SPTAN1 by MLH1. In addition, cellular motility of MLH1 deficient HCT116 and MLH1 deficient HEK293T cells was impaired compared to the MLH1 proficient sister clones. Consequently, overexpression of SPTAN1 increased migration of MLH1 deficient cells while knock down of SPTAN1 decreased cellular mobility of MLH1 proficient cells, indicating SPTAN1-dependent migration ability.

Conclusions

These data suggest that SPTAN1 levels decreased in concordance with MLH1 reduction and impaired cellular mobility in MLH1 deficient colon cancer cells. Therefore, aggressiveness of MLH1-positive CRC might be related to SPTAN1.

Molecular cDNA cloning and tissue distribution of mRNA encoding a novel ATP-binding cassette (ABC) half-transporter

The majority of proteins belonging to the ATP-binding cassette (ABC) superfamily catalyzes translocation of substrates across biological membranes. Employing a reverse transcription-PCR approach with degenerate primers, we have identified a full-length cDNA from rat hepatocytes encoding a novel ABC transporter termed umat (ubiquitously expressed mammalian ABC half-transporter). The deduced sequence of 836 amino acids comprises an N-terminal membrane anchor domain and a single conserved C-terminal nucleotide binding fold, specifying umat as an ABC half-transporter. While the first 250 amino acid positions are highly divergent from other ABC transporters, clusters of conserved residues are evident along the rest of the protein. The greatest sequence similarity was observed with the fission yeast heavy metal tolerance protein hmt1 (44.5% identity in a 626-amino-acid overlap). Umat mRNA, expressed in all tissues analyzed, was most abundant in testis. Substantial umat mRNA expression in cultured primary rat hepatocytes suggests that hepatocyte cultures should represent an adequate model for investigation of umat function and regulation.

S1 nuclease hybrid analysis of mitochondrial DNA amplified by long-distance PCR: rapid screening for small-scale rearrangements

We report on a method suitable for screening large regions (>3 kb) of mtDNA for structural changes of <500 bp and their localization. Heteroduplexes consisting of a wild-type and a mutant strand are cleaved by S1nuclease when single-stranded loops are present due to deletions or duplications/insertions. This strategy was successfully applied to screen the muscle mtDNA of 20 patients with mitochondrial encephalomyopathies. In three of them, an altered cleavage pattern was observed caused by a homoplasmic 9 bp deletion as shown by subsequent mapping and sequencing studies.

Hypoparathyroidism and deafness associated with pleioplasmic large scale rearrangements of the mitochondrial DNA: a clinical and molecular genetic study of four children with Kearns-Sayre syndrome

In four children with hypoparathyroidism and deafness as initial major manifestations of Kearns-Sayre syndrome, a unique pattern of mitochondrial DNA rearrangements was observed. Hypocalcemic tetany caused by PTH deficiency started between age of 6-13 y and was well controlled by small amounts of 1.25-(OH)2-cholecalciferol. Rearranged mitochondrial genomes were present in blood cells of all patients and consisted of partially duplicated and deleted molecules, created by the loss of 7813, 8348, 8587, and 9485 bp, respectively. The deletions were localized between the origins of replication of heavy and light strands and encompassed at least eight polypeptide-encoding genes and six tRNA genes. Sequence analysis revealed imperfect direct repeats present in all rearrangements flanking the break-points. The duplicated population accounted for 25-53% of the mitochondrial genome and was predominant to the deleted DNA (5-30%) in all cases. The proportions of the mutant populations (30-75%) correlated with the age at onset of the disease. We conclude that, unlike heteroplasmic deletions, pleioplasmic rearrangements may escape selection in rapid-dividing cells, distribute widely over many tissues, and thus cause multisystem involvement. Hypoparathyroidism and deafness might be the result of altered signaling pathway caused by selective ATP deficiency.

Gene polymorphism at position -308 of the tumor-necrosis-factor-alpha (TNF-alpha) in multiple sclerosis and it's influence on the regulation of TNF-alpha production

Tumor-necrosis-factor alpha (TNF-alpha) is a major mediator of the inflammatory immune response and may play an important role in the pathogenesis and progression of Multiple Sclerosis (MS). Increased TNF-alpha levels of cerebrospinal fluid (CSF) and peripheral blood were found in patients with chronic progressive MS and patients with acute relapses, but not in the stable form of the disease. Considering the association of different TNF-alpha alleles with diverse autoimmune diseases we sequenced the TNF-alpha promotor region (-674 to +201) of 23 patients with relapsing/remitting MS, of 27 patients with chronic progressive MS (21 patients had primary progressive course and six patients had a secondary progressive course) and of 22 healthy controls, who had no history of MS in their families. In three of 21 patients (14%) with primary chronic progressive MS a homozygous point-mutation at position -308 could be demonstrated where guanine (G) was substituted by adenosine (A). This mutation could neither be detected in patients with relapsing/remitting MS nor in healthy controls. However, 40% of the patients with relapsing/remitting MS and 43% of the primary chronic progressive MS patients were heterozygous at position -308 for G/A, whereas only 32% of healthy controls showed this heterogeneity. The genetic variations were demonstrated by polymerase chain reaction (PCR)-amplification of the TNF-alpha promotor-region and consecutive direct automatic sequencing. Functional analysis of the promoter region using the chloramphenicol-acetyltransferase (CAT) assay revealed spontaneous production with the homozygous mutation at -308 only.

Deletion screening of mitochondrial DNA via multiprimer DNA amplification

We report an application of multiprimed polymerase chain reaction (PCR) which allows a rapid, nonradioactive detection of deletions in mitochondrial DNA using EDTA-blood and muscle samples. The use of two primer sets consisting of three forward and five reverse primers, respectively, allows a competitive PCR resulting in significant amplification products only in the presence of deletion-harbouring DNA species. Under the conditions described, deletions causing Kearns-Sayre syndrome (KSS) and progressive external ophthalmoplegia (PEO) have been successfully detected. The location of the primers on mitochondrial DNA used in this study should allow identification and localization of most of the large-scale deletions (i.e. more than 1 kb) of mitochondrial DNA reported so far.