EARLY CARCINOMA TONGUE – SURGICAL OPTIONS

A retrospective analysis of 127 surgically treated cases of T-1, T-2 carcinoma of oral tongue during the period 1987-1990 was undertaken. 68.5 per cent (87) underwent hemiglossectomy and 31.5 per cent (40) underwent wide excision. There were loco-regional recurrences in 22 per cent (27). In the hemiglossectomy group 9 per cent (8 of 87) had local recurrences compared to 25 per cent (10 of 40) of wide excision group, (P = 0.01). Mean disease free survival was 40 months and 33 months for hemiglossectomy group and wide excision group respectively, (P = 0.006). It is seen that local recurrences are significantly less for the hemiglossectomy group compared to the wide excision group.KEY WORDS: Disease free survival, Early cancer, Recurrence, Surgery, Tongue     

Long-term potentiation induced in dendrites separated from rat's CA1 pyramidal somata does not establish a late phase

In 14 transversal hippocampal slices from rats the extracellular field-EPSP (excitatory postsynaptic potential) in the dendritic region of the CA1 subfield was recorded after isolating the apical dendrites from their somata by microsurgical cuts through the proximal stratum radiatum. Contrary to intact slices which, after tetanic stimulation of the Schaffer collaterals, showed long-term potentiation (LTP) until the end of registration after 8-10 h, LTP declined in the isolated dendrites to baseline values after 3 h. It is concluded that de-novo protein synthesis in postsynaptic cell bodies might be necessary for the maintenance of late phases of LTP.     

Probabilistic Fiber-Tracking Reveals Degeneration of the Contralateral Auditory Pathway in Patients with Vestibular Schwannoma

BACKGROUND AND PURPOSE:Vestibular schwannomas cause progressive hearing loss by direct damage to the vestibulocochlear nerve. The cerebral mechanisms of degeneration or plasticity are not well-understood. Therefore, the goal of our study was to show the feasibility of probabilistic fiber-tracking of the auditory pathway in patients with vestibular schwannomas and to compare the ipsi- and contralateral volume and integrity, to test differences between the hemispheres.MATERIALS AND METHODS:Fifteen patients with vestibular schwannomas were investigated before surgery. Diffusion-weighted imaging (25 directions) was performed on a 3T MR imaging system. Probabilistic tractography was performed for 3 partial sections of the auditory pathway. Volume and fractional anisotropy were determined and compared ipsilaterally and contralaterally. The laterality ratio was correlated with the level of hearing loss.RESULTS:Anatomically reasonable tracts were depicted in all patients for the acoustic radiation. Volume was significantly decreased on the hemisphere contralateral to the tumor side for the acoustic radiation and diencephalic section, while fractional anisotropy did not differ significantly. Tracking did not yield meaningful tracts in 3 patients for the thalamocortical section and in 5 patients for the diencephalic section. No statistically significant correlations between the laterality quotient and classification of hearing loss were found.CONCLUSIONS:For the first time, this study showed that different sections of the auditory pathway between the inferior colliculus and the auditory cortex can be visualized by using probabilistic tractography. A significant volume decrease of the auditory pathway on the contralateral hemisphere was observed and may be explained by transsynaptic degeneration of the crossing auditory pathway.

Vestibular schwannoma, also known as acoustic neurinoma, is a common intrameatal and intracranial tumor evolving from the eighth cranial nerve with an incidence of 10–15 per million per year.¹ The tumor usually arises from Schwann cells within the vestibular part of the eighth cranial nerve. The benign tumor is characterized by a slow growth pattern for years.^2,3 The slow-but-steady increase in size causes progressive damage to the neurons of the eighth cranial nerve, leading to hearing impairment, tinnitus, and vertigo.^4–6 Typically the vertigo symptoms are transient, while hearing impairment can progressively deteriorate toward unilateral deafness ipsilateral to the lesion side. To estimate the extent of hearing loss, examination of tone audiometry and speech discrimination is crucial.^6–9 Large tumors involving neighboring structures such as the fifth or seventh cranial nerve or even the brain stem and cerebellum may cause facial paresis and numbness, cerebellar ataxia, or corticospinal tract–related sensorimotor deficits. There are various classification systems, but tumor extension is usually classified on the basis of the size from T1 (intrameatal localization) to T4 (compression of the brain stem).¹⁰ Treatment options include surgical removal of the tumor and radiation therapy. During the past decades, the surgical goal has shifted from gross total resection toward optimal functional outcome.^8,11Despite surgical tumor removal, improvement of hearing is unusual, even if anatomic preservation of the eighth cranial nerve has been achieved and resection has led to decompression of the nerve. Apparently, the cochlear nerve itself and possibly cortical and subcortical auditory structures have a low potential for regeneration after nerve damage. In contrast, the function of the damaged vestibular nerve is compensated by the integrating circuitry of the equilibrium: The latter involves the vestibular, visual, and somatosensory systems¹² and therefore provides a more robust reserve for compensation. Although functional outcome has been the treatment focus, the interest was limited to the individual nerve structures, while the cerebral mechanisms of degeneration or plasticity of the associated white matter tracts and cortex areas are rarely investigated and understood.The first studies by DTI, in unselected hearing disorders, succeeded, in some cases, in illustrating abnormality of white matter integrity of the auditory pathway. Wu et al¹³ found decreased fractional anisotropy (FA) at the contralateral inferior colliculus and lateral lemniscus in 19 patients with non-tumor-related sensorineural hearing loss. Chang et al¹⁴ reported abnormalities of fractional anisotropy in several parts of the auditory pathway when comparing 10 patients with sensorineural hearing loss with healthy subjects. Both investigations indicated a transsynaptic degeneration of the auditory pathway. An association between DTI-derived measures and abnormalities in brain stem auditory-evoked potentials was illustrated in preterm infants.¹⁵ These previous investigations measured DTI-derived parameters like FA or radial diffusivity by using ROI analyses. While the feasibility of fiber-tracking has been shown previously in auditory pathway investigation,^16–18 this method has not been hitherto applied to the auditory pathway in patients with vestibular schwannoma. A detailed analysis of the white matter microstructure of the auditory pathway and of possible abnormalities in patients with vestibular schwannoma does not exist, to our knowledge. Therefore, the primary goal of our study was to show the feasibility of probabilistic fiber-tracking of partial sections of the auditory pathway in patients with vestibular schwannomas and to quantify the volume and integrity of these sections ipsi- and contralateral to the tumor side to test for differences between the hemispheres. The secondary goal was to identify associations of the integrity of the auditory pathway with audiometric measurements, including speech discrimination and the electrophysiologic brain stem–evoked potentials.     

空气喷磨和酸蚀与树脂突超微结构的关系

目的 体外评价５种处理方法对树脂突超微结构的影响。方法 对照组：对１颗离体磨牙常规预防性树脂充填。其余４颗磨牙用空气喷磨处理,分别用５０μ和２７μ氧化铝微粒,酸处理其中２颗磨牙。窝洞用复合树脂充填后,用１０％盐酸溶解牙釉质,扫描电镜观测树脂突超微结构。结果 对照组呈典型窝状结构。空气喷磨的树脂突呈不规则结构,结合酸蚀的树脂突表面更加粗糙。结论 空气喷磨具有一定的蚀刻作用但不如酸蚀作用强。     

Eingeladener Kommentar zu: J. Mayr, M. Fechter undW. Grechenig: Funktionelle Elektrostimulation (FES) nach Schädel-Hirn-Trauma im Kindesalter (Acta Chir Austriaca 1999; 31: 167–169)

Ohne Zusammenfassung     

Molecular characteristics of two esophageal carcinosarcomas: a hint for theclonality of carcinomatic and sarcomatic tumor components

AIM To study the clonality of the esophageal carcinosarcoma by using molecular approaches.METHODS Two esophageal carcinosarcomas were included in the study. Tumor area from dysplasticlesion, squamout cell carcinoma, basaloid cell carcinoma and spindle cell elements were microdissectedseparately. Each element was analyzed with 14 microsatellite markers and direct sequenced for p53 gene andras gene mutation.RESULTS Both tumors displayed a typical histologic feature of carcinosarcoma. Both cases showed thedivergent differentiation by immunohistochemistry study. In case 1 the identical LOH at p53 and hMLH1 lociwas detected. The heterogenous LOH was detected only in carcinosarcoma at RB1 and BRCA1 loci, whilethe LOH at ACTC locus was seen only in sarcoma. The same mutation of the splice site of exon 6-intron 6displayed in the two tumor elements. In case 2, a coordinate LOH at RB locus was demonstrated in threetypes of tumor elements: sqamous carcinoma, basaloid carcinoma and spindle cell element. A heterogenousLOH was seen only in spindle cells at TAP1 locus. No mutation in exon 5-8 of p53 gene has been found incase 2. No mutation of K-ras gene was found.CONCLUSION Although the different differentiation, the two elements of esophageal carcinosarcoma mayhave a single clonality. The p53 gene mutation occurred before the two differentiation directions switched.The distinct molecular genotype can be determined through molecular biological analysis. The microsatelliteprofiling can serve as an approach to find out which genetic alteration occurs before or after thedifferentiation is determines.     

冠状动脉狭窄的16层螺旋CT造影检查

目的以常规X线冠状动脉造影为标准,评价16层螺旋CT（MSCT）无创性检查冠状动脉及诊断冠状动脉狭窄的价值。资料与方法65例临床初诊为冠心病,无冠状动脉成形术和搭桥术史的患者,在冠状动脉16层MSCT造影检查后,回顾性重建心电门控轴位图像,并采用容积成像（VR）、多平面重建（MPR）、曲面MPR、最大密度投影（MIP）等后处理方法,对所有冠状动脉及其分支进行重建,统计可供临床评价的、管径≥1．5mm的冠状动脉段,以选择性冠状动脉造影（SCA）为标准,对比分析MSCT诊断冠状动脉显著性狭窄（管腔平均直径缩小超过50％）的准确性。其中8例在检查前心率超过80次／min的患者使用了B受体阻滞剂。结果93％的冠状动脉节段和94％的冠状动脉主干可供评价,不能评价的主要原因分别为：心脏运动伪影（58％）,致密钙化（28％）和管腔显影不良（14％）。除外不能评价的冠状动脉,按节段和主干分类,MSCT诊断冠状动脉显著性狭窄的敏感性和特异性分别达到92％、98％和95％、97％。结论无需常规使用B受体阻滞剂,16层MSCT冠状动脉造影即可获得较好的图像质量用于诊断冠状动脉狭窄,是一种值得临床医师信赖的检查冠状动脉有无狭窄的非创伤性方法。     

Flotillin-1 is essential for PKC-triggered endocytosis and membrane microdomain localization of DAT

Plasmalemmal neurotransmitter transporters (NTTs) regulate the level of neurotransmitters, such as dopamine (DA) and glutamate, after their release at brain synapses. Stimuli including protein kinase C (PKC) activation can lead to the internalization of some NTTs and a reduction in neurotransmitter clearance capacity. We found that the protein Flotillin-1 (Flot1), also known as Reggie-2, was required for PKC-regulated internalization of members of two different NTT families, the DA transporter (DAT) and the glial glutamate transporter EAAT2, and we identified a conserved serine residue in Flot1 that is essential for transporter internalization. Further analysis revealed that Flot1 was also required to localize DAT within plasma membrane microdomains in stable cell lines, and was essential for amphetamine-induced reverse transport of DA in neurons but not for DA uptake. In sum, our findings provide evidence for a critical role of Flot1-enriched membrane microdomains in PKC-triggered DAT endocytosis and the actions of amphetamine.     

Facial motor evoked potentials in cerebellopontine angle surgery: technique, pitfalls and predictive value

Objective

To obtain information on functional integrity of the facial nerve by transcranial electrical motor evoked potentials independent of nerve visualization and to improve prediction of postoperative function.

Patients and methods

In a prospective clinical study, 68 patients with cerebello-pontine angle tumors and 5 patients with trigeminal neuralgia were investigated by facial motor evoked potentials (FMEP) elicited by multi-pulse transcranial electrical motor cortex stimulation. For recording the same electrode set-up was used as for continuous EMG monitoring of the orbicularis oculi and oris muscles. Pre-surgical FMEP amplitudes and latencies were correlated with tumor extensions. End to start amplitude ratios were compared to early and long-term facial nerve function by House-Brackmann-Grading (HB) documented by pre- and post-operative photo and video documentation.

Results

Reliable FMEP were obtained in 57 patients. FMEP responses at the start of surgery correlated with the degree of tumor extension. Largest FMEP amplitudes and shortest latencies were found in patients with trigeminal neuralgia. FMEP quality was reduced with increasing tumor extension (P < 0.05). The ratio of end-operative to start-operative FMEP-amplitude showed a positive correlation with early and late facial nerve function. Correlation was especially close with early function: an amplitude preservation rate of 86% led to HB°1 or HB°2, of 67% to HB°3, at 33% to HB°4 and at 15% or lower to HB°5 or HB°6.

Discussion

Initial FMEP amplitudes correlate with the presumed pre-operative nerve affection by space occupying tumors, a phenomenon reported here for the first time. Intact FMEP are highly reliable for preserved nerve continuity and hereby are of special help to the neurosurgeon for those surgical phases where the facial nerve is not visible and still covered by tumor and where conventional EMG monitoring is of very limited use. The end-to-start amplitude ratio of the FMEP is closely related to early and late clinical function. Amplitude reduction by 30% or more should result in a change of microsurgical action to enable fast recovery.

Conclusion

As an adjunct to intraoperative EMG, FMEP are superior in two respects, first in identifying pre-surgical latent nerve lesions and second in monitoring nerve integrity without direct nerve visualization. FMEP are highly reliable in predicting early and late postoperative function.     

eLearning in education and advanced training in neuroradiology: introduction of a web-based teaching and learning application

Introduction New information technologies offer the possibility of major improvements in the professional education and advanced training of physicians. The web-based, multimedia teaching and learning application Schoolbook has been created and utilized for neuroradiology.Methods Schoolbook is technically based as a content management system and is realized in a LAMP environment. The content is generated with the help of the developed system and stored in a database. The layout is defined by a PHP application, and the webpages are generated from the system.Results Schoolbook is realized as an authoring tool so that it can be integrated into daily practice. This enables the teacher to autonomously process the content into the web-based application which is used for lectures, seminars and self-study. A multimedia case library is the central building block of Schoolbook for neuroradiology, whereby the learner is provided with original diagnostic and therapeutic data from numerous individual cases. The user can put individual emphasis on key learning points as there are various ways to work with the case histories. Besides the case-based way of teaching and learning, a systematically structured way of dealing with the content is available.Conclusion eLearning offers various opportunities for teaching and learning in academic and scientific as well as in economic contexts. Web-based applications such as Schoolbook may be beneficial not only for basic university education but also for the realization of international educational programmes such as the European Master of Medical Science with a major in neuroradiology.