Biomedical subjects

I Niedermayer

Publications and source records attributed to I Niedermayer.

24 records · Page 2Linked to original sources

PubMed1995

Triple approach for diagnosis and grading of meningiomas: histology, morphometry of Ki-67/Feulgen stainings, and cytogenetics.

With regard to meningioma grading and the recently introduced "atypical" meningioma, we evaluated 160 cases retrospectively by conventional histology and image analysis. For that, the cell nuclei were stained with a Ki-67 (MIB1)/Feulgen-method on paraffin sections, thus enabling the assessment of both the Ki-67 proliferation index and nuclear morphometric features, such as tumour cell arrangement, nuclear pleomorphism, and cellularity. It could be demonstrated that the Ki-67 proliferation index is the most important criterion for distinguishing anaplastic meningiomas (WHO "grade" III) (mean Ki-67 index: 11%) from those of common type (WHO "grade" I) (mean Ki-67 index: 0.7%). The parameter for the "relative volume weighted mean nuclear volume" is another valuable morphometric feature. The "atypical" meningioma (WHO "grade" II) which should represent an intermediate category between common type and anaplastic meningiomas is characterized by a mean Ki-67 proliferation index of 2.1%. Common type meningiomas which comprise almost 50% of the cases of this series have a relapse rate of 9%. "Atypical" and anaplastic meningiomas recurred in 29% and 50%, respectively. Since the term "atypical" meningioma is confusing in the context of tumour grading, the term "intermediate type meningioma" is proposed. Furthermore, the results of cytogenetic analyses of 142 cases of this series were evaluated and compared with the meningioma grades. Thereby, 25 cases disclosed, independent of the typical loss of one chromosome 22, cytogenetic features assumed to be progression-associated, e.g., the gain or loss of different chromosomes and the deletion of the short arm of one chromosome 1 (hyperdiploidy, increased hypodiploidy, 1p-), when correlated to the histological and morphometric findings or the high relapse rate. For meningioma diagnosis and grading, a practical guideline is proposed based upon histology, morphometry (Ki-67), and cytogenetics.

Biomarkers, Tumor↗

PubMed1995

Automated grading of astrocytomas based on histomorphometric analysis of Ki-67 and Feulgen stained paraffin sections. Classification results of neuronal networks and discriminant analysis.

In stereotactically obtained astrocytoma biopsies, four morphometric nuclear parameters were determined with the use of an image analysis system. A special Ki-67 (MIB1)/Feulgen stain made it possible to quantify the essential characteristics of gliomas of the astrocytoma/glioblastoma group: growth pattern, cellularity, proliferation tendency and nucleus pleomorphism. A grading scale based on a cluster analysis resembling the WHO-scheme, which is suitable for automated astrocytoma grading, was developed. Large back propagation neural networks were used and their results compared with those of a classical multivariate discriminant classification analysis. It is possible to show that the neural network technology is superior to the statistical approach for automated astrocytoma grading. Based on the results of our study we believe neural network technology to be useful for tumour grading problems. The presented approach can be generalized for the automated grading of other tumour entities.

Astrocytoma↗

PubMed1994

[Computer assisted grading of gliomas of the astrocytoma/glioblastoma groups].

For automated astrocytoma grading morphometric parameters are determined by means of an image analysis system and a special Ki-67(MIB1)/Feulgen-staining method allowing the quantification of the essential characteristics of malignant gliomas: growth pattern, cellularity, proliferation index and nucleus pleomorphism. Based upon a cluster analytical approach a grading scale resembling the WHO-scheme is established which is suitable for automatic glioma grading purposes (HOM-scale). For automatic glioma grading backpropagation neural networks are employed. The results are compared with those of a classical multivariate discriminant classificatory analysis. The presented approach can also be employed for automatic grading of other tumour entities.

Astrocytoma↗

PubMedDate not supplied

Cerebroretinal vasculopathy and leukoencephalopathy mimicking a brain tumor. Report of two early-onset cases with Fanconi's anemia-like phenotypes suggesting an autosomal-recessive inheritance pattern.

We report two sisters affected with a unique disorder characterized by recurrent space-occupying brain lesions and retinal vasculopathy since their early twenties. Affection status was associated with abnormalities characteristic of Fanconi's anemia, i.e. aplastic anemia, microcephaly, short stature, an unusual face and pigmentation abnormalities of skin. In cytogenetic analyses performed in childhood signs of chromosome fragility or any chromosomal aberration were lacking. Histopathological examination of brain biopsy samples in both cases demonstrated identical histomorphological features of an unusual occlusive vasculopathy with multilayered basement membranes and coagulation necroses which were confined to the white matter. A veno-occlusive retinopathy with neovascularization attributed to progressive visual loss. One of the sisters died at an age of just 24 years, the other is now 27 years old. Unlike any other published cases of hereditary cerebroretinal vasculopathy, the sisters' complex early-onset vaso-occlusive CNS-/eye-disease seems to be genetically associated with their Fanconi's anemia-like phenotypes and is suggested to constitute an autosomal-recessive variant. Patchy white matter calcifications, an incidental finding in either of the affected sisters, may represent preclinical manifestation of disease onset in childhood.

Adult↗

PubMedDate not supplied

An electronic tutorial of neurosurgical pathology--application of multi-media in clinical pathology.

We present an electronic tutorial of neurosurgical pathology developed for standard MS-DOS-computers. No additional software requirements are necessary. Digital pictures are displayed on the computer screen in Super-VGA quality. The user interface allows a dialogue between the pathologist and the engine. The dialogue component consists of scroll bar menus with lists of possible suggestions and answers. For each case the user is supplied with the basic clinical information and a set of representative pictures of the histological specimens. In some cases radiographs and CT-images are available. During the consultation session both routine and special staining methods are available on request. If the user proposes a wrong diagnosis the system offers a commentary. The presented cases are part of a teaching series developed for residents in neuropathology.

Computer-Assisted Instruction↗

PubMedDate not supplied

Characterization of intermediate type (WHO "atypical") meningiomas.

The intermediate type meningioma (formerly "meningioma variant with signs of increased proliferation activity"; WHO "atypical" meningioma) represents a meningioma group the mean Ki-67 index and the recurrence rate of which lie between those of the ordinary and the anaplastic type [Kolles et al. 1995]. In the study cited (n = 160) the percentage of recurrences was 9% in the common, 29% in the intermediate, and 50% in the anaplastic type. The present study focuses on 49 subsequently diagnosed meningiomas of the intermediate type. Apart from certain histopathological features, the most important independent factors associated with recurrence were Ki-67 indices covering the 95% confidence interval between 3.7% and 4.9%. At the light-microscopic level, however, meningiomas in general, and especially those supposed to belong to the intermediate type, are highly variable in tissue architecture and do, in contrast to the anaplastic type, not display frank histological features of anaplasia. Morphologically, the growth pattern of solid ("syncytial") sheets, micronecroses, and large distinct nucleoli are suspicious. Cytogenetically, independent of the loss of one chromosome 22, it has been shown that terminal loss of the short arm of one chromosome 1 (1p-) or complete loss of this chromosome were useful additional indicators of meningioma progression.

Adult↗