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Biomedical subjects

H D Mennel

Publications and source records attributed to H D Mennel.

At least 73 records · Page 4Linked to original sources
PubMed1990

Automated percutaneous lumbar discectomy with and without chymopapain pretreatment versus non-automated discoscopy-monitored percutaneous lumbar discectomy. An experimental study in human cadaver spines.

Percutaneous lumbar discectomy has gained growing interest during recent years as an alternative to open surgery for protrusions and non-sequestrated subligamentous intervertebral disc herniations. As a less invasive method it competes with chemonucleolysis. At least two modifications are known to date: automated percutaneous lumbar discectomy (APLD) with a 2-mm suction probe and non-automated, discoscopy-monitored percutaneous lumbar discectomy with a suction rongeur and a motor-driven shaver (NAPLD). In this study these two methods are compared for the amount of material extracted, dependence upon the degree of degeneration of the disc and intrinsic technical problems, using 20 human cadaver lumbar specimens for experimental testing. Total nucleotomy was not possible with either method. APLD yielded significantly less material and proved to be less effective in severely degenerated intervertebral discs than the NAPLD procedure, as preexisting gaps within the degenerated nucleus pulposus allowed the tissue to shift away from the tip of the 2-mm probe and facilitated displacement of the probe within the anulus fibrosus. By contrast, the rongeur, which first cuts the material to be removed and then carries it away by suction, was much more effective. Further data to support the advantages of non-automated percutaneous nucleotomy are discussed. Pretreatment of the disc with chymopapain did not result in a higher yield of nucleus material when combined with APLD.

Chymopapain↗
PubMed1990

Proliferative potential of human brain tumours as assessed by nucleolar organizer regions (AgNORs) and Ki67-immunoreactivity.

Two proliferation markers, silver stained nucleolar organizer regions (AgNOR) and immunoreactivity with Ki-67, were used to assess the proliferative activity in 80 smear preparations from neurosurgically removed intracranial tumours. These included 45 gliomas, 18 meningiomas, 8 metastases and 9 others. We found a remarkably close correlation between the results obtained with both methods. Increasing malignancy, as determined by conventional grading, was paralleled by an increase in the growth fraction and the number of nucleolar organizer regions. Linear regression analysis yielded the following equation: AgNORs/cell = 0.35 x L1 (Ki-67) + 3.24, with a correlation coefficient of rs = 0.53 (Spearman rank correlation test, p less than 0.0001). Thus, both the Ki-67 L1 and the AgNOR technique appear suitable for estimating the proliferative potential in smear preparations of human intracranial neoplasms. The AgNOR technique may be particularly useful for application to stereotaxic biopsies since it can easily be performed on minute tumour samples.

Antigens, Surface↗
PubMed1990

Immunohistochemical investigations in experimentally induced tumors of the nervous system.

35 tumors of brain, spinal cord and cranial and peripheral nerves were induced with ENU (ethyl-nitrosourea) in the offspring of treated BD-IX pregnant rats. 36 tumors--35 of the nervous system, one nephroblastoma--were observed in 14 rats. With these results, the number of experimental nervous system tumors of the own collection induced in BD-IX rats and classified next to the rules of human neurooncology, amounts to 2,216. All 35 tumors of the nervous system were treated by a panel of immunohistochemical reactions comprising antibodies against cytoskeleton intermediary filaments such as GFAP (glial fibrillary acid protein), neurofilament proteins, vimentin and cytokeratins and some nervous system antigens such as NSE (neuron specific enolase), MBP (myelin basic protein) and S-100 protein. In central tumors, considered to be malignant gliomas, focal reactivity against vimentin and GFAP was found. Expression of other tested markers was weak or absent. In neurinoma of trigeminal and peripheral nerves, reactivity to S-100 antigen was lacking, whilst there was strong reaction to the vimentin antigen.

Animals↗
PubMed1990

Protective effect of nimodipine against ischemic neuronal damage in rat hippocampus without changing postischemic cerebral blood flow.

The purpose of the present study was to investigate the neuroprotective action of nimodipine. Furthermore, the influence of nimodipine on postischemic local CBF (LCBF) was examined. Forebrain ischemia of the rat was performed for 10 min by bilateral carotid clamping, administration of trimethaphan, and blood withdrawal to obtain an MABP of 40 mm Hg. LCBF was measured after 10 min of postischemic recirculation by injecting [14C]iodoantipyrine in saline solution. Nimodipine (0.1, 0.3, and 1.0 mg/kg) was suspended in miglyol oil and applied orally 60 min prior to ischemia. Histological evaluation was performed 7 days after ischemia. Hippocampal neuronal damage was determined as the percentage of necrotic neurons. After preischemic application of nimodipine, neuronal damage was significantly reduced in the hippocampal CA1 subfield. Postischemic LCBF was not affected by treatment with nimodipine. These findings show that nimodipine is able to protect neurons against ischemic damage. The neuroprotective effect of nimodipine was not mediated by a postischemic cerebral vasodilation, but by a direct action on the neurons.

Animals↗
PubMed1990

PAF antagonist ginkgolide B reduces postischemic neuronal damage in rat brain hippocampus.

We investigated the effect of the known antagonist of platelet-activating factor (PAF), ginkgolide B, on postischemic neuronal damage in the rat. Neuronal necroses were evaluated in the hippocampus 7 days after a 10-min forebrain ischemia. Preischemic application of ginkgolide B (50 mg/kg p.o.) significantly reduced neuronal damage. It is suggested that the antagonism of PAF is responsible for this beneficial effect of ginkgolide B.

Animals↗
PubMed1990

Assessment of histogenesis and proliferative potential in cytologic specimens of human brain tumors. Value of immunocytochemistry and nucleolar organizer regions.

The value of immunocytochemistry and nucleolar organizer regions (NORs) for the histogenetic identification and the estimation of the proliferative potential of brain tumors was assessed by the investigation of imprint smears of 51 neurosurgical tumor specimens. A panel of five monoclonal antibodies was used to cover a broad range of immunohistochemical markers. For the assessment of NORs, a silver staining technique (AgNOR) was used. NORs were enumerated and measured by means of an interactive image analysis system. The immunocytochemical results were similar for the smears and paraffin-embedded sections for 95.6% of the investigations performed and for 76.2% of the cases. Glial fibrillary acidic protein (GFAP) was positive in 9 of 17 tumors of glial origin, but was negative in 9 metastatic tumors. Vimentin was positive in 10 of 10 and fibronectin in 9 of 10 meningiomas investigated. The number of NORs increased steadily with the increasing grade of malignancy. Especially in glioblastomas, the number of NORs per cell exhibited a wide range, which might reflect the heterogeneity of these neoplasms. Metastases revealed a higher number of NORs per cell than did glioblastomas. In the cytologic differential diagnosis of these tumors, an absence of GFAP expression combined with a high NOR count is suggestive of a metastatic tumor.

Adult↗
PubMed1990

Routine immunohistochemical characterization of short term in vitro explants from human intracranial tumours.

35 intracranial tumours, 18 gliomas, 12 meningiomas, one neurilemmoma (neurinoma), one malignant melanoma and two metastases were successfully grown in-vitro and were submitted to immunocytochemical reactions, including cytokeratin, glial fibrillary acid protein (GFAP), vimentin, fibronectin, S-100 protein, neurofilament proteins, neuron-specific enolase (NSE) and basic myelin protein (MBP). Cytokeratin in metastases, GFAP and vimentin in gliomas, vimentin in meningiomas were consistently positive. S-100 protein was weakly and partially positive in gliomas, meningiomas, the neurilemmoma and malignant melanoma. Positive demonstration of fibronectin within cells was interpreted as a consequence of phagocytosis, except in meningiomas where fibronectin expression next to cell membranes seemed genuine. All other tested markers proved negative. The most important result seems to be that cells expressed markers irrespective of cellular shape and cytological morphology. It can be concluded that the cellular population as a whole consisted of tumour cells during the short time under observation and that supportive cell contamination during this early growth period was negligible.

Biomarkers, Tumor↗
PubMed1990

Nucleolar organizer regions in meningiomas. Correlation with histopathologic malignancy grading, DNA cytometry and clinical outcome.

Eighty-one meningiomas (63 grade I, 9 grade II and 9 grade III) and 2 meningeal sarcomas (grade IV) were investigated by a simple one-step silver staining for nucleolar organizer region (NOR)-associated proteins (AgNOR technique) and by DNA cytometry. The number of NORs per cell and the NOR area per cell were correlated with the histopathologic grading, as were the 5c exceeding rate and the 2c deviation index (2cDI) obtained by DNA cytometry. The differences in NOR parameters were only significant (at P less than .001) between grades I and II; P was less than .05 for the 2cDI between grades I and II. No significant differences between grades II and III were found. Among recurrent tumors, the AgNOR technique revealed the proliferative potential in 8 of 11 tumors studied, whereas DNA cytometry failed to recognize malignant features in 8 of 10 tumors investigated.

DNA, Neoplasm↗
PubMed1990

[Prognosis in meningiomas. Relevance of morphologic studies and clinical risk factors].

Since the introduction of the WHO-classification of tumours of the central nervous system in 1979, meningiomas are subdivided in 8 histological types and graded I to IV. The basis for this classification were histopathological investigations combined with clinical follow-up data. Since the introduction of immunocytochemistry as a diagnostic tool in neurooncology, morphological methods have gained renewed interest among neurosurgeons and neurologists. Some of the more recent developments, as well as the classical methods of the neuropathologist, are discussed here, and the results of the impact of morphology on prognosis is discussed on 139 own cases. Beside the histopathological grading, the application of so called proliferative markers as Ki-67 and BUdR seems to be most promising in the prediction of recurrences. Clinical parameters as patients age, preoperative physical status, tumor size and location on the other hand are of particular importance concerning postoperative mortality.

Biomarkers, Tumor↗
PubMed1990

[Spinal angiomatous malformation: clinical course and limits of technical diagnosis].

The sensitivity of the diagnostic procedures in space occupying lesions of the spine have been markedly improved in the recent past, mainly due to the application of CT and MRI--technology and the introduction of superselective angiography. Despite these 'high-tech'-investigations, neurological examination still provides the sole in neurological diagnosis. To show the discrepancies between the techniques mentioned, we present a case of a vascular malformation of the spine with secondary myelopathy (so-called "Foix-Alajouanine-syndrome").

Adult↗
PubMed1989

Monoclonal antibodies against epitopes on ganglioside GD2 and its lactones. Markers for gliomas and neuroblastomas.

Monoclonal antibodies (mAbs) BW 625 and BW 704, of the IgG3 isotype, bound to immunochemically indistinguishable epitopes on ganglioside II3(Neu-Ac)2-GgOse3-Cer. Despite this fact the mAbs showed a differential binding pattern on human glioma cell lines i.e. immunohistochemical data indicate that the detected epitopes are not identical. Furthermore, either mAb is able to mediate the antibody-dependent cellular cytotoxicity reaction (ADCC) and the human-complement-dependent cytotoxicity reaction (CDC) with epitope-expressing tumor cells. All cryopreserved tissue specimens from gliomas and neuroblastomas were immunohistochemically stained, whereas the other small round cell tumors of childhood, as well as melanomas and small-cell lung carcinomas, were essentially negative. Positive staining of normal cryopreserved tissues was restricted to amyelinic axons, Hassal's bodies and some connective tissue fibers in thymus and the tegumentary epithelium of skin. The high selectivity of mAb BW 704 for gliomas and neuroblastomas, the lack of cross-reactivity with major tissues and the strong ADCC and CDC potential argue for the use of mAb BW 704 in immunotherapy of neuroblastomas and gliomas.

Antibodies, Monoclonal↗
PubMed1989

Dumb-bell ganglioneuroma of the spine misinterpreted as progressive idiopathic scoliosis. Case report.

A giant ganglioneuroma generating a progressive scoliosis in a 16-year-old girl is presented. The interval between the start of the orthopaedic treatment and the diagnosis of the true nature of the disease was more than 4 years, thus allowing the development of a giant partly intracanalicularly partly retroperitonealy expanding tumor mass. The report emphasizes and describes the combined neurosurgical, general surgical and orthopaedic surgical treatment and presents the results of light- and electron microsopical, immunohistochemical and quantitative neurochemical investigations of the resected tumor.

Adolescent↗
PubMed1989

Cystic meningioma with unusual histopathological features.

A parasagittal meningioma of an eighty year old female patient showed by light and electron microscopy cystic architecture (forme humide) as well as nuclear vacuoles (indentations) and cytoplasmic inclusions. The latter are the known pseudopsammoma bodies or hyaline inclusions as demonstrated by light and electron microscopy. Light microcopy on paraffin sections and cytological smear preparations revealed, in addition to the cells of endotheliomatous meningioma and those containing the inclusions a third type with small granular cytoplasmic content. Electron microscopy showed characteristic features of meningioma such as folded double membranes, desmosomes and filaments and thus gave evidence of the meningiomatous nature of the tumor. By immunohistochemistry tumor cells in slightly focal distribution contained vimentin, whereas small clusters of cells with hyaline inclusions were strongly positive for cytokeratin. The dispersed cells of granular cytoplasmic content were positive for fibronectin. These findings, especially of the inclusion containing cytokeratin positive cell clusters may shed new light upon the concept of histogenesis and classification.

Aged↗
PubMed1989

Reliability of simple cytological methods in brain tumour biopsy diagnosis.

Stereotactic procedures in brain tumour diagnosis and therapy are used increasingly because small lesions are more frequently detected and methods of interstitial irradiation are gaining wide acceptance among neurosurgeons. The diagnosis of underlying pathological processes has to be performed from very small tissue samples. The method of smear and/or squash preparations therefore has long been used by neurosurgeons. Neuropathologists, formerly reluctant, are becoming more and more enthusiastic over this simple and elegant method. Since the diagnostic reliability in such small samples is questioned, we have undertaken to analyse 200 open tumour biopsies in a comparative investigation: the diagnosis from smear preparation on the one hand has been performed without knowledge of the lesion, and on the other hand the remaining material was submitted to the whole pattern of diagnostic methods including frozen sections, paraffin sections with special staining, immunohistochemistry, electron microscopy and tissue culture. Diagnostic reliability was estimated in a four step procedure: Is there tumour or not--is there neuroepithelial newgrowth or metastasis--what kind of tumour is it--has the degree of malignancy--according to the criteria of the WHO--been estimated correctly? The overall diagnostic reliability in our material is about 75%. This is less than the diagnostic reliability of other methods, mostly due to the lack of histologic "architecture" criteria in evaluating the cytological biopsies.

Adolescent↗
PubMed1989

Naftidrofuryl protects neurons against ischemic damage.

The effects of naftidrofuryl on postischemic neuronal damage and on local cerebral blood flow (LCBF) were examined in a rat model of forebrain ischemia (occlusion of carotid arteries and hypotension). Ischemia was induced for 10 min. LCBF was measured after 2 and 10 min of recirculation. A histological evaluation of cell loss in the hippocampal areas was performed 7 days after ischemia. Naftidrofuryl (10 mg/kg) was administered intraperitoneally 15 min before ischemia. The drug reduced the percentage of necrotic neurons in the CA1 and CA4 sector of the hippocampus, while the LCBF of these hippocampal sections was not significantly altered. Thus, naftidrofuryl is suggested to protect hippocampal neurons against ischemic damage mainly by a direct effect on brain parenchyma.

Animals↗
PubMed1988

Effects of flunarizine on postischemic blood flow, energy metabolism and neuronal damage in the rat brain.

The effects of flunarizine on local cerebral blood flow, cortical energy metabolism and neuronal necrosis were evaluated in a rat model of forebrain ischemia. The application of flunarizine (2 X 40 mg/kg p.o.) at 24 and 4 h before ischemia accelerated the restoration of cortical high-energy phosphates during early post-ischemic recirculation and also increased the flow in cortical but not in hippocampal areas. Neuronal necrosis was reduced in the hippocampal CA 1 sector but unchanged in the cortex. It is concluded that flunarizine reduces ischemic damage mainly via a direct effect on brain tissue.

Animals↗