Biomedical subjects

M Warich-Kirches

Publications and source records attributed to M Warich-Kirches.

15 recordsLinked to original sources

PubMed2001

High frequency of mitochondrial DNA mutations in glioblastoma multiforme identified by direct sequence comparison to blood samples.

In an earlier study, we showed that heteroplasmy in the mitochondrial genome of gliomas sometimes occurs in a D-loop polycytosine tract. We extended this study by pairwise comparisons between glioma samples and adjacent brain tissue of 55 patients (50 glioblastomas, 1 astrocytoma WHO grade III, 4 astrocytomas WHO grade II). We used a combination of laser microdissection and PCR to detect and quantify variations in the polycytosine tract. New length variants undetectable in the adjacent brain tissue were observed in 5 glioblastomas (9%). In 2 of these cases, samples from a lower tumor stage (WHO grade II) could be analyzed and revealed the early occurrence of these mutations in both cases. Since the mitochondrial D-loop contains additional repeats and highly polymorphic non-coding sequences, we compared 17 glioblastomas with the corresponding blood samples of the same patients by direct sequencing of the complete D-loop. In 6 of these tumors (35%), instability was detected in 1 or 2 of 3 repeat regions; in 1 of these repeats, the instability was linked to a germline T-to-C transition. Furthermore, of 2 tumors (12%) 1 carried 1 and the other 9 additional transitions. In the latter patient, 6.7 kb of the protein coding mtDNA sequence were analyzed. Six silent transitions and 2 missense mutations (transitions) were found. All base substitutions appeared to be homoplasmic upon sequencing, and 89% occurred at known polymorphic sites in humans. Our data suggest that the same mechanisms that generate inherited mtDNA polymorphisms are strongly enhanced in gliomas and produce somatic mutations.

Adult↗

PubMed2001

[Interesting case no. 45. Pharyngeal manifestation of chondroid chordoma].

Chordomas usually occur in the axial skeleton and they arise from the remnants of notochord. Their growth is slow and they often metastase. Most frequently chordomas are situated in sacral bone (50%), in spheno-occipital region of the skull base (35%) and in the cervical and lumbar spine (15%). We reported an unusual case of chordoma of the cervical spine with participation of the parapharyngeal space. The cervical chordoma was excised by total resection of the tumor mass with partial vertebrectomy C2/C3.

Aged↗

PubMed2001

Heterogeneous tissue distribution of a mitochondrial DNA polymorphism in heteroplasmic subjects without mitochondrial disorders.

CONTEXT: Several maternally inherited point mutations of the mitochondrial genome cause mitochondrial disorders, but the correlation between genotype and phenotype remains obscure in many cases. The same mutation may cause various diseases, probably because of a different tissue distribution. OBJECTIVE: To assess the role of random somatic segregation in generating interperson differences by analysis of an apparently neutral polymorphism. DESIGN: Screening of 81 brain samples from subjects without mitochondrial disorders and selection of five necropsy cases showing a high level of heteroplasmy for the polymorphism. MAIN OUTCOME MEASURES: A proportion of various distinct genotypes in the mtDNA pool of the tissues, identified by fluorescent PCR products, representing a short polycytosine tract of variable length in the mitochondrial displacement loop. RESULTS: Differences were found between organs or groups of organs within subjects, pointing towards somatic segregation of mtDNA. In addition, marked differences of this organ distribution occurred between subjects, which cannot be explained by tissue specific selection. CONCLUSIONS: The observed interperson differences can be explained by somatic segregation, which occurs randomly at various developmental stages. Besides tissue specific selection, this process might participate in the distribution of pathogenic mtDNA mutations.

Adolescent↗

PubMed1999

Loss of heteroplasmy in the displacement loop of brain mitochondrial DNA in astrocytic tumors.

The aim of this study was the determination of D-loop heteroplasmy in astrocytic brain tumors. DNA fragments corresponding to the hypervariable region 2 of the mitochondrial displacement loop (D-loop) from 12 astrocytic tumors and 2 corresponding brain samples were cloned into a plasmid vector. Heteroduplex analysis revealed high sequence variability in the brain samples and a subfraction of grade 2 and grade 3 tumors. Furthermore, the results were suggestive of a very low degree of heteroplasmy in all glioblastomas. This was confirmed by direct sequencing of 223 cloned DNA samples from nine individuals. Heteroplasmy was caused in most cases by a well-known length polymorphism of a homopolymeric c-tract. Heteroplasmy of the two reference brain samples was lost in the corresponding tumors. Genes Chromosomes Cancer 26:80-83, 1999.

Adult↗

PubMed1998

Correlation of TGF-alpha and EGF-receptor expression with proliferative activity in human astrocytic gliomas.

Fifty-nine paraffin-embedded astrocytic gliomas (four WHO grade 1, 21 WHO grade 2, 17 WHO grade 3 and 17 glioblastomas, WHO grade 4) were immunohistochemically investigated for expression of transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGF-R) and oncoprotein c-erbB-2 by semiquantitative assessment. Proliferative activity was simultaneously analyzed by using the antibody Ki-67 (MIB-1). Immunostaining in neoplastic cells was quantified by image analysis. Concerning the antibodies used, the percentage of immunoreactive cells increased with histologic malignancy. There was no expression of EGF-R and c-erbB-2 in the majority of low-grade astrocytomas. However, small focal expressions of TGF-alpha and EGF-R were observed in several low-grade astrocytomas (11/25), suggesting an early stimulation of malignant transformation. With regard to percentage, a strong positive correlation between TGF-alpha and EGF-R-stained cells was found, indicating an autocrine stimulation of the mitogenic pathway of the TGF-alpha/EGF-R system. Likewise, indices of EGF-R and c-erbB-2 positive cells correlated significantly. Less significant correlations were also seen between EGF-R, c-erbB-2 frequencies and the Ki-67 labeling index. However, there was no correlation between TGF-alpha and Ki-67 indices. The results suggest that TGF-alpha expression is not directly related to the proliferative potential as judged by the Ki-67 labeling index. Furthermore, besides EGF-R and c-erbB-2, other growth factors and their receptors or mutant EGF-R might participate in the proliferative activity of gliomas.

Astrocytoma↗

PubMed1998

mtDNA depletion and impairment of mitochondrial function in a case of a multisystem disorder including severe myopathy.

The ratio of mtDNA and a nuclear reference gene was estimated by Southern blotting in the skeletal muscle DNA of a 3-year-old girl who suffered from congenital brain damage, focal epilepsy, hepatomegaly, malabsorption syndrome and severe myopathy. The signal ratio of mtDNA versus 18S rDNA was 22% of the mean value obtained from controls. No major deletions or insertions were found and the MERRF, MELAS and NARP mutations were ruled out. Mitochondrial DNA-encoded enzyme activities and mitochondrial respiration were reduced. The analysis of the NAD(P)H and flavoprotein redox states of intact fibres revealed the presence of mitochondrial dysfunction. In tissue sections a moderate elevation of type I and type II fibre diameter variation was detected, aberrant NADH- and succinate dehydrogenase staining and some ragged red fibres. This suggested that a mitochondrial disorder caused by a decrease in the amount of intact wild-type mtDNA was responsible for the severe myopathy.

Abnormalities, Multiple↗

PubMed1997

Immunohistochemical expression of P-glycoprotein and glutathione S-transferases in cerebral gliomas and response to chemotherapy.

The expression of the drug resistance-related proteins glutathione S-transferases (GST) and P-glycoprotein (Pgp) was analyzed quantitatively in samples of 53 astrocytic gliomas (eight WHO grade 1, 11 WHO grade 2, 9 WHO grade 3 and 25 glioblastomas, WHO grade 4). Sections of these tumors were immunohistochemically stained with antibodies to Pgp (MDR1-gene product) and to GST subclasses alpha, mu and pi. Pgp expression was not detected in tumor cells of the majority of low-grade astrocytomas (69%) and the percentage of Pgp stained cells generally increased with tumor grade. However, 4 of the 34 malignant gliomas were negative. Many neoplastic cells of most tumors were dominantly stained for GST-pi. The other two subclasses were expressed in a less consistent fashion with no linear correlation to grading. Grade 2 astrocytomas exhibited the highest percentage of cells with GST expression. GST-alpha was absent in 9 tumors, GST-mu in 8 and GST-pi in 4. Four tumors showed no expression of any GST subclass or Pgp in neoplastic cells. Of 13 patients 5 with a more favorable clinical course after radiation and chemotherapy had a lower percentage of neoplastic cells immunostained for Pgp and the three GST subclasses than 8 patients with a worse clinical course. These results suggest a relationship between expression of drug resistance-related proteins in gliomas and response to chemotherapy with ACNU/VM26.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1997

Immunohistochemical detection of vascular growth factors in angiomatous and atypical meningiomas, as well as hemangiopericytomas.

The arachnoideal compartment provides the vascular sources for three different tumor types rich in vessels: angiomatous meningioma, some atypical meningioma with high vascularity and meningeal hemangiopericytoma. We investigated immunohistochemically the expression and distribution of vascular mitogenes in 7 angiomatous meningiomas, 8 atypical meningiomas with high vasculature and 4 hemangiopericytomas. On the one hand it should be studied which vascular growth factors such as VPF/VEGF-1, VPF/VEGF-2, bFGF, PDGF and TGF-alpha could be responsible for the close meshwork of vessels within the tumors. On the other hand we were interested in whether or not there are differences in vascular mitogens between slowly growing angiomatous meningiomas and both other types with their increased tendency to recur. PDGF and TGF-alpha were extensively expressed in the endothelium and smooth muscle cells of the vessels, as well as tumor cells. VEGF-2 could only be found in endothelial cells of all three tumor entities. bFGF was localized in some vessels of angiomatous meningiomas and VEGF-1 revealed a very low expression with a localization comparable with VEGF-2. Moreover, uPAR was diffusely expressed in nearly all tumor cells and endothelial cells. The fact that tumor cells of hemangiopericytomas and meningiomas did not show any immunohistochemical reaction with VEGF's could indicate a lower priority of these growth factors for neovascularization in this type of neoplasm. A different expression of vascular mitogens between benign angiomatous meningiomas and atypical meningiomas as well as hemangiopericytomas with their tendency for recurrence could not be observed. The morphological evidence for extravasates of IgG-proteins, Fibrin and Fibronectin due to VPF-effects seems not to be a renouncable condition for neoangiogenesis in the tumors investigated.

Adult↗

PubMed1997

Hypothalamic osteolipoma: a case report.

The authors present a case of an ossified lipoma at tuber cinerum, an incidental finding when performing an autopsy of a 61-year old male. A tight connection to right communicans posterior artery led first to the diagnosis of a calcified saccular aneurysm, but histologic examination revealed an osteolipoma consisting of mature adipose tissue and formation of bone. Intracranial lipomas are neither hamartomas nor true neoplasms, but they are more likely to be congenital malformations. The recent literature is reviewed, and the two most current embryologic concepts of the development of intracranial lipomas are discussed.

Autopsy↗

PubMed1996

Immunohistochemically detectable p53 and mdm-2 oncoprotein expression in astrocytic gliomas and their correlation to cell proliferation.

The aim of this report was to investigate the expression of the p53 and mdm-2 oncoproteins in astrocytic gliomas and to assess their interrelation to proliferating activities. Using monoclonal antibodies directed against p53 and mdm-2, these proteins were stained immunohistochemically in 60 astrocytic brain tumors with different histologic grade. Positive p53 stained nuclei were detected in 25.4% of the tumor cases. Mdm-2 staining products were only localized in 10.5% of specimens. Significant correlations could be found between p53, MIB-1, PCNA and mitotic index on the one hand, and tumor grade on the other hand. There were no clear relations between mdm-2 expression and proliferation markers. The grade of ploidy has a lower priority for the proliferating activity. In most cases mdm-2 immunoreactivity was strongly associated with a low or negative p53 expression.

Astrocytoma↗

PubMedDate not supplied

Mitochondrial tRNA(Cys) mutation A5823G in a patient with motor neuron disease and temporal lobe epilepsy.

We discovered a new homoplasmic mutation in the mitochondrial cysteine tRNA of a 60-year-old Caucasian male suffering from asymmetrical pure lower motor neuron disease (MND) and temporal lobe epilepsy (TLE). Furthermore, titrations with Amytal, an inhibitor of NADH:CoQ oxidoreductase, revealed mild mitochondrial dysfunction in skeletal muscle tissue, which was described in patients with MND in an earlier report. The mutation was undetectable in 155 Caucasian controls of both sexes, in 40 MND patients and in 13 individuals suffering from TLE. It was, however, detected in a heteroplasmic state in the patient's mother, who did not suffer from a neurological disorder. Since this rare mutation affected a nonconserved base position and was not observed in MND or TLE materials, its relation to disease remains unclear.

Blotting, Southern↗

PubMedDate not supplied

Expression of matrix metalloproteinases in a series of 12 meningiomas.

The expression of metalloproteinases was evaluated in a series of 12 meningiomas of various histological subtypes including 3 meningotheliomatous, 3 fibroblastic, 4 transitional and one psammomatous meningioma (WHO grade I) as well as one anaplastic meningioma (WHO grade III). No gelatinolytic activity could be detected in all tumor samples pointing towards no or very low activity of both MMP-2 and MMP-9. At least MMP-2 mRNA could be found in 10 out of 12 tumor samples by the reverse transcription PCR method (RT-PCR) followed by electrophoresis on silver-stained polyacrylamide gels, which allows the detection even of small traces of a specific mRNA. The PCR products were identified as MMP-2 sequences without introns (mRNA-derived) by direct sequencing, thereby demonstrating a low transcriptional activity of the gene. The translation of these mRNAs, however, did not result in amounts of protein detectable by immunohistochemistry or Western blotting. Therefore, neither MMP-2 nor MMP-9 should play a major role for tumor growth within dura mater or bone structures or for brain infiltration in our tumor series. Therefore, other mechanisms must be responsible for extracellular matrix degradation at least in a fraction of meningiomas.

Gene Expression Regulation, Enzymologic↗

PubMedDate not supplied

Mdr1 mRNA expression differs between grade III astrocytomas and glioblastomas.

104 N2-frozen samples from 33 astrocytic tumors previously untreated with cytotoxic drugs have been analyzed for the expression of p-glycoprotein transcripts (mdrl) by RT-PCR using beta2-microglobulin as an internal control. A remarkable variation was observed even within a single tumor in 50% of the cases. Nevertheless, a difference became visible between the groups of anaplastic astrocytomas and glioblastomas. While 78% of the grade 3 astrocytomas contained at least a minimum of 1 sample with a very low mdr1 expression, this was the case only in 23% of the glioblastomas. This supports an earlier observation revealing a positive correlation between tumor grading and the tumor cell fraction stained with the monoclonal antibody JSB1. On the other hand, no major differences were found between the histological groups when the samples with the highest mdr1 expression were selected to represent the individual tumors. Those samples are less informative. They might be derived from tumor regions in which capillaries deliver a larger fraction of the total mRNA pool. No induction of mdr1 was observed in some early astrocytoma or glioblastoma cell cultures even after administration of high concentrations of the drugs ACNU and VM26, often used in glioma therapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Stiff-man syndrome: possible autoimmune etiology targeted against GABA-ergic cells.

We report the case of a female patient, who died at the age of 66 years. Besides an insulin-dependent diabetes mellitus (IDDM) she had developed the clinical symptoms of stiff-man-syndrome (SMS) and harbored autoantibodies against glutamate-decarboxylase (GAD) in blood and liquor. GAD catalyzes the biosynthesis of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). The autopsy revealed typical alterations observed in diabetes mellitus including an incomplete fibrosis of pancreatic Langerhans islets. A decrease of GABA-ergic cells in the cerebellar cortex was observed, and a size reduction of Renshaw cells in the spinal cord. Furthermore, a dilution series of a polyclonal GABA antibody delivered a reduced immunofluorescence in the cerebellum. In skeletal muscle a neurogenic atrophy was observed. As described in literature, the clinical symptoms decayed following clonazepam administration. We suggest that this case including GAD autoantibodies, dramatic loss of GAD-expressing pancreatic cells, and loss or atrophy of GABA secretory neurons, supports the hypothesis that SMS may be an autoimmune disease directed against GABA-ergic cells. Furthermore, we suggest a neuronal hypersensitivity at the spinal cord level caused by the atrophic Renshaw cells.

Aged↗

PubMedDate not supplied

MGMT- and P450 3A-inhibitors do not sensitize glioblastoma cell cultures against nitrosoureas.

UNLABELLED: AIM, MATERIAL AND METHODS: Using RT-PCR and immunohistochemistry the expression of cytochrome P450 was evaluated in a series of 22 glioblastomas and 4 anaplastic astrocytomas (WHO grade III). Since rat liver P450 can catalyze the denitrosation of the nitrosourea compound BCNU in vitro, cell culture experiments were performed to test a possible sensitizing effect of P450 3A inhibitors (tiamulin and ketoconazole) in BCNU treatment of glial tumor cells. O6-benzylguanine (BG), an inhibitor of the DNA repair enzyme O6-methylguanine-DNA-methyltransferase (MGMT), was used in parallel experiments, since MGMT is discussed as a main mechanism in nitrosourea resistance. RESULTS: RT-PCR reactions with primers designed according to the sequences for CYP1A1 and CYP2E1 were always positive, while those for CYP1A2 and CYP2D6 were negative. The strongest PCR products were detected with CYP3A primers, but CYP3A expression was heterogeneous within the tumor samples. Antibodies to human liver CYP3A4 stained a subfraction of tumor cells (18% of the cells in glioblastomas and 14% in grade III astrocytomas) and to some extend neurons in normal brain areas, while astrocytes were negative. For cell culture experiments with P450 3A and MGMT inhibitors, early passages of 3 glioblastomas, a late passage of an immortalized cell line derived from a reoccurring glioblastoma, and the human glioblastoma line LN405 were used. The sensitivity of the tumor cells for both nitrosourea compounds was very low, when low concentrations were applied (comparable to the achievable blood concentrations in glioma patients). Strong effects did only occur when the concentrations were raised 9-fold or 27-fold. CONCLUSION: In no case could a significant sensitizing effect of P450 3A- and MGMT inhibitors be demonstrated.

Antineoplastic Agents↗