Distribution and biochemical characterization of somatostatin receptors in tumors of the human central nervous system.

Fifty-two brain tumors, consisting of 17 astrocytomas, 4 oligodendrogliomas, 20 glioblastomas, 3 neurinomas, 2 ependymomas, 1 neurofibroma, 1 ganglioneuroblastoma, 1 medulloblastoma, 1 plexus papilloma, 1 teratoma, and 1 germinoma, were tested for their content of specific somatostatin receptors using autoradiographic techniques or in vitro binding assays with membrane homogenates. Somatostatin receptors were found in most of the differentiated glia-derived tumors such as astrocytomas and oligodendrogliomas whereas the poorly differentiated glioblastomas were usually free of receptors. Tumors originating from neuroblasts, i.e., ganglioneuroblastoma and medulloblastoma, contained a high density of somatostatin receptors, whereas neurinomas and neurofibromas as well as the ependymomas, one teratoma, and one plexus papilloma were lacking such receptors. In one germinoma, low amounts of somatostatin receptors were observed over the lymphocytic elements. Receptor-positive tumors had saturable and high affinity receptors with pharmacological specificity for somatostatin and somatostatin analogues resembling that of normal human central nervous system tissue. In most instances, they could be labeled with two different iodinated radioligands, a somatostatin octapeptide derivative (204-090) or a somatostatin-28 analogue. This is the first time that somatostatin receptors have been shown to exist not only on neuronal structures of the central nervous system but also on glial elements. The precise function of such somatostatin receptors on glial cells, which may be different from neurotransmission, remains to be determined.

Brain glycoprotein in tumours of the nervous system.

We studied various tumours of the nervous system by the immunofluorescence technique using an anti-brain specific alpha 2 glycoprotein antiserum (anti-NSA3 antiserum). We found the antigen in 24/27 astrocytomas and 4/4 oligodendrogliomas but in none of the 8 meningiomas tested. There was an identity between the astrocytoma/oligodendroglioma antigen and that of normal brain as shown by the immunoprecipitation technique. By the immunofluorescence technique using inhibition of the antiserum we demonstrated that the tumour antigen is devoid of some specific nervous system determinants present in normal brain.

Immunohistochemical recognition of ethylnitrosourea induced rat brain microtumors by anti-Leu 7 monoclonal antibody.

This immunocytochemical study was undertaken to clarify the histogenesis of ethylnitrosourea-induced rat brain tumors. The tumors induced in offspring of Sprague-Dawley rats injected with ethylnitrosourea on day 18 of gestation were used in these experiments. Controls consisted of pregnant Sprague-Dawley rats similarly injected with saline alone. Both microtumors (less than 1 mm) and macrotumors were examined immunocytochemically. The cells present in both macro- and microtumors were reactive with anti-Leu 7, an antibody which recognizes oligodendrocytes. Intermixed with, but distinct from the tumor cells were glial fibrillary acidic protein positive cells morphologically identical to astrocytes found in other areas distant to tumors in the treated animals, and in controls. These data suggest that both early and late tumors are oligodendrogliomas, not astrocytomas or mixed gliomas, and that the cell of origin of the tumor is the oligodendrocyte rather than an uncommitted stem cell as previously suggested.

Estimation of chemical composition and density from computed tomography carried out at a number of energies.

A method is presented by whichcomputed tomography scans carried out at a number of energies may be utilized to obtain cross-sectional images of density and atomic number in addition to the conventional array of linear attenuation coefficients. This type of analysis has been carried out for various substances of biological relevance. Computer simulated reconstructions of clinical situations suggest that the method shows promise for providing additional diagnostic information and might dispense to some extent with the necessity of injecting contrast agents into the patient.

Calmodulin content in human brain tumors.

Using a radioimmunoassay method, the particulate and soluble calmodulin levels were determined in biopsied specimens from normal human brain and from various human brain tumors. Both in normal and pathological tissues the major portion of calmodulin was revealed in the cytosol. The chromatographic elution profiles of calmodulin obtained from soluble and particulate fractions of the same specimen were identical, thus suggesting an identity of the supernatant and particulate form of calmodulin. In all the examined oncotypes, the calmodulin content was lower than in normal extracts and this biochemical feature could not have been correlated with the degree of malignancy of the neoplasia. Furthermore, the translocation of calmodulin from the particles to the cytoplasm, reported in other rapidly growing tumors, lacks in human cerebral ones. Our findings indicate that in human brain oncotypes the calmodulin distribution is quite different from that found in tumors taken from other tissues, where its level is increased and a positive correlation between calmodulin concentration and growth rate of neoplastic tissue has been revealed.

Mixed oligodendroglioma and astrocytoma: fine structural and immunohistochemical studies of four cases.

Four mixed oligodendrogliomas and astrocytomas were investigated by electron microscopy and immunohistochemistry (GFAP, NSE and MBP). GFAP-positive oligodendroglioma cells and their transitional cells to GFAP-negative oligodendroglioma cells were present, suggesting successive morphological changes of astrocytic tumor cells. NSE-positive cells, suggestive of residual neurons, also exhibited round nuclei and perinuclear halos. On electron microscopy, oligodendroglioma cells that showed glial filaments, vascular end-feet and zonulae adherentes were occasionally present. The tumor cells with or without astrocytic characteristics showed common features of cytoplasmic organelles. These findings suggest that most oligodendroglioma cells in mixed gliomas are of an astrocytic nature and that characteristic microscopic features of oligodendroglioma are of a common cellular form that can be taken by various types of cells under certain circumstances.

The distribution of nuclear DNA from human brain-tumor cells.

Flow cytometry (FCM) is a technique that measures the quantity of DNA contained in individual nuclei and records a frequency distribution of the DNA content per nucleus in the sampled cell population. Nuclei from a variety of human brain-tumor types were isolated by means of tissue grinding, purified by centrifugation through 40% sucrose (15 minutes at 4000 rpm), fixed with 10% formalin, stained with acriflavin-Feulgen, and analyzed by FCM. Profiles of DNA distribution in histologically benign tumors, such as meningiomas, pituitary adenomas, neuroblastomas, and low-grade astrocytomas, revealed a large diploid population (2C) with a few nuclei in DNA synthesis, as well as a small premitotic population (G2 cells) that contains a 4C DNA complement. In contrast, malignant gliomas, including glioblastomas, consist of more cells in DNA synthesis; these tumor cells show a highly variable distribution of ploidy consisting not only of diploid, and/or aneuploid, but also of triploid, tetraploid, and possibly octaploid populations. Also, a large variability between different regions of each tumor was always observed. In contrast, metastatic brain tumors, despite the fact that they contain a considerable number of cells undergoing DNA synthesis, demonstrate little variability within each individual tumor. The ability to rapidly characterize the cell populations of human brain tumors with FCM may enhance the effectiveness of their clinical management.

Glial fibrillary acidic protein (GFAP) in oligodendrogliomas: a reflection of transient GFAP expression by immature oligodendroglia.

Fourteen pure oligodendrogliomas were studied by light- and electronmicroscopy and immunohistochemistry to examine glial fibrillary acidic protein (GFAP) positivity in the tumors. To compare the immunohistochemical staining patterns of neoplastic oligodendroglia and immature oligodendroglia, myelination glia in the white matter of eight normal brains from children under 6 months of age were studied. The tumors possessed light microscopic and ultrastructural features characteristic of oligodendrogliomas. Microtubules were found in the cytoplasm of nine tumors on electronmicroscopy. In one, intermediate filaments and microtubules were observed in occasional tumor cells with polygonal crystalline structures in the cytoplasm. Using the peroxidase-antiperoxidase technique, all specimens were stained for GFAP, vimentin, S-100 and neuron-specific enolase (NSE). In nine tumors, variable numbers of cells with an oligodendroglial morphology reacted positively for GFAP. All tumors were positive for S-100 and negative for vimentin and NSE. The myelination glia in the eight normal brains stained positively for GFAP but not for vimentin. Vimentin is expressed by developing, reactive and neoplastic astrocytes. Thus, GFAP positivity combined with vimentin negativity in both neoplastic and immature oligodendroglia suggests that GFAP positivity in oligodendrogliomas may reflect the transient expression of this intermediate filament by immature oligodendroglia.

GFAP in brain tumor diagnosis: possibilities and limitations.

Investigation of GFAP (Glial Fibrillary Acidic Protein) in 175 brain tumours showed varying amounts of fibrillary acidic protein in every glioma. In ependymal and oligodendroglial tumours a high number of positive neoplastic elements were detected, GFAP positive were also the peri-vascular cells of a so-called astroblastoma. In pilocytic astrocytomas, Rosenthal fibers were in part GFAP positive, in part negative. In giant cells gliomas, giant cells were GFAP negative or weakly positive. Intraleptomeningeal growing tumour cells presented usually a very strong positivity. In 8 recurring oligodendrogliomas, the number of GFAP positive tumour cells was the same in the primary tumour and in its recurrence. These results demonstrate that GFAP is not a specific astrocytic, but a glial-specific protein. Although GFAP is usually present in greater concentration in differentiated, slow growing gliomas, absolute reliable predictions on biological behaviour of the individual tumour are not possible, because a high GFAP content can be detected also in malignant tumours. GFAP investigation does not seem reliable for solving the pathogenetic problems of undifferentiated tumours: the results obtained in 50 medulloblastomas showed that the investigation of small tumour samples or the positivity of a single cell are inadequate data for a correct evaluation of the findings, especially bearing in mind that GFAP of degenerated astrocytes can be phagocytised by other cells, these findings giving rise to misinterpretations.

Flow-cytophotometry of nuclear DNA in biopsies of 45 human gliomas and after primary culture in vitro.

DNA distribution in biopsies and cell cultures of human gliomas was examined by flow-fluorescence-cytometry using ethidium bromide staining. Glioblastomas (n = 25) showed "polyploid", "marked tetraploid", or "hypertetraploid" aneuploid karyograms, comparable to subtypes previously proposed by Japanese authors. "Diploid-hyperdiploid" DNA patterns were manifest in 3 cases plus 1 sarcoma--glioblastoma, containing abundant rapidly growing mesenchymal cells. Most tumors showed S-phase increment. "Near-diploid" patterns could be a result of aggregated cells, and small 4 C peaks could be due to non-representative specimens (3 cases). During cultivation, the DNA distribution usually remained stable, but maxima occasionally shifted. Oligodendrogliomas (n = 11) and astrocytomas (n = 9) of low-grade showed low 4 c peaks. High-grade gliomas, however, showed abnormal DNA patterns. Thus, one case of an oligodendroglioma--I developed an abnormal "marked tetraploid" glioblastoma after a 3-year interval presenting its malignant transformation. DNA distribution can obviously vary during tumor evolution. However, it may well support the assessment of grading and more closely define the prognosis in gliomas.

Ether-linked glycerolipids in human brain tumors.

In this investigation, the lipid composition of a number of human brain tumors was determined and compared to that of normal adult brain. Glioblastomas (11 samples), astrocytomas (4 samples), an acoustic neurinoma, an oligodendroglioma, and a meningioma were analyzed. All of the tumors had substantial levels (0.8-3.4% of total phospholipids) of choline plasmalogen which was present in only trace amounts in normal brain. With the exceptions of the acoustic neurinoma and the meningioma, the concentration of alkylacylglycerophosphorylcholine was also higher in the tumors than in normal brain. Neutral lipids of brain tumors also contained high concentrations of both alkyl (1.6-4.8% of total neutral gsults from this investigation indicate that increases in ether-linked glycerolipids may be characteristic of human brain tumors.

Na+/K+ ATPase and cell growth IV: a metabolic marker of human brain tumors?

The activity of total, Mg++ dependent and Na+/K+ ATPase as well as the content of cAMP and cGMP in homogenates of human brain tumors have been investigated. Results are compared to values obtained from normal cortices. Na+/K+ ATPase and cAMP are decreased with a close relationship with the degree of malignancy, while Mg++ dependent activity is lower than in normal cortex but with no differences between the various tumors, and cGMP is unaffected. We conclude with a discussion on the metabolism of brain tumors and the suggestion of Na+/K+ ATPase activity as a marker of the malignancy of neoplastic growth.

[Cell proliferation and glial fibrillary acidic protein in brain tumors]. / Zellproliferation und Expression des sauren Gliafaserproteins (GFAP) in Hirntumoren.

The results of histoautoradiographic and immunohistochemical studies of biopsy specimens of 15 brain tumours are reported. The specimens were labeled with 3H-thymidine using an in vitro technique. Meningiomas, oligodendrogliomas and well differentiated astrocytomas showed a median S-phase fraction of about 1%. In contrast, the labeling indices of 4 from 7 anaplastic astrocytomas were higher (2.1, 3.0, 3.5, 11.4). With increasing degree of malignancy the proliferative heterogeneity of the tumours increases. In every glioma varying amounts of glial fibrillary acidic protein (GFAP) were detected immunohistochemically (PAP technique). In 3 high-grade gliomas (2 glioblastomas, 1 anaplastic astrocytoma) an inverse relation of the investigated parameters (high S-phase fraction, low GFAP expression) was found. An exact prediction on biological behaviour of an individual tumour by GFAP detection immunohistochemically is not possible, because a high GFAP content can be detected also in some malignant tumours. However, the 3H-thymidine labeling indices of viable parts of the tumours, probably reflecting the growth fraction seem to be clinically important parameters, especially in respect to the prognosis.

[Clinicopathological study of oligodendroglioma with special reference to immunohistochemical investigation].

The present study was undertaken to evaluate the utility of pathologic features and specific immunohistochemical studies in estimating the prognosis of oligodendroglioma. The pathological diagnosis of an oligodendroglioma was made on HE stained-sections according to WHO classification. Sixteen oligodendrogliomas, twelve mixed oligoastrocytomas and ten anaplastic oligodendrogliomas were immunotested by the peroxidase-antiperoxidase (PAP) method with anti-GFAP serum, anti-S-100 serum and anti-MBP (Myelin basic protein) serum and by the avidin biotin peroxidase-complex (ABC) method with anti-vimentin serum and ant-Leu 7 monoclonal antibody. GFAP positive cells were interpreted as reactive astrocytes, neoplastic astrocytes and neoplastic oligodendrocytes, S-100 positive cells were interpreted as reactive astrocytes and neoplastic astrocytes. Leu 7 positive cells were found in only one case of anaplastic oligodendroglioma. Anti-Leu 7 could not be considered as a specific marker for oligodendroglioma. Of the anaplastic oligodendroglioma 60% displayed MBP positively and 70% displayed vimentin positively. NSE positive cells were found in a few anaplastic oligodendrogliomas. The present study has not so far uncovered any marker that is restricted to oligodendrogliomas. However GFAP may be useful to assess the extent of reactive astrocytes and neoplastic astrocytes in the oligodendroglioma or mixed oligoastrocytoma. MBP and vimentin will help to determine the malignancy of oligodendroglioma.

[MBP and GFAP immunohistochemistry of oligodendrogliomas with relationship to myelin-forming glia in cell differentiation].

The histologic feature of oligodendroglioma is constituted by the monotonously arranged sheets of tumor cells intersected with delicate vascular stroma. The shape of the tumor cells is usually uniform and occasionally rather pleomorphic. In order to clarify biological characteristics of the tumor cells at level of cell differentiation, immunohistochemical stains for myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) with PAP method were performed on 13 oligodendrogliomas obtained by surgical removal. The cells stained positive with MBP immunostain were encountered in 5 tumors and their incidence was ranging from 1% to more than 30% of all tumor cells. The MBP-positive cells were characterized by having a large clear nucleus with a prominent nucleolus and relatively abundant cytoplasm, that seemed to mimic myelin-forming glia appearing in normal developing brain. The cells with poor cytoplasm or surrounded by a perinuclear halo were MBP-negative, and the pleomorphic cells in majority of anaplastic oligodendrogliomas were also negative. On the other hand, with GFAP stain the positive cells were observed in 8 tumors. It is still controversial to interpret the occurrence of GFAP-positive cells in oligodendrogliomas. In this study the GFAP-positive cells were morphologically identical to the MBP-positive cells, so that both MBP and GFAP are supposed to exist in the same tumor cells. It is assumed that some of oligodendroglioma cells which showed such immunostainabilities could possess an intrinsic character to express a phenotype of myelin-forming glia. Possibly, MBP substance is applicable as one of immunohistochemical markers for oligodendroglioma cells to indicate a certain cell differentiation.

[Factors affecting the prognosis of brain tumors].

A variety of tumors with different histologic types are included in a group of brain tumors. Although each histologic type of tumor has its own range of malignancy, the prognosis seems to be affected by several clinical, histologic and cell-biological factors. For example, relative survival rate of patients with glioblastoma is lower if the patient is older than 50 or 60 years. The leptomeningeal dissemination of glioma cells is a sign of poor prognosis. The presence of necrotic foci in the astrocytic tumors suggests shorter astrocytic tumors suggests shorter survival. Using a monoclonal antibody to bromodeoxyuridine (BrdU), the growth activity of the tumor can be estimated by BrdU labeling index (BrdU-LI, %). Higher BrdU-LI is correlated with more malignant histologic features in astrocytic tumors. In meningiomas, higher BrdU-LI is correlated with a more frequent or rapid recurrence of the tumor. The significance of growth factor receptors and oncogene of growth factor receptors and oncogene products as a cell-biologic marker of malignancy was investigated with an immunohistochemical method. Transferrin receptor was demonstrated in all tumors, and epidermal growth factor in about 40% of astrocytic tumors. The immunoreaction to c-myc oncogene product was detected in most astrocytic tumors; with higher intensity in anaplastic astrocytomas and glioblastomas than in low-grade astrocytomas. The role of these markers in the prognosis of brain tumors is, however, still unclear. Total or subtotal resection of glioblastoma results in longer resection of glioblastoma results in longer survival. Both postoperative radiotherapy and chemotherapy are effective. However, maintenance of chemotherapy longer than longer than 2 years does not significantly improve the prognosis.

[Relation between the protein composition of glial tumors and various clinico-morphologic indices]. / Zavisimost' belkovogo sostava glial'nykh opukholei ot nekotorykh kliniko-morfologicheskikh pokazatelei.

The work was concerned with the study of 57 gliomas, among which were 30 glioblastomas, 20 astrocytomas, and 7 oligodendrogliomas. Specimens collected from 26 patients who underwent operation for severe craniocerebral trauma, meningioma, and carcinoma metastasis were examined as controls. The proteins of the tumor tissues and those of the brain matter surrounding the tumor and of normal brain matter were fractionated in polyacrylamide gel. It was found that the amount of water soluble protein, both in the total protein content and in all its fractions, was much greater in the glial tumors than in normal brain matter. The effect of 11 factors on the tissue protein composition was studied by factor analysis. The histological structure and extent of vascularization of the tumor as well as the presence of intracranial hypertension were found to produce the highest effect on the fractional distribution of the proteins.