Pauli Helén

Neuropeptide Y (NPY)-like immunoreactivity in rat sympathetic neurons and small granule-containing cells

The distribution of neuropeptide Y-like immunoreactivity (NPY-LI) was examined in the rat superior cervical and hypogastric ganglia. NPY-LI was localized in the majority of the sympathetic neurons, a few small granule-containing (SGC) cells and nerve terminals. Most of the NPY-immunoreactive sympathetic neurons were also tyrosine hydroxylase (TH)-immunoreactive but in hypogastric ganglia few neurons with NPY-LI were devoid of TH-immunoreactivity. Electron microscopically NPY-LI was found in the Golgi complexes of sympathetic neurons, in large cytoplasmic granules (100-150 nm in diameter) of the SGC cells and in large dense-cored vesicles (80-100 nm in diameter) of the nerve terminals. NPY-LI coexists mainly with noradrenaline in sympathetic neurons, and may have regulatory functions in sympathetic ganglia and in target organs.

INCREASED EXPRESSION OF PERIPHERAL BENZODIAZEPINE RECEPTORS AND DIAZEPAM BINDING INHIBITOR IN HUMAN TUMORS SITED IN THE LIVER

The peripheral benzodiazepine receptor system triggers intracellular metabolic events and has been associated with cell proliferation. Its endogenous ligand, the diazepam binding inhibitor, contributes to steroidogenesis by promoting cholesterol delivery to the inner mitochondrial membrane. The present study was undertaken to verify whether this system is altered in tumors sited in the liver. Peripheral benzodiazepine receptors and diazepam binding inhibitor were studied using immunocytochemistry and in situ hybridization in 9 human tumors sited in the liver, in liver hyperplasia, cirrhotic nodular regeneration, intestinal adenocarcinoma and in surrounding non-tumoral tissue. Immunocytochemical staining and in situ hybridization demonstrated that peripheral benzodiazepine receptors and diazepam binding inhibitor were more prominently expressed in neoplastic cells than in non-tumoral tissue. They were present in the same cells, suggesting that diazepam binding inhibitor may act in an intracrine manner in these cells. Higher peripheral benzodiazepine receptors and diazepam binding inhibitor expression in tumor cells suggest an implication of this system in the metabolism of neoplastic cells. Furthermore the evaluation of peripheral benzodiazepine receptor and diazepam binding inhibitor expression might be useful in evaluating malignancy and in diagnostic approaches of tumors in liver tissue.

CDKN2/p16 predicts survival in oligodendrogliomas: comparison with astrocytomas.

Cyclin-dependent kinase 4 inhibitor (CDKN2/p16) is a cell cycle regulatory protein that has been demonstrated to be inactivated by mutations, deletions or transcriptional silencing during pathogenesis of a variety of human malignancies. We studied the correlation of CDKN2/p16 expression with cell proliferation activity and patient survival in 42 oligodendrogliomas and 36 astrocytomas. CDKN2/p16 expression was frequently decreased in grade II and anaplastic oligodendrogliomas (17/42) where lack of CDKN2/p16 protein predicted poor survival (p=0.0045). In astrocytomas low CDKN2/p16 expression was associated with high histologic malignancy grade (p=0.002): CDKN2/p16 protein level was decreased in 9 out of 10 glioblastomas, in 5 out of 9 anaplastic astrocytomas, in 3 out of 10 grade II astrocytomas and in none of pilocytic astocytomas (0/7). Low CDKN2/p16 expression was also associated with high cell proliferation activity (MIB-1 immunocytochemistry: p=0.004; mitotic index: p=0.007) and poor patient survival (p=0.025) in astrocytomas. Low CDKN2/p16 mRNA expression had the same topographic distribution as nuclear CDKN2/p16 immunoreactivity proving for reliability of the immunocytochemical findings. Our results are in agreement with earlier studies demonstrating CDKN2/p16 inactivation during tumorigenesis of astrocytic tumors. Furthermore, our findings suggest that loss of CDKN2/p16 expression may also play an important role in the progression of oligodendrogliomas. According to our findings CDKN2/p16 immunocytochemistry could be used as a tool to identify those oligodendrogliomas and low grade astrocytomas that are likely to progress and have poor outcome, and thus would need more aggressive therapy.

Localization of [Met5]- and [Leu5]-enkephalin-like immunoreactivity in nerve terminals in human paravertebral sympathetic ganglia

Abstract Both [Leu 5 ]- and [Met 5 ]-enkephalin have been localized immunohistochemically in nerve fibres and in small, intensely fluorescent cells of adult human sympathetic ganglia. The nerve fibres showing enkephalin-like immunoreactivity formed a network varying in density around the sympathetic neurons, some being closely related to the perikarya. No labelled neuronal cell bodies were found. No structures within the ganglion were labelled after reaction with antibodies to vasoactive intestinal polypeptide, adrenocorticotrophin or substance P. No differences between the distributions of [Leu 5 ]-and [Met 5 ]-enkephalin-like immunoreactivities were found. The physiological roles of enkephalins are still unknown, but it is possible that they might act as neurotransmitters or neuromodulators in the human sympathetic nervous system.

Electron-microscopic localization of enkephalin-like immunoreactivity in axon terminals of human sympathetic ganglia

SummaryThe peroxidase-antiperoxidase method was applied to demonstrate enkephalin-like immunoreactivity in the human sympathetic ganglia. A network of immunoreactive fibres was found in light microscopy between the nonreactive neurons. Electron microscopy showed immunostaining to be restricted to axonal profiles containing both large and small vesicles. The strongest reaction was associated with large vesicles.

Cyclin D1 expression in astrocytomas is associated with cell proliferation activity and patient prognosis.

An important positive regulator of the cell cycle, cyclin D1, is often amplified and overexpressed in malignancies. Cyclin D1 aberrations were analysed in grade II–IV astrocytomas by fluorescence in situ hybridization (FISH), mRNA in situ hybridization and immunohistochemistry. Proliferation activity was determined by Ki‐67MIB‐1 immunolabelling and mitotic counting. High cyclin D1 expression was observed in grade IV astrocytomas (grades II–III versus grade IV; mRNA expression: p < 0·001; immunoexpression: p = 0·013), and correlated with poor patient survival (p < 0·001, n = 46). Upregulated cyclin D1 expression was also closely associated with poor patient prognosis in grade II–III astrocytomas (p < 0·001, n = 30). Cyclin D1 gene was not found to be amplified (n = 7). Cell proliferation activity was significantly increased in tumours exhibiting high cyclin D1 mRNA levels (Ki‐67MIB‐1: p < 0·001; mitotic count: p < 0·001) and high cyclin D1 protein expression (Ki‐67MIB‐1: p = 0·002; mitotic count: p = 0·012). These results indicate that increased production of cyclin D1 is closely associated with high cell proliferation activity and aggressive behaviour in diffusely infiltrating astrocytomas. Copyright

Cancer incidence in families with multiple glioma patients

Twenty‐four Finnish families with 2 or more glioma patients were identified through questionnaires sent to 369 consecutive glioma patients receiving surgery at Tampere University Hospital during 1983–94. To explore whether unusual cancer susceptibility is involved, the cancer risk of 2,664 family members was estimated using population‐based data from the Finnish Cancer Registry. Among the total cohort of relatives, 88 cancers were observed during 1953–97. The overall cancer risk among 12 families with juvenile onset gliomas was significantly decreased (standardized incidence ratio [SIR] 0.6, 95% confidence interval [CI]: 0.4–0.9). Among 12 families with adult onset gliomas, the overall cancer risk was equal to that of the reference population (SIR 1.1, 95% CI: 0.8–1.4) whereas the risk of skin melanoma (SIR 4.0, 95% CI: 1.5–8.8) and meningioma (SIR 5.5, 95% CI: 1.1–16) were significantly increased. Several other tumors, including those associated with neurofibromatosis 1 and 2, tuberous sclerosis and Li‐Fraumeni and Turcot syndromes were surveyed, but no elevated risks were observed. In conclusion, the presence of meningiomas and skin melanomas in glioma families may indicate a novel association as a cancer susceptibility trait.

Analysis of p53 tumor suppressor gene in families with multiple glioma patients.

The high incidence of gliomas in Li–Fraumeni families and the high frequency of somatic p53 mutations in sporadic glial tumors have raised the possibility that germline p53 mutations could play an important role in familial aggregation of gliomas. In the present study, 18 families with two or more gliomas were screened for germline p53 mutation. The families were identified through questionnaires sent to 369 consecutive glioma patients operated at Tampere University Hospital during 1983–1994. In these families, a family history of cancer was verified through the Finnish Cancer Registry. Interestingly, the questionnaires revealed only 15 of 57 cancers (index gliomas excluded) retrieved through the Cancer Registry. None of the 18 families fulfilled the criteria for classic Li–Fraumeni syndrome. Immunostaining analysis of p53 protein accumulation suggested that alterations of the p53 gene are as common in familial as in sporadic gliomas. Sequencing analysis of exons 4–10 of the p53 gene revealed no germline mutations in any of the 18 families. Thus, although occasional glioma families carrying germline p53 mutations have been identified in earlier studies, systematic evaluation of familial glioma patients suggests that the p53 gene is not a common susceptibility gene in case of familial gliomas. The p53 tumor suppressor gene seems to have a similar role in the tumorigenesis of most familial and sporadic gliomas.

Chromosome imbalances in familial gliomas detected by comparative genomic hybridization

Familial occurrence of gliomas, in the absence of well‐defined hereditary multisystem disorders, is reported occasionally. We describe 17 families that have been afflicted with two or more gliomas but do not raise suspicion of other inheritable syndromes. The families were identified among 369 consecutive glioma patients operated at the Tampere University Hospital during 1983–1994. We applied comparative genomic hybridization (CGH) analysis on 21 gliomas occurring in these 17 families. The most frequent genetic alterations, detected in over 20% of the tumors, were losses of 6q, 10, 4q, 9p and gains of 7, 19, 20q, 1p. We compared the chromosomal alterations detected in the familial gliomas to those reported previously on 209 sporadic gliomas in nine different CGH studies. In this comparison, the familial gliomas more often showed losses of chromosome arms 4q and 6q and gains of 1p and 22q. The most frequent losses (9/21 tumors) in the familial gliomas resided on chromosome arm 6q (P = 0.005, Fishers exact test; with Bonferroni correction, P = 0.04). The loss of 6q was also the most common intrafamilial aberration, present in four separate gliomas belonging to two families. The minimal common area of loss on this chromosome resided at 6q14–16. In conclusion, we have found several characteristic aberrations by CGH in the familial gliomas and we present new chromosomal regions possibly involved in the familial predisposition to gliomas.

Somatostatin-like immunoreactivity in human sympathetic ganglia

SummaryThe localization of somatostatin-like immunore-activity (SOM-LI) was examined in human lumbar sympathetic ganglia using the peroxidase-antiperoxidase method. Few of the principal neurons showed immunolabelling for somatostatin and sparse networks of nerve terminals were unevenly associated with ganglion cells. Using light microscopy, the most intense SOM-LI was seen in the perinuclear zone of the neurons. Electron-microscopically, the staining was localized on the membranes of the Golgi apparatuses. In the nerve terminals, SOM-LI was seen inside the small vesicles (40–60 nm diameter). All neurons with SOM-LI were also found to be tyrosine-hydroxylase immunoreactive when excamined with a double-staining technique. These results provide evidence that somatostatin and noradrenaline co-exist in human sympathetic neurons.