STAT-1 expression in human glioblastoma and peritumoral tissue.

BACKGROUND: Glioblastoma is a very aggressive brain tumour with poor prognosis despite radical surgery or radiotherapy. Signal transducers and activators of transcription (STAT) proteins are important elements in intracellular signalling and part of the JAK-STAT pathway. They are activated by growth factors and cytokines and translocate into the nucleus upon activation to exert their function as transcription factors. STAT-1 can be induced by interferons and has also been found to be important in sensitizing tumours to chemotherapeutic drugs. MATERIALS AND METHODS: Forty-six glioblastoma samples have been analysed for the expression of STAT-1 by immunohistochemistry. RESULTS: In our study performed by immunohistochemistry, 22 out of 46 glioblastomas (48%) were strongly positive for staining with a STAT-1 antibody, 9 (20%) showed an intermediate reactivity, 8 (17%) low immunoreactivity, and 7 (15%) were completely negative. In the tumour tissue, STAT-1 expression was mostly localized in the cytoplasm. This location of STAT-1 suggests the predominant presence of an inactive form of STAT-1. Tumour giant cells were frequently strongly stained. Part of the peritumoral brain tissue showed strongly positively reactive glial cells. Interestingly, within the infiltration area strong STAT-1 expression was found in reactive astrocytes, glia, and particularly in microglial components. CONCLUSION: The expression of STAT-1 in the majority of glioblastomas, together with its documented role in apoptosis and in the action of chemotherapeutic drugs on tumour cell lines point to a possible function of this protein in the response of glioblastomas to chemotherapy.

The serotonin-immunoreactive system of the suprachiasmatic nucleus in the hibernating ground squirrel, Spermophilus richardsonii.

In the suprachiasmatic nucleus (NSC) of hibernating and non-hibernating ground squirrels, the distribution of serotonin-immunoreactive (5HT-IR) fibers was studied by the use of the peroxidase-antiperoxidase technique. The cytology of perikarya giving rise to these suprachiasmatic 5HT-IR fibers was investigated in the anterior raphe nuclei. Differences in the immunoreactivity of suprachiasmatic fibers between hibernating and non-hibernating ground squirrels were determined by digital image analysis. The cellular activity was determined by digital image analysis. The cellular activity was determined densitometrically after RNA-staining in anterior raphe neurons and suprachiasmatic perikarya. Abundant 5HT-IR fibers were observed in the medial and ventromedial portions of the NSC. Frequently, the fibers were found in close contact with perikarya of suprachiasmatic neurons. The central portion of the nucleus and the surrounding hypothalamic areas contained only a few scattered 5HT-IR fibers. Inside the raphe nuclei, 5HT-IR fibers and perikarya formed a dense network. In hibernating ground squirrels, the immunoreactivity to serotonin was approximately 45% higher than in non-hibernating controls. This difference is in accordance with signs of higher neuronal activity (40% higher RNA-content, 20% larger cell nuclei) in 5HT-IR perikarya of the raphe nucleus and the persisting activity of the NSC during hibernation; the activity of other brain regions dropped conspicuously in torpid animals.

[Bronchial cyst in the endocardium of the left heart. Case report with review of cardiac heterotopic tissues]. / Bronchiale Zyste im Endokard des linken Herzens. Fallbericht mit Ubersicht über kardiale heterotopien.

Connatal heterotopies are rare accidental findings fore-most without clinical symptoms. The present case report describes an asymptomatic multilocular bronchial cyst of a 72 years old woman which occurred in the left ventricular endocard of the anterior papillary muscle and which was covered with ciliated and occasionally multilayered epithelium. Today the knowledge about these rare cardial heterotopies is important, because they are not only accidental postmortal findings but also the clinical importance is rising as consequence of the improved diagnostic imaging procedures with a high resolution. The histogenesis and the classification of cardial heterotopies is discussed.

[Meningeal melanocytoma]. / Das meningeale Melanozytom.

A 38-year-old man presented with an intracranial extra-axial tumour at the base of the left posterior fossa which proved to be a meningeal melanocytoma. Meningeal melanocytoma is a rare, benign melanotic tumour of the leptomeninges occurring predominantly in the posterior fossa or the upper spinal cord in adults. It shows characteristic cytologic features with isomorphic epitheliod or spindle-shaped cells, often with prominent nucleoli and a variable content of intracytoplasmic melanin. It usually lacks signs of malignancy such as high mitotic rate, necroses or infiltrative growth and shows a low labeling index in proliferation marker studies. Its immunohistological profile with S-100 protein-, vimentin- and HMB-45-positive tumour cells is similar to that of (primary or metastatic) malignant melanoma. This differential diagnosis is crucial because of the totally different therapeutic and prognostic implications. Therefore, everyone dealing with surgical neuropathology should be familiar with the rare, but clinically important diagnosis of meningeal melanocytoma.