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Summary. p21/WAF1 blocks cell cycle progression through inhibition of cyclin/cyclin-dependent kinases (cdks) complexes and, simultaneously, has been associated with cell cycle exit and the process of differentiation. In this series, the expression of p21/WAF1 was assessed immunohistochemically in 47 cases of pituitary adenomas in relation to endocrine activity and cell proliferation. To evaluate cell proliferation, a monoclonal antibody, MIB-1, against Ki-67 antigen was used in all of the available cases. The study revealed positive p21/WAF1 staining in 24 cases of 26 functioning parenchymas, whereas 14 cases of 21 non-functioning parenchymas stained negative. The MIB-1 index ranged from less than 1% to 5.1% (mean: less than 1.7%) in functioning adenomas, and from less than 1% to 3.6% (mean: less than 1.6%) in non-functioning adenomas. Regardless of endocrine activity, p21/WAF1 positivity did not correlate with the MIB-1 index. Double staining techniques revealed the co-expression of p21/WAF1/GH or p21/WAF1/PRL in functioning adenomas. In 22 cases of p21/WAF1-positive functioning adenomas, p21/WAF1 immunoreactivity was seen in the cytoplasma as well as nuclei. These results indicate that in pituitary adenomas, p21/WAF1 expression is associated with endocrine activity, but not with cell proliferation. Taken together with recent findings demonstrating that cytoplasmic p21/WAF1 acts as an inhibitor of apoptosis, it is possible that pituitary adenomas expressing cytoplasmic p21/WAF1 have resistance against DNA-damaging agents such as ionizing radiation. [ABSTRACT FROM AUTHOR]

Many factors have been suggested as possible mechanisms for the development of peritumoural oedema in meningioma. Venous compression by the tumour is thought to be one factor, but reports presenting a direct relationship between venous compression and the formation of oedema are rare. We have recently observed 6 meningioma patients in whom venous stasis contributed to peritumoural oedema. The stasis was due to Venous compression and stasis seem to be related not only to the formation of peritumoural oedema but also to the occurrence of haemorrhagic infarction after the resection of meningiomas. [ABSTRACT FROM AUTHOR]

Describes a case of orbital syndrome after a vestibular schwannoma surgery via the middle fossa approach. Claim that the cause of the orbital syndrome was the blockage of the venous drainage from the orbit into the cavernous sinus; Suggestion that other factors such as jugular compression might lead to intracranial venous distention contributing to the stasis of flow at the right superior ophthalmic vein.