The role of dopamine agonist treatment in corticotroph pituitary tumors is controversial. The aim of this study was to evaluate D(2) receptor expression in 20 corticotroph pituitary tumors and to correlate it to the in vitro effect of dopamine agonists on ACTH secretion and the in vivo effect of short-term cabergoline treatment on cortisol secretion. D(2) expression was evaluated by receptor-ligand binding, immunohistochemistry, and RT-PCR. A 50% or more decrease in daily urinary cortisol levels was considered a significant clinical response. At receptor-ligand binding, specific binding of [(125)I]epidepride was found in 80% of cases. At immunohistochemistry, specific D(2) immunostaining was found in 75% of cases. D(2) expression was found in 83.3% of cases (D(2long) in 40%, D(2short) in 20%, and both in 40%) by RT-PCR. Significant in vitro inhibition of ACTH secretion was found in 100% of D(2)-positive cases, but not in 100% of D(2)-negative cases by either bromocriptine or cabergoline. A significant in vivo inhibition of cortisol secretion after 3-month cabergoline treatment was found in 60%, although a normalization of cortisol secretion was found in 40% of cases. All cabergoline-responsive cases were associated with D(2) expression, whereas all noncabergoline-responsive cases but one were not associated with D(2) expression. In conclusion, functional D(2) receptors were expressed in approximately 80% of corticotroph pituitary tumors. The effectiveness of cabergoline in normalizing cortisol secretion in 40% of cases supports its therapeutic use in the management of Cushing's disease.
The endoscopic endonasal transsphenoidal approach has been proposed in the past decade as a minimally invasive surgical technique for the removal of pituitary tumors. From January 1997 to November 1999, 100 consecutive patients with pituitary tumors underwent endoscopic endonasal surgery, according to Jho's technique. We employed 0 degrees, 30 degrees, 45 degrees, and 70 degrees rigid endoscopes, 18 - 30 cm in length, 4 mm in diameter with an outer sleeve for irrigation and secured to a holder. Among the 87 pituitary adenomas, tumor removal was total in 51, subtotal (> 80 %) in 20 and partial in 16 cases. Four craniopharyngiomas were totally removed and an intra-suprasellar arachnoid cyst was emptied; a biopsy was performed in the two patients with a clivus chordoma. The two cases of sphenoid sinusitis were cured by surgery, the three patients with spontaneous CSF rhinorrhea were successfully treated and the residual nasal meningocele was removed. The endoscopic endonasal transsphenoidal approach appeared to be less traumatic than the traditional microsurgical approach, was very effective, and was characterized by a reduced number of complications. However, the relatively small series together with the short follow-up do not allow us to draw definitive conclusions. The post-operative reduction in hospital stay (two days in 40 of 100), significantly reduced the cost of patient's management.
Glioblastoma is the most frequent brain tumor in adults and is the most lethal form of human cancer. Despite the improvements in treatments, survival of patients remains poor. In order to identify microRNAs (miRs) involved in glioma tumorigenesis, we evaluated, by a miRarray, differential expression of miRs in the tumorigenic glioma LN-18, LN-229 and U87MG cells compared with the non-tumorigenic T98G cells. Among different miRs we focused our attention on miR-221 and -222. We demonstrated the presence of a binding site for these two miRs in the 3′ untranslated region of the protein tyrosine phosphatase μ (PTPμ). Previous studies indicated that PTPμ suppresses cell migration and is downregulated in glioblastoma. Significantly, we found that miR-221 and -222 over-expression induced a downregulation of PTPμ as analyzed by both western blot and real-time PCR. Furthermore, miR-222 and -221 induced an increase in cell migration and growth in soft agar in glioma cells. Interestingly, the re-expression of PTPμ gene was able to revert the miR-222 and -221 effects on cell migration. Furthermore, we found an inverse correlation between miR-221 and -222 and PTPμ in human glioma cancer samples. In conclusion, our results suggest that miR-221 and -222 regulate glioma tumorigenesis at least in part through the control of PTPμ protein expression.
Symptomatic treatment with conventional antiepileptic and antimyoclonic drugs.
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