PubMed Health⌕ Search

Biomedical subjects

Yoko Nakasu

Publications and source records attributed to Yoko Nakasu.

6 recordsLinked to original sources
PubMed2006

Pituicytoma. Two case reports.

Pituicytoma is a rare tumor in the sellar or suprasellar region with distinct histological characteristics of glial neoplasm. A 42-year-old woman presented with a history of amenorrhea and vertigo, and a 62-year-old woman presented with mild headache. Both patients had mild hyperprolactinemia and one had mild anterior pituitary dysfunction. They underwent transcranial partial resection of a suprasellar tumor. The tumors were characterized by storiform pattern of elongated cells immunoreactive for S-100 protein and glial fibrillary acidic protein. Ultrastructural study showed abundant cytoplasmic intermediate filaments and tumor/blood vessel basal lamina, but no desmosomes between tumor cells. The residual tumors showed no changes in size without adjuvant therapy at 56 and 18 months after surgery. Pituicytoma is a glial neoplasm of adults with low proliferative activity. Patients often present with visual symptoms or anterior pituitary dysfunction. Symptoms and signs of neurohypophysis are rare. Neuroimaging reveals an intra- or suprasellar mass with non-specific features. The prognosis and role of adjuvant therapy remain unclear for this discrete noninfiltrative glioma.

Adult↗
PubMed2004

Ectopic growth hormone-releasing adenoma in the cavernous sinus--case report.

A 55-year-old woman presented a rare ectopic pituitary adenoma in the right cavernous sinus manifesting as acromegaly. The tumor was removed via transsphenoidal approach. Intraoperative observation showed the adenoma was located entirely within the right cavernous sinus, and separated from the normal pituitary gland by the medial wall of the cavernous sinus. There was no communication between the tumor and the pituitary. Histological examination showed a growth hormone-releasing adenoma. Including our case, only eight of 86 reported ectopic adenomas have occurred in the cavernous sinus. Such ectopic presentation may be responsible for failed transsphenoidal surgery for endocrinologically active tumors.

Acromegaly↗
PubMed2004

Tissue plasminogen activator levels after single intracisternal injection in patients with subarachnoid hemorrhage.

Tissue plasminogen activator (tPA) levels were investigated in the cisternal fluid of patients with subarachnoid hemorrhage treated with single intracisternal injection of recombinant tPA during radical surgery for ruptured aneurysms. Seven patients received different doses of tPA: two of 400 microg/ml, three of 500 microg/ml, one of 700 microg/ml, and one of 800 microg/ml in a total amount of 20 ml distilled water at pH 7. Cerebrospinal fluid samples were taken directly from the cisternal fluid at 15-minute incubation after injection, immediately after irrigation during surgery, and by lumbar tap 2 days after surgery. Cisternal tPA levels decreased to about 60% of the mean injected doses after 15-minute incubation. Simple linear regression analysis showed these tPA levels after incubation correlated with the initial doses. After copious irrigation with Ringer solution at pH 8, tPA levels decreased rapidly without correlation with the initial doses. After spinal drainage for 2 days, tPA levels further decreased by an order of 10(-4) to 10(-6) from the initial dose. These values were still greater than normal controls. The final values of tPA levels were not related to the initial dose. None of the patients suffered from systemic or wound complications. Cisternal tPA injection with increased doses and irrigation may be beneficial for the selective rapid removal of blood clots with controllable safety.

Adult↗
PubMed2003

Immunohistochemical proliferation markers may overestimate the growth potential after ionizing radiation: in vivo study in the rat anterior pituitary gland.

The effect of ionizing radiation on the expression of immunohistochemical proliferation markers was examined in the rat pituitary gland. Rats were irradiated in the pituitary region with a dose of 40 Gy, or were sham-irradiated as controls. Bromodeoxyuridine (BrdU) was given to the rats after one week, either one hour (Br-1 group) or 17 hours (Br-17 group) before perfusion fixation. Immunohistochemical staining for BrdU, topoisomerase II-alpha (TopoII), Ki-67 (MIB-5), p21WAF1/Cip1 (p21), and p27Kip1 (p27) was performed. Apoptotic cells were detected by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling method. The mean BrdU labeling index (LI) and MIB-5 LI were significantly higher in the irradiated rats than in the sham rats in the Br-1 group. TopoII LI was higher in the irradiated rats than in the sham rats, although not significantly. p27-positive cells decreased in irradiated rats, but p21-positive cells increased more than in the sham rats. The number of apoptotic cells increased significantly after radiation. BrdU LIs were lower in the irradiated rats than in the sham rats in the Br-17 group. A few small BrdU-positive fragments with apoptotic features were phagocytosed in the anterior lobe cells. These results indicate that some "immunohistochemically proliferating cells" subsequently undergo apoptosis in the irradiated pituitary gland. The values of proliferative indices should be cautiously interpreted after irradiation of tissue.

Animals↗