Mao Takei

Expression of Neuro D1 in Human Normal Pituitaries and Pituitary Adenomas

Many transcription factors have important roles in the function and differentiation of the human pituitary adenomas. Forkhead box gene transcription factor L2, Foxl2, is expressed during mouse pituitary development and co-localizes with the expression of α-glycoprotein hormone subunit (αGSU). In addition, Foxl2 regulates expression of the αGSU gene (Cga) in cell culture. To elucidate the functional role of FOXL2 in the human pituitary, we examined the expression and localization of FOXL2 in normal human pituitaries and various types of pituitary adenomas. Human pituitary adenomas were obtained by trans-sphenoidal surgery from 67 patients. Three normal adult pituitaries were obtained from autopsies of non-endocrine cases. The localization of FOXL2 and pituitary hormones in these pituitary patients was examined by immunohistochemical staining and RT–PCR. Quantitative analysis of FOXL2 protein was performed by immunoblotting. FOXL2 was localized in the nuclei of ∼20% of normal pituitary cells that also co-expressed gonadotropins including follicule-stimulating hormone β (FSHβ), luteinizing hormone β (LHβ), and αGSU, whereas it was observed in minor proportion of thyroid-stimulating hormone (TSH)-producing cells, prolactin (PRL)-producing cells, and precursor of adrenocorticotropic hormone (ACTH)-producing cells. FOXL2 immunoreactivity was not detected in growth hormone (GH)-producing cells or S100-positive folliculo-stellate cells. In human pituitary adenomas, FOXL2 was expressed in the nuclei of the adenoma cells. FOXL2 was detected in 13 of 15 gonadotropin-subunit-producing adenoma (Gn-oma) cases and 8 of 11 null cell adenoma cases, but its incidence was reduced or not detected in the other types of adenomas. The results of this study suggest that FOXL2 contributes to the human-specific functional expression and the differentiation of gonadotroph cells and adenomas.

Expression of Wnt4 in Human Pituitary Adenomas Regulates Activation of the β-Catenin-Independent Pathway

The Wnt signaling pathway has been implicated in the genesis of numerous human cancers. A member of the Wnt family of genes, Wnt4, has been known to regulate proliferation of anterior pituitary cell types in the mouse during embryonic development. In order to elucidate the roles of Wnt signaling in human pituitary adenomas, we examined the expression of Wnt4 and its putative receptor Frizzled6 (Fzd6) by immunohistochemistry in pituitary adenomas and normal pituitaries. Expression of Wnt4 was higher in growth hormone-producing adenomas (GHomas), prolactin-producing adenomas (PRLomas), and thyroid-stimulating hormone-producing adenomas (TSHomas) than in the normal pituitary. Fzd6 was widely expressed in GHomas, PRLomas, TSHomas, and gonadotropin subunit (GnSU)-positive adenomas. In normal pituitary glands, Wnt4 and Fzd6 were colocalized predominantly in follicle-stimulating hormone-, luteinizing hormone-, and α-subunits of glycoprotein hormone-positive cells. The canonical Wnt/β-catenin signaling pathway was analyzed by β-catenin immunohistochemistry. β-Catenin was localized at the cell membrane in all pituitary adenomas, but not in the nuclei. On the other hand, Erk1/2 was highly activated in GHomas and TSHomas. These results suggested that activation of Wnt4/Fzd6 signaling through a “β-catenin-independent” pathway played a role in proliferation and survival of the pituitary adenoma cells. Detailed involvement of transcription factors including Pit-1 remains to be further investigated.

Selection of buffer pH by the isoelectric point of the antigen for the efficient heat-induced epitope retrieval: re-appraisal for nuclear protein pathobiology

Epitope retrieval (ER) using heating causes a dramatic improvement in the sensitivity of immunohistochemistry for formalin-fixed paraffin-embedded (FFPE) tissue sections. Here, the relationship between the pH of the retrieval buffer used for heat-induced epitope retrieval (HIER) and the isoelectric points (pI) of the antigen recognized by antibodies against nuclear proteins (mainly human pituitary transcription factors in this study) was investigated using FFPE tissue sections. A universal buffer, with a buffering capacity over a wide pH range from 2.0 to 12.0, was used for HIER. We found that the intensity of staining for most nuclear proteins after HIER depended simply on the pH of the buffer. Importantly, for efficient HIER, antigens with acidic pI required basic pH buffer conditions, while antigens with alkaline pI required acidic conditions. This implies that the electrostatic charge of the antigens contributed significantly to the efficiency of HIER. We conclude that appropriate selection of the pH of the buffer based on the pI of the individual antigens is of great importance for efficient ER. It is concluded that the mechanism of HEIR may, therefore, depend to a large extent on the pI of the antigen under investigation.

Expression of pituitary tumour-derived, N-terminally truncated isoform of fibroblast growth factor receptor 4 (ptd-FGFR4) correlates with tumour invasiveness but not with G-protein alpha subunit (gsp) mutation in human GH-secreting pituitary adenomas

Objective  Apart from the constitutively activating mutation of the G‐protein alpha subunit (Gsα) (gsp mutation), factors involved in tumorigenesis or those in tumour behaviour remain elusive in sporadic GH‐secreting pituitary adenomas. Recently, the N‐terminally truncated form of fibroblast growth factor receptor‐4 (ptd‐FGFR4) was identified in pituitary adenomas. This aberrant receptor has transforming activity, and causes pituitary adenomas in transgenic mice. The clinical relevance of this receptor warrants investigation. Our objective was twofold: first, to examine how the expression of ptd‐FGFR4 relates to gsp mutations; and second, to see whether patients with this receptor have unique clinical characteristics.

Blood patch therapy for spontaneous intracranial hypotension: safe performance after epidurography in an unconscious patient.

IMPLICATIONS Epidurography was useful for identifying the epidural space and determining the likely spread of an epidural blood patch in an unconscious patient with spontaneous intracranial hypotension.

Retroperitoneal Hematoma as a Serious Complication of Endovascular Aneurysmal Coiling

Retroperitoneal hematoma (RH) due to radiologic intervention for an intracranial lesion is relatively rare, difficult to diagnose, and can be life-threatening. We report a case of RH that developed in a patient on anticoagulant therapy following endovascular coiling of a ruptured anterior communicating artery (AcoA) aneurysm. An 82-year-old man presented with a 12-day history of headache. Computed tomography (CT) on admission demonstrated slight subarachnoid hemorrhage, and left carotid angiography revealed an AcoA aneurysm. The next day, the aneurysm was occluded with coils via the femoral approach under general anesthesia. The patient received a bolus of 5,000 units of heparin immediately following the procedure, and an infusion rate of 10,000 units/day was initiated. The patient gradually became hypotensive 25 hours after coiling. Abdominal CT showed a huge, high-density soft-tissue mass filling the right side of the retroperitoneum space. The patient eventually died of multiple organ failure five days after coiling. RH after interventional radiology for neurological disease is relatively rare and can be difficult to diagnose if consciousness is disturbed. This case demonstrates the importance of performing routine physical examinations, sequentially measuring the hematocrit and closely monitoring systemic blood pressures following interventional radiologic procedures in patients with abnormal mental status.

Evidence that PKA activity is constitutively activated in human GH‐secreting adenoma cells in a patient with Carney complex harbouring a PRKAR1A mutation

Context  The GHRH–protein kinase A (PKA) signalling pathway is essential for cell proliferation and GH synthesis/secretion in somatotrophs. An inactivating mutation of PRKAR1A is one of the causes of somatotrophinoma in Carney complex (CNC). The basal PKA activity of somatotroph adenoma cells from CNC has not been evaluated because of a limited amount of available tissue.

Sellar Chondroma with Endocrine Dysfunction that Resolved after Surgery: Case Report

Chondromas originating from the sella turcica are rare, and the most common initial symptoms are headache and visual disturbance. We describe a case of sellar chondroma with endocrine impairment as an initial manifestation that completely resolved after surgery. A 40-year-old Japanese woman with amenorrhea and galactorrhea for the last 2 years was referred to our department of neurosurgery for the evaluation of high prolactin levels and a tumor in the sella turcica. A biochemical assessment indicated endocrine dysfunction. Magnetic resonance imaging and computed tomography indicated a tumor in the sella turcica. The patients presentation favored the preoperative diagnosis of pituitary adenoma or Rathkes cleft cyst. However, because calcification was detected, other types of tumors, such as craniopharyngioma, meningioma, and chordoma, were also considered. Endoscopic transsphenoidal surgery was performed, and the possibility of a bony tumor was recognized. Finally, the tumor was completely removed, and the histopathological findings confirmed chondroma. The postoperative course was uneventful, and endocrine function improved. Five years after surgery, the patient is doing well without pituitary insufficiency, pituitary hormone medications, or signs of tumor recurrence. In cases of sellar chondroma, endocrine dysfunction sometimes precedes other symptoms, such as headache and visual disturbance. When examining a patient with an intrasellar tumor harboring calcification, clinicians must consider the possibility of sellar chondroma. Furthermore, to the best of our knowledge, this case is the first of sellar chondroma treated with endoscopic surgery to be reported.