Mitsuo Yamaguchi-Okada

Imaging mass spectrometry revealed the production of lyso-phosphatidylcholine in the injured ischemic rat brain

To develop an effective neuroprotective strategy against ischemic injury, it is important to identify the key molecules involved in the progression of injury. Direct molecular analysis of tissue using mass spectrometry (MS) is a subject of much interest in the field of metabolomics. Most notably, imaging mass spectrometry (IMS) allows visualization of molecular distributions on the tissue surface. To understand lipid dynamics during ischemic injury, we performed IMS analysis on rat brain tissue sections with focal cerebral ischemia. Sprague-Dawley rats were sacrificed at 24 h after middle cerebral artery occlusion, and brain sections were prepared. IMS analyses were conducted using matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS) in positive ion mode. To determine the molecular structures, the detected ions were subjected to tandem MS. The intensity counts of the ion signals of m/z 798.5 and m/z 760.5 that are revealed to be a phosphatidylcholine, PC (16:0/18:1) are reduced in the area of focal cerebral ischemia as compared to the normal cerebral area. In contrast, the signal of m/z 496.3, identified as a lyso-phosphatidylcholine, LPC (16:0), was clearly increased in the area of focal cerebral ischemia. In IMS analyses, changes of PC (16:0/18:1) and LPC (16:0) are observed beyond the border of the injured area. Together with previous reports--that PCs are hydrolyzed by phospholipase A(2) (PLA(2)) and produce LPCs,--our present results suggest that LPC (16:0) is generated during the injury process after cerebral ischemia, presumably via PLA(2) activation, and that PC (16:0/18:1) is one of its precursor molecules.

Multifaceted Effects of Selective Inhibitor of Phosphodiesterase III, Cilostazol, for Cerebral Vasospasm after Subarachnoid Hemorrhage in a Dog Model

Background: Selective inhibition of phosphodiesterase type III (PDE III) may be involved in the pathophysiology of vasospasm and a PDE III inhibitor, cilostazol, is thus expected to attenuate vasospasm after subarachnoid hemorrhage (SAH). We tested the therapeutic effects of cilostazol on angiographic and morphological vasospasm. Method: Twenty-one mongrel dogs were divided into 4 groups: (1) control (n = 3); (2) SAH (n = 6); (3) SAH with low-dose treatment (n = 6), and (4) SAH with high-dose treatment (n = 6). We used the established double-hemorrhage model of SAH achieved by injecting autologous blood. Angiography was performed on day 0 and day 7. The animals were euthanized after a second angiogram, and Western blotting was performed to analyze phenotypic changes in smooth muscle cells of the basilar artery. The basilar artery was sectioned for immunohistochemistry of SM1, SM2 and SMemb to analyze phenotypic changes (SM1, SM2 for the contractile type of smooth muscle myosin heavy chain and SMemb for the synthetic type). Intact endothelial cells were counted under a microscope. Results: Severe vasospasm was obtained in the SAH group (42 ± 1%). Cilostazol attenuated angiographic vasospasm in both treatment groups (63 ± 2 and 74 ± 4%, respectively). Prevention of endothelial damage and phenotypic changes in smooth muscle cells were observed in both treatment groups (p < 0.05 vs. control, ANOVA). Conclusion: Cilostazol attenuates vasospasm following SAH in dogs by suppressing phenotypic changes in the basilar artery and preventing endothelial damage. Therefore, we anticipate that cilostazol may be useful in the management of vasospasm.

Endoscopic Endonasal Surgery for Purely Intrathird Ventricle Craniopharyngioma

BACKGROUND Extended endoscopic transsphenoidal surgery (EETS) is a safe and effective treatment for many suprasellar craniopharyngiomas, including those with third-ventricle involvement. Craniopharyngioma entirely within the third ventricle (purely intraventricular type), however, is generally regarded unsuitable for treatment with EETS. CASE DESCRIPTION Three patients underwent total removal of a purely intraventricular craniopharyngioma with inferior extension via EETS by direct incision of the bulging, stretched ventricular floor and fine dissection from the ventricular wall. In 2 patients with an anteriorly displaced chiasm, the space between the chiasm and pituitary stalk created a wide corridor to the ventricle, whereas in the third case, in which the infrachiasmal space was somewhat narrowed, partial sacrifice of the pituitary gland was necessary to obtain sufficient space. Despite preservation of the stalk in 2 patients, hypopituitarism and diabetes insipidus developed after surgery. There was no other complication including obesity. CONCLUSIONS Selected patients with purely intraventricular craniopharyngioma can be treated effectively and safely with EETS. Those with inferior extension in the interpeduncular fossa and anterior displacement of the chiasm may be suitable candidates.

Asymptomatic non-functioning ectopic pituitary adenoma in the suprasellar region: a case report.

Asymptomatic non-functioning ectopic pituitary adenomas (EPAs) are extremely rare. To our knowledge, this is the first case report of an asymptomatic non-functioning EPA in the suprasellar region treated by cranio-orbital skull base surgery. EPAs should be considered in the differential diagnosis and histological confirmation is necessary.

Intraosseous schwannoma of the cervical vertebral body: A case report and review of the literature

Intraosseous schwannomas (IOS) of non-sacral vertebra are extremely rare; only 14 cases were reported previously. We described a case of IOS involving a cervical vertebral body, successfully treated by surgical resection, with a review of the literature and discussion of this extremely rare tumour.

The roles of cross-talk mechanisms in the signal transduction systems in the pathophysiology of the cerebral vasospasm after subarachnoid haemorrhage — what we know and what we do not know

Background We have investigated the role of protein kinase C (PKC) in the mechanism of cerebral vasospasm, and showed the pivotal roles of PKC isoforms (PKCδ and α) in that mechanism. On the other hand, protein tyrosine kinase (PTK) is also activated during the maintenance of cerebral vasospasm. The aim of this study is to clarify the relationship between PKC and PTK activations in the mechanism of cerebral vasospasm, and discuss what we know and what we do not know about the roles of cross-talk mechanisms in the signal transduction systems.

Low-Grade Glioma of the Neurohypophysis: Clinical Characteristics and Surgical Outcomes

BACKGROUND Low-grade glioma (LGG) of the neurohypophysis is an extremely rare tumor arising from the pituicytes of the posterior pituitary or the infundibulum. The preoperative imaging findings of these tumors mimic those of pituitary adenomas, and radical resection is often challenging in affected patients due to the hypervascularity of the tumor. Here we describe the clinical and radiologic features of this clinical entity. METHODS We identified 8 patients with LGG of the neurohypophysis who underwent surgery at Toranomon Hospital between January 2007 and March 2017. We retrospectively reviewed the clinical and radiologic data for these patients. RESULTS The patient cohort comprised 5 men and 3 women, with a mean age of 57 years. The presenting symptoms included visual disturbance in 7 patients and anterior pituitary dysfunction in 7 patients. No patient had diabetes insipidus (DI). Preoperative magnetic resonance imaging (MRI) showed a thick anterior pituitary gland located anterior to the tumor in 3 patients and flow voids on T2-weighted images in 6 patients. All patients underwent transsphenoidal surgery, and gross total resection was achieved in 4 patients. Postoperative morbidities included deterioration of anterior pituitary function in 4 patients and permanent DI in 3 patients. CONCLUSIONS Anterior displacement of a thick anterior pituitary by a tumor combined with evidence of flow voids on preoperative MRI is helpful in the preoperative diagnosis of LGG of the neurohypophysis. Radical resection should be attempted in these tumors, especially during primary surgery, even though it is associated with postoperative pituitary dysfunction.

Clinical characteristics of streptococcus pneumoniae meningoencephalitis after transsphenoidal surgery: three case reports.

We report three extremely rare cases of Streptococcus pneumoniae meningoencephalitis (SPM) after transsphenoidal surgery (TSS). Between 2004 and 2010, we experienced three cases of severe SPM after surgery out of 1,965 patients undergoing TSS (0.15%). The three cases included a 4-year-old boy with a large cystic craniopharyngioma, a 40-year-old man with a non-functioning pituitary adenoma, and a 55-year-old man with acromegaly. The similarity among these SPM patients was that severe clinical events occurred suddenly 1–2 months postoperatively without any history of sinusitis or pneumonia. Despite intensive care these patients notably had residual neurological sequelae. In no case was rhinorrhea associated with SPM. It should be noted that SPM was not detected from bacterial cultures of the sphenoidal sinus mucous membranes (BCSM) obtained during TSS in two of the patients examined. Severe postoperative SPM can occur suddenly without cerebrospinal fluid (CSF) leakage within 2 months after surgery and requires emergency treatment. Reduced resistance to infection may play a role in the occurrence of SPM in our three patients. Our study indicates that BCSM is not useful for predicting postoperative meningitis.

Endoscopic Endonasal Surgery for Subdiaphragmatic Type Craniopharyngiomas

Subdiaphragmatic type craniopharyngiomas are tumors that originate within the sella. They are divided into two types; those localized within an enlarged sella (intrasellar type) and those accompanying a suprasellar extension (suprasellar extended type). The clinicopathological features and the recent outcomes of endoscopic endonasal surgery were retrospectively reviewed in 32 patients, with 11 surgeries for recurrence. These tumors showed a preponderance in young patients (19 patients were younger than 18-year-old) and suprasellar extended type (25 cases), were mostly composed of a large cyst (96.9%) and were frequently adamantinomatous type (68.8%). Combined transcranial-endoscopic endonasal surgery was applied in three patients with extremely large tumors and significant frontal extension. Total tumor resection and stalk preservation were achieved in 26 and 17 patients, respectively. No complications developed after surgery apart from pituitary dysfunction and visual deterioration. 5 of 6 patients with subtotal tumor resection and 6 of 7 patients with no improvement or deterioration of visual function were in the recurrent cases. Although this type is basically an extraarachnoidal tumor, the suprasellar portion of the tumor showed adherence to important tissues in some patients with recurrence. Pituitary function remained normal in only one third of patients with stalk preservation. To avoid pituitary dysfunction after surgery, sharp excision of firm adherence to the stalk should be considered in some patients.

Therapeutic outcomes of transsphenoidal surgery in pediatric patients with craniopharyngiomas: a single-center study

OBJECTIVE The aim of this study was to analyze the outcomes of transsphenoidal surgery (TSS) in a single-center clinical series of pediatric craniopharyngioma patients treated with gross-total resection (GTR). METHODS The authors retrospectively reviewed the surgical outcomes for 65 consecutive patients with childhood craniopharyngiomas (28 girls and 37 boys, mean age 9.6 years) treated with TSS (45 primary and 20 repeat surgeries) between 1990 and 2015. Tumors were classified as subdiaphragmatic or supradiaphragmatic. Demographic and clinical characteristics, including extent of resection, complications, incidence of recurrence, pre- and postoperative visual disturbance, pituitary function, and incidence of diabetes insipidus (DI), as well as new-onset obesity, were analyzed and compared between the primary surgery and repeat surgery groups. RESULTS Of the 45 patients in the primary surgery group, 26 (58%) had subdiaphragmatic tumors and 19 had supradiaphragmatic tumors. Of the 20 patients in the repeat surgery group, 9 (45%) had subdiaphragmatic tumors and 11 had supradiaphragmatic tumors. The only statistically significant difference between the 2 surgical groups was in tumor size; tumors were larger (mean maximum diameter 30 mm) in the primary surgery group than in the repeat surgery group (25 mm) (p = 0.008). GTR was accomplished in 59 (91%) of the 65 cases; the GTR rate was higher in the primary surgery group than in the repeat surgery group (98% vs 75%, p = 0.009). Among the patients who underwent GTR, 12% experienced tumor recurrence, with a median follow-up of 7.8 years, and recurrence tended to occur less frequently in primary than in repeat surgery patients (7% vs 27%, p = 0.06). Of the 45 primary surgery patients, 80% had deteriorated pituitary function and 83% developed DI, whereas 100% of the repeat surgery patients developed these conditions. Among patients with preoperative visual disturbance, vision improved in 62% but worsened in 11%. Visual improvement was more frequent in primary than in repeat surgery patients (71% vs 47%, p < 0.001), whereas visual deterioration was less frequent following primary surgery than repeat surgery (4% vs 24%, p = 0.04). Among the 57 patients without preoperative obesity, new-onset postoperative obesity was found in 9% of primary surgery patients and 21% of repeat surgery patients (p = 0.34) despite aggressive resection, suggesting that hypothalamic dysfunction was rarely associated with GTR by TSS in this series. However, obesity was found in 25% of the repeat surgery patients preoperatively due to prior transcranial surgery. Although there were no perioperative deaths, there were complications in 12 cases (18%) (6 cases of CSF leaks, 3 cases of meningitis, 2 cases of transient memory disturbance, and 1 case of hydrocephalus). Postoperative CSF leakage appeared to be more common in repeat than in primary surgery patients (20% vs 4.4%, p = 0.2). CONCLUSIONS The results of TSS for pediatric craniopharyngioma in this case series suggest that GTR should be the goal for the first surgical attempt. GTR should be achievable without serious complications, although most patients require postoperative hormonal replacement. When GTR is not possible or tumor recurrence occurs after GTR, radiosurgery is recommended to prevent tumor regrowth or progression.