Biomedical subjects
Publications and source records attributed to Masaki Niiro.
In rat-cultured astrocytes, pituitary adenylate cyclase-activating polypeptide (PACAP) activates gene expression and secretion of C-type natriuretic peptide (CNP) in a dose- and time-dependent manner. These results suggest that PACAP might be involved in the regulation of CNP biosynthesis in astrocytes.
OBJECT: The authors reviewed angiograms obtained in patients with cavernous malformations to identify and characterize coexisting venous drainage. METHODS: Fifty-seven patients with cavernous malformations treated at the authors' institutions between 1994 and 2002 were classified into three groups according to the venous system adjacent to the malformation on angiography studies. In Group A patients (23 patients) the malformations had no venous drainage; in Group B patients (14 patients) the lesions were associated with typical venous malformations; and in Group C patients (20 patients) the lesions had atypical venous drainage (AVD). The risk of hemorrhage based on the type of associated venous drainage was analyzed, and the usefulness of magnetic resonance (MR) imaging compared with digital subtraction (DS) angiography in demonstrating associated AVD was determined. Fifty-seven patients harbored 67 cavernous malformations: Group A patients had 29 cavernous malformations with no associated venous drainage; Group B patients had 17 lesions associated with venous malformations; and Group C patients harbored 21 lesions, 20 of which manifested AVD. Symptomatic hemorrhage was present in 10 (43.5%) of 23 Group A patients and in 28 (82.4%) of 34 Groups B and C patients. Although high-resolution MR imaging revealed the presence of associated venous malformations in 11 (78.6%) of 14 Group B patients, such studies demonstrated AVD in only two (10%) of 20 Group C patients. CONCLUSIONS: Patients harboring cavernous malformations plus venous malformations or AVD are more likely to present with symptomatic hemorrhage than are patients with cavernous malformation alone. The actual incidence of associated venous drainage may be underestimated when MR imaging alone is used rather than combined with DS angiography.
Regarding glioblastoma, there has been controversy over whether a large number of infiltrating macrophages act as anti-tumor effectors or not. It has been exhibited that intratumoral lipid environments have a possible influence on anti-tumor immunity. Necrosis of glioblastoma and non-necrotic tissues of astrocytic tumors were analyzed to compare the amount of free docosahexaenoic acid (DHA) content. The apoptosis inducible effects of DHA on macrophages derived from peripheral blood monocytes and cultured glioma cells were evaluated by flow cytometry. The influence of DHA on the anti-tumor effects of macrophages was assessed at 0, 30, 60, and 90 mM of DHA by (51)Cr releasing assay and MTT assay. The mean concentration of free DHA in necrotic tissues (757.6 mmol/kg) was 5 times higher than that in non-necrotic tissues (147.2 mmol/kg). The DHA concentration of 30 mM induced apoptosis in macrophages, however, glioma cells were not affected even at a DHA concentration of 60 mM. Macrophages pre-exposed to DHA for 24 h decreased the cytotoxicity to U251MG cells as shown by (51)Cr releasing assay. Total viability of co-cultured macrophages and U251MG cells showed an increase at high concentrations of DHA (60 and 90 mM) according to 24 h MTT assay, although each separate culture did not. The DHA concentration in necrosis of glioblastoma was sufficient for macrophages to cause apoptosis and suppress their anti-tumor effects. The results suggest that liberated DHA in necrosis can induce apoptosis in macrophages and inhibit their functions.
The authors report on a 52-year-old woman with a cerebellar hemangioblastoma who presented with a 2-year history of intractable hiccups. Computerized tomography scans and magnetic resonance images revealed a cerebellar hemangioblastoma with compression of the brainstem at the level of the medulla oblongata. The patient has been free of hiccups and has been neurologically intact since the day after total removal of the tumor. A review of the literature on medullary lesions presenting with intractable hiccups is provided.
We report an infant with a huge arachnoid cyst of the posterior fossa with dysplasia of the cerebellar tentorium and meningeal sinus and associated juvenile polyposis. Neuroimaging studies disclosed a huge median cystic lesion extending posterosuperiorly over the cerebellum. The cerebellar tentorium was raised to the parietal area; the vermis was normoplastic. Cystography showed no direct communication with the 4th ventricle or subarachnoid space. We discuss the differential diagnosis of median cysts of the posterior fossa and the association of juvenile polyposis.
OBJECTIVE AND IMPORTANCE: Desmoplastic infantile gangliogliomas (DIGs) are extremely rare tumors that respond well to treatment. However, their biological behavior remains to be clarified. We describe two patients whose DIGs spontaneously regressed after surgery, without adjuvant therapy. CLINICAL PRESENTATION: A 9-month-old girl presented with left hemiparesis, and a 6-month-old boy presented with increasing head circumference. For both patients, neuroimaging demonstrated a huge cystic tumor that included a solid portion and was widely attached to the dura. Gadolinium-diethylenetriamine penta-acetic acid produced strong enhancement. INTERVENTION: One patient underwent partial and the other subtotal tumor removal. Histologically, both tumors were diagnosed as DIGs. Postoperatively, the residual tumors were monitored without adjuvant therapy, and both regressed in several months. CONCLUSION: Our experience suggests that DIGs may include a subgroup of tumors with a tendency for spontaneous regression, possibly attributable to the induction of apoptosis.
A 28-year-old man presented with progressive mental deterioration. Thirteen years earlier he had undergone radiation therapy for a pineal germinoma. Neuroimaging showed a homogeneously enhanced mass lesion along the ventricular wall. The cerebrospinal fluid (CSF) level of human chorionic gonadotropin (HCG) was high. Endoscopic biopsy revealed that the tumor was a two-cell pattern germinoma. The diagnosis was germinoma with syncytiotrophoblastic giant cells (STGC). He first received three cycles of chemotherapy with carboplatin and etoposide and then two cycles with ifosfamide, cisplatin, and etoposide. Subsequently, the tumor size decreased markedly and the CSF level of HCG returned to normal. However, he died 22 months after the recurrence. Histological verification and measurement of tumor markers are necessary for the optimum treatment of germ cell tumors. Adequate initial chemotherapy and long-term follow up are essential for patients with germinoma with STGC.
A 7-year-old boy presented with acute onset of left hemiparesis and headache, followed by disturbance of consciousness. Neuroimaging studies showed pontine hemorrhage. Surgery was performed to remove a massive hematoma. Histological examination of the wall revealed anaplastic astrocytoma. Postoperative radiation therapy and several types of chemotherapy were administered. However, the tumor recurred and he died 9 months after onset. Hemorrhagic onset of pontine glioma is rare and carries an extremely poor prognosis.
A 6-year-old boy presented with mental disturbance and progressive left hemiparesis. Magnetic resonance imaging demonstrated large intracranial mass lesions with ring-like enhancement. His neurological condition deteriorated rapidly. Open biopsy via craniotomy was performed under the suspicion of tumor. Histological examination showed massive demyelination and axon preservation, but no tumor cells. The diagnosis was myelinoclastic diffuse sclerosis (MDS). He was treated with high-dose methylprednisolone and improved dramatically. MDS is a rare demyelinating disorder of the central nervous system that affects mainly children and may mimic a brain tumor. MDS must be included in the differential diagnosis in young patients with a brain tumor with atypical radiological appearance.
Tissue factor (TF) is a cell-surface glycoprotein responsible for initiating the extrinsic pathway of coagulation; this is inhibited by tissue factor pathway inhibitor (TFPI). As TF reportedly regulates tumor growth and angiogenesis, we investigated the role of TF in meningioma. Using immunohistochemical methods, we studied the expression of TF, TFPI, MIB-1 labeling index in 44 meningiomas to determine whether those factors reflect histological grade and proliferative ability. CD31 and CD68 immunostaining was used to assess vascular density and macrophage infiltration, respectively. Additionally we assessed the influence of TF on meningioma cell proliferation by MTT assay. TF was expressed in 1 of 34 (2.9%) benign, 1 of 5 (20%) atypical, and all of 5 anaplastic meningiomas. TFPI was detected in 2 benign (5.9%), 1 atypical (20%), and 3 (60%) anaplastic meningiomas. Both TF and TFPI expression was significantly correlated with the MIB-1 labeling index (LI). However, neither TF nor TFPI showed a correlation with vascular density. The density of tumor-associated macrophages was not correlated with TF or TFPI immunoreactivity. MTT assay revealed that TF increased the proliferation of meningioma cells. Although some macrophages expressed TF, a great number of the TF immunopositive parenchymal cells in the meningiomas were tumor cells. The present study suggest that the TF system reflects the proliferative ability and malignancy of meningiomas.