Masanori Sasaki - Academia.edu (original) (raw)

Papers by Masanori Sasaki

Journal of the neurological sciences, Jan 15, 2018

Recurrence is inevitable in glioblastomas (GBMs) and requires multifactorial processes. One of th... more Recurrence is inevitable in glioblastomas (GBMs) and requires multifactorial processes. One of the factors that cause recurrence is the strong migratory capacity of GBM cells. We recently reported that actin, alpha, cardiac muscle 1 (ACTC1) could serve as a marker to detect GBM migration in clinical cases. This study aimed to clarify whether the knockdown of highly expressed ACTC1 can inhibit the migratory capacity of cells in the GBM cell line. ACTC1 expression was examined using immunocytochemistry and droplet digital polymerase chain reaction. The motility of GBM cells that were either treated with siRNA to knock down ACTC1 or untreated were investigated using a time-lapse study in vitro. The relatively high ACTC1 expression was confirmed in a GBM cell line, i.e., U87MG. The ACTC1 expression in U87MG cells was significantly inhibited by ACTC1-siRNA (p < 0.05). A cell movement tracking assay using time-lapse imaging demonstrated the inhibition of U87MG cell migration by ACTC1 k...

World neurosurgery, Jan 5, 2018

SERPINA1 plays an anti-inflammatory role in protecting tissues from proteolytic mechanisms. SERPI... more SERPINA1 plays an anti-inflammatory role in protecting tissues from proteolytic mechanisms. SERPINA1 is positive in gliomas by immunohistochemical analysis; however, the role of SERPINA1, including the relationship with prognosis, has been uncertain. In recent years, digital polymerase chain reaction (PCR) has provided ultra-sensitive assessment of messenger RNA expression from formalin-fixed paraffin-embedded (FFPE) tissues. In this study, we quantitatively determined the expression of SERPINA1 in high-grade gliomas (HGGs) using digital PCR, and we analyzed its relationship with prognosis. Twenty-nine FFPE surgical samples from patients with HGGs (7 of World Health Organization [WHO] grade III and 22 of WHO grade IV), and human glioblastoma cell lines, U87 and U118, were used for analysis. A qualitative assessment using immunostaining and quantitative assessment using digital PCR were performed to assess the expression of SERPINA1. The expression of SERPINA1 was demonstrated in gli...

Epilepsy research, Jan 14, 2018

Status epilepticus (SE) causes neuronal cell death, aberrant mossy fiber sprouting (MFS), and cog... more Status epilepticus (SE) causes neuronal cell death, aberrant mossy fiber sprouting (MFS), and cognitive deteriorations. The present study tested the hypothesis that systemically infused mesenchymal stem cells (MSCs) reduce epileptogenesis by inhibiting neuronal cell death and suppressing aberrant MFS, leading to cognitive function preservation in a rat model of epilepsy. SE was induced using the lithium-pilocarpine injection model. The seizure frequency was scored using a video-monitoring system and the Morris water maze test was carried out to evaluate cognitive function. Comparisons were made between MSCs- and vehicle-infused rats. Immunohistochemical staining was performed to detect Green fluorescent protein (GFP)MSCs and to quantify the number of GAD67and NeuNneurons in the hippocampus. Manganese-enhanced magnetic resonance imaging (MEMRI) and Timm staining were also performed to assess the MFS. MSC infusion inhibited epileptogenesis and preserved cognitive function after SE. Th...

Biochimica et biophysica acta, Jan 20, 1974

The Journal of Toxicological Sciences, 2012

The relationship between methylmercury (MeHg) exposure and aquaporin (AQP) expression in the brai... more The relationship between methylmercury (MeHg) exposure and aquaporin (AQP) expression in the brain is currently unknown. To investigate this, we used a common marmoset model of acute MeHg exposure to examine AQP1, AQP4 and AQP11 gene expression. MeHg (1.5 mg Hg/kg/day p.o.) was given to three marmosets for 14 days, followed by 14 days without. All treated marmosets showed slight akinesia before sacrifice. In the frontal lobe, occipital lobe and cerebellum, total mercury concentrations following MeHg administration were 26.7, 31.4, and 22.6 µg/g, respectively. Slight apoptosis was observed in the occipital lobe. Immunohistochemistry showed increased expression of glial fibrillary acidic protein, its mRNA and Iba1 with MeHg, indicating that neuronal injury activated astrocytes and microglia. There was no significant difference between control and MeHg-administered groups in AQP1 protein or AQP11 mRNA in the frontal lobe, occipital lobe or cerebellum. The ratio of AQP4 mRNA expression in MeHg-administered marmosets to the mean AQR4 expression in the controls (n = 3) were 1.3, 1.5 and 1.2, 1.7, 1.9 and 1.5, and 1.5, 1.6 and 1.2 for the frontal lobe, occipital lobe and cerebellum, respectively. Western blotting showed significantly increased AQP4 protein in the occipital lobe and cerebellum with MeHg administration, but no obvious up-regulation in the frontal lobe. Immunofluorescence analysis with double staining revealed low AQP4 expression in the cell body of reactive astrocytes in the MeHg-administered group. These results indicate that AQP4 expression might be stimulated by MeHg exposure in astrocytes in the occipital lobe and cerebellum, suggesting a role for AQP4 in MeHg neurotoxicity via astrocyte dysfunction.

Environmental Toxicology and Pharmacology, 2014

Methylmercury Neurotoxicity Phosphorylation a b s t r a c t The molecular mechanisms mediating me... more Methylmercury Neurotoxicity Phosphorylation a b s t r a c t The molecular mechanisms mediating methylmercury (MeHg)-induced neurotoxicity are not completely understood. Because myristoylated alanine-rich C kinase substrate (MAR-CKS) plays an essential role in the differentiation and development of neuronal cells, we studied the alteration of MARCKS expression and phosphorylation in MeHg-induced neurotoxicity of neuroblastoma SH-SY5Y cells and in the rat brain. Exposure to MeHg induced a decrease in cell viability of SH-SY5Y cells, which was accompanied by a significant increase in phosphorylation and a reduction in MARCKS expression. Pretreatment of cells with a protein kinase C inhibitor or an extracellular Ca 2+ chelator suppressed MeHg-induced MARCKS phosphorylation. In MARCKS knock-down cells, MeHg-induced cell death was significantly augmented in comparison to control siRNA. In brain tissue from MeHg-treated rats, MAR-CKS phosphorylation was enhanced in the olfactory bulb in comparison to control rats. The present study may indicate that alteration in MARCKS expression or phosphorylation has consequences for MeHg-induced neurotoxicity. (M. Shiraishi).

CHEMICAL & PHARMACEUTICAL BULLETIN, 1987

Archives of Environmental Contamination and Toxicology, 2012

The in vivo and in vitro pharmacokinetics of mercury (Hg) were compared between methylmercury chl... more The in vivo and in vitro pharmacokinetics of mercury (Hg) were compared between methylmercury chloride (MeHg·Cl) and methylmercury cysteine (MeHg-Cys) using rats and Caco2 cells because humans can be exposed to MeHg compounds through dietary fish. The in vivo pharmacokinetics of Hg immediately after the digestion of MeHg compounds are still obscure. In Caco2 cells, membrane uptake and subcellular distribution of MeHg compounds were examined. When rats received it intravenously, MeHg·Cl showed 20-fold greater plasma and 2-fold greater blood concentrations of Hg than MeHg-Cys, indicating that their pharmacokinetic properties are different. One hour later, however, Hg concentrations in plasma and blood became virtually identical between MeHg·Cl and MeHg-Cys, although blood Hg concentrations were &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;100-fold greater than those in plasma. When administered into the closed rat&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s jejunum loop, MeHg·Cl and MeHg-Cys were rapidly and efficiently taken up by intestinal membranes, and Hg was retained in intestinal membranes for a relatively long time. When administered orally, no difference was observed in plasma and blood Hg concentrations between MeHg·Cl and MeHg-Cys: plasma and blood Hg concentrations increased gradually and reached steady levels at 8 h after administration. In Caco2 cells, uptake of MeHg-Cys was significantly suppressed by L-leucine, although this was not seen with MeHg·Cl. In Caco2 cells, 81 % of Hg was recovered from cytosol fractions and 13 % of Hg from nuclear fractions (including debris) after a 2-h incubation with MeHg-Cys. In conclusion, the mechanism of membrane uptake and volume of distribution in the initial distribution phase were clearly different between MeHg·Cl and MeHg-Cys. However, such pharmacokinetic differences between them disappeared 1 h after intravenous and after oral routes of administration, possibly due to the metabolism in the body.

European Urology Supplements, 2015

Journal of neurosurgery, Jan 15, 2016

OBJECTIVE Glioma is a major class of brain tumors, and glioblastoma (GBM) is the most aggressive ... more OBJECTIVE Glioma is a major class of brain tumors, and glioblastoma (GBM) is the most aggressive and malignant type. The nature of tumor invasion makes surgical removal difficult, which results in remote recurrence. The present study focused on glioma invasion and investigated the expression of actin, alpha cardiac muscle 1 (ACTC1), which is 1 of 6 actin families implicated in cell motility. METHODS mRNA expression of ACTC1 expression was analyzed using quantitative real-time polymerase chain reaction (qRT-PCR) in 47 formalin-fixed, paraffin-embedded glioma tissues that were graded according to WHO criteria: Grade I (n = 4); Grade II (n = 12); Grade III (n = 6); and Grade IV (n = 25). Survival was analyzed using the Kaplan-Meier method. The relationships between ACTC1 expression and clinical features such as radiological findings at the time of diagnosis and recurrence, patient age, Karnofsky Performance Scale status (KPS), and the MIB-1 index were evaluated. RESULTS The incidence o...

Neurosurgical review, Jan 19, 2016

Arteriovenous malformations (AVMs) are congenital abnormal vessels that shunt blood directly from... more Arteriovenous malformations (AVMs) are congenital abnormal vessels that shunt blood directly from the arterial to the venous system without a capillary bed. The underlying pathology of AVMs is not fully understood. The objective of the study was to determine the association between the expression patterns of tissue factor (TF) and interleukin-6 (IL-6) in AVMs with clinical and pathological findings. Eighteen cases of sporadic AVM with operative specimens were included in this study. The expression of messenger RNA (mRNA) of TF and IL-6 was assayed, and association with clinical factors was investigated. The distribution of TF and IL-6 was examined with immunofluorescence. The mRNA expression of TF was significantly higher in AVM specimens than in control tissues (P = 0.002) and significantly higher in the symptomatic group than in the asymptomatic group (P = 0.037). The mRNA expression of IL-6 was likewise significantly higher in AVM specimens than in control tissues (P = 0.038). Ex...

Acta neurochirurgica, 2016

The use of distal filter protection alone is associated with a high risk of ischemic complication... more The use of distal filter protection alone is associated with a high risk of ischemic complications when vulnerable carotid stenosis is treated by carotid artery stenting (CAS). Double balloon protection, a combination of distal balloon protection and proximal balloon occlusion, can be utilized. We assessed the outcome and complications of the double balloon protection method for vulnerable carotid stenosis. Among 130 patients who underwent CAS from 2009 to 2014, we enrolled the following patients: those whose target lesion was vulnerable as evaluated by MRI, i.e., a signal ratio of plaque to posterior cervical muscle on T1-weighted images before CAS of ≥1.5, and those who underwent diffusion-weighted imaging (DWI) studies within 48 h after the procedure. Ninety patients were enrolled. We investigated DWI findings of the double balloon protection group compared with those of the simple distal balloon protection and distal filter protection groups. Sixty-four patients (71 %) underwent...

Liu/Toxicology of Mercury, 2011

Plast Reconstr Surg, 2005

Journal of Toxicological Sciences, Nov 30, 1994

Teratogenesis Carcinogenesis and Mutagenesis, 1998

Pregnant rats were treated with a single intravenous or oral administration of indium chloride (I... more Pregnant rats were treated with a single intravenous or oral administration of indium chloride (InCl 3 ) on day 9 of pregnancy and their fetuses were examined for growth and malformation on day 20 of pregnancy. By intravenous administration, fetal weight was significantly decreased and the incidences of fetal mortality and malformation were significantly increased at 0.4 mg In/kg. Fetal malformations of the tail and digits, e.g., kinked tail, brachyury, and oligodactyly, were observed at high incidences. By oral administration, similar tendencies in the fetal effects were observed, but there were no significant differences compared to the control even at 300 mg In/kg. Indium concentrations in the serum of pregnant rats showed low bioavailability of indium by oral administration. It was concluded from these results that indium showed teratogenicity in rats. Oral treatment with indium may be developmentally toxic at 300 mg In/kg, but this is difficult to state with certainty given the limited number of animals that were used in this study.

Head Neck J Sci Spec Head Nec, Jul 1, 1999

Carbohydrate antigens in cancer cells are considered to be involved in the binding of cancer cell... more Carbohydrate antigens in cancer cells are considered to be involved in the binding of cancer cells to the endothelium during metastasis. Seventy cases of primary oral squamous cell carcinoma (SCC) were obtained from biopsy specimens and were analyzed immunohistochemically using an antibody against sialyl Lewis (Le)a or sialyl Le(x). Flow cytometry was performed to detect the sialyl Le(a) or sialyl Le(x) expressed on oral SCC cell lines. The expressions of sialyl Le(a), but not sialyl Le(x), of primary tumors significantly correlated to nodal metastasis; 71% of the metastatic cases express sialyl Le(a) and the cases with positive sialyl Le(a) and no sialyl Le(x) demonstrated a high incidence of metastasis (80%). A flow cytometric study demonstrated the oral SCC cell line, which can metastasize in nude mice, to express a high level of sialyl Le(a). The high expression of sialyl Le(a) in primary tumors may thus be involved in nodal metastasis and therefore predict a poor prognosis in oral SCC.

Journal of Endocrinology and Metabolism, May 19, 2010