Publications by authors named "Masayasu Okada"

26 Publications

  • Page 1 of 1

Peripheral precocious puberty in a girl with an intracranial hCG-producing tumor: case report and literature review.

Endocr J 2021 Jul 17. Epub 2021 Jul 17.

Division of Pediatrics, Department of Homeostatic Regulation and Development, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan.

Human chorionic gonadotropin (hCG)-producing tumors cause peripheral precocious puberty (PP) in boys, but generally not in girls. Homology between LH and hCG activates the LH receptor in testicular Leydig cells, increases testosterone production, and causes virilization. However, since FSH action is required for follicle development, hCG action alone does not increase estradiol (E2) production and does not cause feminization. Only a few cases of peripheral PP with hCG tumors in girls have been reported. We describe the case of a 7-year-old Japanese girl with peripheral PP associated with an hCG-producing tumor. She had prolonged vomiting, loss of appetite, and Tanner stage III breast development. Although no apparent increase in growth rate, bone age was advanced at 9.8 years. Serum E2 was slightly elevated and LH and FSH were below the measurement sensitivity, and abdominal ultrasonography and computed tomography images showed no abnormal findings in the uterus or ovaries. Subsequently, she developed visual field disturbance and loss of consciousness, and brain magnetic resonance imaging revealed an intracranial tumor. Based on pathological findings and abnormally high serum hCG-β level (48,800 IU/L), intracranial choriocarcinoma was diagnosed. 2.5 months after the start of chemotherapy, the hCG-β level became almost negative and the breast development disappeared synchronously. Tissue immunostaining of the tumor showed strong positivity for aromatase and hCG, indicating that the choriocarcinoma cells themselves may have produced estrogen via aromatase. This unique case highlights the possibility that hCG-producing tumors can cause peripheral PP in girls as well as boys.
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http://dx.doi.org/10.1507/endocrj.EJ21-0117DOI Listing
July 2021

Predicting BRAF V600E mutation in glioblastoma: utility of radiographic features.

Brain Tumor Pathol 2021 Jul 3;38(3):228-233. Epub 2021 Jul 3.

Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Detection of BRAF V600E mutation in glioblastomas (GBMs) is important because of potential therapeutic implications. Still, the relative paucity of these mutations makes molecular detection in all GBMs controversial. In the present study, we analyzed clinical, radiographic and pathologic features of 12 BRAF V600E-mutant GBMs and 12 matched controls from 2 institutions. We found that a majority of BRAF V600E-mutant GBMs displayed a combination of well-circumscribed lesions, large cystic components with thin walls and solid cortical component on MRI, but with some overlap with matched BRAF wildtype controls (p = 0.069). BRAF V600E-mutant GBMs were also apt to gross total resection (83% vs 17%, p = 0.016) and morphologically displayed epithelioid features (83% vs 0%, p < 0.0001). Identification of these clinical, radiographic, and pathologic characteristics should prompt testing for BRAF V600E in IDH-wildtype GBM.
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http://dx.doi.org/10.1007/s10014-021-00407-0DOI Listing
July 2021

[The Present and Future of Less-invasive Liquid Biopsy for the Diagnosis of Gliomas and Brain Tumors].

No Shinkei Geka 2021 May;49(3):527-534

Department of Neurosurgery, Brain Research Institute, Niigata University.

There is growing interest in liquid biopsy, the less-invasive detection of circulating tumor DNA(ctDNA)or circulating tumor cells(CTCs)from cerebrospinal fluid(CSF)and/or serum of patients, for the diagnosis of brain tumors. We share our experience of detecting hot spot point mutations using droplet digital PCR(ddPCR)in ctDNA obtained from the CSF of patients with brain tumors. The detection of mutations such as R132H, V600E, and promoter mutations in gliomas can be diagnostic. For optimal detection of ctDNA, which is only seen at very low concentrations, proper handling and storage of CSF, high-yield extraction of ctDNA, and usage of sensitive PCR methods for detection are imperative. We discuss which mutations can be assessed when diagnosing brain tumors, with a specific focus on gliomas. Finally, we look at what the near future holds for liquid biopsy of brain tumor patients, including next-generation sequencing panel analysis and accurate assessment of fusion genes.
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http://dx.doi.org/10.11477/mf.1436204425DOI Listing
May 2021

Low Detection Rate of H3K27M Mutations in Cerebrospinal Fluid Obtained from Lumbar Puncture in Newly Diagnosed Diffuse Midline Gliomas.

Diagnostics (Basel) 2021 Apr 9;11(4). Epub 2021 Apr 9.

Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.

Recent studies have suggested the feasibility of detecting H3K27M mutations in the cerebrospinal fluid of diffuse midline glioma (DMG) patients. However, cerebrospinal fluid from patients in these studies were collected mainly during biopsy, ventriculo-peritoneal shunt procedures or postmortem. We assessed circulating tumor DNA (ctDNA) extracted from cerebrospinal fluid (CSF) and plasma in a series of 12 radiographically suspected and/or pathologically confirmed diffuse midline glioma patients and assessed for K27M mutation using digital droplet PCR. In 10 patients, CSF was obtained by lumbar puncture at presentation. A definitive detection of K27M mutation was achieved in only one case (10%); K27M mutation was suspected in three other cases (30%). K27M mutation was detected in two patients in CSF obtained by ventricular tap during a ventriculo-peritoneal shunt for obstructive hydrocephalus. Cases in which a definitive assessment was possible (definite K27M or definite wildtype) tended to be younger (median 7.5 years vs. 40.5 years; = 0.07) and have a higher concentration of CSF protein (median 123 mg/dL vs. 27.5 mg/dL; = 0.21) compared to nondefinite cases. Low proliferation and apoptotic rates seemed to be characteristics of DMG unfavorable for liquid biopsy. More advanced lesions with necrosis and evidence of dissemination were unlikely to be candidates for lumbar puncture due to the fear of exacerbating obstructive hydrocephalus. Methods to safely sample CSF and a more sensitive detection of ctDNA are necessary for reliable liquid biopsy of DMG at presentation.
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http://dx.doi.org/10.3390/diagnostics11040681DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070169PMC
April 2021

Phosphorylation of GAP-43 T172 is a molecular marker of growing axons in a wide range of mammals including primates.

Mol Brain 2021 04 8;14(1):66. Epub 2021 Apr 8.

Departments of Neurochemistry and Molecular Cell Biology, School of Medicine and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, 951-8510, Japan.

GAP-43 is a vertebrate neuron-specific protein and that is strongly related to axon growth and regeneration; thus, this protein has been utilized as a classical molecular marker of these events and growth cones. Although GAP-43 was biochemically characterized more than a quarter century ago, how this protein is related to these events is still not clear. Recently, we identified many phosphorylation sites in the growth cone membrane proteins of rodent brains. Two phosphorylation sites of GAP-43, S96 and T172, were found within the top 10 hit sites among all proteins. S96 has already been characterized (Kawasaki et al., 2018), and here, phosphorylation of T172 was characterized. In vitro (cultured neurons) and in vivo, an antibody specific to phosphorylated T172 (pT172 antibody) specifically recognized cultured growth cones and growing axons in developing mouse neurons, respectively. Immunoblotting showed that pT172 antigens were more rapidly downregulated throughout development than those of pS96 antibody. From the primary structure, this phosphorylation site was predicted to be conserved in a wide range of animals including primates. In the developing marmoset brainstem and in differentiated neurons derived from human induced pluripotent stem cells, immunoreactivity with pT172 antibody revealed patterns similar to those in mice. pT172 antibody also labeled regenerating axons following sciatic nerve injury. Taken together, the T172 residue is widely conserved in a wide range of mammals including primates, and pT172 is a new candidate molecular marker for growing axons.
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http://dx.doi.org/10.1186/s13041-021-00755-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8034164PMC
April 2021

[Pituitary Hypertrophy].

No Shinkei Geka 2021 Mar;49(2):301-315

Department of Neurosurgery, Uonuma Kikan Hospital, Uonuma Institute of Community Medicine.

Pituitary adenomas are the most common cause of sellar masses although there are a number of other neoplastic, infectious, inflammatory, developmental, and vascular etiologies that should be considered. Pregnancy promotes a physiological increase in the size of the maternal pituitary gland, especially adenohypophysis. The normal maturation sequence of the pituitary gland apparently involves a period of physiological hypertrophy in teenagers. As most incidentalomas in pediatric patients are not associated with hormonal hypersecretion or hypopituitarism, and structural progression is not common, it is hypothesized that the extensive follow-up assessment recommended for adults might not be necessary for children. Patients presenting with a pituitary lesion should undergo a complete history and physical examination that includes evaluations for evidence of hypopituitarism and hormone hypersecretion syndrome. Patients with evidence for either of these conditions should undergo an appropriately directed biochemical evaluation. All patients presenting with a pituitary lesion abutting the optic nerves or chiasm on magnetic resonance imaging should undergo a formal visual field examination. Emergencies in pituitary disease can result from the failure of the pituitary gland to secrete one or more pituitary hormones or from neuro-ophthalmological symptoms due to the mass effect of an expanding hypothalamic-pituitary lesion. Early diagnosis and prompt treatment of endocrine emergencies are mandatory.
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http://dx.doi.org/10.11477/mf.1436204392DOI Listing
March 2021

GLI3 Is Associated With Neuronal Differentiation in SHH-Activated and WNT-Activated Medulloblastoma.

J Neuropathol Exp Neurol 2021 01;80(2):129-136

Department of Pathology, Brain Research Institute, Niigata University.

Glioma-associated oncogene homolog 3 (GLI3), whose main function is to inhibit GLI1, has been associated with neuronal differentiation in medulloblastoma. However, it is not clear what molecular subtype(s) show increased GLI3 expression. GLI3 levels were assessed by immunohistochemistry in 2 independent cohorts, including a total of 88 cases, and found to be high in both WNT- and SHH-activated medulloblastoma. Analysis of bulk mRNA expression data and single cell RNA sequencing studies confirmed that GLI1 and GLI3 are highly expressed in SHH-activated medulloblastoma, whereas GLI3 but not GLI1 is highly expressed in WNT-activated medulloblastoma. Immunohistochemical analysis has shown that GLI3 is expressed inside the neuronal differentiated nodules of SHH-activated medulloblastoma, whereas GLI1/2 are expressed in desmoplastic areas. In contrast, GLI3 is diffusely expressed in WNT-activated medulloblastoma, whereas GLI1 is suppressed. Our data suggest that GLI3 may be a master regulator of neuronal differentiation and morphology in these subgroups.
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http://dx.doi.org/10.1093/jnen/nlaa141DOI Listing
January 2021

Phosphoproteomic and bioinformatic methods for analyzing signaling in vertebrate axon growth and regeneration.

J Neurosci Methods 2020 06 8;339:108723. Epub 2020 Apr 8.

Departments of Laboratory of Bioinformatics, School and Medicine and Graduate School of Medical/Dental Sciences, Japan.

Phosphorylation is the most important post-translational modification of proteins in many cells, including neurons. Phosphoproteomics is a relatively new technique for comprehensively identifying phosphorylation sites in the whole proteome of a given system. We applied this method to developmental neurobiology research to understand the signaling pathways that regulate the mammalian growth cone, which is formed at the tips of developing neurites to ensure accurate neuronal network formation. Using this powerful technique, we identified at least four phosphorylation sites tightly associated with axon growth. Because phosphoproteomic results include relatively large numbers of phosphopeptides, the data are typically analyzed using bioinformatics. We utilized three bioinformatics tools to identify the responsible protein kinases, the putative functions of the phosphorylated protein groups, and the evolutional aspects of the phosphorylated proteins. Collectively, these data indicate phosphoproteomics is a cutting-edge tool for neuroscience research.
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http://dx.doi.org/10.1016/j.jneumeth.2020.108723DOI Listing
June 2020

[Coexisting Symptomatic Adrenocorticotropic Hormone- and Growth Hormone-producing Double Pituitary Adenomas with Difficulty in Tumor Localization:A Case Report].

No Shinkei Geka 2020 Mar;48(3):253-260

Department of Neurosurgery, Fukushima Medical University.

Double functional pituitary adenomas are rare, and only a few cases of excessive clinical symptoms of both adrenocorticotropic hormone(ACTH)and growth hormone(GH)have been reported. We herein report a case of symptomatic ACTH-and GH-producing double pituitary adenomas, which were discretely located within the same pituitary gland. A 38-year-old woman presented with general malaise, facial and lower limb edema, unexplained weight gain, facial redness, acne, and nasal enlargement. Endocrinological findings matched with the diagnostic criteria for both acromegaly and Cushing's disease. Preoperative magnetic resonance imaging showed a 15-mm cyst-like lesion on the right side of the sellae surrounded by what was thought to be the normal contrast-enhancing pituitary gland. We assumed that the cyst-like lesion was an adenoma and performed endoscopic endonasal transsphenoidal surgery. However, the cyst-like lesion was a parenchymal tumor. Furthermore, the region we considered to be a normal pituitary gland was also found to be an adenoma. Both adenomas were completely resected. The postoperative blood analysis showed ACTH<1.0pg/dL, cortisol 1.8μg/dL, and insulin-like growth factor-1 60ng/mL, all of which were below reference levels. The histopathological examination confirmed the coexistence of two adenomas, a GH-producing adenoma and an ACTH-producing adenoma. We concluded that these adenomas were endocrinologically active within the pituitary gland. Thus, a diagnosis of double pituitary adenomas was made. When treating a patient with symptoms caused by hypersecretion of multiple anterior pituitary hormones, the possibility of coexisting multiple pituitary adenomas should be considered.
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http://dx.doi.org/10.11477/mf.1436204171DOI Listing
March 2020

The JNK pathway represents a novel target in the treatment of rheumatoid arthritis through the suppression of MMP-3.

J Orthop Surg Res 2020 Mar 4;15(1):87. Epub 2020 Mar 4.

Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, Chuo-ku, Niigata, Niigata, Japan.

Background And Aim: The pathophysiology of rheumatoid arthritis (RA) is characterized by excess production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) by neutrophils and macrophages in synovium. Additionally, these cytokines promote the production of reactive oxygen species (ROS), and increased production of matrix metalloproteinases (MMPs), including MMP-3, in synoviocytes that result in joint destruction. There is limited information on how proteolytic enzymes such as MMP-3 can be regulated. We evaluated the effect of the antioxidant N-acetylcysteine (NAC) on RA and identified the relationship between the c-Jun N terminal kinase (JNK) pathway and MMP-3. We hypothesized that elucidating this relationship would lead to novel therapeutic approaches to RA treatment and management.

Methods: We investigated the effect of administering a low dose (1000 μM or less) of an antioxidant (NAC) to human rheumatoid fibroblast-like synoviocytes (MH7A cells). We also investigated the response of antioxidant genes such as nuclear factor erythroid -derived 2-related factor 2 (Nrf2) and Sequestosome 1 (p62). The influence of MMP-3 expression on the JNK pathway leading to joint destruction and the mechanisms underlying this relationship were investigated through primary dispersion culture cells collected from the synovial membranes of RA patients, consisting of rheumatoid arthritis-fibroblast-like synoviocytes (RA-FLS).

Results: Low-dose NAC (1000 μM) increased the expression of Nrf2 and phospho-p62 in MH7A cells, activating antioxidant genes, suppressing the expression of MMP-3, and inhibiting the phosphorylation of JNK. ROS, MMP-3 expression, and IL-6 was suppressed by administering 30 μM of SP600125 (a JNK inhibitor) in MH7A cells. Furthermore, the administration of SP600125 (30 μM) to RA-FLS suppressed MMP-3.

Conclusions: We demonstrated the existence of an MMP-3 suppression mechanism that utilizes the JNK pathway in RA-FLS. We consider that the JNK pathway could be a target for future RA therapies.
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http://dx.doi.org/10.1186/s13018-020-01595-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7371465PMC
March 2020

MGMT Expression Contributes to Temozolomide Resistance in H3K27M-Mutant Diffuse Midline Gliomas.

Front Oncol 2019 21;9:1568. Epub 2020 Jan 21.

Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan.

Diffuse midline gliomas (DMGs) show resistance to many chemotherapeutic agents including temozolomide (TMZ). Histone gene mutations in DMGs trigger epigenetic changes including DNA hypomethylation, one of which is a frequent lack of O6-methyl-guanine-DNA methyltransferase () promoter methylation, resulting in increased MGMT expression. We established the NGT16 cell line with K27M and G328E gene mutations from a DMG patient and used this cell line and other DMG cell lines with gene mutation (SF7761, SF8628, JHH-DIPG1) to analyze promoter methylation, MGMT protein expression, and response to TMZ. Three out of 4 DMG cell lines (NGT16, SF8628, and JHH-DIPG1) had unmethylated promoter, increased MGMT expression, and showed resistance to TMZ treatment. SF7761 cells with gene mutation showed promoter methylation, lacked MGMT expression, and sensitivity to TMZ treatment. NGT16 line showed response to ALK2 inhibitor K02288 treatment . We confirmed that MGMT expression contributes to TMZ resistance in DMG cell lines. There is an urgent need to develop new strategies to treat TMZ-resistant DMGs.
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http://dx.doi.org/10.3389/fonc.2019.01568DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985080PMC
January 2020

Phosphorylation sites of microtubule-associated protein 1B (MAP 1B) are involved in axon growth and regeneration.

Mol Brain 2019 11 11;12(1):93. Epub 2019 Nov 11.

Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8510, Japan.

The growth cone is a specialized structure that forms at the tip of extending axons in developing and regenerating neurons. This structure is essential for accurate synaptogenesis at developmental stages, and is also involved in plasticity-dependent synaptogenesis and axon regeneration in the mature brain. Thus, understanding the molecular mechanisms utilized by growth cones is indispensable to understanding neuronal network formation and rearrangement. Phosphorylation is the most important and commonly utilized protein modification in signal transduction. We previously identified microtubule-associated protein 1B (MAP 1B) as the most frequently phosphorylated protein among ~ 1200 phosphorylated proteins. MAP 1B has more than 10 phosphorylation sites that were present more than 50 times among these 1200 proteins. Here, we produced phospho-specific antibodies against phosphorylated serines at positions 25 and 1201 of MAP 1B that specifically recognize growing axons both in cultured neurons and in vivo in various regions of the embryonic brain. Following sciatic nerve injury, immunoreactivity with each antibody increased compared to the sham operated group. Experiments with transected and sutured nerves revealed that regenerating axons were specifically recognized by these antibodies. These results suggest that these MAP 1B phosphorylation sites are specifically involved in axon growth and that phospho-specific antibodies against MAP 1B are useful markers of growing/regenerating axons.
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http://dx.doi.org/10.1186/s13041-019-0510-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6849251PMC
November 2019

Dramatic response of BRAF V600E-mutant epithelioid glioblastoma to combination therapy with BRAF and MEK inhibitor: establishment and xenograft of a cell line to predict clinical efficacy.

Acta Neuropathol Commun 2019 07 25;7(1):119. Epub 2019 Jul 25.

From the Departments of Neurosurgery, Niigata University, 1-757 Asahimachidori, Chuo-ku, Niigata, Japan.

Epithelioid glioblastoma is a rare aggressive variant of glioblastoma (GBM) characterized by a dismal prognosis of about 6 months and frequent leptomeningeal dissemination. A recent study has revealed that 50% of epithelioid GBMs harbor three genetic alterations - BRAF V600E mutation, TERT promoter mutations, and homozygous deletions of CDKN2A/2B. Emerging evidence support the effectiveness of targeted therapies for brain tumors with BRAF V600E mutation. Here we describe a dramatic radiographical response to combined therapy with BRAF and MEK inhibitors in a patient with epithelioid GBM harboring BRAF V600E mutation, characterized by thick spinal dissemination. From relapsed tumor procured at autopsy, we established a cell line retaining the BRAF V600E mutation, TERT promoter mutation and CDKN2A/2B loss. Intracranial implantation of these cells into mice resulted in tumors closely resembling the original, characterized by epithelioid tumor cells and dissemination, and invasion into the perivascular spaces. We then confirmed the efficacy of treatment with BRAF and MEK inhibitor both in vitro and in vivo. Epithelioid GBM with BRAF V600E mutation can be considered a good treatment indication for precision medicine, and this patient-derived cell line should be useful for prediction of the tumor response and clarification of its biological characteristics.
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http://dx.doi.org/10.1186/s40478-019-0774-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6659204PMC
July 2019

Comparison of circulating tumor DNA between body fluids in patients with primary central nervous system lymphoma.

Leuk Lymphoma 2019 12 15;60(14):3587-3589. Epub 2019 Jul 15.

Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan.

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http://dx.doi.org/10.1080/10428194.2019.1639169DOI Listing
December 2019

Podoplanin Expression and IDH-Wildtype Status Predict Venous Thromboembolism in Patients with High-Grade Gliomas in the Early Postoperative Period.

World Neurosurg 2019 Aug 15;128:e982-e988. Epub 2019 May 15.

Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata.

Objective: Venous thromboembolism (VTE) often is encountered in patients with high-grade gliomas. The underlying mechanisms are unclear, as is the optimal prophylactic protocol. The purpose of the present study was to identify risk factors of VTE and examine the validity of early VTE detection in high-grade gliomas.

Methods: We reviewed the medical records of 165 patients with newly diagnosed high-grade glioma treated at Niigata University Hospital during the years 2009 to 2016. If the serum D-dimer levels increased to 5.0 μg/mL or more, computed tomography was performed to detect VTE. Furthermore, immunohistochemistry with antibodies against podoplanin was performed on available 101 tumor tissues.

Results: Of the 165 patients, 44 (26.7%) developed VTE. Of the 44 patients, 34 (79.5%) developed VTE within 7 days after surgery. No fatal VTE occurred and major complications secondary to anticoagulation occurred in only 2 (1.2%) patients. On multivariate analysis, lower Karnofsky Performance Scale status, podoplanin expression, and isocitrate dehydrogenase-wildtype status were independently associated with the risk of VTE (P < 0.05).

Conclusions: We found that most VTEs occurred early in the postoperative period and commonly in patients with lower Karnofsky Performance Scale status and isocitrate dehydrogenase-wildtype gliomas, which expressed podoplanin.
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http://dx.doi.org/10.1016/j.wneu.2019.05.049DOI Listing
August 2019

EGFRvIII Is Expressed in Cellular Areas of Tumor in a Subset of Glioblastoma.

Neurol Med Chir (Tokyo) 2019 Mar 21;59(3):89-97. Epub 2019 Feb 21.

Department of Pathology, Brain Research Institute, University of Niigata.

Epidermal growth factor receptor variant III (EGFRvIII) is a tumor-specific cell surface antigen often expressed in glioblastoma and has drawn much attention as a possible therapeutic target. We performed immunohistochemistry on histology sections of surgical specimens taken from 67 cases with glioblastoma, isocitrate dehydrogenase-wild type, and evaluated the morphological characteristics and distribution of the EGFRvIII-positive tumor cells. We then evaluated the localization of EGFRvIII-expression within the tumor and peritumoral areas. EGFRvIII immunopositivity was detected in 15 specimens taken from 13 patients, including two recurrent specimens taken from the same patient at relapse. Immunofluorescence staining demonstrated that EGFRvIII-positive cells were present in cells positive for glial fibrillary acidic protein (GFAP), and some showed astrocytic differentiation with multiple fine processes and others did not shown. The EGFRvIII-positive cells were located in cellular areas of the tumor, but not in the invading zone. In the two recurrent cases, EGFRvIII-positive cells were markedly decreased in one case and retained in the other. With regard to overall survival, univariate analysis indicated that EGFRvIII-expression in patients with glioblastoma was not significantly associated with a favorable outcome. Double-labeling immunofluorescence staining of EGFRvIII and GFAP showed that processes of large, well differentiated, GFAP-positive glia extend to and surround less differentiated, EGFRvIII-positive glial cells in cellular areas of tumor. However, in the tumor periphery, EGFRvIII-positive tumor cells were not observed. This finding suggests that EGFRvIII is involved in tumor proliferation, but that invading glioma cells lose their EGFRvIII expression.
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http://dx.doi.org/10.2176/nmc.oa.2018-0078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6434422PMC
March 2019

Growth Cone Phosphoproteomics Reveals that GAP-43 Phosphorylated by JNK Is a Marker of Axon Growth and Regeneration.

iScience 2018 Jun 31;4:190-203. Epub 2018 May 31.

Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan; Center for Trans-disciplinary Research, Institute for Research Promotion, Niigata University, Chuo-ku, Niigata 951-8510, Japan. Electronic address:

Neuronal growth cones are essential for nerve growth and regeneration, as well as for the formation and rearrangement of the neural network. To elucidate phosphorylation-dependent signaling pathways and establish useful molecular markers for axon growth and regeneration, we performed a phosphoproteomics study of mammalian growth cones, which identified >30,000 phosphopeptides of ∼1,200 proteins. The phosphorylation sites were highly proline directed and primarily MAPK dependent, owing to the activation of JNK, suggesting that proteins that undergo proline-directed phosphorylation mediate nerve growth in the mammalian brain. Bioinformatics analysis revealed that phosphoproteins were enriched in microtubules and the cortical cytoskeleton. The most frequently phosphorylated site was S96 of GAP-43 (growth-associated protein 43-kDa), a vertebrate-specific protein involved in axon growth. This previously uncharacterized phosphorylation site was JNK dependent. S96 phosphorylation was specifically detected in growing and regenerating axons as the most frequent target of JNK signaling; thus it represents a promising new molecular marker for mammalian axonal growth and regeneration.
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http://dx.doi.org/10.1016/j.isci.2018.05.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6147025PMC
June 2018

MGMT Expression Contributes to Temozolomide Resistance in H3K27M-Mutant Diffuse Midline Gliomas and MGMT Silencing to Temozolomide Sensitivity in IDH-Mutant Gliomas.

Neurol Med Chir (Tokyo) 2018 Jul 31;58(7):290-295. Epub 2018 May 31.

Department of Neurosurgery, Brain Research Institute, Niigata University.

Histone H3 mutations are frequently found in diffuse midline gliomas (DMGs), which include diffuse intrinsic pontine gliomas and thalamic gliomas. These tumors have dismal prognoses. Recent evidence suggests that one reason for the poor prognoses is that O-methylguanine-DNA methyltransferase (MGMT) promoter frequently lacks methylation in DMGs. This review compares the epigenetic changes brought about by histone mutations to those by isocitrate dehydrogenase-mutant gliomas, which frequently have methylated MGMT promoters and are known to be sensitive to temozolomide.
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http://dx.doi.org/10.2176/nmc.ra.2018-0044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6048353PMC
July 2018

Has acromegaly been diagnosed earlier?

J Clin Neurosci 2018 Feb 4;48:138-142. Epub 2017 Nov 4.

Department of Neurosurgery, Brain Research Institute, Niigata University, Japan.

Purpose: We investigated whether acromegaly has been diagnosed earlier at the Niigata Medical and Dental University Hospital.

Methods: Patients with acromegaly (n = 81) who underwent their first transsphenoidal surgery from 2006 to 2015 were reviewed. Two groups were compared: those who underwent surgery between 2006 and 2010 (n = 35) and those who underwent surgery between 2011 and 2015 (n = 46). We compared clinical features and serum levels of the growth hormone (GH) and insulin-like growth factor-1 (IGF-1), hypertension (HT) and diabetes mellitus (DM) prevalence between the two groups.

Results: Compared with the early group, microadenomas (<10 mm) were more prevalent in the late group (0% vs. 15.2%, p < .05). Serum IGF-1 standard deviation score (SDS) was significantly lower in the late group (8.57 ± 2.50 vs. 6.44 ± 2.30, p < .001). In both groups, mean IGF-1 SDS was significantly lower in patients without DM than in those with DM (6.9 ± 2.6 vs. 8.3 ± 2.4, p = .02). Logistic regression analysis showed that serum GH and IGF-1 levels were significantly higher in patients with DM than in those without DM.

Conclusion: Regarding operated cases of GH-producing pituitary adenoma, acromegaly clinical manifestations tended to be milder at diagnosis in later years of the decade, and acromegaly was diagnosed at lower IGF-1 levels and in smaller lesions. Further study is mandatory for the generalization of this trend.
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http://dx.doi.org/10.1016/j.jocn.2017.10.086DOI Listing
February 2018

Reliable diagnosis of IDH-mutant glioblastoma by 2-hydroxyglutarate detection: a study by 3-T magnetic resonance spectroscopy.

Neurosurg Rev 2018 Apr 27;41(2):641-647. Epub 2017 Sep 27.

Department of Neurosurgery, Brain Research Institute, University of Niigata, Niigata, Japan.

We have previously reported that reliable detection of 2-hydroxyglutarate (2HG) in isocitrate dehydrogenase (IDH)-mutant WHO grade 2 and 3 gliomas is possible utilizing 3.0-T single-voxel magnetic resonance spectroscopy (SVMRS). We set out to determine whether the same method could be applied to detect 2HG in IDH-mutant glioblastoma. Forty-four patients harboring glioblastoma underwent pre-operative MRS evaluation to detect 2HG and other metabolites. Presence of IDH-mutations was determined by IDH1 R132H immunohistochemical analysis and DNA sequencing of surgically obtained tissues. Six out of 44 (13.6%) glioblastomas were IDH-mutant. IDH-mutant glioblastoma exhibited significantly higher accumulation of 2HG (median 3.191 vs. 0.000 mM, p < 0.0001, Mann-Whitney test). A cutoff of 2HG = 0.897 mM achieved high sensitivity (100.0%) and specificity (92.59%) in determining IDH-mutation in glioblastoma. Glioblastoma with high 2HG accumulation did not have significantly longer overall survival than glioblastoma with low 2HG accumulation (p = 0.107, log-rank test). Non-invasive and reliable detection of 2HG in IDH-mutant glioblastoma was possible by 3.0-T SVMRS.
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http://dx.doi.org/10.1007/s10143-017-0908-yDOI Listing
April 2018

Third Ventricle Germ Cell Tumor Originating from the Infundibulum with Rapidly Expansive Enlargement.

Pediatr Neurosurg 2018 26;53(1):49-54. Epub 2017 Sep 26.

Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan.

We present a pediatric case of a rapidly expanding third ventricle germ cell tumor (GCT). A 14-year-old boy suffered from gradual-onset central diabetes insipidus (DI) and received desmopressin treatment. Magnetic resonance imaging (MRI) showed nonspecific findings of the pituitary-hypothalamic axis. Nine months after the initial DI diagnosis, he developed progressively worsening headache. MRI demonstrated a third ventricle tumor causing noncommunicating hydrocephalus, although an MRI 16 weeks before admission did not show the lesion. We performed gross total resection (GTR) of the tumor in 2 stages: a translamina terminalis approach and an extended transsphenoidal approach. The lesion was histologically diagnosed as immature teratoma with some germinoma. His noncommunicating hydrocephalus resolved after surgery. Through postoperative radiochemotherapy (whole ventricle: 23.4 Gy/13 fractions, tumor bed: 27.0 Gy/15 fractions, and 3 courses of carboplatin-etoposide), he has was in complete remission at the 3-year follow-up and has continued his high school program. This case suggests the following: (1) a mixed GCT originating from the neurohypophysis/infundibulum can show rapidly expansive growth in a child with central DI; (2) GTR and adjuvant radiochemotherapy can result in a good therapeutic outcome in rapidly expanding GCT; and (3) the extended transsphenoidal approach is a complementary approach to transcranial resection of anterior third ventricle GCTs.
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http://dx.doi.org/10.1159/000480021DOI Listing
July 2018

Perifocal Inflammatory Reaction with Volume Fluctuation Caused by Diagnostic Radiation-Induced Regression in Germinoma Makes Histological Diagnosis Difficult despite Its Disappearance following Treatment: A Significant Pitfall and Countermeasures to It.

Pediatr Neurosurg 2017 11;52(2):87-92. Epub 2016 Nov 11.

Department of Neurosurgery, Uonuma Institute of Community Medicine, Niigata University Medical and Dental Hospital, Niigata, Japan.

We present a pediatric case of neurohypophyseal germinoma with a perifocal inflammatory reaction (PIR) with volume fluctuation caused by diagnostic radiation-induced regression (DRIR). On-target biopsy failed to confirm the histology because PIR hardly contained any germinoma cells. DRIR-related fluctuation of the tumor volume disguised germinoma as inflammation. We analyzed the cerebrospinal fluid (CSF) and detected a high level of placental alkaline phosphatase (PLAP), which demonstrated the neurohypophyseal lesion to be germinoma and brought the patient from successful radiochemotherapy up to complete remission. PIR adjacent to the germinoma (PIRAG) disappeared completely following radiochemotherapy, although it contained almost no germinoma cells. Examination of the CSF-PLAP level can complement the diagnosis of germinoma and will decrease the risk of misdiagnosis. Neurosurgeons should keep in mind PIRAG, DRIR, and the diagnostic value of CSF-PLAP when germinoma is suspected.
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http://dx.doi.org/10.1159/000450583DOI Listing
March 2017

Early morphological recovery of the optic chiasm is associated with excellent visual outcome in patients with compressive chiasmal syndrome caused by pituitary tumors.

Neurol Res 2015 Jan 18;37(1):1-8. Epub 2014 Jun 18.

Objectives: The study objectives are (1) to identify factors predicting the excellent visual recovery after transsphenoidal removal of pituitary tumors and (2) to describe the association of excellent visual recovery and early restoration of symmetry of the decompressed optic chiasm.

Methods: Thirty-five patients with visual symptoms due to pituitary tumors underwent endoscopic endonasal surgery. All patients received perioperative diagnostic magnetic resonance (MR) imaging and ophthalmological assessments within 2 weeks before surgery, within 2 weeks after surgery, and 3 months or later after surgery. Preoperative best-corrected visual acuity (BCVA ≧ 20/20), degree of visual field deficit (VFD, less than half of VF), thickness of retinal nerve fiber layer (RNFL) measured by optical coherence tomography (OCT), and thickness of ganglion cell complex (GCC) measured by OCT were considered for statistical analysis as predictive factors of VF outcome. Multivariate logistic regression models were used in statistical evaluation of data.

Results: In the multivariate analysis, RNFL (odds ratio  =  62.137, P < 0.001) and preoperative VFD (odds ratio  =  8.244, P < 0.02) proved to be effective as factors predicting sufficient VF recovery. Postoperative restoration of symmetry of the optic chiasm was related to sufficient VF recovery (P < 0.0001, Fisher's exact test) and RNFL (P < 0.0001, Fisher's exact test).

Discussion: Early decompression is crucial for sufficient VF recovery, in particular, while RNFL preserves normal or borderline thickness and while VFD keeps within hemianopia. Morphological reversibility is associated with functional reversibility in the optic chiasm compressed by a pituitary tumor. In particular, early morphological recovery suggests functional recovery, which indicates neurocyte reserve in the compressed optic pathway with functional recovery.
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http://dx.doi.org/10.1179/1743132814Y.0000000407DOI Listing
January 2015

Chondroitin sulphate N-acetylgalactosaminyl-transferase-1 inhibits recovery from neural injury.

Nat Commun 2013 ;4:2740

1] Department of Neurochemistry and Molecular Cell Biology, Brain Research Institute, Niigata University, 1-757 Asahi-machi, Niigata 951 8510, Japan [2] Center for Transdisciplinary Research, Brain Research Institute, Niigata University, 1-757 Asahi-machi, Niigata 951 8510, Japan.

Extracellular factors that inhibit axon growth and intrinsic factors that promote it affect neural regeneration. Therapies targeting any single gene have not yet simultaneously optimized both types of factors. Chondroitin sulphate (CS), a glycosaminoglycan, is the most abundant extracellular inhibitor of axon growth. Here we show that mice carrying a gene knockout for CS N-acetylgalactosaminyltransferase-1 (T1), a key enzyme in CS biosynthesis, recover more completely from spinal cord injury than wild-type mice and even chondroitinase ABC-treated mice. Notably, synthesis of heparan sulphate (HS), a glycosaminoglycan promoting axonal growth, is also upregulated in TI knockout mice because HS-synthesis enzymes are induced in the mutant neurons. Moreover, chondroitinase ABC treatment never induces HS upregulation. Taken together, our results indicate that regulation of a single gene, T1, mediates excellent recovery from spinal cord injury by optimizing counteracting effectors of axon regeneration--an extracellular inhibitor of CS and intrinsic promoters, namely, HS-synthesis enzymes.
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http://dx.doi.org/10.1038/ncomms3740DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3831297PMC
June 2014

Advantages of dose-dense methotrexate protocol for primary central nervous system lymphoma: comparison of two different protocols at a single institution.

Neurol Med Chir (Tokyo) 2013 25;53(11):797-804. Epub 2013 Oct 25.

Department of Neurosurgery, Brain Research Institute, Niigata University.

The efficacy and toxicity of high-dose methotrexate (HD-MTX)-based chemotherapy were retrospectively reviewed in patients with primary central nervous system lymphoma (PCNSL). All immunocompetent patients with histologically or radiographically diagnosed PCNSL treated between 2006 and 2012 at Niigata University Hospital were enrolled. Thirty-eight patients with a diagnosis of PCNSL were treated with one of two regimens during different time periods. During the first period, from 2006 to 2009, three 3-week cycles of MPV (MTX + procarbazine + vincristine) were administered (MPV3 group). In the second period, from 2010 to 2012, five 2-week cycles of MTX were administered (MTX5 group). High-dose cytarabine was used in both groups following HD-MTX-based chemotherapy. Whole-brain radiotherapy was used for patients who did not attain a complete response (CR) based on magnetic resonance images. In the MPV3 group, 20 out of 23 patients (87%) completed the planned treatment. The CR rate after chemotherapy was 30%, and 57% after radiation therapy. Thirteen out of 15 patients (87%) in the MTX5 group completed the planned treatment. The CR rates after chemotherapy and radiation therapy were 53% and 93%, respectively. Renal dysfunction was assessed by measuring creatinine clearance rates, which were very similar in both groups. In terms of hematologic toxicity and other adverse reactions, there was no significant difference between the two groups. In conclusion, dose-dense MTX chemotherapy improved outcome with acceptable toxicity compared with the treatment schedule for three cycles of MPV treatment.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4508721PMC
http://dx.doi.org/10.2176/nmc.oa2013-0195DOI Listing
April 2015

Observation of the neurohypophysis, pituitary stalk, and adenohypophysis during endoscopic pituitary surgery: demonstrative findings as clues to pituitary-conserving surgery.

Acta Neurochir (Wien) 2013 Jun 27;155(6):1049-55. Epub 2013 Mar 27.

Department of Neurosurgery, Brain Research Institute, University of Niigata, 1-757 Asahimachi-dori Chuo-ku, Niigata, 951-8585, Japan.

Background: High-definition imaging in endoscopic transsphenoidal pituitary surgery accounts for significantly better identification of anatomic structures. This report presents the clinical images of the adenohypophysis and neurohypophysis under high-definition endoscopic observation, and provides some clues for pituitary-sparing surgery.

Methods: Ten demonstrative cases of pituitary lesions, including three cases of gonadotropin-producing pituitary adenoma, two cases of somatotropin-secreting pituitary adenoma, and five cases of Rathke's cleft cysts, were entered in this study. From these cases, we extracted helpful intraoperative findings that affected the surgeon's decision about surgical procedures and led to favorable results.

Results: The extracted findings contain the following lessons: (1) to find a boundary plane that separate a lesion from the pituitary; (2) to mark the difference of color between the adenohypophysis and the neurohypophysis; (3) to identify the location of the pituitary stalk connecting to the neurohypophysis; (4) to observe the color change of the pituitary induced by decompression; (5) to know pathological findings of the pituitary surface; (6) to distinguish the parenchyma of the neurohypophysis from pathological tissues; and (7) to recognize the intrasellar findings at the completion of removal. Recognition of these findings led to an excellent result in each case.

Conclusions: Despite being shown in a limited number of cases, on the basis of HD endoscopic images, accurate identification of the neurohypophysis and the pituitary stalk as well as adenohypophysis during surgery contributes to pituitary-conserving operations.
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http://dx.doi.org/10.1007/s00701-013-1687-zDOI Listing
June 2013
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