Hisashi Nitta

Immunohistochemical localization of tissue-type plasminogen activator in the lining wall of chronic subdural hematoma.

Capsules of chronic subdural hematoma were immunohistochemically stained with monoclonal antibody against tissue-type plasminogen activator. Endothelial cells of sinusoids and capillaries in the outer membrane showed strong immunostaining. Endothelial cells of veins and arteries in the dura mater showed moderate and weak staining. No cells other than the endothelial cells were stained. In the inner membrane, tissue-type plasminogen activator immunoreactivity was not seen. The mean concentration of tissue-type plasminogen activator in the hematoma content was higher than that in the plasma. The more the sinusoids in the outer membrane were developed, the higher the concentration of tissue-type plasminogen activator contained in the hematoma fluid. In chronic subdural hematoma, overproduction and oversecretion of tissue-type plasminogen activator from the sinusoidal and capillary endothelial cells in the outer membrane cause increased fibrinolysis, which in turn impairs hemostasis, and hemorrhage from the capillaries recurs, resulting in enlargement of the chronic subdural hematoma.

Expression of multidrug resistance-associated protein (MRP) in human gliomas.

Drug resistance is a major clinical problem in the chemotherapy of human gliomas. The multidrug resistance-associated protein (MRP), a membrane transporter related to non-P-glycoprotein multidrug resistance, is overexpressed in some drug-selected cancer cell lines. To investigate whether MRP is involved in the intrinsic drug resistance of human gliomas, surgical specimens of 20 gliomas (11 glioblastomas, 6 anaplastic astrocytomas, and 3 astrocytomas), 3 normal brain specimens, and 4 glioma cell lines (U87MG, U251MG, U373MG, and T98G) were analyzed. The expression of MRP was studied by RT-PCR and immunohistochemistry in the surgical specimens. The MRP expression levels in the cell lines were assessed by the quantitative RT-PCR and Western blot analyses. Sensitivity to adriamycin (ADM), etoposide (VP-16), cisplatin (CDDP), and 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU), were determined by MTT assay, and antisense treatment was evaluated in the cell lines. The expression of MRP was detected in 9 of 11 glioblastomas and 3 of 6 anaplastic astrocytomas. The quantitative analyses of the cell lines revealed that the MRP mRNA and protein levels were increased 4.5-fold in the T98G cells as compared to U87MG. T98G cells showed the highest resistance to all drugs. Western blot analysis revealed that treatment with the antisense oligonucleotide reduced the level of MRP expression to 25% of the sense oligonucleotide treatment in T98G cells. The sensitivity to ADM, VP-16 and CDDP was significantly increased in the antisense-treated cells as compared with the sense-treated cells. These results suggest that the MRP expression may be related to the intrinsic multidrug resistance in human gliomas.

Cervical spinal cord infarction after surgery for a pineal region choriocarcinoma in the sitting position: case report.

OBJECTIVE AND IMPORTANCE Spinal cord injury is one of several devastating complications after operation in the sitting position. Young patients exhibiting extraordinary growth spurts demonstrate a higher risk for this complication. CLINICAL PRESENTATION We describe a 7-year-old male patient with a pineal region choriocarcinoma in whom a cervical spinal cord infarction (C5-T1) developed as an acute complication after operation in the sitting position. Preoperatively, high serum levels of human chorionic gonadotropin (5867.7 mIU/ml) and somatomedin-C (704 ng/ml) and an extreme growth velocity in height (16 cm/yr) were noted. CONCLUSION It is assumed that, in addition to head flexion, the abnormal skeletal growth spurt resulting from an excessive secretion of human chorionic gonadotropin from a tumor was a possible predisposing factor for this complication. To prevent this complication, surgeons need to pay great attention to head positioning, especially in a young patient experiencing an active growth spurt.

Molecular analysis for p53 and mdm2 in intracranial germ cell tumors

Abstract Intracranial germ cell tumors (ICGTs) are uncommon neoplasms. The histological appearance of ICGTs is indistinguishable from that of the usual testicular germ cell tumors (TGTs). Recently, several reports have associated molecular abnormalities of p53 and mdm2 in TGTs with their malignancies. However, whether ICGTs are associated with molecular abnormalities is still unknown. We analyzed a series of 16 ICGTs for mutations in the TP53 gene by single-strand conformation polymorphisms, and for amplification of the MDM2 gene using differential PCR. In addition, the same 16 tumors were examined for p53 and mdm2 protein overexpression using antibodies directed against p53 [monoclonal antibodies (mAb) 1801 and DO7] and mdm2 (IF2), respectively. Twelve (75%) and 2 (13%) of the 16 ICGTs reacted with DO7 and PAb1801, respectively, and 1 (6%) carried a TP53 gene mutation. Thirteen (81%) of the 16 ICGTs reacted with IF2, and 3 (19%) carried MDM2 gene amplification. The less frequent TP53 gene mutation compared with MDM2 gene amplification, and the frequently expressed p53 and mdm2 protein, are similar to the case for TGTs. It is tempting to speculate that ICGTs might have the same cellular origins as TGTs with abnormalities in p53 and mdm2, which could play an important role of tumorigenesis.

Metallothionein in Gliomas

Metallothionein (MT) is a low molecular weight, intracytoplasmic protein that has a high affinity for heavy metals. MT plays a role in the storage and metabolism of essential trace elements and in detoxification of toxic heavy metals in normal tissues. In systemic malignant tumors, MT is thought to be related to the cellular mechanism of drug resistance to anticancer agents, especially platinum compounds. We studied the expression of MT in 20 gliomas and 3 autopsied brains using immunohistochemical and reverse transcriptase-polymerase chain reaction (RT-PCR) methods. In autopsied brains, MT expression was seen in astrocytes in the cerebral gray matter and white matter and in the cerebellum. Neurons, ependyma, and oligodendrocytes did not show MT immunoreactivity. In gliomas, MT staining was seen in both nucleus and cytoplasm of tumor cells. Expression of MT was most prominent in glioblastomas and less intensive in low-grade gliomas. We concluded that intensity of MT expression may correlate with histological grading of gliomas.