Differential regulation of intracellular Ca2+ signalling induced by high K+ and endothelin-1 in single smooth muscle cells of intact canine basilar artery: detection by means of confocal laser microscopy

Changes in intracellular calcium concentration ([Ca2+]i) in smooth muscle cells play the key role in regulation of vascular smooth muscle tone and pathogenesis of cerebral vasospasm. In this study, we adopted the confocal laser microscopy to detect the fluorescence signals arising from the individual smooth muscle cells of canine basilar artery. Ring preparations were made, loaded with fluo-3 and changes in fluorescence induced by high K+ and endothelin-1 (ET-1) were measured by confocal laser microscopy. In some unstimulated smooth muscle cells Ca2+ waves arising from discrete region of the cell propagated to the whole cell with a velocity of approximately 10 microm/s. High K+ (80 mmol/L) induced a rapid rise in [Ca2+]i, the peak level being consistently reached approximately 10 s after stimulation. In contrast, the time to peak level of [Ca2+]i induced by ET-1 (0.3 micromol/L) varied widely between 13 and 26 s among individual cells, an indication that the extent of nonuniform coordination of increases in [Ca2+]i in individual cells may be partly responsible for the different time courses of tension development of vascular smooth muscle in response to the vasoactive stimulants. The increase in [Ca2+]i induced by ET-1 was transient but a pronounced and sustained contraction developed further in response to ET-1. Thus ET-1 has a biological property as a potential candidate to elicit cerebral vasospasm. Confocal laser microscopy could be a useful tool to measure the changes in [Ca2+]i in individual smooth muscle cells of cerebral artery.

Structures of primer-template hybrids in arbitrarily primed polymerase chain reaction

Nucleotide sequence analysis of arbitrarily primed PCR products from two known regions of human genome revealed that at least six contiguous bases at the 3'-end of a primer of 20 bases, were perfectly matched in the primer-template hybrids.

[A case of vertebrobasilar dissection which was associated with progressing stroke and was successfully treated by intravascular surgery in the acute stage]

A case of vertebrobasilar dissection which deteriorated in the acute stage and was successfully treated by intravascular surgery is described. A 26-year-old male presented with sudden onset of occipitalgia, weakness of the right upper and lower extremities, and speech disturbance. He was transferred to our hospital 3 hours after the onset. On admission, neurological examination showed right hemiparesis including the face and dysarthria. CT of the head showed no definite abnormality and left vertebral angiograms (VAG) revealed only slight wall irregularity of the basilar artery. T2-weighted MR imaging demonstrated an area of high intensity in the left side of the pons. He was treated conservatively under a diagnosis of pontine infarction. On the 8th hospital day, he developed left hemiparesis. T2-weighted MR imaging revealed a new high intensity lesion in the opposite side of the pons. 3D-SPGR images showed double lumen of the left vertebral artery. Angiography showed that the wall irregularity of the basilar artery had become more obvious. These findings strongly suggested a dissection extending from the left vertebral artery to the basilar artery. Progression of the dissection was presumed to have caused the worsening in clinical symptoms, and further progression of the dissection would involve perforators of the basilar artery top and would be fatal. To prevent further progression of the dissection, the left vertebral artery was occluded at the proximal site of the orifice of the dissection with platinum coils after a test occlusion on the same day. Postoperatively, further deterioration of the clinical symptoms ceased. Left VAG on the 33rd postoperative day demonstrated improvement in the wall irregularity of the basilar artery. His clinical symptoms improved markedly and he was ambulatory at discharge and returned to his previous occupation. We emphasize that a progressive vertebrobasilar dissection that causes clinical deterioration in the acute stage can be prevented from progressing further by occlusion at the proximal site of the orifice of the dissection.

Detection of DNA abnormalities by arbitrarily primed PCR fingerprinting: allelic losses in chromosome 10q in lung cancers

DNA fingerprinting using arbitrarily primed PCR (AP-PCR) is useful for detecting cancer-specific DNA aberrations without targeting any particular genes or knowing any nucleotide sequences in advance. AP-PCR fingerprinting is an efficient method for finding loss of anonymous chromosomal regions in cancers. We analyzed DNA from 44 human non-small cell lung cancers by fingerprinting using a single primer and found a loss of signal intensity in a DNA fragment amplified from chromosome 10 (fragment F) in 15 tumors. The detailed location of the fragment F locus on chromosome 10q was determined by PCR-based analysis of radiation hybrid panels using a sequence-tagged site established for the fragment. In 12 of the 15 tumors, loss of the signal detected by AP-PCR fingerprinting was in agreement with the results obtained by analysis of allelic imbalances using 7 polymorphic CA-microsatellite DNA markers for loci around the fragment F locus (p=0.0009). We conclude that a hitherto unknown suppressor gene for lung cancer resides at 10q in the vicinity of fragment F.

Edema along the optic tract: a useful MR finding for the diagnosis of craniopharyngiomas

BACKGROUND AND PURPOSE

The pattern of edema caused by craniopharyngiomas and other common suprasellar masses could be useful for determining the differential diagnosis of lesions in this region. The purpose of this study was to ascertain whether the pattern of edema spread on MR images can be used in the diagnosis of craniopharyngiomas.

METHODS

The preoperative MR images in eight consecutive patients with craniopharyngiomas, 15 patients with large pituitary adenomas compressing the optic chiasm, and six patients with tuberculum sellae meningiomas were evaluated. All the patients were treated surgically at our hospital and a pathologic diagnosis was obtained. We analyzed the spread of edema surrounding the tumor on the coronal dual-echo fast spin-echo images and compared this finding with tumor location and size as seen on contrast-enhanced T1-weighted images.

RESULTS

Not only peritumoral edema but also edema spreading along the optic tracts was observed in five patients with craniopharyngiomas, one of whom also had edema within one optic nerve. The location of edema in the visual pathway was not always associated with the degree of visual disturbance. None of the patients with large pituitary adenomas or with tuberculum sellae meningiomas had such edema along the visual pathway.

CONCLUSION

Edema caused by craniopharyngiomas tends to spread along the optic tracts. It is a useful MR finding for distinguishing craniopharyngiomas from other common parasellar tumors.

Production and secretion of endothelin-1 by cultured choroid plexus carcinoma cells

Choroid plexus carcinoma is a rare neoplasm derived from the epithelium of the choroid plexus. The production and secretion of endothelin-1 (ET-1) by cultured human choroid plexus carcinoma cells were studied by radioimmunoassay and Northern blot analysis. Immunoreactive (IR)-ET was detected in the culture medium (2.78 +/- 0.12 fmol/10(5) cells/24 h; n = 5; mean +/- SEM) but not in the unconditioned medium. Reverse-phase high-performance liquid chromatography of the extract of the culture medium showed a single peak eluting in the position of ET-1. Treatment with tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) or a combination of interferon-gamma (IFN-gamma), TNF-alpha, and IL-1 beta caused significant increases in the IR-ET levels in the culture medium. Northern blot analysis of total RNA showed the expression of ET-1 mRNA in choroid plexus carcinoma cells. The expression levels of ET-1 mRNA were increased by treatment with a combination of IFN-gamma, TNF-alpha, and IL-1 beta. The present study has shown the production and secretion of ET-1 by cultured human choroid plexus carcinoma cells and suggests the possibility that ET-1 formation is related to the pathophysiology of this tumor.

Three-dimensional and ultrastructural ICAM-1 distribution in the choroid plexus, arachnoid membrane and dural sinus of inflammatory rats induced by LPS injection in the lateral ventricles

To investigate immunological environment in the cerebrospinal fluid (CSF) system, ultrastructural and three-dimensional localization of intercellular adhesion molecule-1 (ICAM-1) was studied in the choroid plexus, arachnoid membrane and dural sinus of LPS-stimulated rats with immuno-SEM and TEM. The choroid plexus epithelial cells expressed rich ICAM-1 along the microvilli. The arachnoid trabeculae fibroblast-like cells demonstrated ICAM-1 expression on both sides facing the subarachnoid space moderately. The dural sinus endothelial cells, however, showed only few ICAM-1 expression and no specific localization. These results suggest that the choroid plexus and arachnoid membrane may play an important mutual role for leukocyte migration in the CSF system, and that the CSF system may function in immunoreaction independently of the vascular system with the aid of up-regulated ICAM-1 expression.

[Transsphenoidal surgery and gamma-knife radiosurgery for a treatment of recurrent craniopharyngioma with moyamoya vessels]

A recurrent craniopharyngioma associated with moyamoya vessels was successfully treated by partial removal of the tumor via the transsphenoidal approach followed by gamma-knife radiosurgery. This 19-year-old man was first treated by partial tumor removal and radiotherapy (54Gy) at the age of 6 years. Growth hormone and human chorionic gonadotropin were given from the ages of 13 to 18 years. At ag 17 years, follow-up magnetic resonance imaging (MRI) revealed regrowth of the tumor. At the age of 19 years, he was readmitted for treatment of the enlarging remnant tumor. Neurological examination revealed bilateral blindness. MRI showed marked suprasellar, sphenoidal and bilateral cavernous sinus extension of the tumor. Angiography revealed stenosis of the right internal carotid artery and the M1 and A1 segments of the right cerebral arteries, as well as occlusion of the C3 segment of the left internal carotid artery. There were vault and ethmoidal moyamoya vessels. The patient underwent tumor removal via the transsphenoidal approach, instead of craniotomy, to avoid injury to the transdural anastomosis. The intrasellar solid tumor was partially removed. The tumor was then irradiated by the gamma knife. MRI 15 months after the treatment showed marked reduction of the tumor. The pathogenesis of the moyamoya phenomenon and the choice of the treatment in this patient are discussed.

[A case of infantile anaplastic astrocytoma treated with surgery and chemotherapy]

A 5-month-old girl presented with enlargement of the head circumference. Neurological examination revealed right hemiparesis and bulging of the anterior fontanel. T1-weighted magnetic resonance imaging with gadolinium DTPA showed a well-enhanced, huge tumor extending from the left frontal lobe to the parietal lobe. Cerebral angiography showed the main feeding arteries were the central sulcus artery and the posterior parietal artery. The tumor was totally removed using a sulcotomy and temporary clipping of these feeding arteries to control bleeding. The histological diagnosis was anaplastic astrocytoma. Postoperative radiation therapy was avoided so as to prevent the side effect of radiation therapy such as mental retardation and growth impairment. Chemotherapy using VP-16 and CDDP was given every six months as adjunct therapy. No tumor recurrence has been recognized for over a period of 2 years and 5 months after surgery and growth and mental development have been satisfactory. Total removal using great care not to damage neurological function followed by postoperative chemotherapy is the treatment of preference to obtain good prognosis and quality of survival in infant with such tumors.

[Comparative study of pre- and postoperative three-dimensional contrast-enhanced MRI with surgical finding in patients with hemifacial spasm]

The purpose of this study was to assess the utility of three-dimensional (3D) contrast-enhanced MRI in patients with hemifacial spasm. We performed preoperative MRI in 36 patients in whom microvascular decompression (MVD) was performed and postoperative MRI in 29. All MRI studies were obtained with a 1.5T MRI system using the spoiled GRASS (SPGR) method. In all patients, neurovascular compression of the facial nerve could be detected prior to MVD, and the rate of accuracy was 91.7%. Postoperative 3D-MRI was useful in confirming of displacement of the offending vessels and assessing of its severity.

[A case of tuberous sclerosis presenting intractable adversive seizure, successfully resected with the technique of "gyrectomy"]

We report a 9-year-old girl with tuberous sclerosis presenting intractable adversive seizure. She had been suffering from frequent attacks of consciousness loss since the age of 6 years. Although a considerable amount of antiepileptic drugs had been administered, her epileptic attacks were not controlled, but instead rather increased. She had been suffering from adversive seizure to the right for more than 2 years. CT scan failed to show any abnormal density area. MRI showed a small lesion in the left frontal subcortical area. The electroencephalogram showed relatively mild abnormal waves in the left hemisphere. We undertook surgical removal of the lesion with epileptogenic foci because her epilepsy has not been controlled and the lesion could be a glioma. Abnormal spike waves were detected around the lesion with electrocorticogram. "Gyrectomy" technique was employed and the spike waves totally disappeared. After the surgery, no neurological deterioration was presented. She has suffered no seizure attack since the surgery even though the amount of the antiepileptic drugs has been significantly decreased. Resection of the epileptogenic foci as well as the abnormal lesion using the technique of gyrectomy is useful for the control of the intractable epilepsy, and makes the quality of life of patients much higher.

[A case of a ruptured lingual artery aneurysm treated with endovascular surgery]

A rare case of a ruptured lingual artery aneurysm treated with endovascular procedure in presented. A 67-year-old woman undergoing treatment in our hospital for right thalamic hemorrhage complained of sudden swelling in the submandibular area and breathlessness. The swelling was so rapid and progressive that her breathing was disturbed. She was intubated as soon as possible. Computed tomography (CT) showed a massive subcutaneous hematoma, extending from the left submandibular area to the neck, which had compressed the trachea to the right. CT with contrast medium showed extravasation of the medium for this lesion. Angiography showed that the aneurysm was located on the periphery of the left ingual artery. Extravasation of contrast medium from the aneurysm was also observed. We considered that direct surgery was difficult to perform safely, so we chose an endovascular procedure to treat this lesion. The lingual artery was successfully embolized using four platinum coils. No rebleeding or other complication occurred after the coil embolization. Disturbance of breathing due to air way obstruction is an important symptom of a ruptured lingual artery aneurysm. Endovascular surgery may be the first choice for treatment of the bleeding origin.

Adult respiratory distress syndrome in patients with malignant astrocytoma--three case reports

Three patients treated for intracranial malignant astrocytomas developed adult respiratory distress syndrome (ARDS). All three patients had a Karnofaky performance status score of at least 80% and similar clinical characteristics. All demonstrated hypersensitivity to phenytoin. ARDS occurred in two patients during radiotherapy and in one with radiation-induced brain damage following initial radiochemotherapy. ARDS occurred shortly after tapering the long-term administration of betamethasone. The initial symptoms were dry cough, fever, and generalized toxic eruption. Serum lactic acid dehydrogenase (LDH) concentrations were increased up to 2500 IU/l. Several days later, the patients suddenly complained of dyspnea. All patients fulfilled the diagnostic criteria for ARDS. Two patients recovered, but a young woman died. Clinical symptoms such as fever of unknown origin, dry cough and skin eruptions, accompanied by abnormally increased serum LDH concentrations during or following the tapering of long-term administration of corticosteroids, are warning signs of ARDS in patients being treated for malignant gliomas.

[The EMG findings of spasmodic torticollis--the character of the EMG findings of neurogenic torticollis]

Spasmodic torticollis is a clinical entity that is hard to treat though various symptomatic therapy have been tried. On the other hand, microvascular decompression operation have been established for cranial nerve vascular compression syndrome such as hemifacial spasm. Case reports on the decompression of the spinal accessory nerve for the treatment of spasmodic torticollis have been published on the basis of the concept of cranial nerve vascular compression syndrome. Thus, spasmodic torticollis related to unilateral accessory nerve has attracted much attention for selecting an optimal treatment, although there have not been any diagnostic criteria with electromyographic study. From the viewpoint of the clinical electrophysiological findings on hemifacial spasm those we have acquired by EMG study, we have examined the EMG findings of various types of spasmodic torticollis and here report the classification of spasmodic torticollis based on the EMG study. Thirty-five patients with spasmodic torticollis were analyzed. The symptoms were classified to the horizontal rotation type, the lateral bending type and the mixed type with the number of each group of 23, 2 and 10, respectively. As we have shown the criteria of the EMG findings on hemifacial spasm, the EMG of the patients with spasmodic torticollis were analyzed on four conditions as follows; (1) distribution of the involved muscles, (2) maximum firing rate of the abnormal spontaneous activity of the sternocleidomastoid muscle, (3) synkinetic discharge between the muscles innervated by unilateral accessory nerve and (4) alteration of the spontaneous muscle discharge by posture change. Abnormal spontaneous muscle discharges were recorded only from the sternocleidomastoid muscle and the trapezius muscle on the same side in twelve patients. Maximum firing rate of spontaneous muscle discharge was higher than that of maximum voluntary contraction in twenty-two patients. Abnormal synkinetic discharge was recorded between the sternocleidomastoid muscle and the trapezius muscle on the same side in twenty-one patients. Spontaneous EMG activities of the muscles innervated by the accessory nerve increased when the patients stood up from the resting supine position in thirty-one patients. Thus, ten patients out of thirty-five subjects had all four conditions mentioned above as typical patients with hemifacial spasm usually had. These ten patients with spasmodic torticollis were thought to have strong similarity to the EMG characteristics of hemifacial spasm that suggested hyperexcitability of unilateral accessory nervous system. This classification with EMG is considered to be useful in diagnosing the spasmodic torticollis related to unilateral accessory nerve and can be applied for selecting an optimal treatment.

Immunohistochemical detection of tumor marker in recurrent clivus enterogenous cyst--case report

A 26-year-old male presented with recurrence of an enterogenous cyst in the intracranial region 10 years after the first operation. The cyst was drained and the cyst wall partially resected at both operations with good outcome. Histological examination showed a change from one layer epithelium in the first specimen to glandular structures in the second. Alcian blue, periodic acid-Schiff, and immunohistochemical staining for epithelial membrane antigen, S-100 protein antigen, keratin, and carcinoembryonic antigen were used to confirm the accurate diagnosis. Immunohistochemical staining showed CA19-9 antigen was positive in both specimens. The CA19-9 level in the cerebrospinal fluid was extremely high (621.5 U/ml) at the second operation. Patients with enterogenous cyst should be monitored to detect possible recurrence.

Multiple intracranial mixed germ cell tumors

A case of sequential occurrence of multiple intracranial mixed germ cell tumors is presented. An 8-year-old boy with a cystic calcified tumor in the basal ganglia and an increased serum alpha-fetoprotein concentration was initially treated with radiotherapy. Six years later, a tumor composed of embryonal carcinoma and immature teratoma arose from the right temporo-parietal lobe. This tumor was treated successfully with surgery and radiochemotherapy. The possibility of multicentricity or intra-axial metastasis distant from the original site during the long-term course should be considered in treatment for intracranial germ cell tumors.

[Localized glioma in the occipital lobe manifesting as scintillating scotoma: case report]

An 11-year-old female presented with headache in May 1993. Magnetic resonance (MR) imaging disclosed a small lesion (9 mm in diameter) in the left occipital lobe. No treatment was performed because the lesion was small. She subsequently developed frequent episodes of scintillating scotoma in the right visual field eleven months later. MR imaging eleven months after the first MR imaging showed the lesion had enlarged to 14 mm in diameter. Preoperative surface electroencephalography (EEG) detected no spike waves. The diagnosis was localized glioma. The mass was totally removed by gyrectomy in December 1994. Intraoperative cortical EEG demonstrated spike waves which disappeared after tumor removal. The histological diagnosis was pleomorphic xanthoastrocytoma. No postoperative neurological deficit was recognized, and scintillating scotoma and headache disappeared. Postoperative stereotactic radiosurgery was performed. The scintillating scotoma was caused by the tumor, because the spike wave and phase reversal were detected by the intraoperative cortical EEG. Intraoperative EEG is useful for the diagnosis of epilepsy caused by tumor. Sulcotomy and gyrectomy are the optimal surgical treatments for epilepsy caused by a localized glioma.

Production and secretion of adrenomedullin by cultured choroid plexus carcinoma cells

Adrenomedullin is a potent vasodilator peptide that was originally isolated from pheochromocytoma. The production and secretion of adrenomedullin by cultured choroid plexus carcinoma cells were studied by radioimmunoassay and northern blot hybridization. Choroid plexus carcinoma is a rare malignant tumor derived from the epithelium of the choroid plexus. Immunoreactive adrenomedullin was detected in the conditioned medium of choroid plexus carcinoma cells (40.8 +/- 7.5 fmol/10(5) cells/24 h; mean +/- SEM, n = 5). Reverse-phase HPLC of the conditioned medium showed one major peak of the immunoreactive peptide eluting in the position of synthetic human adrenomedullin and two smaller peaks eluting earlier. Addition of interleukin-1 beta (10 ng/ml) alone or in combination with three cytokines, interferon-gamma (100 U/ml), tumor necrosis factor-alpha (20 ng/ml), and interleukin-1 beta (10 ng/ml), caused significant increases in the immunoreactive adrenomedullin concentrations in the medium (approximately 175 and 293% of the control level, respectively). Northern blot analysis showed the expression of 1.6-kb adrenomedullin mRNA in the total RNA sample prepared from cultured choroid plexus carcinoma cells. Treatment with either interleukin-1 beta or the combination of three cytokines caused significant increases in levels of adrenomedullin mRNA in parallel with those in immunoreactive adrenomedullin concentrations in the conditioned medium. These findings raise a possibility that adrenomedullin is secreted from the choroid plexus and has physiological roles in the CNS via the CSF. In addition, adrenomedullin secreted from choroid plexus carcinoma may be related to the pathophysiology of the tumor.

Clinical and biological considerations regarding glioma based on the TUNEL method and immunohistochemical staining using apoptosis-related antibodies

We examined 36 gliomas both by the terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick-end-labeling (TUNEL) technique and by immunostaining of antibodies against apoptosis-related antigens. The apoptotic index (AI) obtained by the TUNEL method was 10.77 +/- 3.78% in astrocytomas, 6.19 +/- 1.81% in anaplastic astrocytomas, and 5.21 +/- 1.14% in glioblastomas. The AI of anti-Fas antibody and Le(Y) antibody in gliomas also showed a similar tendency as the results with the TUNEL method. As a result, statistically significant differences were observed in the distribution of survival between the two groups according to the AI obtained by the TUNEL method. Therefore, an analysis of the AI is considered to be useful for prognosis.

Production and secretion of adrenomedullin from glial cell tumors and its effects on cAMP production

The expression of adrenomedullin (ADM) and its mRNA was studied in human glial cell tumors and cultured glioblastoma cell lines, T98G and A172. Northern blot analysis showed that ADM mRNA was expressed in all brain tumors examined (three anaplastic astrocytomas and two glioblastomas multiforme) and in the glioblastoma cell lines. Immunoreactive (IR-) ADM was detectable in these brain tumors by radioimmunoassay (0.31-2.0 pmol/g wet weight), except for one anaplastic astrocytoma. Reverse phase high performance liquid chromatography of the tumor extracts showed a single peak eluting in the position of ADM-(1-52). IR-ADM concentrations in the cultured media of T98G cells were 205.5 +/- 8.4 fmol/10(5) cells/24 h (mean +/- SEM, n = 5). Treatment of T98G cells with interferon gamma or interleukin 1 beta increased the expression levels of ADM mRNA and the IR-ADM concentrations in the cultured media, whereas tumor necrosis factor alpha decreased them in a dose-dependent manner. Treatment with synthetic ADM-(1-52) (10(-8) or 10(-7) mol/l) increased the cAMP concentrations in the cultured media of T98G cells. These findings suggest that ADM is secreted from glial cell tumors and is related to the pathophysiology of these tumors.

Antioxidant property of Fructus Momordicae extract

The antioxidant effect of Fructus Momordicae extract, FME (mogrosides 75 approximately 80%), was studied. FME reduced the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and scavenged superoxide radicals (O2-) generated by a hypoxanthine and xanthine oxidase system. It also scavenged hydroxyl radicals (.OH) generated by Fenton reaction. In addition, FME inhibited Fe(II) induced lipid peroxidation in rat cortex homogenates in a dose-dependent manner, as indicated by decreased thiobarbituric acid-reactive substances (TBARS) formation. Oral administration of FME inhibited TBARS and malonaldehyde (MDA) formation in the ipsilateral cortex 30 min after iron-salt injection into the left cortex of rat. FME showed inhibitory effect on 4-hydroxy-2(E)-nonenal (4-HNE) formation induced by Fe(III) injection into the rat cortex. These data suggest that Fructus Momordicae extract has an antioxidant activity against free radicals and lipid peroxidation.

IGF2 but not H19 shows loss of imprinting in human glioma

Genomic imprinting is a gamete-specific modification resulting in the allele-specific expression of genes in somatic cells. A loss of imprinting (LOI) has been found in many embryonal and adult tumors, suggesting that it plays a role in tumor development. The incidence of LOI, however, does not seem to be ubiquitous among tumors because neuroblastoma and colorectal cancer revealed no LOI. We examined the involvement of LOI of IGF2 and H19 genes in human gliomas. The two genes were imprinted in normal brain subcortex tissues. In glioma, 8 of 14 informative cases (57%) revealed LOI in IGF2. The frequency did not depend on the tumor grade. For H19, in contrast, all 13 informative cases maintained imprinting. These results suggest that LOI of IGF2 but not H19 plays a role in the development of human glioma.