Isolation of radiosensitive and radioresistant mutants from a medulloblastoma cell line

Two mutant clones, one radiosensitive (OS-3) and one resistant (OR-5), were isolated from ONS-76 after screening 2400 clones by the replica micro-well technique. These two clones exhibited significantly different radiosensitivity, with D37 values of 4.7Gy in OR-5 and 1.7Gy in OS-3. After gamma irradiation (8Gy), OR-5 exhibited greater G2 arrest than sensitive clone OS-3. Administration of 5mM of caffeine resulted in greater cell killing in OR-5 than in OS-3, with an almost complete release of G2 block. These observations support the notion that the G2 block contributes to the repair process of DNA damage after irradiation. The present results suggest that clones with a large postirradiation G2 block may show a greater reduction in radiosensitivity if the G2 block is released artificially. The study of the mutant clones described herein may provide important clues to the mechanism by which glioma cells acquire radioresistance.

Tumor specific contrast enhancement study of Mn-metalloporphyrin (ATN-10)--comparison of rat brain tumor model, cytotoxic and vasogenic edema models

ATN-10, Mn-metalloporphyrin, has been developed as a tumor selective contrast agent for magnetic resonance (MR) imaging. To investigate the tumor specificity of ATN-10, we produced three experimental in vivo models; rat bran tumor (9L glioma) model, vasogenic (cold injury) and cytotoxic brain edema (24-hour MCA occlusion) models. The time course of contrast enhancement was compared after intravenous injection of ATN-10 or Gd-DTPA, measuring the signal intensity of the region of interest. After ATN-10 administration, the 9L glioma model showed early (5 min) and delayed (24 hr-) peak enhancement whereas the cold injury model showed only early enhancement and the 24-hour MCA occlusion model did not show significant enhancement. After Gd-DTPA administration, all three models showed similar pattern of only early enhancement. As a contrast agent for MR imaging, ATN-10 showed different behavior than Gd-DTPA in demonstrating the blood-brain barrier disruption and moreover ATN-10 showed selective enhancement in experimental brain tumors.

Elevated levels of mortalin expression in human brain tumors

We have performed immunohistochemical studies of mortalin in normal and tumor human brain sections. In normal brain sections, the expression was seen mainly as being confined to neurons. Normal astrocytes showed undetectable expression of this unique member of the heat shock 70 protein family. Three grades of astrocyte tumors (low-grade astrocytoma, anaplastic astrocytoma, and glioblastoma), however, showed an increasing number of mortalin-positive cells. Other types of brain tumors, such as meningiomas, neurinomas, pituitary adenomas, and metastases, also showed elevated levels of mortalin expression compared to those in the normal brain. Mortalin has earlier been reported to have differential intracellular distribution in normal and transformed cells in vitro. Therefore, we substantiated the present study with immunofluorescence localization of the protein in normal and glioblastoma cells. The observations indicated that the tumors might be expressing a nonpancytosolic mortalin. An increase in number of mortalin-positive cells with malignant progression of brain tumors and its correlation with Ki-67 (a cell proliferation marker)-positive cells further suggested an involvement of nonpancytosolic mortalin(s) in malignant transformation of cells in vivo.

[Subependymal tumor with metaplastic bone formation: a case report]

A 26-year-old woman was admitted to our hospital because of headache. CT scan and MRI showed a right subependymal nodule and a left ventricular tumor, neither of which had any enhancement nor were they stained in angiography. Although no skin abnormality was detected, the patient was suspected of tuberous sclerosis. The diagnosis was made because of the subependymal nodule on CT scan and MRI. On June 29, 1995, total removal of a left ventricular tumor was performed by a transcortical approach. Histological sections of this tumor consisted of astrocytic and meningothelial components, containing metaplastic bone formation. Histological diagnosis was dysplastic subependymal tumor. Postoperative course was uneventful. Regrowth of the tumor has not been observed as of now. This case was suspected to involve factors of tuberous sclerosis from a subependymal nodule. However, the ventricular tumor was not diagnosed as a subependymal giant cell astrocytoma.

[Transient decrease in the size of an enhanced anaplastic astrocytoma seen on magnetic resonance imaging: a case report]

We report unusual radiographic findings which were seen during the management of a patient with anaplastic astrocytoma. An enhanced region in a gyrus of the right frontal lobe was demonstrated in a 38-year-old woman who had had a generalized seizure. Following treatment with steroid- and osmotherapy, this enhanced region decreased clearly on magnetic resonance imaging (MRI). Six months later, an enhancing mass lesion appeared in the same position. After surgery, this was diagnosed as being an anaplastic astrocytoma. It is speculated that the initial enhancement was caused by transient dysfunction of the blood-brain following the seizure. In this case, the most important radiologic image was a T2-weighted image of MRI which was able to demonstrate the existence of the lesion until the time of its removal by surgery.

[FLAIR images of cerebral and brain stem infarction]

FLAIR (fluid-attenuated inversion recovery) images are MR images obtained with an inversion recovery sequence having a long inversion time (TI) and a long echo time (TE). We examined 47 cases (56 graphics) of lacunar infarction (LI), 28 cases (32 graphics) of cortical infarction (CI) and 16 cases (23 graphics) of stem infarction (SI) with a FLAIR sequence having a repetitive time (TR) of 6500 msec, a TI of 1700 msec and a TE of 110 msec, and compared these graphics with T2-weighted images by spin-echo sequence (TR 2500 msec, TE 90 msec). LI and CI were better demonstrated with FLAIR images than with conventional T2-weighted images. FLAIR images were very useful in detecting lesions adjacent to the lateral ventricles and the cerebral sulci in particular, because the cerebrospinal fluid signals in the lateral ventricles and the cerebral sulci were low-intensity, with brain tissue appearing as high-intensity areas. In a number of old infarctions, FLAIR images revealed cystic structures, constructed out of internal low-intensity areas and peripheral high-intensity areas. These structural changes suggested that FLAIR images can provide information on pathological changes.

Brainstem arteriovenous malformation with a pedicle aneurysm treated by endovascular surgery and proton-beam radiosurgery--case report

A 39-year-old male presented with a small pontine hemorrhage and subarachnoid hemorrhage. Angiography showed a small left pontine arteriovenous malformation (AVM) associated with a small aneurysm on the pedicle feeding the AVM. The pedicle aneurysm was occluded by microcoils. The AVM was then treated by proton-beam radiosurgery. Follow-up angiography 2 years later revealed that the AVM had disappeared completely without neurological deficit. The combination of embolization and proton-beam radiosurgery was curative in this patient with a pontine AVM associated with an aneurysm on the feeding artery, showing that these techniques can be used to treat inoperable vascular lesions safely.

[FLAIR images of patients with head injuries]

FLAIR (fluid-attenuated inversion recovery) images are MR images obtained with an inversion recovery sequence, which has a long inversion time (TI) and a long echo time (TE). We examined 29 cases (49 graphics) of cerebral contusion, 11 cases (22 graphics) of diffuse axonal injury (DAI) and 11 cases (11 graphics) of traumatic subarachnoid hemorrhage (t-SAH) with FLAIR sequence consisting of a repetitive time (TR) of 6500 msec, TI of 1700 msec and TE of 110 msec, and these graphics were compared with T2-weighted images by spin-echo sequence (TR 2500 msec, TE 90 msec) and computed tomographic (CT) scans. Some lesions of DAI were demonstrated more clearly with FLAIR images than with conventional T2-weighted images. Although contusion could be detected with FLAIR images as well as with conventional T2-weighted images, lesions adjacent to cerebral sulci were better delineated with FLAIR images. Because the cerebrospinal fluid signals in cerebral sulci were low-intensity, FLAIR images were useful in detecting lesions of the cerebral cortex adjacent to cerebral sulci. Although it has been reported that detection of SAH is difficult with standard T1- and T2-weighted images, the presence of t-SAH could be confirmed with FLAIR images as seen in CT scans.

Cerebral radiation necrosis with accumulation of thallium 201 on single-photon emission CT

A patient who had previously undergone resection of a malignant glioma followed by radiation therapy was found to have a focus of a high accumulation of thallous chloride Tl 201 on single-photon emission CT scans, suggesting recurrent tumor. Resection of this area was performed and the specimen showed radiation necrosis, including such reactive changes as reactive astrocytes and lymphocytes in the necrotic tissue. This case illustrates a diagnostic pitfall in the use of 201Tl single-photon emission CT for distinguishing radiation necrosis from recurrent tumor in patients treated for malignant glioma.

Expression of N-ras gene in gliomas

Expression of N-ras gene was examined by northern blot analysis in two cases of astrocytoma (grade II), four cases of glioblastoma multiforme (six samples including two recurrent tumors), and normal brain tissues. Expression of N-ras gene was only found in the two recurrent glioblastoma multiforme samples. Southern blot analysis found no significant difference in copy numbers of N-ras gene in pre- and post-recurrence samples. The histological diagnosis of the two recurrent tumors was glioblastoma multiforme at both first recurrent presentation. However, the tumors had progressed during recurrence, because of worsened histological findings, such as increased cellularity, pleomorphism, and vascularity. These tumors recurred at very short intervals. Enhanced expression of N-ras gene by disorder of transcription may be a factor in the progression of glioblastoma multiforme.

[Rupture of thoracic aorta due to blunt trauma: a report of three cases]

Three cases of the thoracic aortic rupture due to blunt trauma were successfully treated. All of the cases were young male motorcyclists. The chest X-ray on admission showed either a widened mediastinum or an apical extrapleural cap sign. Ruptures were confirmed by an enhanced CT clearly showing the presence of a psuedoaneurysm and a hematoma around the isthmus of the aorta. One of them was operated upon urgently and others in whom heparin could not be used because of associated injuries were operated upon electively two and three months after the traffic accident, respectively. In two of them, aneurysms were removed and replaced with dacron grafts and in the remaining one, the aneurysm was resected and repaired directly under the femoro-femoral bypass. Post-operative courses were uneventful. They discharged and are doing well after the treatment for associated injuries. In view of the high early mortality of aortic rupture, an early diagnosis and treatment is important. But in the case who has stable hemodynamics and contraindication for heparinization, a delayed operation may be recommended.

Concentration of vascular endothelial growth factor in the serum and tumor tissue of brain tumor patients

Vascular endothelial growth factor (VEGF) has been investigated as a potent mediator of brain tumor angiogenesis, vascular permeability, and glioma growth. Using a VEGF ELISA, we determined the concentration of VEGF in the sera and tumor extracts of 19 brain tumor patients including glioblastoma, anaplastic astrocytoma, low grade astrocytoma, meningioma, malignant lymphoma, and metastatic brain tumor as well as normal brain. Although VEGF concentration of the serum was not correlated with that of the tissue, VEGF concentrations of glioblastoma cyst fluid were 200-300-fold higher than those of serum in the patients. VEGF concentration in the tumors was significantly correlated with the vascularity measured by counting vessels stained with von Willebrand factor antibody. VEGF protein localized to the cytoplasm of tumor cells and vasculature in gliomas, predominantly in the peripheral microvessel "hot spots" as well as around the necrosis in glioblastomas. VEGF immunopositivities were well reflected with VEGF concentration determined by ELISA. VEGF ELISA demonstrated time-dependent increase of the VEGF concentration in the serum-free conditioned medium of various glioma cell lines. The conditioned medium with high VEGF concentration induced endothelial cell migration. These observations suggest that VEGF represents a useful marker and measurable element of glioblastoma angiogenesis. The measurement of VEGF concentration by ELISA in tumor and tumor cyst fluid may allow for the assessment of vascularity in gliomas.

Assessment of a Continuing Education Evaluation Framework

This study analyzes a systems model for evaluation research of continuing education (CE) and reports on the result of a quasi-experimental study of a stoma care CE program. Holzemer's conceptual framework for evaluating CE consisting of the learner, setting, and program along with a systems model was used as an organizing framework. A quasi-experimental design (n = 24 experimental group and n = 27 control group) was used to evaluate the impact of the CE program. Pre- and post-tests of participants' knowledge and skills of stoma care were evaluated. Participants' satisfaction with the course was surveyed by questionnaire during the course, on completion and four months after the course. No significant differences were found between the two groups. The revised framework included the concept of needs assessment and the impact of the CE program on patient care.

Correlation of histopathological factor of brain tumor and high thallium-201 uptake in single photon emission computed tomography

This study was undertaken to investigate the relationship between several histological features and the degree of TI-201 uptake in brain tumors. T1-201 SPECT was performed on 52 patients with intracranial lesions. Histological examinations were carried out to determine the gradation of tumor cell density, vascularization, small-cell density, and matrix loosening, and the presence of necrosis, atypia, mitoses, and endothelial proliferation. The histological findings were classified into three categories. While the early uptake of T1-201 depended on the degree of necrosis of glial tumor, the delayed T1-201 uptake was closely related to the degree of necrosis, tumor cell density, and small-cell density, and may thus be of value for estimating the viability and degree of malignancy of glial tumors. In the non-glial tumors, the early and delayed T1-201 uptakes were closely related to all histological parameters, with the increase of necrosis and vascularization in the tumor tissue being particularly closely related to high uptake levels.

Induction of human autologous cytotoxic T lymphocytes against minced tissues of glioblastoma multiforme

The authors induced autologous cytotoxic T lymphocytes (CTLs) directly from peripheral blood lymphocytes by preparing a coculture of minced tissue fragments of glioblastoma multiforme (GBM) with interleukins-1, -2, -4, and -6 and interferon-gamma in RHAM alpha medium containing 5% autologous plasma for 2 weeks. At the end of this period, the frequencies of CD3+, CD4+, CD8+, and CD16+ lymphocytes were 95% to 99%, 40% to 62%, 37% to 38%, and 0.2%, respectively. The lymphocytes killed 82% to 100% of the GBM cells within 48 hours at an effector-to-target cell ratio of 1.67, whereas in a separate coculture, autologous lymphokine-activated killer (LAK) cells killed only 33% of GBM cells under the same conditions. The lymphocytes showed no cytotoxicity against LAK-sensitive Daudi cells, natural killer-sensitive K562 cells or autologous fibroblasts grown from the brain tumor, although they did show slight cytotoxicities against allogeneic GBM cell lines. These results lead the authors to suggest that the lymphocyte population contains specific CTLs for autologous brain tumor cells and that these CTLs could be effective in adoptive immunotherapy to combat brain tumor.

Separation of B-3 monodesamidoinsulin from human insulin by high-performance liquid chromatography under alkaline conditions

The separation of human insulin (HI) and related compounds such as A-21 monodesamido HI (A-21DHI) and B-3 monodesamido HI (B-3DHI) was investigated using reversed-phase HPLC and capillary zone electrophoresis (CZE). In the case of HPLC under the usual acidic conditions, whereas A-21DHI was separately eluted, B-3DHI was included in the HI peak. Then it was found that by applying a novel ODS column resistant to alkaline conditions, a good separation of B-3DHI from HI could be achieved using an alkaline eluent, and two peaks corresponding to B-3DHI were eluted in front of the HI peak.

Nuclear morphometry and DNA densitometry of human gliomas by image analysis

In 48 patients with gliomas in whom complete clinical follow-up was obtained, DNA ploidy was evaluated by using formalin-fixed paraffin-embedded tissues and by means of image analysis. The mean DNA indices, determined by averaging DNA indices of all tumor cells in a tumor, were mainly affected by mean DNA indices of the nuclei of SG2M phase tumor cell (including S phase and G2M phase cells) (SG2M DNA indices) and that mean DNA indices correlated with the SG2M phase fraction. The SG2M DNA indices and the percentage of tumor cells with S phase and G2M phase were higher in high grade gliomas including anaplastic glioma and glioblastoma multiforme than in low grade gliomas. Patients with G2M-hypertetraploid tumors demonstrated a shorter time to tumor progression than those with G2M-tetraploid in high grade glioma. Morphometrically, the nuclei of SG2M phase glioma cells were larger and more deformity than those of G0G1 phase (including G0 phase and G1 phase cells) cells. The G2M-hypertetraploid tumors were highly malignant and demonstrated large nuclei, greater nuclear deformity, and a higher proliferative potential. The G2M-tetraploid gliomas demonstrated a shorter time to tumor progression in cases whose the SG2M fraction was large. In contrast, G2M-hypotetraploid gliomas revealed an insignificant trend towards a longer time to tumor progression than those associated with tetraploid and hypertetraploid gliomas. We emphasize herein the prognostic importance of the SG2M phase cell, as well as other proliferation indices.

Cerebral gumma mimicking glioblastoma on magnetic resonance images--case report

A 39-year-old female presented with a syphilitic cerebral gumma mimicking small glioblastoma multiforme manifesting as visual impairment. Magnetic resonance imaging showed a low signal intensity area on T1-weighted images and marked small ring-like enhancement less than 1 cm in diameter following the administration of gadolinium. The symptoms and radiological abnormalities improved several weeks after penicillin therapy. The small ring-like enhancement was probably caused by inflammation associated with treponemal infection. A mass with a small ring-like enhancement less than 1 cm in diameter is a useful finding indicating an inflammatory lesion rather than a glial tumor.

[Low incidence of point mutation of N-ras oncogene in human gliomas]

We examined the incidence of point mutations in codon 12 and 61 of N-ras gene in human gliomas using PCR with mismatched primers. This method detects point mutations. PCR with mismatched primers induced restriction sites in normal DNA but not in mutational DNA. Genomic DNAs were extracted from paraffin-embedded tissues and were amplified with nested PCR. Among 17 cases, point mutation has not been able to be found so far, when examined in codon 12 of N-ras gene and among 10 cases in codon 61 of N-ras gene. It can thus be said that point mutational activation of N-ras oncogene is an uncommon event in human gliomas.

[Transient cerebellar mutism after removal of a posterior fossa tumor in two cases]

We have reported the cases of two young patients who presented transient mutism in the course of recovery from removal of a cerebellar medulloblastoma. Although cerebellar symptoms were observed immediately after surgery, neither consciousness disturbance nor sensory aphasia was observed when the patients were mutic. From the analysis of serial magnetic resonance imaging (MRI). Gd-enhanced regions were noticed in the dentate nucleus and the cerebellar peduncle when mutism appeared, and they disappeared when mutism was gone. Although the mechanism of this interesting symptom is not clear, these MRI findings may indicate that focal ischemia or edema associated with surgical procedure may play a role in the appearance of this symptom.

Difference between cancer cells and the corresponding normal tissue in view of stereoselective hydrolysis of synthetic esters

This study has aimed at taking information necessary for design of anticancer prodrugs modified with chiral acyl group, especially about the effect of chirality of the acyl group on its enzymic removal in specific cells. Thus, 13 species of chiral esters were synthesized and stereoselectivity in their enzymic hydrolysis was investigated with six cancer cell lines, solid tumors, and the corresponding normal tissues. Cultured cancer cells from rat liver, pancreas, and muscle hydrolyzed the R enantiomer of (+/-)-ethyl 2-methoxy-2-phenylacetate (3c) more preferentially than its antipode, whereas this stereoselectivity was reversed in the reaction by homogenate of the corresponding normal tissue of rat. The difference in stereoselectivity between cancer cells and normal tissue was also found in the hydrolysis of other esters including those of actual anticancer agents, p-hydroxyaniline mustard and 5-fluorouridine. The investigation was expanded to real tumor to show that the degree of stereoselectivity or the hydrolytic activity was significantly different between a human brain tumor and its surrounding normal tissue for such substrates as (+/-)-ethyl 2-phenoxypropanoate and N-trifluoroacetylphenylalaninate. The esterases of rat liver cancer cells (Anr4) and normal rat liver gave different band patterns in active staining after gel electrophoresis. The enzymes were fractionated by ion exchange column chromatography and then tested on their stereoselectivity against (+/-)-3c. Comparison of the results and electrophoretograms of the fractions suggests that esterases with different stereoselectivity are expressed in different ways by normal and cancer cells. These results show that stereoselectivity in enzymic hydrolysis of some synthetic chiral esters is different between cancer and normal cells, leading to the possibility that specific activation of ester-type anticancer prodrugs in cancer cells would be controlled by the chiral structure of the acyl group.

Nuclear characterization and G2M ploidy in human brain tumors using semiautomated image analysis

We used image analysis to study nuclear morphometry and DNA content in relation to time to tumor progression in a series of 88 patients with brain tumors. Clinical follow-up was obtained for 73 patients. The patients with diploid tumors had a longer time to tumor progression than those with triploid, tetraploid, or hypertetraploid tumors. Mean SG2M-DNA indices (DIs) increased significantly with a increase in mean DIs in all tumors. The mean DIs appeared to be dependent on the number of SG2M phase cells. We conclude that tumors with hypertetraploid in G2M ploidy are highly malignant. Those tumor cells have a large nuclear size, much deformity in nuclear shape, and great proliferative potential. The G2M-tetraploid tumors showed a shorter time to tumor progression when the number of SG2M fractions was large. In contrast, the G2M-hypotetraploid tumors showed a longer time to tumor progression in comparison with other tetraploid and hypertetraploid tumors, but the difference was not significant.

Osteomas of the skull: comparison of magnetic resonance imaging and histological findings

Magnetic resonance (MR) images of five patients with osteomas of the skull and six patients with other primary skull tumors were reviewed. All osteomas appeared as low-intensity areas on T1-weighted images. T2-weighted images showed homogeneous low-intensity areas in two dense osteomas, a high-intensity area in one spongy osteoma, and mixed intensity areas in two mixed spongy and dense osteomas, respectively. The signal intensities of osteomas on T2-weighted MR images correlated well with the histological findings. Other skull tumors showed no specific MR imaging appearance.

Leukoencephalopathy associated with intra-arterial ACNU in patients with gliomas

Thirty cases of gliomas treated by surgery, radiotherapy and intra-arterial (IA) ACNU were reviewed with a focus on the late side-effect known as leukoencephalopathy. All cases were classified into three groups; remission (10 cases), regrowth (15 cases) and leukoencephalopathy (5 cases) from their outcome. The average total doses of IA ACNU were 49.8 mg/sqm body surface area in the remission group, 157.3 mg/sqm in the regrowth group and 203.1 mg/sqm in the leukoencephalopathy group. There were significant differences in the total IA ACNU doses between the remission group and both regrowth and leukoencephalopathy groups, while no significant differences were noticed in the dose of radiation given. There was a correlation between the total dose of IA ACNU and the occurrence of leukoencephalopathy. An autopsy of a typical case of leukoencephalopathy revealed various degrees of myelin breakdown and thickening of arterial walls, which probably manifested progressive dementia accompanied by urinary incontinence and gait disturbance.