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Biomedical subjects

A Zama

Publications and source records attributed to A Zama.

At least 19 recordsLinked to original sources
PubMed2000

Glioma/glioblastoma-specific adenoviral gene expression using the nestin gene regulator.

For glioma- and glioblastoma-specific gene expression, we utilized a nestin regulatory element whose activity was evaluated by the reporter gene lacZ. Nestin is a 38-kDa intermediate filament protein, and is expressed specifically in the neuroepithelial stem cells. Nestin is detected in gliomas and glioblastomas, but not in normal brain tissue. We constructed a nestin gene regulator by placing nestin's second intron before the 5' upstream region (2iNP). To obtain enhanced expression of this tissue-specific regulator, we utilized the adenovirus double-infection method with a Cre-loxP on/off switching system. We constructed a 'regulator' vector, Ax2iNPNCre, which expresses Cre recombinase under the control of the nestin regulatory element, 2iNP. A 'reporter' vector, AxCALNLNZK, expresses lacZ under the control of a strong CAG promoter when the stuffer sequence has been removed by Cre recombinase at a pair of loxP sites. We used seven human glioma/glioblastoma cell lines: U251, KG-1C, NGM5, U87 MG, LN-Z308, NP-2 and T98G. Of these, nestin was expressed highly in U251 and KG-1C, less in NGM5, and undetectably in the other four lines. With the use of the two adenovirus vectors, we found X-gal staining and high nestin regulator-promoted beta-galactosidase activities in four of the seven glioma/glioblastoma cell lines. Staining was strong in U251, KG-1C and NGM5, and less in U87 MG. LacZ expression was nearly undetectable in the non-glioma cell line, HeLa, but a little in COS-7. The adenovirus double-infection method, which uses a nestin regulator, is applicable for glioma/glioblastoma-specific expression.

Adenoviridae↗
PubMed1999

[Cranial fasciitis of a neonatal case with massive intra- and extracranial extension].

We report a neonatal male case of cranial fasciitis in childhood. He was born with a large skull tumor in his left fronto-parietal region. The day after his birth, he was admitted to our hospital. On inspection, the mass was firm, non mobile, and had two humped peaks. The size of the mass was 7 x 5 x 4 cm, and it was located on the left coronal suture and fontanelle. The overlying skin was normal. Skull X-rays revealed osteolytic defect and linear bone remnant skirted the outer rim of the tumor. CT scan showed a slightly high-density large frontal mass with a low density area in the center of it and marked enhancement. MR images revealed a large mass with massive intra- and extracranial extension. Cerebral angiography showed the remarkable vascularization of the tumor. Preoperatively, the branches of the external carotid artery were partly embolized. On surgery, the profusely bleeding, elastic hard, yellowish-white mass arising from the dura was partially removed with the surrounding bone. A small mass remained subdurally. The boundary of the mass and the dura was not well demarcated. After the operation, no neurological deficits were seen. 16 months after the surgery, MRI revealed the unfolded brain with no evidence of tumor. Histological examination showed characteristic proliferation of spindle-shaped fibroblasts embedded in a collagenous stroma. Inflammatory lymphocytes and acidophils were also noted. Electron micrograph revealed a tumor cell rich in rough endoplasmic reticulum and nuclei with numerous indentations. Immunostaining confirmed that these cells were positive for vimentin but negative for smooth muscle actin, GFAP, S-100 protein, and desmin. No recurrence of this tumor has been detected at four years of follow-up.

Actins↗
PubMed1998

Assessment of malignancy of glioma by positron emission tomography with 18F-fluorodeoxyglucose and single photon emission computed tomography with thallium-201 chloride.

The histological diagnosis and proliferative potential measured by bromodeoxyuridine (BrdU) labelling index (LI) were correlated with preoperative CT and contrast-enhanced, MRI, 18F-fluorodeoxyglucose positron emission tomography (PET) and 201T1 single photon emission computed tomography (SPECT) in 43 patients with various grades of glioma. 201T1 SPECT had slightly higher sensitivity to tumours with BrdU LI > or = 5% (showing 10/10) than 18F-FDG PET (7/8 tumours). 18F-FDG PET was better for identifying tumours of BrdU LI < 1% (13/15) than 201T1 SPECT (13/22). Accumulation of 201T1 in the tumour was slightly different from contrast enhancement on CT and/or MRI, and gave "false-positive" results in some low-grade gliomas. However, 201T1 SPECT, which is available in many hospitals and may cost less, provided useful information to supplement that from CT and MRI.

Astrocytoma↗
PubMed1998

Management of recurrent pilocytic astrocytoma with leptomeningeal dissemination in childhood.

Two cases of recurrent pilocytic astrocytoma with leptomeningeal dissemination (LMD) are described. A 6-year-old boy presented with a cerebellar tumor, which was subtotally removed. Tumor recurrence with LMD occurred 4 years later. Reoperation for tumor removal followed by craniospinal irradiation stabilized the LMD over 5 years. A 4-year-old girl presented with a chiasmatic-hypothalamic tumor. Partial removal of the tumor was followed by radiation therapy. Tumor regrowth with LMD occurred 4 years later and was managed by reoperation, chemotherapy and radiotherapy. Tumor recurrence with LMD can be stabilized by multimodal treatment without tumor progression.

Arachnoid↗
PubMed1997

Clinicohistological study of oligodendroglioma and oligoastrocytoma.

The clinical and histological characteristics of oligodendroglioma and oligoastrocytoma were investigated in patients, mainly adults with supratentorial tumors, who were treated with surgery and radiotherapy, and with chemotherapy for recurrent, anaplastic tumors, or both. The median survival time was 13.2 years for oligodendroglioma (four patients), 12.7 years for anaplastic oligodendroglioma (five patients), 13.5 years for oligoastrocytoma (seven patients), and 4.8 years for anaplastic oligoastrocytoma (four patients). Two of three recurrent oligodendrogliomas and two of two recurrent oligoastrocytomas showed malignant transformation. Minigemistocytes were sometimes recognized in recurrent tumors and had a sinister prognosis. Oligodendroglioma and oligoastrocytoma may transform into each other at recurrence.

Adolescent↗
PubMed1997

Technetium-99m(V)-DMSA and thallium-201 in brain tumor imaging: correlation with histology and malignant grade.

UNLABELLED: This study was performed to compare imaging ability between pentavalent 99mTc-DMSA and 201TlCl in primary and metastatic brain tumors and to evaluate the relationship between retention and histologic malignancy. METHODS: Patients with a brain tumor were selected by MRI and/or CT. Dynamic, early and delayed static SPECT images of the brain were obtained immediately, 30 min and 3 hr after intravenous administration of approximately 555 MBq 99mTc(V)-DMSA and 111 MBq 201Tl-Cl, respectively. Both studies were performed on separate days within a week. Uptake ratios, retention ratio and retention index were calculated and compared with tumor histology and malignancy grade. RESULTS: One-hundred six studies were performed on 100 patients and 118 lesions were demonstrated: 16 glioblastomas, 13 anaplastic astrocytomas (Grade III), 19 astrocytomas (Grade II), 29 meningiomas, 11 schwannomas and 14 metastases. Approximately 93% and 88%, respectively, of primary and metastatic brain tumors were demonstrated by 99mTc(V)-DMSA and 201TlCl. The early uptake ratios were closely related to the tumor vascularity, but had no statistically significant difference in the tumor histology or histologic malignancy on either radiopharmaceuticals. The delayed uptake ratio, retention ratio and retention index were higher in malignant tumors than benign ones on 99mTc(V)-DMSA, however, there was no statistically significant difference between benign and malignant tumors on 201TlCl. CONCLUSION: Technetium-99m(V)-DMSA washout from the tumor was highly dependent upon its histology and histologic malignancy. The delayed uptake ratio, retention ratio and retention index significantly reflected tumor histology and clearly distinguished between benign and malignant tumors with a statistically significant difference. There was no statistically significant difference in 201TlCl uptake or washout among the brain tumors. Technetium-99m-DMSA is superior to 201TlCl in imaging quality, sensitivity to brain tumors and specificity for differentiating benign tumors from malignant ones. These results could suggest the clinical utility of 99mTc(V)-DMSA in imaging primary and metastatic brain tumors and differentiating their histological malignancy grade noninvasively.

Brain Neoplasms↗
PubMed1996

A comparison of children with suprasellar germ cell tumors and craniopharyngiomas: final height, weight, endocrine, and visual sequelae after treatment.

BACKGROUND: Although treatment results of craniopharyngiomas and germ cell tumors in children have been reported extensively, the relationship between various posttreatment sequelae and the nature of the tumor is not well understood. METHODS: From 1968-94, 47 children with 23 suprasellar germ cell tumors and 24 craniopharyngiomas were treated at Gunma University Hospital, Japan. Forty survivors were assessed with regard to Karnofsky scores, visual scores, final height, final weight, and other endocrine sequelae as long-term functional prognostic indicators. RESULTS: Kaplan-Meier life-table estimates and Karnofsky scores were not significantly different between the two histologic groups. The visual function of survivors did not differ significantly at diagnosis. However, the final visual function following treatment in the germ cell tumor group was better than in the craniopharyngioma group (p < 0.05). Antidiuretic hormone secretion was significantly impaired at diagnosis in the germ cell tumor group (p < 0.0001). However, there was only a marginally significant difference in posttreatment persistent diabetes insipidus. Craniopharyngioma children were shorter and more obese at diagnosis (p < 0.02), and became much more obese than germinoma children with the same hormone therapy (p < 0.003), although the height difference became insignificant following growth hormone treatment. CONCLUSIONS: Children with craniopharyngiomas tended to have more visual disturbances, increased dwarfism and obesity, and less diabetes insipidus than patients with germ cell tumors despite adequate therapy. The method of quantifying visual function may in itself be useful.

Adrenocorticotropic Hormone↗
PubMed1996

Radiobiological effects of gamma knife radiosurgery on brain tumors studied in autopsy and surgical specimens.

To elucidate the radiobiological effect of Gamma Knife radiosurgery on brain tumors, we performed a histological study on nine cases. In two, the material was obtained at autopsy and in seven following surgery. In the central region of the radiation field, destructive changes occurred both in tumor cells and in vessels. In the peripheral area, destructive and proliferative vascular changes were intermingled with residual tumor tissue. Immunohistochemical staining of surgical specimens showed that the vascular proliferative changes consisted of pericytic proliferation with or without endothelial proliferation. These characteristic changes might suppress tumor growth, at least in the short-term.

Adolescent↗
PubMed1996

Gamma Knife radiosurgery for acoustic schwannoma: effects of low radiation dose and functional prognosis.

The effects of relatively low dose Gamma Knife irradiation on acoustic schwannoma were evaluated in 29 patients followed over 2 years after treatment. The mean dose delivered to the tumor periphery was 12.1 Gy. Lowering of the magnetic resonance signal intensity in the tumor center appeared in 69% and signs of tumor shrinkage appeared in 59% of cases. The cyst in the tumor enlarged in 3 cases, and 2 cases developed hydrocephalus. The percentage of pure-tone hearing preservation was 82% at 3 months, 73% at 6 months, 68% at 12 months. 64% at 18 months and 59% at 24 months in 22 out of 29 cases. Relatively low dose Gamma Knife radiosurgery was effective in suppressing tumor growth, with preservation of hearing.

Adult↗
PubMed1996

Pathobiology of cerebral gliomas in children and the role of radiosurgery.

Twenty-five gliomas of the cerebral hemisphere in children were examined. Most hemispheric gliomas in children have relatively clear margins and less infiltrative potential. Radiosurgery has a role in the treatment of these tumors in addition to reducing the risk of radiation injuries developing later. Fifteen patients were alive 1-27 years (mean 8.4) following treatment and 10 patients died. Histologic examination demonstrated 10 differentiated gliomas, 10 poorly differentiated gliomas and 5 other gliomas. Most tumors had relatively clear margins on computed tomography and/or magnetic resonance images, and peritumoral edema was slight. In 9 autopsy cases, tumor dissemination and/or metastasis were seen in 7. However, tumor infiltration was not extensive, and clear tumor margins were found in some cases. Thus, cerebral gliomas in children have relatively clear margins and low infiltrative potential. Radiosurgery has a role in the treatment of these tumors.

Adolescent↗
PubMed1995

Calcified astrocytoma of the amygdalo-hippocampal region in children.

Three pediatric cases of temporal lobe seizure due to calcified glioma of amygdalo-hippocampal region are described. Computed tomography and magnetic resonance imaging showed dense calcification with no postcontrast enhancement in the amygdalo-hippocampal region. Positron emission tomography showed low oxygen metabolism, low glucose metabolism, hypermetabolism of amino acids, and low regional cerebral blood flow in the tumors. Single photon emission computed tomography showed a high accumulation of 201Tl chloride and 123I-isopropyl iodoamphetamine in one tumor, but otherwise low radioisotope uptake. These studies indicated low-grade malignancies. The patients were treated by partial tumor removal and radiotherapy. Histological examination of the tumor specimens showed astrocytoma with interstitial calcification. One patient died due to tumor recurrence, while the others are doing well with minimal seizure. We recommended temporal lobectomy in similar cases to achieve complete remission.

Adolescent↗
PubMed1995

Fractionated Gamma Knife radiosurgery for malignant gliomas: neurobiological effects and FDG-PET studies.

Experimental single-dose neural irradiation was performed in rats and monkeys. Acute and 'early' late damage was observed following single high-dose treatments. By contrast, following a single low-dose treatment, neither 'early' nor 'delayed' late damage was noted. Based on these experiments, a clinical trial of fractionated Gamma Knife surgery for malignant gliomas was begun, and patients were followed by FDG-PET studies. An acute response of the tumor was obtained without damage to the surrounding brain. Fractionated Gamma Knife surgery is a potential alternative treatment for malignant gliomas.

Adult↗
PubMed1995

Diagnosis and treatment of brainstem abscess using magnetic resonance imaging and microsurgical aspiration--case report.

A 6-year-old boy presented with a pontine abscess initially misdiagnosed as brainstem glioma, but he deteriorated rapidly and developed new symptoms of respiratory distress. Magnetic resonance (MR) imaging revealed a rapidly growing mass lesion in the pons. Microsurgical evacuation of the abscess via a suboccipital retromastoid approach resulted in neurological improvement and resolution of the lesion on MR images. Brainstem abscess can be successfully treated with early, accurate diagnosis based on MR imaging and appropriate microsurgical and antibiotic management.

Brain Abscess↗
PubMed1995

Hypothalamic hamartoma: anatomic, immunohistochemical and ultrastructural features.

Four patients with hypothalamic hamartoma were examined by CT and/or MR imaging, immunohistochemistry and electron microscopy. The hamartomas arose from the hypothalamus and extended inferiorly. LH-RH neurons were detected in three cases by immunohistochemistry. Electron microscopy revealed large myelinated axons, axon terminals containing dense-core vesicles and axon terminals with clear vesicles forming asymmetrical synapses. The development of hypothalamic hamartoma and its functional manifestations (precocious puberty and laugh attacks) are discussed in reference to the migration of LH-RH neurons from the olfactory placode.

Axons↗
PubMed1994

Factors affecting functional prognosis in survivors of primary central nervous system germinal tumors.

We evaluated 79 patients of whom 62 survived treatment for intracranial germinal tumors between 1964 and 1992. The survivors were assessed for their Karnofsky scores and intellectual and reproductive functions to verify factors associated with better prognosis. Thirty-one tumors were pineal, 17 were suprasellar, and ten were in the basal ganglia. These included 50 germinomas, five teratomas, and seven tumors of extra-embryonic origin producing alpha-fetoprotein or human chorionic gonadotropin. Although patients with germinoma or benign teratoma had better Kaplan-Meier survival rates than those with extra-embryonic origin tumors, the mean Karnofsky scores of the survivors did not differ significantly among the three histologic groups. On the other hand, although survival rates did not differ significantly among different tumor site groups, the mean Karnofsky score of the pineal group was higher than that of the suprasellar or basal ganglia group. Intellectual and reproductive functions were severely affected in the basal ganglia and suprasellar tumor groups, respectively. The Karnofsky score of survivors treated after 1977 was higher than for those treated before 1977. The score of patients who received less than 55 Gy irradiation was better than those who received more than 55 Gy. No patient who received less than 45 Gy developed a recurrence, suggesting that a lower dose may suffice for pure germinomas. Tumors of extra-embryonic origin, however, should be treated with combined chemotherapy to minimize subsequent irradiation. Factors affecting survivors' capabilities are discussed.

Adolescent↗
PubMed1994

Small gliomas: metabolism and blood flow.

Eight patients with small gliomas (6 low-grade and 2 high-grade) localized in a single gyrus or less than 2 cm diameter were investigated using positron emission tomography and single photon emission computed tomography. All three tumors examined demonstrated hypermetabolism of amino acids. High-grade gliomas demonstrated hypermetabolism of glucose and high blood flow, but normal or low oxygen metabolism. High-grade gliomas also showed accumulation of 201Tl chloride and high or low accumulation of 123I-isopropyl iodoamphetamine. These indications allow preoperative diagnosis of the malignancy of small gliomas, which is important because small gliomas with high-grade malignancy need more extensive removal and adjuvant therapy.

Adult↗
PubMed1994

Changes of the bromodeoxyuridine labeling index of astrocytic tumors between primary and recurrent lesions.

Changes of bromodeoxyuridine labeling index at recurrence were examined in 6 glioblastomas, 2 anaplastic astrocytomas, and 3 fibrillary astrocytomas. Decreased labeling index occurred in 5 glioblastomas, probably due to the effects of combined radiotherapy and chemotherapy, but was not correlated with a favorable outcome. No change of labeling index occurred in 1 anaplastic astrocytoma. Increased labeling index was seen in 1 glioblastoma, 1 anaplastic astrocytoma, and 3 fibrillary astrocytomas, possibly indicating rapid progression just before surgery for recurrent tumor. Recurrent astrocytomas had become anaplastic astrocytoma or glioblastoma, but demonstrated no specific histopathology or labeling index of the primary lesion.

Adult↗