Biomedical subjects

K Kiya

Publications and source records attributed to K Kiya.

At least 19 recordsLinked to original sources

PubMed1995

Demonstration of the venous systems with gadolinium-enhanced three-dimensional phase-contrast MR venography.

The purpose of this study was to evaluate the usefulness and advantages of gadolinium-enhanced three-dimensional phase-contrast MR venography for demonstrating the venous systems. The three-dimensional phase-contrast MR venography was performed with a velocity encoding gradient settings from 5 to 20 cm/s on 22 normal subjects. In 8 of normal subjects, gadolinium-enhanced phase-contrast MR venography was performed. 22 subjects (100%) had detectable flow in the sphenoparietal sinus, transverse sinus, basal vein, and internal cerebral vein. With a VENC setting at 10 cm/s, venous system was visualized selectively and clearly. Detection ratio in inferior petrosal sinus, superior petrosal sinus, and superior ophthalmic vein increased from 0% to 25%, from 28.6% to 62.5%, and from 28.6% to 37.5%, respectively, after administration of gadopentate dimeglumine. In conclusion, gadolinium-enhanced three-dimensional phase-contrast MR venography was useful for demonstrating the venous systems.

Adolescent↗

PubMed1995

MRI of intracranial germ cell tumours.

We reviewed MRI findings in proven intracranial germ cell tumours in 22 cases, 12 of whom received Gd-DTPA. On T1-weighted images, the signal intensity of the tumour parenchyma was moderately low in 19 cases and isointense in 3; on T2-weighted images, it was high in all cases. Regions of different intensity thought to be cysts were found in 17 (77%): 7 of 12 patients with germinoma (58%) and in all other cases. Of the 13 patients with pineal lesions T1-weighted sagittal images showed the aqueduct to be obstructed in 5, stenotic in 7 and normal in 1. Strong contrast enhancement was observed in all 12 cases. Of the 14 patients with suprasellar lesions, 5 were found to have an intrasellar extension, and in 3 of these, the normal pituitary gland, which could be distinguished from the tumour, was displaced anteriorly. Ten patients (45%) had multiple lesions.

Adolescent↗

PubMed1995

Surface anatomy scanning (SAS) in intracranial tumours: comparison with surgical findings.

We evaluated the usefulness of surface anatomy scanning (SAS) in intracranial tumours, comparing it with surgical findings. We examined 31 patients with brain tumours preoperatively. The tumours included 16 meningiomas, 8 gliomas, 4 metastases and 3 others. SAS clearly demonstrated the tumours, allowing them to be distinguished from the structures of the brain surface, including oedema, except in cases of metastasis. SAS clearly demonstrated large cortical veins. SAS is useful for three-dimensional delineation of the brain surface before surgery.

Brain↗

PubMed1995

Clinicopathologic growth factors of acoustic neuromas.

BACKGROUND Understanding the tumor growth rate is very important when considering strategies for the treatment of an acoustic neuroma, although the natural course of acoustic neuromas has not been reviewed in detail. METHODS The clinicopathologic features and the postoperative growth of tumors were evaluated in 32 patients with acoustic neuromas. This study was undertaken to assess the variability of the growth potential of cells within an acoustic tumor and to determine the relationships between the growth rate and the clinicopathologic characteristics of the patients with acoustic neuromas, including age at surgery, gender, tumor location and preoperative size, the duration of the symptoms, the presence of cystic regions, the presence of Antoni type A and B cells, the tumor cell density, tumor vascularity, mitotic rate, the presence of hyaline degeneration and hemosiderin deposition, nucleolar organizer regions (NORs), and the level of proliferating cell nuclear antigen (PCNA). RESULTS The growth patterns of the tumors were divided into three groups according to their growth rate: a regression group, a "no-growth" group (growth rates from 0-0.11 cm/year) and a progression group (growth rates from 0.19-1.72 cm/year). An additional operation was required in all patients whose growth rate was more than 0.38 cm/year. A statistical study on the factors associated with an increased growth rate showed that the three histopathologic factors most significantly associated with a postoperative growth rate were hyaline degeneration (p < 0.05), cell density (p < 0.005), and PCNA labeling index (p < 0.005). CONCLUSIONS These results strongly suggest that acoustic tumors can be subdivided into several groups, based upon different biologic activities and tumor growth rates.

Adult↗

PubMed1995

[A case report of cranial bone defect with a porencephalic cyst in an adult].

A case of cranial bone defect with porencephalic cyst in an adult was reported. A 47 year-old male was admitted with epilepsy. He had a round lytic bone defect lesion in the left frontal skull. The porencephalic cyst was under the bone defect. The mechanism of bone defect is thought to be as follows. He had received some head trauma in childhood and the frontal skull bone had fractured. The contusioned brain changed to a porencephalic cyst. The linear bone fracture may have enlarged according to the mechanism of a growing skull fracture. Persistent pulsative pressure from the porencephalic cyst toward the fractured bone edge might be able to make the bone defect oval.

Brain Diseases↗

PubMed1994

Embolisation of orbital varix.

A 34-year-old man with intermittent exophthalmos, found to have a large varix in the right orbit, was treated by endovascular surgery. Percutaneous transfemoral venous catheterisation and embolisation of the orbital varix was performed on two occasions. A Tracker 18 microcatheter was introduced through the right inferior petrosal sinus, cavernous sinus, superior ophthalmic vein and then into the varix, following a guidewire. Superselective venography of the right ophthalmic vein showed the varix. A total of 204 platinum microcoils was used to pack the varix. At the time of discharge, the exophthalmos had largely resolved. As this technique is much less invasive than surgical resection, we recommend an attempt at endovascular embolisation of orbital varices prior to surgical removal.

Adult↗

PubMed1994

A case report suggesting a common pathogenesis for IgA nephropathy and Henoch-Schönlein purpura.

A 7-year-old boy who had been followed for asymptomatic haematuria and elevated serum IgA levels developed Henoch-Schönlein purpura (HSP) after a streptococcal infection of the tonsils. Findings on renal biopsy were compatible with mild IgA nephropathy (IgAN); tonsillectomy was also performed as he had chronic tonsillitis. This case suggests that there is a common pathogenesis for IgAN and HSP, at least in some patients.

Child↗

PubMed1994

O6-alkylguanine-DNA alkyltransferase activity of human malignant glioma and its clinical implications.

Activity of the DNA repair protein O6-alkylguanine-DNA alkyltransferase (AGT) is an important determinant of responsiveness of tumor cells to chloroethylnitrosoureas (CENUs), representative chemotherapeutic agents for primary malignant gliomas. In order to assess the real states of this repair protein in human malignant gliomas, we assayed AGT activity in surgically extirpated 42 malignant glioma samples and studied the distribution of the activity under certain clinical conditions. There were wide variations in AGT activity between individuals. No significant difference in AGT activity on average was seen either between glioblastoma and anaplastic astrocytoma, nor between primary and recurrent tumors. Among 42 malignant gliomas, 7 samples (16.7%) had low AGT activity less than 0.1 pmoles/mg protein. In the case of glioblastoma, tumors possessing higher AGT activity tended to be less responsive to post-operation remission-induction therapy including CENUs. The result of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) chemosensitivity assay by using the corresponding surgical specimens suggested a close relationship between cellular resistance to CENUs and AGT activity. It was found to be unlikely that a short term administration of CENUs had a significant effect on AGT activity of brain tumors in human body. We could detect a bit of definite evidences of the relevance of AGT to resistance to CENUs and need to conduct further investigations for other resistance factors.

Astrocytoma↗

PubMed1994

Combined antitumor effects of TNF and G-CSF on a human medulloblastoma xenograft line.

The antitumor effects of TNF and G-CSF on a xenograft line of human medulloblastoma were examined. (Method):1) A human medulloblastoma xenograft line was transplanted into nude mice. Tumor bearing nude mice were divided into the following eight groups: untreated controls (C); those receiving a subcutaneous injection of G-CSF for one week (G1); for four weeks (G2); those receiving an intratumoral injection of TNF for four weeks (Tit); an intravenous injection of TNF (Tiv); those receiving a combination of G1 and Tit (G1 + Tit); a combination of G2 and Tit (G2 + Tit); and a combination of G2 and Tiv (T2 + Tiv). The relative tumor weight in each group was calculated and any antitumor effects were examined by calculating a tumor growth inhibition ratio. 2) Tumor bearing nude mice were divided into the following two groups: those receiving a subcutaneous injection of G-CSF and an intravenous injection of TNF (G+T); and only an intravenous injection of TNF (T). We evaluated the pathological findings from the tumors at 0 h, 0.5 h, 1 h, 3 h, 6 h, 12 h, 24 h and 48 h after the TNF injection. Routine H.E. staining and immunostaining using antigranulocyte and antimacrophage antibodies were performed. (Results): 1) The tumor growth inhibition ratio was 0.112, 0.190, 0.287, 0.451, 0.347, 0.635, and 0.622 at G1, G2, Tit, Tiv, G1 + Tit, G2 + Tit, G2 + Tiv group. A combined antitumor effect was clearly seen in the G2 + Tit and the G2 + Tiv groups. 2) The tumor was fragmented by the infiltration of many inflammatory cells 24 hours after TNF injection. Many more macrophages were observed in the tumors of G+T mice than in the T mice. Granulocytes were observed only in the tumors of the G+T mice.

Animals↗

PubMed1994

In vivo effects of recombinant human lymphotoxin on human medulloblastoma xenograft: enhancement of antitumor activity of etoposide.

The authors investigated the antitumor activities of rHuLT alone and in combination with etoposide on human meduloblastoma xenografts growing subcutaneously in nude mice. Intravenous administration of rHuLT (1.0 x 10(5) U/kg, 5.0 x 10(5)U/kg, 2.5 x 10(6)U/kg, three times a week for three weeks) suppressed medulloblastoma growth depending on the dose. However, the highest dosage caused serious side effects. Combining rHuLT (intravenously, 5.0 x 10(5)U/kg, three times a week for three weeks) with etoposide (intraperitoneally, 20mg/kg, once a week for three weeks) increased the antitumor activity without causing serious toxicity. Microscopically, tumor specimen showed thrombosed tumor vessels and massive necrosis 3 weeks after rHuLT treatment. Ultrastructural examination revealed that 120 minutes after the administration of rHuLT alone, disruption of interendothelial junctions was evident, and that the endothelial cells were destroyed at 240 minutes. Concentration of etoposide in tumor tissue peaked 30 minutes after intraperitoneal administration, and then decreased with time. When etoposide was administered in combination with rHuLT, the concentration of etoposide in tumor tissue after 60 to 240 minutes was significantly higher than when etoposide was given alone, and the area under the concentration versus time curve was also greater for the tumors of mice with combination treatment. The findings suggest that the proper combination of rHuLT and etoposide may have synergistic antitumor activities. Histological changes suggest that increased concentrations of etoposide within the tumor after combination therapy may occur due to increased vascular permeability and/or decreased etoposide clearance which is the result of blood statis in the tumor vasculature.

Animals↗

PubMed1994

Orbital lobe lacrimal ductal cyst.

Lacrimal ductal cysts are rare, especially in the orbit. A case of lacrimal ductal cyst in the orbital lobe, revealed by computed tomography and magnetic resonance imaging, is described in a 16-year-old man who was successfully treated by complete surgical excision. The radiologic and clinical features of this type of lacrimal ductal cyst are discussed.

Adolescent↗

PubMed1994

Clinical evaluation of 33 patients with histologically verified germinoma.

We evaluated 33 patients with histologically verified germinoma between 1978 and 1992. The patients consisted of 23 men and 10 women between 6 and 32 years of age. All patients underwent either biopsy, partial resection, or total resection. All patients received radiotherapy, and all had a complete remission. Recurrence occurred in three patients. Two recurrences were outside of the irradiated area. Though there were four deaths, none were caused by germinoma. Three resulted from the inadequate hormonal replacement. Accurate staging of patients with germinoma using magnetic resonance imaging (MRI), including whole spinal MRI, and development of a radiochemotherapy or chemotherapy method that preserves the hypothalamic-pituitary axis function are needed.

Adolescent↗

PubMed1994

Comparison of three-dimensional phase-contrast magnetic resonance angiography with three-dimensional time-of-flight magnetic resonance angiography in cerebral aneurysms.

Magnetic resonance angiography (MRA) can be divided into two types: namely, the phase-contrast (PC) method and the time-of-flight (TOF) method. The purpose of this study is to determine which method is better suited to demonstrate cerebral aneurysms. In a total of 27 cerebral aneurysms confirmed by cerebral angiography, both three-dimensional (3-D) PC and 3-D TOF methods were performed, and the corresponding findings were compared with conventional cerebral angiographic findings. Aneurysm visualization was grouped into three categories: "good" when clearly distinguishable, "fair" if distinguishable when reconstructed, and "poor" if completely undistinguishable. All MRAs were independently interpreted by two neurosurgeons in our institute. Sensitivity was 92.6% when MRA was performed with the TOF method, whereas it was 70.4% when performed with the PC method. In conclusion, the TOF method was more useful for demonstrating the aneurysms than the PC method due to its higher spatial resolution and shorter imaging time.

Adult↗

PubMed1994

Antitumor effects of antiprogesterones on human meningioma cells in vitro and in vivo.

The presence of the progesterone receptor (PR) in meningioma tissue has been confirmed by previous investigations. Studies have shown that the antiprogesterone drug, mifepristone, is a potent agent that inhibits the growth of cultured meningioma cells and reduces the size of meningiomas in experimental animal models and humans. However, these studies have not fully examined the relationship between the antitumor effects of an antiprogesterone agent and the expression of the PR. The present study examined the antitumor effects of mifepristone and a new potent antiprogesterone agent, onapristone; a correlation between the antitumor effects of these antiprogesterones and the presence of PR's in meningiomas in vitro and in vivo was also investigated. Meningioma tissue surgically removed from 13 patients was used in this study. In the in vitro arm of the study, mifepristone and onapristone exhibited cytostatic and cytocidal effects against cultured meningioma cells, regardless of the presence or absence of PR's; however, three PR-negative meningiomas showed no response to any dose of mifeprestone and/or onapristone. In the in vivo arm, meningioma cells, embedded in a collagen gel, were implanted into the renal capsules of nude mice. Antiprogesterone treatment resulted in a marked reduction of the tumor volume regardless of the presence or absence of PR's. No histological changes in the meningioma cells suggestive of necrosis or apoptosis were detected in any of the mice treated with antiprogesterones. These findings suggest that mifepristone and onapristone have an antitumor effect against meningioma cells via the PR's and/or another receptor, such as the glucocorticoid receptor.

Adult↗

PubMed1993

Interrelationship between O6-alkylguanine-DNA alkyltransferase activity and susceptibility to chloroethylnitrosoureas in several glioma cell lines.

In order to study the dynamic relationship in glioma cells between O6-alkylguanine-DNA alkyltransferase (AGT) activity and resistance to the cytotoxic effect of chloroethylnitrosoureas (CENUs), we investigated the changes in sensitivity to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) after modulation of AGT activity. In ACNU-resistant rat glioma cell lines (9LR1, 9LR3, and 9LR12) and a human glioma cell (HNG-1), O6-methylguanine enhanced cytotoxicity to ACNU following a depletion of AGT activity. But no enhancement of cytotoxicity was seen in an ACNU-sensitive rat glioma cell line (9L). In the 9L and 9LR12 cells, equivalently sublethal doses of ACNU similarly depleted AGT activity but the regeneration rates of this repair protein were different. In the case of a 7-day pretreatment with human recombinant interferon-beta (HuIFN-beta), although it could modulate AGT activity in HNG-1 cells, no definite influence on cellular sensitivity to CENUs was observed. However, a 50-day pretreatment with HuIFN-beta conferred resistance to CENUs on them despite its effect to reduce AGT activity. Thus, diversity was seen in the relation between AGT activity and resistance to CENUs when AGT activity was modulated by HuIFN-beta. The results of this study suggest that AGT activity is one of factors affecting cellular sensitivity to CENUs but that alternative mechanisms of tolerance may be induced depending upon some environmental effects.

Animals↗

PubMed1993

Spontaneous rupture of craniopharyngioma cysts. A report of five cases and review of the literature.

Reports of spontaneous rupture of a craniopharyngioma cyst are extremely rare. Five cases of spontaneous rupture of a craniopharyngioma cysts are reported. Clinical symptoms included chemical meningitis in three patients, alleviation of headache in one, and improvement in a visual disturbance in one. Reduction in cyst size was confirmed by computed tomography or magnetic resonance imaging in three of five patients, and the histopathological diagnosis was confirmed histologically in four patients. Cerebrospinal fluid findings were abnormal in the three patients with chemical meningitis. Spontaneous rupture of craniopharyngioma cysts tended to occur more frequently in adult males. Computed tomography and magnetic resonance imaging were useful in diagnosing cyst rupture, and cerebrospinal fluid findings, especially the presence of cholesterol crystals and an elevated cholesterol concentration, are suggestive, even when no reduction in cyst size is observed radiologically.

Adolescent↗

PubMed1993

Primary malignant rhabdoid tumor of the central nervous system: case report and review of the literature.

Malignant rhabdoid tumor (MRT) is well known as a pediatric malignant tumor of the kidney. Only nine cases of primary MRT of the central nervous system (CNS) have been reported. We are reporting in detail the clinical course and treatment of a patient with primary MRT of the CNS. We cared for a 3-year-old girl with an MRT that extended from the internal auditory canal to the cerebellopontine angle. Despite three surgical attempts at resecting the tumor combined with whole craniospinal axis irradiation, as well as chemotherapy consisting of intravenous nimustine hydrochloride and intrathecal methotrexate injections, the patient died 13 months after her initial hospitalization. The origin of CNS-MRT development is still a question of pathologic debate. Like renal MRT, the prognosis of MRT of the CNS is very poor. The dissemination of MRT of the CNS occurred in most cases.

Brain Neoplasms↗

PubMed1993

Analysis and distribution of etoposide in rat brain tumor model: intracarotid versus intracarotid with angiotensin II-induced hypertension.

The brain tissue distribution of etoposide has been investigated in 9L gliosarcoma-bearing rats with or without hypertension induced by angiotensin II (AT II). The rat brain tumor models were divided into the following two groups according to etoposide administration route: intracarotid injection (IC) group and intracarotid injection with hypertension induced by AT II (IHIC) group. Ten mg/kg of etoposide was given, and 30 min and 2, 4, 8, and 24 hr later the rats were sacrificed. The drug concentrations in the serum, tumor, and normal brain tissue were analyzed by high-pressure liquid chromatography. The etoposide concentration in the serum, tumor, and normal brain tissue peaked at 30 min in both groups. The serum concentration was similar between the two groups. The etoposide concentration in the tumor was at least 2.2 times higher in the IHIC group than in the IC group at 30 min and 2 hr. The area under drug concentration curve (AUC) in the tumor in the IHIC group was about 2.2 times higher than that in the IC group. The etoposide concentration in the normal brain on the drug injection side changed only slightly from 0.5 hr to 4 hr and was about 3 times higher in the IHIC group than in the IC group. The etoposide concentration in the contralateral normal brain was very low in both groups at 30 min and disappeared thereafter. Intracarotid injection of anticancer drugs with AT II-induced hypertension further increases the drug concentration and AUC in the tumor compared with intracarotid injection alone and can be useful in treatment of malignant brain tumors.

Angiotensin II↗