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Biomedical subjects

T Nose

Publications and source records attributed to T Nose.

At least 127 records · Page 7Linked to original sources
PubMed1998

Manganese-metalloporphyrin (ATN-10) as a tumor-localizing agent: magnetic resonance imaging and inductively coupled plasma atomic emission spectroscopy study with experimental brain tumors.

OBJECTIVE: We examined whether selective tumor accumulation of a novel manganese-metalloporphyrin (ATN-10) occurs in Fisher rats bearing intracerebral 9L gliomas. METHODS: After intravenous administration of ATN-10, magnetic resonance imaging of brains with tumors or nontumoral vasogenic brain edema was performed. Tissue manganese concentrations were measured by inductively coupled plasma atomic emission spectroscopy until 48 hours after administration of ATN-10, to evaluate its uptake in tumor, normal brain, and peritumoral brain tissue. RESULTS: In magnetic resonance imaging scans, early enhancement was observed in both tumor tissue and regions of nontumoral vasogenic brain edema at 5 minutes after ATN-10 administration. However, delayed enhancement was noted only in tumor tissue, at 24 hours after intravenous injection of ATN-10. Comparison of rat brain specimens and 24-hour magnetic resonance imaging scans revealed that only the viable portions of tumors were enhanced with ATN-10; necrotic regions and areas of peritumoral brain tissue and nontumoral vasogenic edema were not. Significantly greater uptake of ATN-10 was found in tumor samples, compared with normal and peritumoral brain tissue, at 24 hours. A high tumor/normal brain tissue ratio (10.4) was achieved at 24 hours. CONCLUSION: ATN-10, a manganese-metalloporphyrin, is a potentially useful tumor-localizing agent that accumulates and is preferentially retained in viable tumor tissue.

Animals↗
PubMed1998

Facial spasm and paroxysmal tinnitus associated with an arachnoid cyst of the cerebellopontine angle--case report.

A 59-year-old female presented with a 3-year history of hemifacial spasm and paroxysmal tinnitus associated with an arachnoid cyst of the cerebellopontine angle, which was identified preoperatively by magnetic resonance imaging. Surgical decompression of the cyst and arterial decompression of the facial and acoustic nerves at their root exit zones resulted in complete resolution of the symptoms.

Arachnoid Cysts↗
PubMed1998

Combined carotid endarterectomy and coronary artery bypass graft.

Atherosclerosis is a generalized disease which afflicts a considerable number of patients in both the carotid and coronary arteries. Although the risk of stroke or death use to combined carotid endarterectomy (CEA) and coronary artery bypass graft (CABG) is thought to be higher than that of each individual operation, the combined procedure is generally preferred over staged operations to treat such patients. We performed the combined procedure safely with the aid of intraoperative portable digital subtraction angiography (DSA). This report describes our experience with the operative strategy of simultaneous CEA and CABG. Ninety CEA and 404 CABG were carried out between January 1989 and December 1997. A total of six patients received the combined procedure with the aid of intraoperative DSA; they were studied retrospectively. Postoperative mortality and morbidity after the combined procedure was 0%. In the combined procedure, neurological complications are difficult to detect after CEA because the patient must be maintained under general anesthesia and extracorporeal circulation during the subsequent CABG. However, intraoperative DSA can confirm patency of the internal carotid artery and absence of flap formation after CEA, and the CABG can be performed safely. Intraoperative portable DSA between CEA and CABG is helpful in preventing perioperative stroke in the combined procedure.

Aged↗
PubMed1998

Basal perforating artery aneurysm within the cavum septi pellucidi. Case report.

The authors describe the case of a 16-year-old boy presenting with clinical onset of subarachnoid hemorrhage. The patient was found to have a small aneurysm arising from the distal portion of a basal perforating branch of the anterior cerebral artery (ACA), lying within a cavum septi pellucidi. Neuroimaging demonstrated a hematoma within the cavum septi pellucidi and the aneurysm was resected via a transcallosal approach guided by an intraoperative portable digital subtraction angiography (DSA) system. The origin of the aneurysm was presumed to be idiopathic. This report is the first to describe an aneurysm of a basal perforating artery arising from the ACA that resulted in an intracaval hematoma. When approaching small vascular lesions during surgery, intraoperative DSA is the method of choice to identify the precise trajectory and distance to the lesions.

Adolescent↗
PubMed1998

Adaptive response in embryogenesis: I. Dose and timing of radiation for reduction of prenatal death and congenital malformation during the late period of organogenesis.

An adaptive response was demonstrated during embryogenesis in mice. Whole-body irradiation at a dose of 0-50 cGy was given to condition pregnant ICR mice on day 9 to day 11 of gestation. Then their whole bodies were exposed to a challenging dose of 5 Gy on the next day. The numbers of living fetuses, prenatal deaths and living fetuses with external gross malformations were determined on day 19. A conditioning dose of 30 cGy on day 11 significantly increased the rate of living fetuses and reduced the incidence of congenital malformations induced by a 5-Gy dose on day 12. This indicates the existence of a critical dose and timing for administering a conditioning dose for radioadaptation during the late period of organogenesis in mice. The possible mechanisms involved are discussed.

Abnormalities, Radiation-Induced↗
PubMed1998

Anterior spinal artery syndrome associated with severe stenosis of the vertebral artery.

We describe a 55-year-old man with quadriparesis and impaired pain and temperature sensation in whom T2-weighted MR images revealed a high-intensity lesion in the cord at C3-4. Angiography showed occlusion of the right vertebral artery and severe stenosis of the left vertebral artery. We concluded that the stenosis of the vertebral artery led to the anterior spinal artery syndrome and to a disturbance of consciousness.

Angiography↗
PubMed1998

[Management of putaminal hemorrhage in patients with chronic renal failure].

The treatments of putaminal hemorrhages (PH) were evaluated in 14 patients (15 hematomas) with chronic renal failure (CRF). We compared the data of our series with the data of co-operative study (1990) on PH. With regard to consciousness level (Neurological Grading, NG) and hematoma volume, significantly more serious cases were observed in PH with CRF than in PH of the co-operative study. In PH with CRF, mortality (40%) was significantly higher than that in PH of the co-operative study. However, the mortality rate was 0%, 0%, 20%, and 100% in NG1, 2, 3, and over 4b. The mortality rate was 0% in non-surgically treated cases with 0 to 30 ml of hematoma volume, and 0% in surgically treated cases with 10 to 50 ml of hematoma volume. These mortality rates were equal to those of the co-operative study with the same NG, and equal to those of the co-operative study with the same hematoma volume. With respect to functional prognosis, "good" (ADL1 and 2) resulted in 67% of non-surgically treated cases with NG1 to 2, and in 33% of surgically treated cases with NG3 to 4a. "Good" resulted in 33% of non-surgically treated cases with 0 to 30 ml of hematoma volume, and in 40% of surgically treated cases with 10 to 50 ml of hematoma volume. These morbidity rates were equal to those of the co-operative study with the same NG, and equal to those of the co-operative study with the same hematoma volume. Therefore, the high mortality in PH with CRF was suspected to be due to the fact that, in our study, there was a higher distribution of serious cases. These findings indicate that protection against enlargement of hematomas in the acute phase may bring about improvement of prognosis in PH with CRF.

Cerebral Hemorrhage↗
PubMed1998

[Gelastic seizures treated by partial resection of a hypothalamic hamartoma].

A 13-year-old girl developed atonic seizure at 2 years of age. At the age of 10 years, gelastic seizures were noted. Magnetic resonance imaging (MRI) revealed a hypothalamic mass protruding down into the basal cistern and up into the third ventricle. An interictal electroencephalogram (EEG) showed paroxysmal spike and wave complex discharges. Since the seizures failed to respond to medical therapy, it was decided to try to control them by removing the mass. The operation was carried out through an interhemispheric trans-lamina terminalis approach. The lesion was so similar to normal brain tissue that the resection had to be limited enough to avoid complications. Histological examination of the mass showed a hamartoma. Postoperative MRI showed residual mass, but no seizure has been noted since the operation. The EEG recorded one year after the operation showed no spike and wave complex discharge, although she was still on anticonvulsant drugs. The authors propose that surgical therapy should be considered as a treatment for intractable gelastic epilepsy with hypothalamic hamartoma and that the first operation should be conservative enough to avoid complications, because it can bring about good results even if it is only a partial resection.

Adolescent↗
PubMed1998

Neutron capture therapy with a new boron-porphyrin compound in the rat 9L glioma model.

Neutron capture therapy with a new boron-porphyrin compound was tested in a rat brain tumor model. Although the concentration of boron in the tumor was too low to elicit a therapeutic effect, prominent histopathologic changes, such as necrosis, congestion and bleeding were observed in the tumors of the rats which were administered the boron neutron capture therapy.

Animals↗
PubMed1997

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.

Animals↗
PubMed1997

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.

Animals↗
PubMed1997

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.

Caffeine↗
PubMed1997

Volumetric quantification of brain development using MRI.

We devised a three-dimensional method for estimation of cerebral development and myelination which measures cerebral volume using MRI. Accuracy of the system was estimated using cadaver brains. The mean percentage error in the calculated volumes compared with the real volumes was 2.33%, range 0.00-5.33%. We applied the method to the volume of both cerebral hemispheres (CH), basal ganglia, thalamus and internal capsule (BT), and myelinated white matter (WM) in 44 neurologically normal individuals (4 months to 28 years of age), 13 patients with spastic motor disturbances (2-25 years of age), and 9 patients with athetotic motor disturbances (2-23 years of age). In the neurologically normal cases, the volumes of CH, BT and WM increased with age; the volume of MW more slowly than that of CH. In cases with spastic motor disturbances, the volumes of CH, BT and WM were between -1.4 and 3.5 SD, -1.0 and -3.5 SD, and 0.0 and -5.2 SD respectively, of those of neurologically-normal cases. On the other hand, 7 of the 9 cases with athetotic motor disturbances were within 2 SD of the volume of CH in neurologically normal cases. Our method for direct measurement of cerebral volume based on serial MRI should be useful for the accurate assessment of brain development and quantitative analysis of delayed myelination.

Adolescent↗
PubMed1997

Lack of correlation between gallbladder opacification in delayed CT and contrast-associated nephropathy.

The objective of our study was to determine the correlation between gallbladder opacification by delayed CT and contrast-associated nephropathy (CAN). Delayed CT after angiography was performed in 269 patients. Gallbladder opacification was defined when the CT value in gallbladder was more than 30 HU. Positive renal dysfunction was recognized as CAN which defined as an increase in serum creatinine level > 0.3 mg/dl and > 20 % on days 1, 3, or 7. Gallbladder opacification appeared in 154 of 269 (57 %) patients and CAN in 35 (13 %) patients. Of 117 patients without gallbladder opacification, 17 CAN (14 %) were recognized, and of 152 patients with gallbladder opacification, 18 CAN (12 %) were recognized. No significant correlation existed between delayed gallbladder opacification and CAN.

Angiography↗