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Biomedical subjects

M Sumi

Publications and source records attributed to M Sumi.

At least 91 records · Page 5Linked to original sources
PubMed1995

High dose rate brachytherapy for carcinoma of the uterine cervix: comparison of two different fractionation regimens.

PURPOSE: There is no consensus as to the best dose-fractionation regimen in high dose rate (HDR) brachytherapy for cervix cancer. Since 1983, two fractionation regimens have been used in different time periods at National Cancer Center Hospital, and their treatment results have been compared in terms of 5-year survival, local control, and complication rate to find the better therapeutic regimen. METHODS AND MATERIALS: From November 1983 to October 1990, 130 patients with uterine cervix carcinoma were treated with HDR intracavitary brachytherapy using a remote afterloading system. There were 21 Stage Ib patients, 5 Stage IIa, 29 Stage IIb, 2 Stage IIIa, 68 Stage IIIb, and 5 Stage IVa. The median age was 64 years. The median follow-up time was 50 months. Radiotherapy consisted of external beam irradiation to the pelvis (mean dose of 50 Gy), combined with HDR brachytherapy (mean dose of 20 Gy to point A) given 5 Gy per session twice weekly (group A: 54 patients) or 6 Gy once weekly (group B: 76 patients). RESULTS: The overall 5-year survival was 52% in group A and 72% in group B. Local recurrence rate was 11%, and distant failure rate was 21%, with no difference between the two groups. The complication rate was significantly lower in group B (37%) than in group A (55%). Multivariate analysis has shown that factors affecting survival were stage, brachytherapy dose, and local control status. No factor was predictive of local control, but the external beam radiation dose significantly influenced the risk of complications. CONCLUSION: The once-weekly HDR intracavitary applications combined with properly adjusted external beam pelvic irradiation is a safe and effective treatment for patients with uterine cervix cancer.

Adenocarcinoma↗
PubMed1995

Specific immunocytochemical localization of cathepsin E at the ruffled border membrane of active osteoclasts.

The immunocytochemical localization of cathepsin E, a non-lysosomal aspartic proteinase, was investigated in rat osteoclasts using the monospecific antibody to this protein. At the light-microscopic level, the preferential immunoreactivity for cathepsin E was found at high levels in active osteoclasts in the physiological bone modeling process. Neighboring osteoblastic cells were devoid of its immunoreactivity. At the electron-microscopic level, cathepsin E was exclusively confined to the apical plasma membrane at the ruffled border of active osteoclasts and the eroded bone surface. Cathepsin E was also concentrated in some endocytotic vacuoles of various sizes in the vicinity of the ruffled border membrane, some of which appeared to be secondary lysosomes containing the phagocytosed materials. These results strongly suggest that this enzyme is involved both in the extracellular degradation of the bone organic matrix and in the intracellular breakdown of the ingested substances in osteoclasts.

Animals↗
PubMed1995

Differential diagnosis of extra-axial intracranial tumours by dynamic spin-echo MRI.

Dynamic MRI was performed on 22 patients with extra-axial intracranial tumours. Serial images were obtained every 30 s for 3 min using a spin-echo sequence (TR 200, TE 15 ms) after rapid injection of Gd-DTPA, 0.1 mmol/kg body weight. The contrast medium enhancement ratio (CER) was correlated with the histology of the tumours. Meningiomas and extra-axial metastases showed a sharp rise, then a gradual decline. Although both had a definite early peak of CER, metastases showed a more rapid decline. Neuromas and extra-axial lymphoma showed a slow, steady increase with no peak within 180 s. This study indicates that the CER is helpful in the differentiation of extra-axial tumours.

Adult↗
PubMed1995

The possible role of linac-based stereotactic radiotherapy in the treatment of multifocally and heterochronously recurrent malignant astrocytomas. A case report.

We present a 24-year-old woman with multifocal and heterochronous recurrence of malignant astrocytomas that were consecutively treated by linac-based sterotactic radiotherapy. The patient had previously received multimodalities of treatment for malignant astrocytomas in the right occipital lobe consisting of surgical resection on four occasions, conventional external-beam irradiation, immunological therapy, and systemic chemotherapy. Thereafter she developed relatively small and well-demarcated recurrent lesions in eight different sites, most of which were located in eloquent and deep-seated regions. She underwent ten fractionated linac-based stereotactic radiotherapy courses with a median total dose of 42 Gy, seven fractions of 6 Gy each in 15 days, experiencing neither any adverse effects nor neurologic deterioration. Three out of 10 treated lesions responded well with subsequent reduction in size, and 80% of them did not increase at least for 6 months, although 66.7% of the lesions eventually exhibited enlargement of the enhanced areas, some of which were presumed as radiation necrosis. These clinical results suggest that the fractionated linac-based stereotactic radiotherapy had significant effects on tumor growth inhibition and attainment of acceptable patient performance status.

Adult↗
PubMed1995

Increased neuronal firing in the rat auditory cortex associated with preparatory set.

Extracellular single neuronal firings were recorded in the auditory cortex of rats (n = 4) performing a visual reaction-time task with a warning tone (10 kHz, 10 ms duration), which preceded the imperative light stimulus by an interstimulus interval (ISI) of 1.4 s. Thirty-six neuronal firings were evoked by the warning tone, with the peak latency being between 15 and 55 ms. Among them, nine neurons (25%) showed an increased firing frequency following the evoked response during the ISI, which was, in average, 2.5 times as high as the firing frequency during the baseline period. When the tones were presented independent of the imperative stimulus, such sustained increase in neuronal firing was not observed. Activation of the sensory cortex during the ISI may constitute one of the neuronal modulations related to preparatory set.

Acoustic Stimulation↗
PubMed1995

Effects of metamfetamine on auditory P3 component of event-related potentials in rats.

Three rats were trained with an oddball paradigm, in which 5 kHz frequent and 10 kHz target rare tones were presented with a probability of 0.8 and 0.2. Pressing the lever within 2 s following the onset of the target tones was rewarded with a drop of food paste. Long latency event-related potentials (ERPs) corresponding to those in humans could be recorded in rats. After the administration of metamfetamine (0.2 mg/kg), the amplitude of surface and intracortical N1 increased, indicating an augmentation of the primary cortical response. Surface P3 showed a decrease of amplitude, accompanied by an increase of intracortical negativity. These alterations of ERPs may be caused by the dysregulation of central noradrenergic system.

Amphetamines↗
PubMed1995

Therapeutic efficacy of 5-fluorouracil prodrugs using endogenous serum proteins as drug carriers: a new strategy in drug delivery system.

To establish a novel drug delivery system for 5-fluorouracil (5FU), we have developed a system in which the low-molecular-weight prodrugs of 5FU bound to endogenous serum proteins, thus circulating like those proteins. Subsequently, the prodrugs were slowly hydrolyzed to generate active 5FU in the bloodstream. To examine the therapeutic effect of these prodrugs, we injected them into BALB/c mice previously implanted subcutaneously with Meth A sarcoma. Among the prodrugs, 1-(N-4-chlorophenyl-N-methylcarbamoyl)-5-fluorouracil (5FU-1pCPMC) was effective in reducing tumors and prolonging survival time. The non-hydrolyzable compound, 1-(4-chlorobenzyl)-5-fluorouracil, did not show any therapeutic effect, suggesting that the therapeutic efficacy of 5FU-1pCPMC is due to the sustained release of 5FU from the serum protein-prodrug complex. The data shown here may create a new field in drug delivery system technology.

Animals↗
PubMed1994

Disruption of the blood-cerebrospinal fluid barrier by transient cerebral ischemia.

The influence of transient cerebral ischemia on blood-brain and blood-cerebrospinal fluid (CSF) barrier permeability was studied sequentially by magnetic resonance imaging (MRI) contrast enhancement using gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) in rats. The unilateral internal carotid and middle cerebral arteries were transiently occluded by inserting a nylon thread into the carotid artery and removing it following a variable interval of 5 to 60 min. Contrast enhancement of the lateral ventricle on the affected side was seen in the enhanced T1-weighted image at the early stage of reperfusion 6 h after the start of ischemia in most of the rats subjected to 30- and 60-min ischemia, and in 3 of 6 rats in the 15-min ischemia group. Autoradiograms of Gd-[14C]DTPA in rats subjected to 60-min ischemia demonstrated that the tracer strongly accumulated in the choroid plexus, the wall of the lateral ventricle and its surrounding brain tissue. On the other hand, parenchymal enhancement of the striatum was seen only in the 60-min ischemia group and appeared later on Day 1 or Day 7. These results indicate that ventricular enhancement on MRI in this model is caused by disruption of the blood-CSF barrier at the choroid plexus of the lateral ventricle. This is the first reported study to demonstrate blood-CSF barrier disruption by transient ischemia.

Animals↗
PubMed1994

Event-related potentials during an auditory discrimination task in rats.

Event-related potentials (ERPs) during an auditory discrimination task were recorded both on the surface and at a depth of the auditory cortex in rats. Ten-kilohertz rare and 5-kHz frequent tones were used with the probabilities of 0.2 and 0.8. Lever pressing within 2 s, following the onset of the rare tone, was rewarded with food paste. In the performing condition, the surface ERPs for the rare tones consisted of P30, N50, P80, N130, and P290 components. Only the surface P30 and N50 showed a polarity reversal at the intracortical electrode, suggesting that these components are generated in the auditory cortex. The P290 was elicited in the performing condition but not in the resting condition, showing its task-relevancy. These results suggest that auditory ERPs similar to those in humans can be recorded in rats during an active discrimination task.

Acoustic Stimulation↗
PubMed1994

Case report: hepatocellular carcinoma diagnosed radiologically, treated by transcatheter arterial embolization and limited-field radiotherapy.

Even though the resection rate for hepatocellular carcinoma (HCC) has risen recently, many patients cannot be treated surgically because of the advanced stage of the tumour and/or coexisting cirrhosis. An alternative therapeutic approach for some of these patients is transcatheter arterial embolization (TAE) which has become very common in Japan. However, it is not a curative measure, and an additional therapy is required to eradicate the residual disease. In this communication, we report a case in which a patient with HCC has been successfully treated by TAE followed by limited-field radiotherapy. The results suggest that this is a very promising therapeutic approach for HCC and that the potential of limited-field radiotherapy for HCC with or without TAE also needs to be explored.

Carcinoma, Hepatocellular↗
PubMed1994

Sequential changes in ischemic edema following transient focal cerebral ischemia in rats: magnetic resonance imaging study.

Sequential and regional changes in ischemic edema following various durations of focal cerebral ischemia were studied by magnetic resonance (MR) imaging in a rat unilateral intraluminal middle cerebral artery occlusion model. Occlusion was performed from 5 minutes to 5 hours. T2-weighted images were obtained chronologically 6 hours after onset of ischemia, on day 1 and day 7. An immunohistochemical study using antibodies to calcineurin and glial fibrillary acidic protein was performed to observe histological changes in the ischemic brain. The T2 high-signal-intensity areas representing ischemic edema were observed in the lateral striatum and/or the cerebral cortex by day 1 in all rats with 1- to 5-hour ischemia, and the areas were larger and detected earlier with longer durations of ischemia. In three of six rats with 15-minute ischemia and five of six rats with 30-minute ischemia, the T2 high-signal-intensity areas appeared transiently on day 1 in the dorsolateral striatum where loss of neurons expressing calcineurin immunoreactivity and associated gliosis were found. MR imaging in animal models of reversible focal ischemia can achieve sequential and noninvasive evaluation of dynamic regional changes in ischemic edema.

Animals↗
PubMed1994

[Clinical usefulness of serum assay of EIA-CYFRA 21-1 in lung cancer].

Enzyme immunoassay CYFRA 21-1, a novel lung tumor marker presented in serum (upper limit of normal values: 3.5 ng/ml) was measured in 84 patients with lung cancer and 141 patients with benign respiratory diseases. The positive rate for CYFRA 21-1 in primary lung cancer was 70.3% and the false positive rate in respiratory diseases was 24.1%. In respect to the histological types of lung cancer, CYFRA 21-1 was elevated in 85.0% of squamous cell carcinoma and in 64.8% of other cell types of primary lung cancer. Elevated CYFRA 21-1 levels were found in 40% of Stage I-II, in 80.0% of Stage IIIA-B, and in 73.5% of Stage IV. The overall diagnostic efficiency was 53.4% for CYFRA 21-1 and 44.5% for CEA, respectively. Receiver operating characteristic (ROC) curve analysis suggested that CYFRA 21-1 test has an advantage over CEA. From the results of this study, CYFRA 21-1 was more efficient than CEA as primary diagnostic marker in lung cancer.

Biomarkers, Tumor↗
PubMed1993

Correlation of sequential magnetic resonance imaging of experimental brain ischemia with histologic changes in gerbils.

RATIONAL AND OBJECTIVES: To characterize Gd-DTPA-enhanced T1-weighted images (Gd-T1WI) in the acute phase of cerebral ischemia, sequential magnetic resonance images of 84 Mongolian gerbils with occlusion of the left common carotid artery were evaluated. METHODS: Twelve gerbils were used for each group, among which the occlusion time (5-180 minutes, permanent) varied. Histopathologic changes developing within the first 2 weeks were compared with patterns on T2-weighted images and Gd-T1WI on a 7.05-Tesla system. RESULTS: Although T2-weighted images and Gd-T1WI both demonstrated abnormal findings as early as 3 hours after occlusion, Gd-T1WI demonstrated more definite abnormalities with shorter occlusion than T2-weighted images (especially when there were only mild histologic changes). The earliest changes were an abnormal enhancement around and within the lateral ventricles in temporary occlusions; this was not demonstrated in permanent occlusions. CONCLUSIONS: Magnetic resonance images using Gd-DTPA demonstrated abnormal permeability within 3 hours after occlusion, and the pattern is correlated with intensity of ischemia.

Animals↗
PubMed1993

Clinical features associated with the A-->G transition at nucleotide 8344 of mtDNA ("MERRF mutation").

We looked for the A-->G transition at position 8344 of mtDNA in 150 patients, most of them with diagnosed or suspected mitochondrial disease, to assess the specificity of this mutation for the MERRF phenotype, to define the clinical spectrum associated with the mutation, and to study the relationship between percentage of mutation in muscle and clinical severity. Our results confirm the high correlation between the A-->G transition at position 8344 and the MERRF syndrome, but they also show that this mutation can be associated with other phenotypes, including Leigh's syndrome, myoclonus or myopathy with truncal lipomas, and proximal myopathy. The absence of the mutation in four typical MERRF patients suggests that other mutations in the tRNA(Lys) gene, or elsewhere in the mitochondrial DNA, can produce the same phenotype.

Adult↗
PubMed1993

Chemical and biological degradation of 5-fluorouracil prodrugs having high serum albumin binding potencies.

In order to understand the fundamental structural features which yield both high serum albumin binding potency and desired property as a prodrug, the derivatization was performed at N-1 or N-3 position in 5-fluorouracil. The N-3 derivatives were more stable than N-1 derivatives in vitro, whereas they were metabolized quickly in vivo. It is suggested that N-1 position should be blocked to avoid fast metabolism in vivo.

Animals↗
PubMed1993

The synthesis and in vitro and in vivo stability of 5-fluorouracil prodrugs which possess serum albumin binding potency.

For a new drug delivery system of 5-fluorouracil, we prepared prodrugs possessing certain desired properties. The prodrugs, 1-(N-4-chlorophenyl-N-methylcarbamoyl)-5-fluorouracil and 1-(N-2,4-dichlorophenyl-N-methylcarbamoyl)-5-fluorouracil, contain high serum albumin binding potency and a comparably long half life in the bloodstream in vivo to Tegafur. These two prodrugs are expected to be retained in the bloodstream as a polymeric complex with albumin and to circulate in the body for a long time, like a polymeric prodrug.

Animals↗
PubMed1993

Dynamic MR imaging of hepatoma treated by transcatheter arterial embolization therapy. Assessment of treatment effect.

The effect of transcatheter arterial chemo-embolization therapy (TACE) for hepatoma was evaluated with dynamic MR imaging with Gd-DTPA in 37 patients (44 tumors). TACE was performed using Lipiodol/cis-platinum and gelatin sponge (or microspheres) as an embolic material. All patients were examined with dynamic CT and MR imaging before and after treatment. On conventional spin echo images, changes of signal intensity after treatment varied regardless of presence of Lipiodol. Dynamic MR imaging revealed changes of tumor vascularity before and after treatment. On histologic correlation, areas of persistent tumor enhancement on dynamic MR imaging corresponded to areas of viable tumor cells while areas of non-enhancement corresponded to areas of necrosis. Dynamic MR imaging was superior in contrast resolution and was not influenced by the presence of Lipiodol compared with dynamic CT, and therefore residual viable tumors were better defined by dynamic MR imaging.

Adult↗