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Biomedical subjects

K Mitsuno

Publications and source records attributed to K Mitsuno.

13 recordsLinked to original sources
PubMed1997

Behavioral LTP during learning in rat hippocampal CA3.

Behavioral long-term potentiation (LTP) of the potentials with the advance of learning were investigated in hippocampal mossy fiber (MF)-CA3 synapses. In both acute and chronic experiments, control and test groups of rats were used. Daily learning tasks in the radial arm maze were given to animals in the test groups. Complete acquisition of learning was observed on day 5. In acute experiments, when MF stimulation-induced population spikes (PS) were examined on day 7 of learning task, relatively higher PS were observed in the test group than those in the control group, and tetanic stimulation (TS)-induced LTP was still observed from the increased PS before TS in the test groups. In chronic experiments, in which the MF stimulation-induced PS were recorded daily after the learning tasks with implanted electrodes, amplitude of PS of the test groups, but not the control, increased concomitantly with the progress in learning. The PS potentiation persisted steadily from day 4 to day 7 of training. The fact that LTP in the MF-CA3 system coincided well with the advance of learning suggests that the MF-CA3 system is involved in the acquisition of learning and/or memory storage.

Anesthesia↗
PubMed1997

Factors affecting induction of neurological disorder in mice by PVC viruses and the sequence of env-LTR region of PVC441.

PVC111, PVC211, PVC321 and PVC441 cause neurological disorders associated with tremor and paralysis in rats. We tested the pathogenicity of these viruses in mice. Although histopathological studies revealed spongiform degeneration in the spinal cords of NFS mice infected with each PVC virus, only PVC441 caused a high incidence of tremor and paralysis. Further studies with PVC441 revealed dose and age dependence for tremor induction. In contrast to NFS mice, BALB/c, DBA/2 and C57BL/6 mice infected with PVC441 virus showed no neurological symptoms, although the virus replicated in each strain to titers within 5-fold of the titer in NFS mice. Despite absence of neurological symptoms, high degree of neuronal degeneration in the lumbar spinal cord was found in PVC441-infected BALB/c mice. Low degree of neuronal degeneration was found in PVC441-infected DBA/2 or C57BL/6 mice. Genetic crosses of these resistant mice with susceptible NFS mice indicated that resistance to PVC441-induced tremor induction was dominant in all strains and suggested that various host genes may control the susceptibility of mice to tremor induction by PVC441 virus. Sequencing of env-LTR region of PVC441 revealed an intermediate character between PVC211 and F-MuLV.

Animals↗
PubMed1996

Factors affecting induction of neurological disorders in mice by paralysis-inducing Friend-related PVC viruses.

Our previous studies showed that the passage of the Friend virus complex through rats generated variant MuLVs, designated PVC111, PVC211, PVC321 and PVC441, that induced neurological disorders associated with tremor and paralysis. In this study, we tested the pathogenicity of four different PVC viruses in mice. Although histopathological studies revealed spongiform degeneration in the spinal cords of NFS mice infected with each PVC virus, only PVC441 frequently induced tremor and paralysis. After a long latency, all of these viruses induced leukemia associated with severe anemia. Further studies with PVC441 revealed dose- and age-dependence for tremor induction. In contrast to NFS mice, BALB/c, DBA/2 and C57BL/6 mice infected with PVC441 virus showed no neurological symptoms, although the virus could be isolated from the tissues of central nervous system. Despite the absence of neurological symptoms, a high degree of neuronal degeneration in the lumbar spinal cord was found in PVC441-infected BALB/c mice. A low degree of neuronal degeneration was found in PVC441-infected DBA/2 or C57BL/6 mice. Genetic crosses of these resistant mice with susceptible NFS mice indicated that resistance to tremor induction by PVC441 was dominant in all mouse strains and suggested that various host genes may control the susceptibility of mice to tremor induction by PVC441 virus.

Animals↗
PubMed1994

LTP of mossy fiber-stimulated potentials in CA3 during learning in rats.

The study was done to determine whether long-term potentiation (LTP) of the potentials occurs at mossy fiber (MF)-CA3 synapses with the advance of learning in unrestrained and unanesthetized rats. The rats were divided into two groups, the test and control groups. The test group was given daily learning tasks in the radial arm maze, whereas the control group was similarly handled without learning tasks. Complete acquisition of learning was observed in the test group on day 5, and the learning was maintained over 3 days. Under freely moving conditions, a significant increase in population spikes (PS) elicited by MF stimulation with the progress in learning was observed in the test group, and the PS potentiation remained stable after day 4. Furthermore, on day 7, when MF stimulation-induced PS in the test group were compared with that in the control group in pentobarbital-anesthetized rats, the responses were comparatively higher in the former. As the training-induced PS potentiation in CA3 occurred with the advance of learning, these findings suggest that LTP in CA3 induced by learning may be related to memory storage.

Animals↗
PubMed1989

[The application of vascular endoscope for the extracranial cerebrovascular occlusive disease: the development of the endoscopic system].

Flexible thin fiber catheter is applied as vascular endoscope for occlusive lesions in the extracranial cerebral arteries. This fiber catheter is introduced transfemorally through 6 or 7 french-sized double lumen balloon catheters. Vascular endoscope clearly demonstrates the internal surface of these vessels by transient occlusion of the proximal side of the vessel through balloon inflation. The occlusive lesions in the subclavian artery or in the proximal vertebral artery were revealed as round smooth-surfaced mass to be treated by the percutaneous transluminal angioplasty.

Aged↗
PubMed1989

[Familial occurrence of intracerebral cavernous angioma].

This article reported a familial occurrence of intracerebral cavernous angioma in four members of one generation diagnosed by X-ray CT, MRI or operative specimen. Case 1, a 34-year-old female, was examined just after an episode of sudden convulsive seizure. On examination, she had a cutaneous angioma without any neurological deficit. X-ray CT revealed a high density mass lesion in the left frontal lobe, and MRI demonstrated a mass lesion in the chronic stage with an old hematoma circumscribed by hypointensity ring indicating peripheral hemosiderosis. Complete excision was carried out and a diagnosis of cavernous angioma was made after histological examination. Case 2, the 37-year-old brother of Case 1, suddenly developed left hemiparesis and hypesthesia with severe headache. X-ray CT revealed a high density mass in the right parietal lobe and two other calcifications. The right parietal lesion was excised and a histopathological diagnosis of cavernous angioma with intracerebral hematoma was made. Case 3, the 49-year-old sister of Case 1, suddenly fell into a coma and was admitted immediately. X-ray CT revealed a large pontine hemorrhage. She died on the 4th day of hospitalization without operative treatment. Necropsy was not carried out. Case 4, the 39-year-old sister of Case 1, was asymptomatic, however, she was examined on the supposition of a familial occurrence of intracerebral cavernous angioma. On examination, it was found she had multiple cavernous angioma without any neurological deficit. X-ray CT revealed parietal intracerebral calcification. MRI demonstrated a mass lesion with peripheral hypointensity ring in the right parietal lobe, and another small lesion in the pons.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Problems in the embolization therapy of spinal arteriovenous malformation].

Six cases with spinal arteriovenous malformation refractory to repetitive embolization therapy were reported. In these, de novo feeding arteries appeared after the emboli obliterated the proximal portion of the blood feeding system. Though the malformation disappeared after the embolization therapy in the angiograms of the original feeding arteries, the lesion was visualized in the follow-up angiogram from different segmental arteries via various collaterals. Through angiographic evaluation and magnetic resonance imaging were necessary to point out the "false angiographic disappearance" of the spinal arteriovenous malformation after the embolization therapy.

Adolescent↗
PubMed1985

[Experience in local hyperthermia with using Therma Tech 2000. First report].

Studies of the effects of hyperthermia on neoplastic tumors have been developed on the basis of biology. At the some time, machines for the clinical application of hyperthermia have been slowly improved. The Therma Tech 2,000, however, unlike most other pieces of hyperthermia equipment, generates RF energy at 13.56MHz. In the present study, rabbits bearing VX2 tumors were given hyperthermia treatment and measurements of their temperatures were taken.

Animals↗
PubMed1985

[Experience in local hyperthermia with using ThermaTech 2000--second report].

In the use of hyperthermia treatment, it is apparent from the work of other investigators that only a proportion of large clinical neoplastic tumors of substantial size and deep location can be heated to adequate temperatures (over 42 degrees c). It is therefore of major significance that we have tested the concept that OK-432 can be used as an immunoheat potentiator. A ThermaTech 2000 was used as the radio-frequency generator at 13.56 MHz, including an ancillary computer in the thermometry unit. Minor response in advanced and metastatic tumors was observed in 3 of 3 evaluable patients using OK-432. With other anticancer drugs, no change was observed in 11 of 16 patients, and progressive disease in 5 of 16. However, OK-432 has severe side effects including chills & fever, therefore improved immunoheat potentiators are desirable.

Biological Products↗
PubMed1984

[A case of sclerosing lipogranuloma].

Although sclerosing lipogranuloma is relatively rare, it is of special interest to urologists because the majority of the cases occur in the genital and urinary tracts. A 49-year-old man complained of urinary frequency and lower abdominal pain. IVP examination revealed compression and irregularity of dome of bladder. CT scan showed giant abnormal mass upper dome of bladder. The tumor and part of the bladder which was adhered to it were excised. Histological findings were necrosis of the fat cells with liberation of fat droplets into the intercellular spaces. There were giant cells clinging to fatty masses and small fat vacuoles in them. Essentially sclerosing lipogranuloma is a disease affecting the fat cells which for some unknown reason undergo a degenerative type of change which results in rupture of the cells with liberation of free fat droplets into the surrounding intercellular spaces and then reaction around. Complete surgical excision is the treatment of choice. Otherwise the lesion recurs.

Granuloma↗