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S Imaizumi

Publications and source records attributed to S Imaizumi.

At least 19 recordsLinked to original sources
PubMed1998

Task-dependent laterality for cue decoding during spoken language processing.

The task-dependent laterality of the auditory cortices was investigated by measuring the magnetic fields elicited by three forms of a Japanese verb, which differed in terms of prosodic and phonetic cues. Significant task-dependent magnetic fields were found in both hemispheres during a prosody-related task, but only in the left during a phoneme-related task. The latency was similar to the mismatch negatively which reflects the neural activity of automatic cue decoding. These results suggest that task-dependent schemata are activated at least partially in parallel with automatic cue-decoding processes such that those in the left hemisphere process linguistic information irrespective of acoustic cues whereas those in the right hemisphere process prosodic information.

Adult↗
PubMed1998

Prevention of cerebral vasospasm by vasodilatory peptide maxadilan following subarachnoid hemorrhage in rabbits.

Maxadilan is a vasodilatory peptide isolated from the blood-feeding sand fly Lutzomyia longipalpis. Its vasodilatory activity, estimated by the formation of erythema on rabbit skin, is greater than those of calcitonin gene-related peptide, vasoactive intestinal polypeptide and pituitary adenylyl cyclase activating polypeptide (PACAP). We have recently demonstrated that maxadilan is a specific agonist for the PACAP type I receptor, which is widely distributed in brain. Therefore, we were interested in the vasodilatory effect of maxadilan on cerebral arteries and the possibility of its clinical use for the delayed cerebral vasospasm following subarachnoid (SAH). In the first experiment, 10(-10) mol/kg of maxadilan (in sterile water) was injected into the cisterna magna three days after the induction of experimental SAH in rabbits (n = 6). Maxadilan dilated spastic basilar arteries within 30 min of the injection, but not at 6 h. In the second experiment, to prolong the vasodilatory effect of maxadilan, tablets containing stearic acid, hydrogenated oil, lactose, hydroxypropylcellulose and 15 mg of maxadilan were prepared. In vitro testing showed that 60% of maxadilan could be released slowly within the initial five days. In vivo experiments were performed to implant the maxadilan tablet (n = 7) and the placebo tablet (n = 6) into the cisterna magna after the induction of experimental SAH in rabbits. The spastic response of the basilar artery was maximum on day three in the placebo-treated groups. In contrast, we observed no significant change in the arterial diameter until day five in the rabbits treated with maxadilan tablet. These data suggest that maxadilan may have therapeutic potency in treating cerebral vasospasm.

Animals↗
PubMed1998

Congenital mediastinal dumbbell neuroblastoma with spontaneous regression of liver metastases.

We report a patient with a congenital mediastinal dumbbell neuroblastoma (NB) presenting as respiratory distress at birth rather than a neurologic deficit. The tumor did not respond to low-dose chemotherapy, but radiotherapy and surgery were effective. The patient was observed postoperatively without further therapeutic intervention considering the favorable biologic factors despite the appearance of liver metastases, which ultimately regressed spontaneously. The authors believe that most congenital NBs have favorable outcomes with a possibility of spontaneous regression, and that an understanding of the biologic features of tumors is important to avoid overtreatment of lesions with a favorable prognosis. Keywords Congenital neuroblastoma. Dumbbell tumor. Liver metastasis. Spontaneous regression

Combined Modality Therapy↗
PubMed1998

Characterization and chemosensitivity of two human malignant peripheral nerve sheath tumour cell lines derived from a patient with neurofibromatosis type 1.

Two new cell lines, designated NMS-2 and NMS-2PC, were established in vitro from a malignant peripheral nerve sheath tumour (MPNST) in the right thigh and a retroperitoneal lesion of a 30-year-old man with neurofibromatosis type 1 (NF1). The NMS-2 cell line was derived from the first tumour, and the NMS-2PC cell line from a retroperitoneal metastatic tumour detected 9 months later. Cultured NMS-2 cells showed epithelioid features, while NMS-2PC cells showed fibroblast-like features. However, both cell lines were strongly positive for S-100 protein. The transplanted NMS-2 and NMS-2PC tumours showed the same histological features typical of MPNST. Chromosomal analysis revealed that only the NMS-2 cells had a t (1;2) chromosomal translocation. Chemosensitivity tests demonstrated that NMS-2PC cells were far more sensitive than NMS-2 cells to Adriamycin and etoposide, which had been used clinically. All-trans-retinoic acid induced a morphological change in NMS-2PC cells so that they were no longer fibroblast-like, but epithelioid cells. We believe the epitheloid components in the MPNST were derived from typical spindle cells.

Adult↗
PubMed1998

Staged silo repair of gastroschisis with preservation of the umbilical cord.

BACKGROUND: The optimal surgical approach for gastroschisis remains controversial, although primary closure after vigorous stretching of the abdominal wall and decompression of the intestinal contents is currently preferred. METHODS: Between 1984 and 1997, 24 newborns with gastroschisis were treated at Saitama Children's Medical Center. The average gestational age was 37.3 weeks, and the average birth weight was 2,285 g. One patient had the associated anomaly of intestinal atresia and short bowel. Rupture of the intestines during delivery was noted in one patient. The authors applied their nonaggressive staged repair using a prosthetic silo with preservation of the umbilical cord in 20 of the 24 cases (83.3%). Primary closure with preservation of the umbilical cord was performed in the remaining four cases (16.7%). In these patients, the gastroschisis was mild. RESULTS: In the 20 cases treated by staged repair, the average interval between the first and second operation was 9.8 days. Mechanical ventilation was not required in 16 of 20 (80%) patients treated by staged repair, or in two of four (50%) patients treated by primary repair. The number of days to the first feeding averaged 14.6 days in 23 cases, excluding the patient with short bowel syndrome who required continuous total parenteral nutrition (TPN). TPN through a central venous catheter was required in 3 of 23 patients (13.0%). The overall average hospital stay was 55.1 days. Survival was 24 of 24 or 100%. Complications included perforation of the intestines, gastric bleeding, ventral hernia, and wound infection. No infections were associated with the prosthetic silo. All of the patients had a satisfactory cosmetic outcome. Recent advances in neonatal intensive care, including antibiotic therapy, reduced the possibility of infection. CONCLUSIONS: This staged repair of gastroschisis was simple and safe, neither requiring experienced surgical judgment nor complicated postoperative management, and achieved satisfactory results. Furthermore, preservation of the umbilical cord provided an improved cosmetic appearance.

Abdominal Muscles↗
PubMed1997

Vocal identification of speaker and emotion activates different brain regions.

Regional cerebral blood flow was measured in six healthy volunteers by positron emission tomography during identification of speaker and emotion from spoken words. The speaker identification task activated several audio-visual multimodal areas, particularly the temporal poles in both hemispheres, which may be involved in connecting vocal attributes with the visual representations of speakers. The emotion identification task activated regions in the cerebellum and the frontal lobe, suggesting a functional relationship between those regions involved in emotion. The results suggest that different anatomical structures contribute to the vocal identification of speaker and emotion.

Adolescent↗
PubMed1997

A case of Lyme disease diagnosed serologically.

A 57-year-old Japanese male developed erythema migrans, arthralgia, and neurological symptoms after mountain climbing in Nagano Prefecture. On ELISA, his serum reacted to Borrelia isolated from various sources. The patient's serum reacted with a 41 kilodalton protein which was reactive with monoclonal antibody H9724 specific to flagellin of Borrelia on Western blotting. He recovered after taking minocycline 200 mg daily for 2 weeks.

Antibodies, Viral↗
PubMed1997

Observation of neural processes of auditory scene analysis by magnetoencephalography.

In order to elucidate the auditory mechanism of sensory cue grouping and stream formation, we used a 37-channel SQUID magnetoencephalographic system to analyze the magnetic fields elicited by spoken sound stimuli consisting of an isolated word, an isolated consonant (/k/) burst, and a concurrent but perceptually segregated version of them. Only the overlapped /k/ burst among the five measured neural activities had a statistically significant difference in the location of the equivalent single-current dipoles in both hemispheres. The result suggests that the neurons activated by the overlapped /k/ burst are at least partially different from those activated by the other sounds: thereby supporting our new hypothesis that concurrent auditory events are spatially represented within the auditory cortex.

Adult↗
PubMed1996

Hypomelanosis of Ito associated with neuroblastoma.

We report a patient with hypomelanosis of Ito associated with neuroblastoma. Though not previously reported, the association is plausible since both conditions are forms of "neurocristopathy".

Adrenal Gland Neoplasms↗
PubMed1996

Venopelvic fistula: a rare complication of hyperalimentation.

The prolonged placement of a hyperalimentation catheter via the left great saphenous vein resulted in obstruction of the inferior vena cava and in the formation of a venopelvic fistula. Administration of hyperosmolar fluid via this catheter might be the cause of this complication.

Arteriovenous Fistula↗
PubMed1996

Development of calcitonin gene-related peptide slow-release tablet implanted in CSF space for prevention of cerebral vasospasm after experimental subarachnoid haemorrhage.

The calcitonin gene-related peptide (CGRP), a known potent intrinsic cerebral vasodilator, is contained in the sensory nerves from trigeminal ganglia that inervate the cerebral arteries. We previously reported that human alpha CGRP (hCGRP) dilates spastic cerebral arteries after experimental subarachnoid haemorrhage (SAH) in rabbits. In the present study, we investigated the prophylactic potential of a sustained higher cerebrospinal fluid level of hCGRP against experimental cerebral vasospasm. An hCGRP slow-release tablet (hCGRP s-r tablet) was developed for cisternal implantation. Experimental SAH was induced by percutaneous cisternal injection of autologous arterial blood. Angiography was initiated on day 1 (before SAH) and performed everyday. The hCGRP s-r tablet was implanted into the cisterna magna on day 2 in the treated groups. The spastic response of the basilar artery was maximized on day 4 in the non-treated (80.7% of day 1) and the placebo-treated (79.3%) groups. In contrast, the arterial diameters on day 4 were 96.1% and 90.5% of day 1 in the groups implanted with hCGRP 24 micrograms and 153 micrograms s-r tablets, respectively. We also measured the concentration of hCGRP in the cerebrospinal fluid (CSF) following implantation of the hCGRP 24 micrograms s-r tablet in the cisterna magna. The hCGRP concentration before implantation was below the dectable level. Following implantation, the hCGRP level in the CSF was 23.12 nmol/L on the second day and remained at elevated levels until the fifth day. These experiments suggest that the intrathecal single implantation of the hCGRP s-r tablet could produce an elevated concentration of hCGRP in the CSF over five days and have prevented the cerebral vasospasm after SAH in the rabbit. The hCGRP s-r tablet may be clinically applicable in the treatment of patients with SAH against cerebral vasospasm.

Animals↗
PubMed1996

Effect of calcitonin gene-related peptide on delayed cerebral vasospasm after experimental subarachnoid hemorrhage in rabbits.

BACKGROUND: Calcitonin gene-related peptide (CGRP) is an intrinsic vasodilatory substance contained in perivascular nerve fibers of intracranial arteries. It is suggested that CGRP plays a role in cerebral vasospasm after subarachnoid hemorrhage (SAH). METHOD: An experimental SAH was produced by intracisternal injection of arterial blood in rabbits. The animals were treated with intrathecal administration of CGRP solution 3 days after SAH. The degree of vasospasm and the effect of CGRP were evaluated angiographically by measuring the basilar artery diameter. RESULTS: The basilar artery constricted to 73.0% of the pre-SAH values 3 days after SAH. Fifteen minutes after injection of 10(-10) mol/kg CGRP, the basilar artery dilated to 117.1% (n = 8), which was significantly larger than 67.1% in the vehicle group (n = 8) (p < 0.01). The significant vasodilatory effect of CGRP, compared with the vehicle group, lasted for 6 hours. CONCLUSIONS: Intrathecal administration of CGRP has therapeutic potential for treating cerebral vasospasm.

Animals↗
PubMed1996

The influence of oxygen free radicals on the permeability of the monolayer of cultured brain endothelial cells.

Free radicals have been implicated in the pathogenesis of vasogenic brain edema caused by ischemic or traumatic injury. It has been reported that in transgenic mice overexpressing the human CuZn-superoxide dismutase, brain edema is decreased in many cerebral disorders. To investigate the effects of free radicals on the permeability of the blood brain barrier, we established an in vitro model system of the blood-brain barrier using brain endothelial cells cultivated from transgenic mice and non-transgenic mice. The blood-brain barrier model is originated by a monolayer of brain endothelial cells cultured on a membrane which has 0.45-micron pores. Electrical resistance across the cell monolayer, which reflects the paracellular flux of ionic molecules, was measured. The blood-brain barrier models were incubated with menadione (vitamin K3, an intracellular O2- producing agent), and segmental changes in the electrical resistance across the monolayer were compared between the transgenic and the non-transgenic mice. Superoxide dismutase activity of the cultured brain endothelial cells was 1.7 times higher in the transgenic than in the non-transgenic mice (n = 3, P < 0.001). The electrical resistance was reduced by menadione in the transgenic but not in the non-transgenic mice (n = 7, P < 0.05) in the early stage. Moreover, desferroxamine mesylate (Fe2+ chelating agent) inhibited the menadione-induced early decrease in electrical resistance in the transgenic mice (n = 7, P < 0.05). These results suggest that the permeability of the blood-brain barrier may be affected by hydroxyl radicals and/or peroxynitrite rather than the O2- itself.

Animals↗
PubMed1996

Listener and context dependency in the perception of emotional aspects of infant voice.

Developmental aspects of an infant's ability to express emotions through vocalizations were studied based on perceptual rating experiments against 12 vocalization- and emotion-related reference words. Three groups of listeners, students, mothers with infants, and nursery governesses, rated 28 voice samples recorded from a male infant at 6, 9, 12 and 17 months of age, under a positive or negative context. Among three factors extracted by a factor analysis, one representing the emotional contrast of frightened/angry versus happy was found to be independent of listener group, infant age and context. The other two, one representing contrast between pleased/happy versus demanding/sad and the other seeking affection and rejecting/angry were dependent on infant age and context. These results may indicate that infants even at 6 months of age can express the emotional contrast of 'pleasure' versus 'discomfort' through vocalization, which listeners perceive independently in context.

Anger↗
PubMed1996

Clockwise whirlpool sign at color Doppler US: an objective and definite sign of midgut volvulus.

PURPOSE: To evaluate the clockwise whirlpool sign at color Doppler ultrasound (US) in the diagnosis of midgut volvulus. MATERIALS AND METHODS: Pediatric patients (160 boys, 76 girls; age range, 0 day to 14 years) with possible midgut volvulus underwent abdominal gray-scale US and color Doppler US. Midgut volvulus was diagnosed by recognition of the whirlpool sign (wrapping of the superior mesenteric vein and the mesentery around the superior mesenteric artery). If the whirlpool rotated clockwise with caudal movement of the transducer, the direction of the whirlpool was defined as clockwise. RESULTS: Color Doppler US showed a whirlpool sign that was clockwise in 12 of 13 patients with surgically confirmed midgut volvulus and counterclockwise in three patients without midgut volvulus. Sensitivity, specificity, and positive predictive value of clockwise whirlpool sign for midgut volvulus were 92%, 100%, and 100%. CONCLUSION: The clockwise whirlpool sign is diagnostic of midgut volvulus. Color Doppler US should be performed as an initial imaging study in children suspected of having midgut volvulus.

Adolescent↗