Biomedical subjects

K Kurata

Publications and source records attributed to K Kurata.

At least 55 records · Page 3Linked to original sources

PubMed1998

Quantitative analysis of anti-emetic principle in the tubers of Pinellia ternata by enzyme immunoassay.

A crude globulin fraction was isolated from the tubers of Pinellia ternata (Thunb.) Breit. Tubers of P. ternata are one of the well known Chinese traditional medicines. It is used on account of its anti-emetic effect. 6KDP was separated by means of gel filtration and chromatography on CM-Toyopearl 650 M from the crude globulin fraction. 6KDP is a glycoprotein of M.W. 6 kDa. 6KDP has an anti-emetic activity and hemagglutination activity. Both activities dropped during heat treatment. For the purpose to evaluate the quality of the powdered tubers of P. ternata, the quantitative analysis by means of EIA was established. The contents of 6KDP varied from 5.75 to 8.30%. The assay demonstrated a low cross-reaction with the crude globulin fraction of Colocasia antiquorum, a member of the same family as P. ternata. 6KDP is one of major proteins in the tubers of P. ternata. Thus 6KDP is a marker for quantitative analysis of the tubers of P. ternata.

Antiemetics↗

PubMed1998

Aqueous humor dynamics in beagle dogs with caffeine-induced ocular hypertension.

In order to investigate the possible mechanisms for caffeine-induced ocular hypertension, the intraocular pressure (IOP) and the outflow through the trabecular meshwork were measured in beagle dog eyes after dosing with intravenous caffeine (30 mg/kg) alone or in combination with the topical beta-blocker befunolol [applied as 100 microliters of a 1% (w/v) solution] which inhibits aqueous humor formation in the ciliary body. Intravenous injections of caffeine significantly increased the IOP at 0.25 and 1 hr after a single dose. The ocular hypertension recovered within 2 hr following dosing. Over time, there were no differences in the outflow between the caffeine and control groups. The instillation of befunolol lowered outflow and produced ocular hypotension. The levels of the IOP and outflow in dogs treated with caffeine and befunolol in combination were almost the same as those in dogs treated with befunolol alone. Single-dose and combination-dose studies demonstrate that intravenous caffeine increases the IOP in normal beagle dogs possibly by increasing aqueous humor formation and not by the inhibition of aqueous humor drainage through the trabecular meshwork.

Adrenergic beta-Antagonists↗

PubMed1998

[A case of MPO-ANCA-related vasculitis that recurred as gastrointestinal bleeding and presented difficulty in treatment].

A 54-year-old man, who had been diagnosed as having MPO-ANCA-related glomerulonephritis in 1993, developed severe anemia and was admitted to our hospital on October, 1997. Endoscopic examination of the upper gastrointestinal tract revealed melena due to duodenal ulcer (Dieulafoy type). The level of ANCA titer was elevated considerably (640 EU), but otherwise there was no evidence of systemic vasculitis activation such as fever, arthralgia, skin eruption, renal insufficiency, and rise in C reactive protein. A renal biopsy showed neither crescentic formation nor necrosis of glomerulus. Subsequently he developed hematochezia and renal dysfunction rapidly progressed thereafter. Angiographical examination of superior mesenteric artery revealed that the bleeding was responsible for the lesion of the small intestine, probably the ileum. In spite of TAE (transarterial embolization) he had recurrence of severe hematochezia three days later. Partial ileotomy was performed and progression of the anemia was stopped. Multiple ulcer was found in the resected ileum. The small arteries in the submucosa at the ulceration showed fibrinoid necrosis of the vessel walls. These findings suggested that ANCA-related vasculitis had relapsed. The patient received methylprednisolone pulse therapy, followed by oral administration of prednisolone after the operation. Both serum levels of creatinine and MPO-ANCA gradually decreased after the initiation of treatment. However, 24 days later, he suddenly manifested severe abdominal pain, and was diagnosed as having perforation of the stomach or duodenum. Due to supportive therapy and reduction of the steroid dose, peritonitis subsided, but symptoms caused by systemic vasculitis developed. Later raised the dose of steroid suppressed the activity of systemic vasculitis. In this case, elevation of the ANCA titer demonstrated recurrence of MPO-ANCA-related vasculitis as gastrointestinal bleeding.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1997

Neuropathology of the dentate nucleus in developmental disorders.

The dentate nucleus was examined histologically and immunohistochemically in 47 cases of nonprogressive developmental disorders. Neuronal loss and/or atrophy was observed in 13 cases, while mild neuronal lesions, characterized by dendritic swelling and/or the appearance of eosinophilic materials around the neurons, were exhibited in 20 cases. The former change was accompanied by diffuse central nervous system involvement, and the etiology was perinatal hypoxic ischemic encephalopathy, acute encephalopathy, and meningoencephalitis in most cases. On the other hand, most of the patients with kernicterus showed the latter change. Immunohistochemically, the mild neuronal lesions mimicking grumose, degeneration, described in some neurodegenerative diseases, seemed to reflect the changes of Purkinje cell terminals. It is suggested that secondary structural alteration of the dentate neurons in the absence of severe atrophy can occur in nonprogressive developmental disorders.

Adolescent↗

PubMed1997

Recent progress in treating patients with cleft palate.

Over the last 4 decades remarkable progress has been made in the treatment of cleft palate: the rate of attaining normal or nearly normal speech after surgery has risen from about 65% 40 years ago to nearly 90% or more nowadays. One of the main factors is intratracheal intubation anesthesia that has made the surgery much safer and easier. Improved surgical technique and speech therapy also played a great role. This paper deals with two problems: (1) Slight velopharyngeal incompetence: The combined use of fiberscopy and fluorovideoscopy can provide useful information as to: (a) the exact place of the faulty articulation, (b) the detailed pattern of inconsistent velopharyngeal function, (c) changes in articulation induced by speech therapy, and (d) the relation between velopharyngeal function and faulty articulation. All the above information greatly facilitates speech therapy for cleft palate speech. It should be done with utmost care though due to possible adverse effects of radiation. (2) Analysis of faulty articulation. It was revealed that faulty articulations such as laryngeal fricative and affricates, pharyngeal stop, and glottal stop in cleft palate speech, secondary to velopharyngeal incompetence, were produced by articulation in the larynx at various sites such as the epiglottis, arytenoids, aryepiglottic folds and vocal folds. These faulty articulation points were located lower than supposed on the basis of auditory perception.

Adolescent↗

PubMed1997

Frequency selectivity on aspirin-induced hearing loss in rats with auditory stimulus-induced conditioned suppression.

The conditioned suppression technique was employed to examine the acute effects of aspirin on auditory function in rats. Lever pressing behavior for water reinforcement was suppressed in the presence of an auditory stimulus that had been previously paired with electric shocks. A single intravenous injection of aspirin at a dose of 225 mg/kg caused an erroneous lever pressing response in the broad sound intensities of 2 kHz tone stimulus during the conditioned stimulus period. A statistically significant increase in the threshold for 2 kHz was found 1 to 72 hr after dosing but not for 4, 8 and 10 kHz. These results suggest that the hearing for low sound frequency in rats is vulnerable to the effects of aspirin. This paradigm in rats may be useful to further assess the different outer hair cells along the cochlear duct and provide an additional evidence for the aspirin ototoxicity research.

Acoustic Stimulation↗

PubMed1997

A characteristic of aspirin-induced hearing loss in auditory brainstem response of conscious rats.

The acute effects of aspirin on auditory functions were examined electrophysiologically in conscious rats with chronically implanted electrodes for auditory brainstem response (ABR) recording. A single intravenous injection of aspirin at a dose of 225 mg/kg caused a reduction in the amplitude of the ABR P1 wave evoked by a 2 kHz tone pip 1 and 24 hr after dosing at almost all sound intensity levels, while the P1 amplitude at 4 kHz was reduced mainly 1 hr after dosing, and the P1 amplitude at 8 kHz was not significantly affected at middle and high intensities even 1 hr after dosing. The audiogram obtained from the P1 amplitude showed a significant increase in the sound threshold 1 and 24 hr after dosing at 2 kHz, and 1 hr after dosing at 4 kHz, but not at 8 kHz. The peak latency of the P1 wave was also prolonged. Furthermore, reduction of the P2 and P4 wave amplitude and prolongation of the P1-P2 and P2-P4 interpeak latency were also observed at 2 kHz but not a 4 or 8 kHz. These results suggest that the rat auditory function for low frequency is vulnerable to the effects of aspirin. This paradigm, i.e., frequency selectivity, n rats may be useful to further assess the different outer hair cells along the cochlear duct and provide additional evidence for the mechanism(s) or site underlying aspirin ototoxicity.

Acoustic Stimulation↗

PubMed1997

Relationship between caffeine-induced ocular hypertension and ultrastructure changes of non-pigmented ciliary epithelial cells in rats.

The purpose of this study was to morphologically assess a possible mechanism for caffeine-induced ocular hypertension. Taking into consideration the relationship between the secretion of aqueous humor and the ultrastructure of the ciliary body, the time course of the morphological features in the ciliary epithelium when caffeine was administered intravenously to male Wistar rats was investigated by electron-microscopy. These morphological findings were also compared with the changes in the intraocular pressure (IOP). A significant increase in IOP was noted 15 min and 1 hr after a single dosing of caffeine alone. This change disappeared in all animals within 2 hr after dosing. The IOP in the animals receiving caffeine and the beta-blocker befunolol, which lowers the IOP by inhibiting aqueous humor secretion, decreased significantly from 15 min after dosing, and this change persisted 2 hr after dosing. In electron-microscopy 15 min and/or 1 hr after dosing with caffeine, a slight dilatation in the lateral intercellular spaces near the basement membrane of the non-pigmented ciliary epithelium was observed and the interdigitations between the non-pigmented epithelial cells were intact. Reversal of these changes was observed 2 hr after dosing. On the other hand, the lateral intercellular spaces between the non-pigmented epithelial cells were markedly dilated and the interdigitations were disorganized following dosing with caffeine alone and in combination with befunolol. These results described here indicate that the intravenous administration of caffeine causes ocular hypertension and also changes in the non-pigmented ciliary epithelium, suggesting an enhancement of aqueous humor transportation. This paradigm in the rat is considered to be useful to further assess caffeine-induced ocular hypertension and for use as an animal model in glaucoma research associated with an aqueous humor secretion.

Adrenergic beta-Antagonists↗

PubMed1997

Effects of adenoidectomy on sinusitis.

Effect of adenoidectomy on sinusitis was investigated in 78 children (aged 5 to 7) with adenoid vegetation, sinusitis and otitis media with effusion. After a 6 month period, improvement of the sinusitis was observed in 25 of the 45 children (56%) in the adenoidectomized group, and only in 8 of the 33 children (24%) in the non-adenoidectomized group. This was statistically significant in the adenoidectomized group (mean 2 = 7.65, p < .01). Through nasopharyngeal endoscopy in the adenoidectomized children in the 6 months following surgery, we noted decreased evidence of infection and/or inflammation. These findings may indicate that adenoidectomy is effective for sinusitis in children.

Adenoidectomy↗

PubMed1997

[Cortical status marmoratus in a patient with a sequela of postnatal anoxic encephalopathy].

Status marmoratus (ST) of the basal ganglia and thalamus has been observed in cases of perinatal hypoxic ischemic encephalopathy and rarely of postnatal encephalopathy. In occasional cases, the cerebral cortex is also involved. Here, we reported a 22-year-old male with a sequela of postnatal anoxic encephalopathy. He had been bedridden with severe mental retardation since he suffered anoxic encephalopathy at 3 months of age. ST was found in the cerebral cortex as well as basal ganglia and thalamus. In addition to ST, the cerebral cortex and white matter were remarkably devastated. We also performed a preliminary immunohistochemical study to investigate the process of ST formation, using antibodies against glial fibrillary acidic protein (GFAP), myelin basic protein (MBP) and synaptophysin. MBP-positive abnormal myelinated fibers were identified in the ST areas, which were not colocalized with GFAP-immunopositivity. Synaptophysin was positive in the areas of ST, which were not stained with Holzer method. These results suggest that the myelination in the early infancy damage of basal ganglia and cerebral cortex could be implicated in the formation of ST.

Adult↗

PubMed1997

[Localized lesions on MRI in the globus pallidus, subthalamic nuclei and hippocampus in patients with severe intellectual and motor disabilities].

We examined the clinical picture of eight patients with severe intellectual and motor disabilities, who had experienced prolonged and severe neonatal jaundice, and showed localized lesions in the globus pallidus, subthalamic nuclei and hippocampus on MRI. All patients had athetoid tetraplegia, and five patients showed disturbed ocular movements and seven showed dysphagia. Five patients could communicate with others or utter words, and all showed mental retardation. Auditory brainstem responses were abnormal in seven, and the percentage of REM sleep on all-night polysomnography was reduced in three. Neither CT nor T1-weighted MR images could detect any changes in the pallidum or subthalamic nuclei, while T2-weighted MR images disclosed bilateral high signals in the pallidum, especially in the internal segment, in all patients. Five of the 7 patients, in whom coronal T2-weighted MR imagings were obtained, showed high signals in the subthalamic nuclei. The hippocampus showed atrophy and/or T2-prolongation in seven patients. In one autopsy case, these MRI changes were concordant with pathological lesions. In patients with athetoid cerebral palsy, brainstem dysfunctions, and abnormal ABR, localization of MRI lesions to the pallidum and subthalamic nuclei is evidence for neonatal bilirubin encephalopathy.

Adult↗

PubMed1996

The characterization of the effect of locally applied N-methylquipazine, a 5-HT3 receptor agonist, on extracellular dopamine levels in the anterior medial prefrontal cortex in the rat: an in vivo microdialysis study.

In this study, we examined the effect of n-methylquipazine (NMQ), which is a putative 5-hydroxytryptamine3(5-HT3)receptor agonist, on the extracellular concentrations of dopamine (DA) and one of its metabolites, dihydroxyphenylacetic acid (DOPAC), in the anterior medial prefrontal cortex (AmPFc) of awake, freely moving rats. The administration of NMQ via the perfusion fluid produced a concentration-dependent (10-1,000 microM) increase in extracellular DA levels in the AmPFc. In contrast, NMQ produced a decrease in the extracellular concentrations of DOPAC. The increase in extracellular DA levels returned to baseline after the removal of NMQ from the perfusate. The increase in extracellular DA levels in the AmPFc produced by 100 microM of NMQ was markedly attenuated by either the coadministration of tetrodotoxin (1 microM), which inhibits axonal impulse flow, or the depletion of extracellular Ca2+ by removing CaCl2 and adding EDTA to the perfusate. The intradialysate administration of the 5-HT3 antagonist BRL 46470A produced a concentration-dependent (10-1,000 microM) decrease in extracellular DA levels, and this effect was reversible on removal from the perfusate. In contrast, ondansetron (500 and 1,000 microM), which is another 5-HT3 receptor antagonist, produced a transient increase followed by a sustained decrease in extracellular DA levels. The preinfusion of 10 microM of BRL 46470 followed by coperfusion of BRL 46470A with 50 or 100 microM of NMQ via the dialysis probe did not significantly attenuate the increase of NMQ in extracellular DA levels in the AmPFc. The administration of the selective 5-HT2 receptor MDL 100907 (1 mg/kg, i.p.) also did not alter the increase in basal DA levels produced by 100 microM of NMQ. The pretreatment of rats with alpha-methyl-p-tyrosine produced a significant attenuation in the NMQ-induced increase in extracellular DA levels, suggesting that the elevation by NMQ of DA levels is dependent on newly synthesized stores of DA. Overall, these results suggest that the increase in AmPFc DA levels by NMQ is probably not mediated by its interaction with the 5-HT3 receptor.

Animals↗

PubMed1996

Thoracoscopic repair of traumatic diaphragmatic rupture. A case report.

A 51-year-old man with a traumatic diaphragmatic rupture is presented. Preoperatively, diaphragmatic rupture and herniation of the stomach into the left thoracic cavity were suspected. Under thoracoscopic guidance, the stomach and omentum were repositioned in the abdominal cavity using Babcock forceps, and then the rupture site was closed using an endoscopic hernia stapler. The postoperative course was uneventful and the patient was discharged from our hospital with no symptoms.

Diaphragm↗

PubMed1996

Septo-optic dysplasia with cerebellar hypoplasia in Cornelia de Lange syndrome.

Little is known about the neuropathology of Cornelia de Lange syndrome. We report a unique type of cerebral malformation combined with Cornelia de Lange syndrome in a 5-year-old female child. At autopsy, the optic systems, hypothalamic nuclei, corpus callosum and cerebellar vermis were hypoplastic, and the septum pellucidum, fornix and anterior commissure were rudimentary. The brain had malformative features of septo-optic dysplasia combined with commissural dysplasia and cerebellar vermian hypoplasia. This case suggests an interrelationship between Cornelia de Lange syndrome and midline development of the brain.

Brain↗

PubMed1996

Auditory brainstem response (ABR) and effects of furosemide on ABR in conscious F344 rats.

The present study was conducted to evaluate the variations in the normal auditory brainstem response (ABR) between the F344 and Wistar rats. It was also investigated whether strain differences exist in the ABR profiles of each strain of rat given furosemide, which induced ototoxicity. The typical waveform of ABRs in the F344 rats were similar to those observed in the Wistar rats. There were no significant differences between the strains in almost all parameters, but peak latencies from P1 to P3 in the F344 rats tended to be longer than those in the Wistar rats. After a single intravenous injection of furosemide, the minimum effective dosage levels, at which each peak of the ABR disappeared, were 53.3 +/- 8.2 and 70.0 +/- 8.9 mg/kg in the F344 and Wistar rats, respectively. A single intravenous injection of 100 mg/kg furosemide delayed the reversal of decrease in amplitude, prolongation of peak latency and the reappearance time in F344 rats. Thus, the normal waveform of ABR was comparable in the F344 and Wistar rats, but a tendency towards a prolongation in each latency was noted in the F344 rat. The results also suggested that the ABR of F344 rats were more vulnerable to furosemide ototoxicity than that of Wistar rats.

Animals↗

PubMed1996

Evaluation of Perkin's applanation tonometer and the normal range of intraocular pressure in anesthetized rats.

To assess the reliability of noninvasive measurement of intraocular pressure (IOP) in rats, a Perkin's applanation tonometer was calibrated against direct manometry. The normal values of IOP in male Wistar rats were then detected. The mean tonometer readings against the transducer IOP produced regression formula: y = -0.198 + 1.071 x (r2 = 0.987). The mean IOP with standard deviation in rats was 17.7 +/- 3.5 mm Hg (95% and 99% confidence intervals: 17.2 and 18.1 mm Hg, 17.0 and 18.3 mm Hg for the lower and upper limits of the normal rat IOP, respectively). The IOP could be measured accurately using Perkin's applanation tonometer in anesthetized rats each weighing 300 g and over. Measurement of IOP using this tonometer was considered to be valuable allowing, repeated use in rats because of its small size, portability and noninvasiveness.

Anesthetics↗

PubMed1996

[A procedure for recording electroretinogram (ERG) and effect of sodium iodate on ERG in mice].

A procedure for recording the electroretinogram (ERG) in mice with a coiled stainless steel-type electrode was developed in order to examine retinal toxicity. Mice received a single i.v. of sodium iodate (SI), a retinotoxic compound, via the tail vein at a dose of 12.5, 25, or 50 mg/kg, and the ERG was recorded periodically for 28 days after dosing. In addition, the retina was examined histopathologically on day 30 after dosing. 1. The mice were anesthetized with mixed anesthetics of urethane, xylazine and ketamine after 30 to 60 min of dark-adaptation. Sixteen responses to repetitive 1.2 J light stimuli at a frequency of 0.2 or 0.1 Hz were averaged by a microcomputer. Body temperature of the mice was kept constant at 37 to 38 degrees C using a thermostatically controlled heating mat. Under these conditions, stable ERG a-wave, b-wave, oscillatory potentials and c-wave could be recorded for 28 days. 2. SI at doses of 25 mg/kg or more caused depression of the amplitudes of the oscillatory potentials, and enhancement of the a- and b-wave amplitudes, while the c-wave was already extinguished on day 1 after dosing. Following these changes, the amplitudes of the a- and b-wave decreased from day 3 or 7 after dosing. These changes did not recover until day 28 after dosing. 3. Upon histopathologic examination of the retina, folding of the outer nuclear layer, disarrangement of the rods and cones, decrease of the visual cells and swelling and decrease of the pigment epithelial cells were observed with SI at 25 mg/kg or more. 4. Using this recording technique, it was confirmed that a stable ERG was recorded repeatedly for 28 days in mice, and the effects of SI on the ERG could be detected. Histopathologic findings in the retina revealed the abnormal portions were correlated well with the changes in the ERG. These results indicate that the ERG recording procedure developed in this study is useful for evaluating retinal toxicity in mice.

Animals↗

PubMed1995

Separation of juvenile hormone metabolites with a silica-based gel permeation column.

Metabolites of juvenile hormone (JH) III, JH acid, JH diol and JH acid diol in an aqueous solution were separated by gel permeation chromatography using an UltraSpherogel SEC 2000 column. Each metabolite was eluted in an inclusion volume in the order JH acid diol, JH acid and JH diol. Although JH was the last compound eluted, it was co-eluted with a JH-binding protein (JHBP) when JHBP was present in the solution. Using this method, in vivo and in vitro JH catabolism studies were performed in the fifth stadium larvae of Bombyx mori.

Animals↗