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Biomedical subjects

T Okuno

Publications and source records attributed to T Okuno.

At least 163 records · Page 9Linked to original sources
PubMed1994

[Pathophysiology of infantile hydrocephalus: studies with multivariate analysis].

We investigated factors relating to intellectual outcome in 21 patients with infantile hydrocephalus. Every patient had received V-P shunt operation before, and was followed up for at least one year. The intellectual development was evaluated with multivariate analysis, and was found to be contributed independently by etiology of hydrocephalus, age at onset, association of epilepsy, and shunt troubles. Thus, those with congenital hydrocephalus, onset after the neonatal period, epilepsy or shunt troubles were related to poor intelligence, while those with acquired hydrocephalus, onset during the neonatal period, and without epilepsy were related to favorable outcome. Among the patients, early onset was correlated with early surgical intervention, which also may have been a determining factor. We also conducted multivariate analysis with the results of somatosensory evoked potentials (SEPs) and visual evoked potentials (VEPs) as objective variables. For both SEPs and VEPs, etiology was considered to be the most important, but other factors also contributed considerably, including CT scan findings, current developmental status, and association of congenital anomalies and epilepsy. Clinical pictures of patients with infantile hydrocephalus apparently are very complicated, being determined by multiple factors, but these cerebral evoked potentials are thought to be useful in the evaluation and follow-up of the patients with infantile hydrocephalus.

Evoked Potentials, Somatosensory↗
PubMed1993

mRNA amplification system by viral replicase in transgenic plants.

We have constructed transgenic tobacco plants (M1x2-FCP2IFN plants) expressing viral RNA replication genes of brome mosaic virus (BMV) and BMV RNA3 derivative (FCP2IFN) carrying the human gamma interferon (IFN-gamma) gene. In M1x2-FCP2IFN plants the RNA3 derivative expressed from the integrated cDNA was replicated and subgenomic RNA (i.e. mRNA of IFN-gamma) was produced by BMV replicase. The accumulation level of the mRNA of IFN-gamma was approximately 5-fold higher than that by the cauliflower mosaic virus (CaMV) 35S RNA promoter. In addition IFN-gamma accumulated in M1x2-FCP2IFN plants.

DNA, Complementary↗
PubMed1993

Synthesis of antimicrobial agents. 5. In vivo metabolism of 7-(4-hydroxypiperazin-1-yl)quinolones.

A series of novel pyridone carboxylic acids having a 4-hydroxypiperazin-1-yl, a 4-hydroxy-3-methylpiperazin-1-yl, and a 4-hydroxy-3,5-dimethylpiperazin-1-yl group was prepared, and their metabolism to corresponding piperazinyl derivatives after oral administration to mice and rats was studied. This reductive metabolism appeared to be more extensive in mice than in rats. Moreover, the introduction of a methyl group into the alpha-position of the 4-hydroxy group depressed the metabolism in both species.

4-Quinolones↗
PubMed1993

Depth EEG in mutant epileptic E1 mice: demonstration of secondary generalization of the seizure from the hippocampus.

Mutant epileptic E1 mice are thought to have focal epilepsy of hippocampal origin because glucose utilization is increased in the hippocampus (HPC) during seizures in these mice. However, direct electrographic evidence is still lacking for the notion. We recorded electroencephalograms (EEGs) using depth electrodes in E1 and non-epileptic ddY mice. All the mice were subjected to a conventional seizure-provoking maneuver during EEG recording; each mouse was placed on a mesh floor and observed for 3 min, and then tossed up in the air. When the E1 mice showed signs of abortive seizures or prodromal symptoms including squeaking, running and myoclonus, sporadic spikes or sharp waves were generated exclusively in the HPC. When generalized convulsions followed these prodromes, the sporadic discharges evolved into a burst of generalized spikes which again predominated in the HPC. We also observed the cerebral cortex, amygdaloid, caudate, centro-median thalamic and ventral postero-lateral thalamic nuclei, all of which were found to be only secondarily involved. These findings provide the first electrical evidence that E1 mice have a secondarily generalized seizure that has its initiating focus in the HPC.

Animals↗
PubMed1993

The effect of dehydration level on the NaCl concentration chosen by rats.

The relationship between the level of dehydration (3%, 6%, and 8% body weight) and the preference for water and saline in the rehydration were assessed in rats for 15 h. At the 6% and 8% dehydration levels, rats provided with tap water and 0.9% NaCl solution simultaneously consumed more water than NaCl solution (calculated Na concentration was about 57 mEq/l) within 3 h and then consumed more NaCl solution than water (about 116 mEq/l). The shift of the Na concentration of fluid occurred when about 107% of lost cations and 82% of lost fluid were regained. Urine output and urinary Na output were about 14% of the ingested fluid during the initial 4 h; after that, the output was in amounts almost equal to the ingestion. However, the 3% dehydrated rats consumed almost equal amount of tap water and NaCl solution (about 68 mEq/l) throughout the 15 h. The result indicates that at more than 3% dehydration level, rats initially choose hypotonic NaCl solution, and the volume loss of body fluid is then regained by the consumption of almost isotonic Na solution.

Animals↗
PubMed1993

A case of vessel perforation during interventional neuroradiological procedure. Operative findings of the perforated vessel.

A case of vessel perforation by a guide wire during an interventional neuroradiological procedure is reported. The patient was a 59-year-old woman with a left frontal basal arteriovenous malformation (AVM) fed by the left anterior cerebral artery. Transarterial embolization of the AVM was attempted. During the procedure, vessel perforation by the guide wire occurred at the left A1-A2 junction and resulted in subarachnoid hemorrhage, which stopped spontaneously. The patient developed progressive obstructive hydrocephalus, and surgical treatment was performed. The AVM was totally removed after ventricular drainage, and the arterial perforation site was explored. When clot around the left A1-A2 junction was removed, hemorrhage recurred. This hemorrhage was similar to what has been observed when a small perforating artery was avulsed. The hemorrhage site was coagulated under temporary occlusion of both A1 segments. Surgical intervention was probably not necessary for this type of bleeding if it had stopped spontaneously, because the rebleeding from the small pinhole would be unlikely, and the operation was more hazardous than the usual aneurysmal surgery.

Cerebral Arteries↗
PubMed1993

Reasons for the low accumulation level of aphid transmission factor protein in infected leaves with an aphid-non-transmissible cauliflower mosaic virus isolate, CM1841.

The synthesis and accumulation of aphid transmission factor protein (p18) in cauliflower mosaic virus (CaMV)-infected turnip protoplasts were examined in time course and pulse-labelling experiments, comparing an aphid-non-transmissible isolate (CM1841) with an in vitro recombinant aphid-transmissible CaMV (CMBX) generated from the CM1841 isolate. There was little difference in the synthesis and accumulation of p18 between CM1841- and CMBX-infected protoplasts. When the accumulation of p18 in infected leaves was monitored from 3 to 28 days post-symptom emergence (p.e.) by Western blotting, the amount of p18 accumulated in CM1841-infected leaves continuously decreased from 3 days p.e. throughout the experimental period, whereas the amount of p18 in CMBX-infected leaves was lowest at 3 days p.e. and increased thereafter. These results suggested that CM1841 differed from CMBX not in the synthesis of p18 but in the stability of p18 in infected leaves.

Animals↗
PubMed1993

Efficient production of human gamma interferon in tobacco protoplasts by genetically engineered brome mosaic virus RNAs.

We succeeded in producing human gamma interferon (IFN-gamma) in tobacco protoplasts in quantity using genetically engineered brome mosaic virus (BMV strain ATCC66). This strain of BMV produces two types of coat protein, a full-length coat protein (20K) and a truncated coat protein (19K) which are translated from the first and second initiation codons, respectively. We replaced the truncated coat protein gene with the IFN-gamma gene and synthesized BMV-IFN-gamma chimera RNAs using an in vitro transcription system. The BMV-IFN-gamma chimera RNAs were used to inoculate tobacco protoplasts together with BMV RNA 1 and RNA 2 and produced IFN-gamma to a level of 5 to 10% of total extracted proteins per infected protoplast after 24 h of incubation. The efficient production of IFN-gamma was attributed to the high translation activity of the BMV-IFN-gamma chimera RNA. We demonstrate that 24 nucleotides coding for the N-terminal amino acids of the full-length coat protein were probably involved in the high translation activity of the BMV-IFN-gamma chimera RNA.

Base Sequence↗
PubMed1993

Treatment of vertigo using laser labyrinthectomy.

Benign paroxysmal positional vertigo developed in a patient with perilymph fistula 3 years after closure of the fistula which was in the lower margin of the annular ligament. The patient's symptoms were long-lasting and intractable. The macula utriculi and utriculoampullary nerve were irradiated by argon laser beams through the stapedectomized oval window. Singular neurectomy was performed using Argon laser, although the nerve could not be identified. After surgery, the patient's symptoms disappeared. Pure tone average of the operated side was 50 dB which remained unchanged after surgery. The macula utriculi may have been completely destroyed. Ocular counter-rolling was indicative of hypofunction of the irradiated utricle. The singular nerve may or may not have been sectioned. The ampullary nerves to the lateral canal and probably the anterior canal were intact, judging from the normal caloric reaction.

Acoustic Maculae↗
PubMed1993

[A case of epidural hematoma caused by a vacuum extraction without any skull fractures and accompanied by cephalohematoma].

A case of epidural hematoma associated with cephalohematoma caused by a vacuum extraction was reported. Old liquefied hematoma was removed via a small burr hole in the parietal bone at the age of 23 days. No neurological deficits were recognized at the age of 6 months. As the dura mater does not easily detach from the overlying skull in the neonate, it is a very rare occurrence for this to happen as a complication of the use of forceps or in extractions. To our knowledge, only 4 cases of epidural hematoma after vacuum extraction have been reported. The mechanism of the development of an acute epidural hematoma during extraction is reported to be due to direct force to the dura mater and skull induced by negative pressure of a vacuum extraction. In the present case, it seems that negative pressure produced a detachment of the dura mater from the overlying skull. It suggests that examinations including plain craniogram and CT scan should be performed as soon as possible in the neonate with cephalohematoma when they have been delivered by a vacuum extraction.

Bone Diseases↗
PubMed1992

Assessment study on the high-performance liquid chromatography-type hydroxyapatite chromatography in the presence of sodium dodecyl sulfate.

The HPLC-type hydroxyapatite chromatography in the presence of sodium dodecyl sulfate (SDS) was assessed with special attention to the behavior of the surfactant. A significant amount of SDS was found to be adsorbed to the hydroxyapatite packed in the column from the starting buffer, 50 mM sodium phosphate buffer, pH 7.0, only when the buffer contained SDS in a concentration at or above its critical micelle concentration. When the phosphate buffer concentration was increased while the SDS concentration was kept at 1 mg/ml, the adsorbed surfactant was desorbed in advance of the release of proteins. Polypeptides derived from proteins could be successfully separated only when the column had been thoroughly equilibrated with the above-mentioned starting buffer solution. When a protein polypeptide complexed with SDS, which had been similarly equilibrated, was applied to the column, an amount of SDS corresponding to 75-90% (w/w) of the surfactant originally bound to the polypeptide was released upon its binding to the hydroxyapatite. On the other hand, porin, an Escherichia coli outer membrane protein, retaining its trimeric native structure in the presence of SDS, released a significantly smaller amount of SDS. When the membrane protein was denatured to give a single polypeptide, it behaved in a manner similar to that of the other protein polypeptides. The mechanism of binding of the protein polypeptides was discussed on the basis of these results. The native and denatured entities of porin could be efficiently separated as the result of the difference in their mode of interaction with the hydroxyapatite.

Chromatography↗
PubMed1992

Morphological characteristics of the scalp far-field potentials evoked by median nerve stimulation in infants and children.

We investigated the somatosensory evoked potentials (SEPs) produced by median nerve stimulation in normal infants, children and adults, focussing upon the wave forms of the scalp far-field potentials (FFPs). In adolescents and adults, 3 or 4 positive FFPs preceded the widespread N18 component on the scalp, corresponding to P9, P11, P13 and P14 (or P13-14). In infants and children, however, the scalp FFPs often included 5 positive waves, the initial three of which were characteristically sharp and brief. This distinctive wave form, with 5 positive FFPs, was correlated with an Erb's potential having a bipeaked negative phase. We studied the temporal relationship of the 5 positive FFPs to the Erb's potential and the cervical SEPs and concluded that the initial 3 brief positive waves were produced by overlapping of a bipeaked "P9" and bipeaked "P11." Both "P9" and "P11" are stationary waves that are thought to originate in the first-order afferents, so they probably reflect the bipeaked appearance of the compound nerve action potential.

Action Potentials↗
PubMed1992

Comparison of antiviral assay methods using cell-free and cell-associated varicella-zoster virus.

Assay methods for varicella-zoster virus (VZV) susceptibility to acyclovir (ACV) of VZV were compared by using cell-free (CF) and cell-associated (CA) virus of 6 x plaque-purified VZV. The 50% effective doses (ED50) of ACV, as required to reduce virus plaque formation by 50%, were about 8 times higher for CA virus than for CF virus. Also, the ED50 of 1-beta-D-arabinofuranosyl-(E)-5-(2-bromovinyl)uracil (BVaraU) for CA-VZV was higher than for CF-VZV, and fresh clinical isolates of VZV gave higher ACV ED50 values than CF virus. CA virus prepared at various times after CF virus infection showed a gradual increase of the ACV ED50 with time, ranging from the ED50 for CF virus to that for CA virus.

Acyclovir↗
PubMed1992

Ring 14 chromosome with complex partial seizures: a case report.

A two-year-old girl was found to have a ring 14 chromosome: [46, XX, r(14) (P13 q32.3)]. Her development, including verbal ability, was retarded, her CT scan displayed a low density area anterior to the left temporal lobe, and she suffered from complex partial seizures. Focal central nervous system abnormalities may be present in patients with ring 14 chromosome, and their seizures are not exclusively of the primary generalized type. This is the first case with ring 14 chromosome and complex partial seizures.

Child↗
PubMed1992

"Floating" labyrinth. Pathophysiology and treatment of perilymph fistula.

Collapse of the membranous labyrinth of the pars superior is a morphological change observed in 50% of animals with experimentally produced perilymph fistula, although the extent and degree of the collapse may vary greatly. The moderately collapsed membranous labyrinth may drift with CSF and/or perilymph pressure changes and this may stimulate sensory cells of the utricle and/or semicircular canals if the sensory cells are intact and the collapsed wall is in contact with the otolithic membrane and/or cupula. This condition is termed "floating" labyrinth. Caloric irregularity is often observed in electronystagmograms recorded from animals with experimental perilymph fistula. This is also observed in patients with perilymph fistula. Partial destruction of the vestibular organs using argon laser was performed in a patient with perilymph fistula who was incapacitated because of persistent positional vertigo after closure of the oval window fistula. Irradiation of the argon laser beam was directed to the macula utriculi, utriculoampullary nerve and singular nerve. The hearing of the patient was maintained, and vertigo disappeared after laser labyrinthectomy.

Audiometry, Pure-Tone↗
PubMed1992

Expression of brome mosaic virus-encoded replicase genes in transgenic tobacco plants.

We introduced replicase genes of brome mosaic virus (BMV) to Nicotiana tabacum cv. Petit Habana (SR1) using two different types of transformation vectors containing cDNAs of BMV RNA 1 and RNA 2. One type (V type) contains cDNA from which complete viral RNAs are transcribed. These RNAs can function as templates for viral replicase. The other type (M type) contains cDNA from which viral RNAs without their 3' non-coding regions are transcribed; these RNAs can only function as mRNA. Viral replicase expressed from the integrated cDNAs in both V and M type transgenic plants can complement an infection by BMV RNA 3.

Blotting, Northern↗