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Biomedical subjects

A Ikeda

Publications and source records attributed to A Ikeda.

At least 145 records · Page 8Linked to original sources
PubMed1999

[Imipenem/cilastatin sodium and other beta-lactams for respiratory tract infections: clinical benefit and treatment days for cure].

Therapeutic efficacy and the treatment days for cure of imipenem/cilastatin sodium (IPM/CS) in treatment of pulmonary infections were prospectively determined in comparison with those of beta-lactams other than carbapenems mainly ceftazidime (CAZ) or sulbactam/cefoperazone (SBT/CPZ). The overall response rate was 84.9% (62/73) in the IPM/CS group and 74.7% (56/75) in the beta-lactam group, the difference not being significant. In the subjects having underlying respiratory diseases, the response rate was 91.1% (41/45) and 73.9% (34/46) in the IPM/CS and beta-lactam groups, respectively. In patients with infections secondary to chronic respiratory disease, the rate was 91.2% (31/34) in the former group and 66.7% (24/36) in the latter group, respectively. The differences were significant for both stratified analyses. The treatment days for cure judged by the attending physician were 12.9 +/- 0.6 days in the IPM/CS group, and 14.5 +/- 0.7 days in the beta-lactam group. The difference was not, however, significant. In patients with mild to moderate infections, the treatment days for cure was 12.0 +/- 0.6 days (n = 64) in the IPM/CS group and 14.3 +/- 0.7 days (n = 70) in the beta-lactam group. In patients with underlying respiratory disease, the treatment days for cure were 11.8 +/- 0.7 days (n = 45) and 14.7 +/- 0.9 days (n = 46) in the IPM/CS and beta-lactam groups, respectively. In patients with infections secondary to chronic respiratory disease, the days were 11.1 +/- 0.7 days (n = 34) and 14.7 +/- 1.1 days (n = 36), respectively. Thus, IPM/CS therapy significantly reduced the number of treatment days until cure. There was, however, no significant difference between the two therapy groups in treatment of the patients with severe infections, those without underlying respiratory disease, or those with pneumonia and/or lung abscess. The treatment days for cure were also assessed by the members of review committee taking into consideration of body temperature, leukocyte count, and C-reactive protein. As the result, it was 6.9 +/- 0.5 days in the IPM/ CS and 10.3 +/- 0.7 days in the beta-lactam groups; respectively, and the difference was significant. Time (days) until cure was also compared between the two groups using survival time analysis, confirming a more rapid response in the IPM/CS group. Although IPM/CS therapy was associated with a shorter response time as assessed by both the attending physicians and the review committee, there were considerable differences between the results of these judgements. Thus, the duration of treatment with injectable antibiotics requires reevaluation in the future. No significant differences were observed between the groups with respect to parameters indicating side effects and laboratory abnormalities. There were no severe symptoms or laboratory findings, and symptoms and changes in laboratory values, if any resolved during the course of therapy or after the withdrawal of treatment. In conclusion, IPM/CS seems to be very useful as first-line therapy for respiratory tract infections and for shortening the duration of treatment.

Adult↗
PubMed1999

[Open surgery for pontine hemorrhage: experience in 3 cases].

Experience in three pontine hemorrhage cases which were treated by open surgery is recorded here. They were operated on by trans-fourth ventricular, subtemporal transtentorial on retromastoid suboccipital approaches. The neurological symptom improved noticeably in one case who was operated on through the retromastoid suboccipital approach seven days after the onset. The pontine hemorrhage can even be cured with open surgery which is performed in the early stage and through the operative approach.

Aged↗
PubMed1999

[The relationship between coagulation time and bilateral occurrence in chronic subdural hematoma].

The relationship between the bilateral occurrence and coagulation time was analyzed in 137 cases of chronic subdural hematoma. Bilateral chronic subdural hematomas more frequently happened in the patient with coagulation time elongation beyond the normal control. This tendency was significant in the non-traumatic group and bilateral subdural hematomas were found in: 45% in prothrombin time (PT)-elongated group vs 10.3% in non-elongated group and 38.9% in activated partial thromboplastin time (aPTT)-elongated group vs 14.6% in non-elongated group. The ratio of PT and aPTT coagulation time against the normal control was significantly larger in the bilateral group than in the unilateral group. The ratio was as follows: PT ratio was 1.056 in bilateral group and 0.995 in unilateral group. aPTT ratio was 1.051 in bilateral group and 0.954 in unilateral group. Furthermore the bilateral hematomas tended to happen in hemodialysis cases, and in patients on warfarin or anti-platelet drugs. Bilateral hematomas were found in 41.7%, 37.5% and 33.3% respectively. The ratio of PT and aPTT coagulation time was as follows: PT ratio was 1.040 in hemodialysis cases and 1.082 in warfarin-applicated cases. aPTT ratio was 1.022 in hemodialysis cases and 1.055 in warfarin-applicated cases. These results suggest that the suppressed coagulation ability and platelet function are involved in the genesis of bilateral chronic subdural hematomas.

Aged↗
PubMed1999

[Electrophysiological study of intractable epileptogenicity in human epilepsy: clinical usefulness of ictal DC shifts and cavernous sinus EEG].

In order to clarify the clinical and electrophysiological features in intractable epileptogenicity in human epilepsy, we applied the new techniques, ictal DC shifts and cavernous sinus EEG recording, for presurgical evaluation of patients with intractable partial epilepsy. (1) Ictal DC shifts were successfully recorded with subdural electrodes in 8 patients with intractable neocortical epilepsy, and an analysis of ictal DC shifts would add useful information to delineate an epileptogenic area. Scalp-recorded ictal DC shifts were also investigated in 3 patients with intractable neocortical epilepsy. It also delineated the epileptogenic area, but it was vulnerable for artifacts. (2) By using the techniques of intravascular EEG recording, we recorded EEG from the bilateral cavernous sinus (cavernous sinus EEG) in patients with intractable temporal lobe epilepsy. Cavernous sinus EEG well sensitively recorded interictal, also ictal in selected patients, epileptiform discharges which arose from the mesial temporal structure even though they were not recorded by scalp electrodes. It is concluded that the above two techniques are clinically useful for delineating an epileptogenic area in patients with neocortical epilepsy and temporal lobe epilepsy.

Action Potentials↗
PubMed1999

[Estimation of antibacterial activity of various antibiotics against Pseudomonas aeruginosa by score method].

Antibacterial activity of various antibiotics against Pseudomonas aeruginosa isolated from each hospitals depends on the variety or amount of antibiotics used in each hospital. The antibiotic, which is effective to P. aeruginosa in a certain hospital is not always effective to that in other hospital. The excellent antibiotics in antibacterial activity have low MIC and hard to progress in resistance, and such antibiotics may be effective against P. aeruginosa isolated from any hospitals. Therefore we thought that the antibiotic, which was progress to resistance, would show a great difference in MIC among hospitals, and we investigated MIC and difference of MIC of various antibiotics against P. aeruginosa isolated from six hospitals. Furthermore, we converted the data of MICs and difference of MIC among six hospitals into the score, and tried to estimate antibacterial activity of various antibiotics by using those scores. From the results of analysis in this report, we think the antibiotics actually surpass in antibacterial activity may be imipenem, cefozopran, cefsulodin and amikacin. New analytical method proposed in this report will become one of potential methods to estimate antibacterial activity of antibiotics against bacteria isolated from inpatient with bacterial infections.

Anti-Bacterial Agents↗
PubMed1999

Cell-specific expression of tubby gene family members (tub, Tulp1,2, and 3) in the retina.

PURPOSE: The family of tubby-like proteins (TULPs), consisting of four family members, are all expressed in-the retina at varying levels. Mutations within two members, tub and TULP1, are known to lead to retinal degeneration in mouse and humans, respectively, suggesting the functional importance of this family of proteins in the retina. Despite a high degree of conservation in the carboxy-terminal region (e.g., putative functional domain of the genes) among family members, they are unable to compensate for one another. The purpose of this study was to provide a rationale for this lack of compensation by investigating the spatial distribution of tubby gene family members in the retina and to investigate the mechanism of photoreceptor cell death in tubby mice. METHODS: In situ hybridization using riboprobes specific for each tubby gene family member and immunohistochemistry for TUB and TULP1 were performed to determine their expression patterns in the retina of tubby and wild-type control mice. The terminal dUTP nick-end labeling (TUNEL) assay was performed to detect apoptotic cells in the retina of tubby and wild-type control mice. RESULTS: tub mRNA was found to be expressed throughout the retina, with highest expression in the ganglion cell layer (GCL) and photoreceptor cells. In contrast, Tulp1 expression was observed only in photoreceptor cells and Tulp3 mRNA was expressed at a moderate level only in the inner nuclear layer (INL) and GCL. The results of the immunohistochemical analysis paralleled those observed in the in situ studies. TUB immunoreactivity was most highly concentrated in the GCL, in the inner and outermost regions of the INL, in the outer plexiform layer (OPL), and in the inner segments of photoreceptor cells. Similarly, TULP1 immunoreactivity was observed in the OPL and inner segments of the photoreceptor cells. No differences in expression at the mRNA or protein level were observed for any of the molecules tested in tubby or wild-type mice. TUNEL-positive cells were detected in the ONL of tubby mice, whereas very few were seen in the same layer of age-matched control mice. CONCLUSIONS: Although all tubby gene family members are expressed in the retina, they each have different cell-specific expression patterns, which may account in part for their inability to compensate for the loss of one family member. The photoreceptor cell death in tubby mice occurs through an apoptotic mechanism, which is known to be the common final outcome of other forms of retinal degeneration.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Clonic convulsion caused by epileptic discharges arising from the human supplementary motor area as studied by subdural recording.

In order to help clarify the mechanism of tonic convulsion, which is commonly seen in supplementary motor area (SMA) seizures, we investigated the temporal relationship between ictal discharges arising from the SMA and the associated EMG discharges in the foot, in a patient with SMA seizures, prior to surgical treatment. The patient's intractable seizures consisted of tonic followed by clonic convulsion of the left foot also involving at times, the left hand. Ictal EEGs were investigated by subdural electrodes placed on the SMA-proper and pre-SMA, which were defined by cortical stimulation and by recording cortical-evoked potentials. Interictally, repetitive spike discharges were seen at the pre-SMA. Each seizure initially had a tonic phase associated with an electrodecremental EEG pattern. It was followed by clonic convulsion as shown by clonic EMG discharges of the left tibialis anterior (TA) muscle. It had a duration of 300 to 500 msec, and on each occasion a positive cortical activity at the pre-SMA preceded the EMG onset by 110 msec, and a negative spike at the SMA-proper preceded the EMG onset by 50 to 60 msec. Epileptic discharges originating from the pre-SMA spread to the SMA-proper and possibly also to the primary motor cortex (MI) in this patient. Since both SMA-proper and MI could elicit EMG discharges through the independent corticospinal tracts having different conduction velocities, even a single spike arising from the SMA could give rise to a long EMG burst, which may play some role in the tonic convulsion which characterizes SMA seizures.

Adult↗
PubMed1999

Seizure with prominent tonic initial signs followed by psychomotor features: a case report clinically manifesting an unusual ictal evolution.

A clinically tonic seizure phase, immediately followed by psychomotor features (right hand dystonic posture, left hand and oral automatisms), was recorded by video and EEG, in a patient who had gliosis of the left temporal lobe and left hippocampal atrophy. Interictal epileptiform discharges were frequently seen in the left temporal area, and at the time of the tonic seizure phase, ictal spike discharges were continuously observed at the left posterior temporal area, which was recognized only by applying a high frequency filter (HFF) of 15 Hz to the digitally recorded EEG because EMG artifacts totally obscured the EEG with a HFF of 60 Hz. It is most likely that tonic seizure can occur in an adult patient with temporal lobe epilepsy, and it is speculated that an epileptogenic focus might activate a certain brain area which is regarded as a symptomatogenic zone for tonic seizures. If the tonic seizure phase is immediately followed by psychomotor features as seen in the present patient, the former could be due to focal epilepsy.

Adult↗
PubMed1998

Molecular characterization of a novel tubby gene family member, TULP3, in mouse and humans.

Tubby and related proteins are derived from a small family of novel genes. The carboxytermini of this family are highly conserved across a number of species including humans, mice, Caenorhabditis elegans, Arabidopsis, rice, and maize. Splicing defects in both tub and another member of the gene family, TULP1 (tubby-like protein 1), lead to phenotypes of retinal degeneration in mice and humans, respectively. We describe here the isolation of the human and mouse homologs of a new family member, TULP3. The cDNAs code for proteins of 442 and 460 amino acids, respectively. The level of identity between the human TULP3 and the mouse homolog is 69%, lower than that observed for the homologs of the other family members (96% for human and mouse TUB), and is higher at the amino- and carboxytermini than in the central region of the protein. Phylogenetically, TULP3 is the family member most closely related to TUB. Also, like TUB, it has a wider pattern of tissue expression than either TULP1 or TULP2. TULP3 is detected at high levels in human RNA from testis, ovaries, thyroid, and spinal chord. Tulp3 is also highly expressed in mouse RNA from eyes and adipose depots, tissues not tested in the human Northern analysis. We also report that TULP3 maps to human chromosome 12p13. The murine homolog, Tulp3, maps to the telomere of mouse chromosome 6.

Amino Acid Sequence↗
PubMed1998

Serial processing of the somesthetic information revealed by different effects of stimulus rate on the somatosensory-evoked potentials and magnetic fields.

In order to evaluate information processing in the somatosensory cortex, the effect of two different stimulus rates was investigated by simultaneously recording somatosensory-evoked potentials (SEPs) and magnetic fields (SEFs) in nine healthy adults. During electric stimulation of the median nerve at the wrist, SEFs were recorded with the helmet-shaped whole-head coverage magnetometer array with 122 first-order planar gradiometers while SEPs were simultaneously recorded from seven scalp positions. Interstimulus intervals (ISIs) of 0.9 s and 4 s were compared. In all subjects, N20 as well as its magnetic counterpart, N20m, was clearly demonstrated over the contralateral somatosensory area. Subsequent deflections around 80-200 ms did not make any clear peak and were smaller than those at 20-60 ms (P30m, P40m, N50m and P60m). After 200 ms, SEFs were negligible, whereas SEPs had larger amplitude than those of shorter latencies, constituting a peak around 250 ms (P250). Both SEF and SEP deflections later than 40 ms were decreased in responses at the shorter ISI; this diminution was most prominent for P250. Therefore, it is concluded that the tangential currents in the somatosensory cortex (area 3b) mainly contribute to responses during the first 200 ms after the stimulus, whereas the radially oriented currents (most likely in the crown of the postcentral gyrus) take over for subsequent information processing.

Adult↗
PubMed1998

Human supplementary motor area is active in preparation for both voluntary muscle relaxation and contraction: subdural recording of Bereitschaftspotential.

Bereitschaftspotentials (BPs) preceding muscle relaxation and contraction were compared by using subdural electrodes which were implanted onto the right medial frontal surface in two patients with supplementary motor area (SMA) seizure. The applied movement paradigm (muscle relaxation and contraction tasks) was completely the same as employed in our previous study [Terada, K., Ikeda, A., Nagamine, T. and Shibasaki, H., Electroenceph. clin. Neurophysiol., 95 (1995) 335-345]. In both patients, either negative or positive BPs were observed in the SMA-proper and supplementary negative motor area (SNMA) starting at 1.2-1.8 prior to both movements. In one patient, BP was more widespread in the relaxation task whereas more restricted to the hand area in the contraction task. In the other patient, the BPs were observed in the cortical area rostral to SNMA (pre-SMA), in addition to the SMA-proper, in both tasks. It is concluded that SMA-proper and SNMA, and probably pre-SMA as well, in humans are similarly active in preparation for both voluntary muscle contraction and relaxation.

Adult↗
PubMed1998

Pathogenesis of cortical myoclonus studied by magnetoencephalography.

Myoclonus-associated cortical activities were studied by simultaneous recording of a magnetoencephalogram and an electroencephalogram in 6 patients with cortical myoclonus due to various causes. Cortical activities were averaged, with respect to the precise onset of the myoclonic jerk, to evaluate the myoclonus-associated cortical magnetic fields. The estimated generator of their earliest peak was localized at the contralateral precentral gyrus in all patients. As judged from the direction of the electrical current, surface positive activity preceding the electromyographic discharge was detected in 3 patients with cortical reflex myoclonus and in 1 patient with possible corticobasal degeneration. In contrast, in the remaining 2 patients (Lennox-Gastaut syndrome and Alzheimer's disease), magnetic fields time-locked to the myoclonic jerk were associated with surface negative activity at the precentral cortex. The present study, applying for the first time an off-line jerk-locked back-averaging analysis to magnetoencephalography, demonstrated the important role of the precentral cortex in generating spontaneous myoclonus. It is most likely that the differing polarity of the electromagnetic activity reflects the differing activation patterns within the cortical laminar structure in the precentral area, underlying the generation of various types of myoclonus.

Adult↗
PubMed1998

Electrophysiological studies of early stage corticobasal degeneration.

We conducted electrophysiological studies in two Asian patients with probable corticobasal degeneration (CBD). The duration of illness from onset was 16 and 20 months, respectively. The clinical manifestations were markedly asymmetric and characterized by cortical sensory loss, apraxia, action myoclonus, action tremor, and akinetic-rigid parkinsonism. Neither patient responded to levodopa therapy. Simple photon-emission computed tomography (SPECT) study showed significantly decreased regional cerebral blood flow in the frontoparietal areas and thalamus opposite to the predominantly affected limb. A series of electrophysiological studies failed to identify giant somatosensory evoked potentials (SEPs), enhanced long latency electromyography (EMG) reflex, and cortical spikes preceding myoclonic jerk. However, the earliest cortical component of the median nerve SEP was exclusively enlarged in one patient and preserved with depression of the subsequent components in the other patient. Significantly shorter postmotor-evoked potential (MEP) silent period was found after the transcranial magnetic stimulation of the motor cortex in both patients. CBD is a unique clinical entity characterized by action myoclonus probably the result of the pathologic hyperexcitability of the motor cortex, based on a loss of inhibitory input from the sensory cortex.

Aged↗
PubMed1998

Four-week exposure to diesel exhaust induces nasal mucosal hyperresponsiveness to histamine in guinea pigs.

It has been reported that diesel exhaust (DE) particulates augment increases in nasal congestion and nasal secretion induced by histamine (His). We also showed that short-term (3-h) exposure to DE induces nasal mucosal hyperresponsiveness to His. Therefore, in the present study we investigated that whether 4-week exposure of guinea pigs to diesel exhaust would likewise induce nasal mucosal hyperresponsiveness to His. Sneezing number, nasal secretion from the nostril, and intranasal airway resistance induced by His were measured as indices of sneezing response, rhinorrhea, and nasal congestion, respectively. Guinea pigs of each group were exposed to filtered air, with or without a low or high concentration of DE for 3, 7, or 28 days. Exposure to a low or high concentration of DE itself did not induce sneezing, nasal secretion, or nasal congestion. However, exposure to a high concentration of DE augmented that the number of sneezes induced by His, whereas exposure to a low concentration of DE had no significant effect. Exposure to DE for 7 and days tended to augment an increase in nasal secretion induced by exposure to His aerosol in a DE concentration-dependent fashion. The augmentation, however, was not statistically significant. Exposure to high or low DE for 3 or 7 days had no significant effect on the increase in intranasal pressure (INP) induced by a 10-min exposure to His aerosol, but exposure to high DE for 28 days augmented the increase in INP induced by His, significantly. Exposure to low DE for 28 days did not augment the increase in INP immediately after inhalation of His aerosol. These results reveal that 4-week exposure to high DE induces nasal mucosal hyperresponsiveness in guinea pigs.

Air Pollutants↗
PubMed1998

Reappraisal of the effect of electrode property on recording slow potentials.

Subdural electrodes made of stainless steel, which were believed to be unsuitable for recording slow potentials, can still record Bereitschaftspotential (BP) (Neshige, R., Lüders, H. and Shibasaki, H. Recording of movement-related potentials from scalp and cortex in man. Brain, 1988, 11: 719-736) and ictal DC shifts (Ikeda, A., Terada, K., Mikuni, N., Burgess, R.C., Comair, Y., Taki, W., Hamano, T., Kimura, J., Lüders, H.O. and Shibasaki, H. Subdural recording of ictal DC shifts in neocortical seizures in humans. Epilepsia, 1996b, 37: 662-674) sufficiently. In this study, therefore, the effects of different kinds of metals on slow potential recordings were reevaluated. First, slow electro-oculograms (EOGs) were recorded with 3 different levels of input impedance (200 M omega, 470 k omega and 10 k omega) of a DC amplifier by using surface electrodes made of silver (Ag), silver/silver chloride (Ag/AgCl) and stainless steel. Secondly, BP was recorded by using the above electrodes with a long time constant of 3 s and with a fixed input impedance of 100 M omega. As a result: (1) slow EOGs were equally recorded with the input impedance of 200 M omega and 470 k omega regardless of the kind of metals used, although stainless steel electrodes caused baseline fluctuation, (2) low input impedance of 10 k omega allowed only the Ag/AgCl electrode to record slow EOGs without any decay, and (3) electrodes made of stainless steel could record BP as efficiently as the other two types of electrode with high input impedance. In conclusion, electrodes with a large surface area contact such as cup electrodes and an amplifier with a large input impedance, electrodes made of Ag, and even of stainless steel, can record slow potentials reasonably well.

Contingent Negative Variation↗