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Biomedical subjects

T Nagamine

Publications and source records attributed to T Nagamine.

At least 163 records · Page 9Linked to original sources
PubMed1997

[Use of jerk-locked back averaging for detecting the epileptiform discharge in a patient with supplementary motor seizure].

A 23-year-old, right handed women has suffered from supplementary motor seizures manifesting tonic followed by clonic contractions of the left foot, occasionally spreading to the left hand and trunk, since the age of 7 years. The mean frequency of seizures on admission was about 10 times per day. A brain MRI showed an abnormal intensity area about 3 cm in diameter in the right mesial frontal lobe involving the superior frontal and cingulate gyri. Six habitual seizures were recorded during long-term monitoring with digital EEG segments time-locked to the clonic contractions of the left foot, a negative spike was detected about 50 ms before the EMG onset at the midline fronto-central area slightly lateralized to the left. In the focal motor seizure arising from the mesial frontal lobe like in the present case, jerk-locked back averaging helps detecting the epileptiform activity which is otherwise undetectable.

Adult↗
PubMed1996

Cloning, sequencing and complementation analysis of the recA gene from Prevotella ruminicola.

Degenerate PCR primers based on conserved RecA protein regions were used to amplify a portion of recA [corrected] from Prevotella ruminicola strain 23, which was used as a probe to isolate the full-length recA gene from the P. ruminicola genomic library. The P. ruminicola recA gene encoded a protein of 340 amino acids with a molecular mass of 36.81 kDa, P. ruminicola RecA was highly similar to other RecA proteins and most closely resembled that of Bacteroides fragilis (75% identity). It alleviated the methyl methanesulfonate and mitomycin C sensitivities of Escherichia coli recA mutants, but did not restore the resistance to UV-light irradiation. Mitomycin C treatment of otherwise isogenic E. coli strains showed a higher level of prophage induction in a recA harboring lysogen.

Amino Acid Sequence↗
PubMed1996

Abnormal sensorimotor integration in writer's cramp: study of contingent negative variation.

To investigate the pathophysiology of idiopathic focal dystonia, we recorded contingent negative variation (CNV) as a physiological index of sensorimotor integration in 14 right-handed patients with writer's cramp and compared it with normative data. CNV was recorded in the S2 choice reaction time paradigm: Two kinds of auditory S2 (Go or No-Go) were given 2 s after the auditory S1, and the subject reacted only to the Go signal by extending the wrist. In normal subjects, the late CNV amplitude had no difference at Cz between left- and right-hand tasks and was symmetric without significant amplitude laterality irrespective of the side of hand movement. In patients with writer's cramp, the late CNV amplitude at Cz was relatively larger for the left-hand task than the right-hand task (p < 0.03), and a significant amplitude laterality of the late CNV (larger on the right) was present especially at the central area for the right-hand task (p < 0.03). Since the late CNV is known to be generated, at least in part, from primary and supplementary motor cortices, the significant laterality of the late CNV seen with the right-hand task in patients with writer's cramp might represent functional abnormality of motor cortices possibly as the result of basal ganglia function.

Adult↗
PubMed1996

Time-varying activation of different cytoarchitectonic areas of the human SI cortex after tibial nerve stimulation.

We followed cortical activation in eight healthy adults after electric stimulation of the left tibial nerve at the ankle. The recordings were made noninvasively with a whole-scalp neuromagnetometer. The first cortical activation peaked in different subjects at 37-45 ms in the foot area of the right (contralateral) primary somato-sensory (SI) cortex, with mean source current orientation perpendicular to the longitudinal fissure. The current orientation changed within the next 5 ms counterclockwise in all subjects, with a mean rotation of 64 degrees. A two-dipole time-varying model, with two dipoles differing by 28-119 degrees in orientation but less than 1 cm in location in the right SI cortex, explained the signal pattern satisfactorily during the first 100 ms. We suggest that the observed field patterns reflect sequential activation of different cytoarchitectonic areas in the foot SI cortex and imply considerable differences in the structural organization between the foot and the hand SI cortices. The initial activation is considered to take place in area 3b facing the interhemispheric fissure, and the later source, due to the systematic rotations of the field patterns, is assumed to reflect activation of area 5 in the anterior wall of the marginal ramus of the cingulate sulcus.

Adult↗
PubMed1996

Structural organization of pRAM4, a cryptic plasmid from Prevotella ruminicola.

A total of 530 strains of rumen bacteria were screened for the presence of plasmid DNA. The percentage of plasmid-bearing strains was found to be the highest among the Bacteroides/ Prevotella group (9.9%), while it was less than 1% in the Butyrivibrio (0.2%) and Clostridium (0.6%) genera. A small cryptic plasmid pRAM4 from Prevotella ruminicola T31 was subcloned in Escherichia coli and completely sequenced. Two open reading frames, encoding potential polypeptides of M(r) 32,322 (ORF1) and 32,122 (ORF2) with limited sequence similarity to replication initiation and mobilization proteins, respectively, could be identified within the sequence. The region upstream from ORF1 had an AT-rich (75%) region followed by four 22-bp direct repeats, a structure characteristic of replication origins. The plasmid hybridized at high stringency with plasmids from Bacteroides/Prevotella and Butyrivibrio, and with pBR322, suggesting that at least regions of the plasmid are widespread.

Amino Acid Sequence↗
PubMed1996

Somatosensory evoked potentials following proprioceptive stimulation of finger in man.

Brisk passive flexion of the proximal interphalangeal joint of the middle finger, produced by using a newly devised instrument, elicited evoked potentials on the scalp. The present study carefully excluded the possible contribution of sensory modalities other than proprioception. The initial part of cortical response was a positive deflexion at the contralateral central area (P1 at 34.6 ms after the stimulus). This was followed by a midfrontal negative wave (N1 at 44.8 ms) and a clear positivity at the contralateral centroparietal area (P2 at 48.0 ms). The evoked responses persisted in spite of the abolition of cutaneous and joint afferents of the finger caused by ischemic anesthesia, but they were lost by ischemic anesthesia of the forearm. Thus, the cortical evoked responses obtained in this study most probably reflect muscle afferent inputs. The scalp distribution of P1 suggested that its cortical generator source was different from that of the N20-P20 components of evoked potentials to electrical median nerve stimulation. Brodmann areas 2 and 3a of human brain, which are known to receive deep receptor inputs, are the most plausible generator sites for the early components of the proprioception-related evoked responses. The amplitude of P2 was related to the velocity but not to the magnitude of movement. In conclusion, the present study established a method for recording the evoked responses to the brisk passive movement of the finger joint, which mainly reflect the dynamic aspects of proprioception mediated through muscle afferent.

Adult↗
PubMed1996

Simplified quantification of regional cerebral blood flow with 99mTc-ECD SPECT and continuous arterial blood sampling.

The goal of this study was to develop a simple method for quantification of regional cerebral blood flow (rCBF) with 99mTc-ethyl cysteinate dimer (ECD) SPECT. Following an intravenous constant infusion of ECD for one minute, serial dynamic SPECT imaging was performed for 40 minutes in 6 healthy male volunteers with intermittent arterial blood sampling. PET scan with 15O-water was performed on the same day before the SPECT study for measurement of rCBF. Arterial blood data demonstrated rapid conversion of ECD to the hydrophilic metabolites, and most of the arterial input to the brain was completed within 5 minutes after the injection. Brain activity reached a peak value soon after the cessation of infusion, and was stable thereafter with very little washout. Net extraction of ECD in the brain calculated by arterial input of ECD and rCBF demonstrated a rapid decrease within a few minutes, reaching 42.7% at 5 minutes. The simulation study suggested that the arterial blood activity obtained by continuous drawing for 5 minutes and a single SPECT scan would provide a reasonable estimate of rCBF under the assumption of constant net extraction in the brain.

Adult↗
PubMed1996

Pain-related and cognitive components of somatosensory evoked potentials following CO2 laser stimulation in man.

We recorded cortical potentials evoked by painful CO2 laser stimulation (pain SEP) employing an oddball paradigm in an effort to demonstrate event-related potentials (ERP) associated with pain. In 12 healthy subjects, frequent (standard) pain stimuli (probability 0.8) were delivered to one side of the dorsum of the left hand while rare (target) pain stimuli (probability 0.2) were delivered to the other side of the same hand. Subjects were instructed to perform either a mental count or button press in response to the target stimuli. Two early components (N2 and P2) of the pain SEP demonstrated a Cz maximal distribution, and showed no difference in latency, amplitude or scalp topography between the oddball conditions or between response tasks. In addition, another positive component (P3) following the P2 was recorded maximally at Pz only in response to the target stimuli with a peak latency of 593 msec for the count task and 560 msec for the button press task. Its scalp topography was the same as that for electric and auditory P3. The longer latency of pain P3 can be explained not only by its slower impulse conduction but also by the effects of task difficulty in the oddball paradigm employing the pain stimulus compared with electric and auditory stimulus paradigms. It is concluded that the P3 for the pain modality is mainly related to a cognitive process and corresponds to the P3 of electric and auditory evoked responses, whereas both N2 and P2 are mainly pain-related components.

Adult↗
PubMed1996

Movement-related slow cortical magnetic fields and changes of spontaneous MEG- and EEG-brain rhythms.

Cortical activity was recorded from 5 healthy adults with a 122-channel whole-head magnetometer while the subjects performed during unilateral finger movements at self-paced intervals exceeding 6 s. The readiness field (RF) started over the contralateral somatomotor area 0.3-1 s prior to the movement onset in subjects (Ss) 1, 2, and 4, and culminated in the motor field (MF) 30 ms after it (Ss 1-4). These signals were followed by movement evoked fields MEFI (Ss 1-5) and MEFII (Ss 1-4) at 100-150 ms and 200-250 ms after the movement onset, respectively. One subject showed clear RF over the ipsilateral hemisphere as well. The contralateral dominance of the RF contrasted the more symmetric distribution of the simultaneously recorded electric Bereitschaftspotential (BP). The RF onset never preceded the BP onset. We suggest that BP receives contribution from the early bilateral activation of the crown of the precentral gyrus, whereas RF reflects later activity of the fissural motor cortex. Spontaneous oscillations in the background activity (spontaneous activity) of approximately 10 Hz started to dampen 2-3 s prior to the movement onset in the somatomotor areas of both hemispheres with contralateral predominance (S1 and S3), and returned to a steady level 0.8-2 s after the movement onset in all subjects. Higher frequency bands in the same area displayed a prominent rebound about 1 s after the movement onset in 4 subjects. Execution of self-paced movements is evidently expressed differently in the slow movement-related fields and in the cortical spontaneous activity.

Adult↗
PubMed1996

Antibody responses in volunteers induced by nasal influenza vaccine combined with Escherichia coli heat-labile enterotoxin B subunit containing a trace amount of the holotoxin.

Evaluation of the efficacy of nasal influenza vaccine combined with Escherichia coli heat-labile enterotoxin B subunit (LTB) containing a trace amount of the holotoxin (LT) in inducing antibody responses among volunteers, which was conducted during the winter season of 1993-1994, is reported. A trivalent inactivated vaccine, composed of A/Yamagata/32/89 (H1N1), A/Kitakyusyu/159/93 (H3N2) and B/Bangkok/163/90 influenza virus strains, was used alone or together with the adjuvant, recombinant LTB supplemented with 0.5% recombinant LT (LTB*). The volunteers were divided into two groups: 73 volunteers (mean age 35.0 +/- 12.0 years) inoculated intranasally (i.n.) with LTB*-combined vaccine and 49 volunteers (37.9 +/- 11.3) inoculated i.n. with the vaccine alone. Vaccination was done twice 4 weeks apart. Salivary secretory IgA and serum hemagglutination-inhibiting (HI) antibodies were measured before and 8 weeks after the primary vaccination. For the sake of convenience, more than a 1.4-fold rise in IgA antibody response (units of specific IgA antibody per microgram of total IgA) and a fourfold or greater rise in HI antibody titer after vaccination were regarded as a positive antibody response. Thirty-seven (50.3%) and 36 (49.3%) of the 73 vaccinees, respectively, given the nasal LTB*-combined vaccine showed positive IgA and HI antibody responses to one or more of the three vaccine strains. In comparison, positive antibody responses in the group given vaccine alone were 32.7% for IgA and 30.6% for HI antibody. There was a significant difference between these two groups. These results suggest that the nasal LTB*-combined vaccine could enhance the production of higher levels not only of serum HI antibody but IgA antibodies in the respiratory tract than do the nasal vaccine alone.

Adjuvants, Immunologic↗
PubMed1996

Thrombocytopenia associated with hepatitis C viral infection.

BACKGROUND/AIMS: We investigated whether chronic hepatitis C infection is associated with thrombocytopenia. METHODS/RESULTS: Thrombocytopenia (<15 x 10(4) platelets/mu l) was diagnosed in 151 of 368 patients (41.0%) with chronic hepatitis C, a significantly higher proportion than that observed in patients with chronic hepatitis B (18.9%, p < 0.01). Elevated titers of platelet-associated immunoglobulin G were observed in 88.1% of patients with chronic hepatitis C and in 47.1% of patients with chronic hepatitis B. Platelet-associated immunoglobulin G titers were significantly higher in patients with chronic hepatitis C (87.3 +/- 10.1 ng/10(7) cells) vs. those with chronic hepatitis B (30.3 +/- 6.4) or the control subjects (p < 0.01). There was a significant negative correlation between platelet-associated immunoglobulin G titers and platelet counts in both chronic hepatitis C and B cases. Platelet-associated immunoglobulin G titers were significantly higher in patients with type C cirrhosis than in those with type B cirrhosis. Interestingly, HCV-RNA was detected by RT-PCR in the platelets from 11 of 14 patients with hepatitis C virus. CONCLUSIONS: These data indicate that chronic infection with hepatitis C virus may produce a significant autoimmune reaction to platelets, leading to thrombocytopenia.

Adult↗
PubMed1996

Pain-related somatosensory evoked potentials can quantitatively evaluate hypalgesia in Wallenberg's syndrome.

In 6 patients with Wallenberg's syndrome who showed a dissociated loss of pain sense, we recorded pain-related somatosensory evoked potentials following CO2 laser stimulation of the hand dorsum (pain SEPs). Two components, N2 and P2, were recorded by stimulation of the unaffected hand, whereas on the affected side they were absent or decreased in proportion to the severity of hypalgesia which was evaluated by both needle test and CO2 laser stimulation. Latency of either component, if appeared, was longer in the affected hand stimulation than that in the unaffected one. In contrast, N20 of the conventional electrically-stimulated SEPs (electric SEPs) showed no difference between the two sides. It is concluded that, unlike other electrophysiological methods, pain SEPs following CO2 laser stimulation can quantitatively evaluate functional impairment of the spinothalamic tract in Wallenberg's syndrome.

Adult↗
PubMed1996

Acetaminophen-derived activation of liver microsomal glutathione S-transferase of rats.

Effect of acetaminophen on glutathione (GSH) S-transferase and related drug metabolizing enzymes was studied in vivo. Rats were given acetaminophen (250 mg/kg, i.p.) 24 hr after the treatment with 3-methylcholanthrene (25 mg/kg, i.p.) and killed by decapitation at indicated times. Liver microsomal GSH S-transferase activity was increased to 331%, 193% and 158% of the control level at 3, 6 and 12 hr, respectively, after the administration of acetaminophen, while GSH content in the liver was markedly decreased at 3 and 6 hr. The increase in the transferase activity was not recovered by the treatment with dithiothreitol. Microsomal GSH peroxidase activity was significantly enhanced at 3 hr. Cytosolic GSH S-transferase and aniline hydroxylase in microsomes were gradually decreased with the increase in the time after administration of acetaminophen. Vmax values of both GSH S-transferase and GSH peroxidase activities in microsomes were increased at 3 hr. Two Km values were obtained for the peroxidase in the control, while only one was observed after the acetaminophen treatment. These results indicate that acetaminophen is converted via cytochrome P-450 to the reactive intermediate N-acetyl-p-benzoquinone imine, which binds to microsomal GSH S-transferase, resulting in the activation of the enzyme.

Acetaminophen↗