Search PubMed⌕ Search

Biomedical subjects

Kazuo Abe

Publications and source records attributed to Kazuo Abe.

33 records · Page 2Linked to original sources
PubMed2004

Quantitative magnetic detection of finger movements in patients with Parkinson's disease.

To develop a new measurement tool for quantitatively detecting the finger movement of a patient with Parkinson's disease (PD), we designed a magnetic sensing system consisting of a magnetic induction coil, a sensing coil, and a circuit unit. The sensing coil detects the inducted magnetic field that varies with the distance between the two coils, and the detected signals are demodulated in the circuit unit in order to obtain the variation voltage from the oscillation frequency. To obtain a coefficient for converting voltage to distance, we measured the output voltages for seven fixed finger positions of 12 normal volunteers. The voltage differences corresponding to the finger movement in 20 PD patients, six age-matched controls, and 12 normal volunteers were then recorded for 30s. To investigate the velocity and acceleration of the finger movement, we calculated their waveforms from the measured displacement waveform. We also detected the main frequency of the tapping rhythm by using a fast Fourier transform (FFT). The averaged amplitude of each waveform decreased with the disorder in the Hoehn-Yahr (HY) stage, while the averaged tapping frequency of PD patients did not have any correlation with this stage. It can be concluded that this magnetic sensing system can assess finger movement quantitatively.

Adult↗
PubMed2004

A pitfall in MRI.

Explore the source record for details and available documents.

False Negative Reactions↗
PubMed2004

Prolonged incubation period of salmonellosis associated with low bacterial doses.

In gastroenteritis outbreaks caused by Salmonella-contaminated lunches at elementary, junior high, and nursery schools. outbreaks with long median incubation periods (i.e., 60 to 120 h) were observed frequently between 1990 and 1999 in Japan. We analyzed epidemiological data on 185 outbreaks of Salmonella Enteritidis infection to study the factors underlying the long incubation period. These survey results showed that the median incubation period for Salmonella Enteritidis infection from contaminated school and nursery school lunches was significantly longer than that from other types of cooking facilities. In addition, we analyzed the relationship between the median incubation period and the bacterial dose ingested per person in nine outbreaks of Salmonella Enteritidis infection; the bacterial dose was estimated with reference to the bacterial concentration in the causative foods. A significant negative correlation between the bacterial dose ingested per person and the median incubation period is clearly shown. The time elapsed from the start of the cooking process to the consumption of school and nursery school lunches was significantly shorter than at other cooking facilities, suggesting limited bacterial growth, which in turn is thought to lead to a long incubation period.

Adult↗
PubMed2003

Intralimb incoordination in patients with ataxia.

Intralimb incoordination needs to be distinguished from interlimb incoordination, which is observed in Parkinson's disease (PD). With this aim, intra and inter-limb coordination impairment in the lower limbs were measured in 13 patients with cerebellar ataxia during pedaling of an ergometer with left and right pedals that can be rotated independently. Intralimb incoordination in patients with cerebellar ataxia was compared with interlimb incoordiation in patients with PD. We concluded that impairment of intralimb coordination in ataxia patients leads to inability to maintain pedaling amplitude and speed, but unlike in PD, right and left coordination was roughly preserved. Our method may be useful for assessing the severity of ataxia and detecting hidden parkinsonism in ataxic patients.

Adult↗
PubMed2003

Classifying lower limb dynamics in Parkinson's disease.

To classify lower limb dynamics in patients with Parkinson's disease (PD), we conducted a clinical study by using pedaling exercise.Twenty-seven patients with idiopathic PD were included in this study. We measured rotational velocities of pedals during pedaling movements with a newly developed ergometer. The velocity waveforms exhibited different characteristics among patients, which could be categorized into four different clusters. In cluster 1, the amplitude on each side was constant and the relative phase was locked at 180 degrees. The pattern was the same as seen in normal subjects. In cluster 2, the amplitude on each side was constant, but the relative phase was locked at 90 degrees. In cluster 3, the amplitude on each side was modulated, and the relative phase drifted monotonously from 0 to 360 degrees during pedaling cycles. In cluster 4, the amplitude on each side was synchronously and irregularly modulated, and the relative phase fluctuated with intermittent spike-like decrement. In order to evaluate, the correlation between pattern and severity of PD, we divided 13 patients, who underwent measurement of pedaling patterns more than three times, into three groups, and found that the abnormal coordination pattern correlated with the presence of freezing phenomenon in patients with PD. Our clinical analysis may contribute in analyzing and classifying the dynamics of PD.

Adult↗
PubMed2003

Determination of cabergoline and L-dopa in human plasma using liquid chromatography-tandem mass spectrometry.

We determined cabergoline and L-dopa in human plasma using liquid chromatography-mass spectrometry with tandem mass spectrometry (LC-MS-MS). The deproteinized plasma samples with organic solvent or acid were analyzed directly by reversed-phase liquid chromatography. Using multiple reaction monitoring (MRM, product ions m/z 381 of m/z 452 for cabergoline and m/z 152 of m/z 198 for L-dopa) on LC-MS-MS with electrospray ionization (ESI), cabergoline and L-dopa in human plasma were determined. Calibration curves of the method showed a good linearity in the range 5-250 pg/ml for cabergoline and 1-200 ng/ml for L-dopa, respectively. The limit of determination was estimated to be approximately 2 pg/ml for cabergoline and approximately 0.1 ng/ml for L-dopa, respectively. The method was applied to the analysis of cabergoline and L-dopa in plasma samples from patients treated with these drugs. The precision of analysis showed coefficients of variation ranging from 3.8% to 10.5% at cabergoline concentration of 13.8-26.2 pg/ml and from 2.9% to 8.9% at an L-dopa concentration of 302.5-522.1 ng/ml in patient plasma. As a result, the procedure proved to be very suitable for routine analysis.

Adult↗
PubMed2003

A coupled oscillator model of disordered interlimb coordination in patients with Parkinson's disease.

Coordination between the left and right limbs during cyclic movements, which can be characterized by the amplitude of each limb's oscillatory movement and relative phase, is impaired in patients with Parkinson's disease (PD). A pedaling exercise on an ergometer in a recent clinical study revealed several types of coordination disorder in PD patients. These include an irregular and burst-like amplitude modulation with intermittent changes in its relative phase, a typical sign of chaotic behavior in nonlinear dynamical systems. This clinical observation leads us to hypothesize that emergence of the rhythmic motor behaviors might be concerned with nonlinearity of an underlying dynamical system. In order to gain insight into this hypothesis, we consider a simple hard-wired central pattern generator model consisting of two identical oscillators connected by reciprocal inhibition. In the model, each oscillator acts as a neural half-center controlling movement of a single limb, either left or right, and receives a control input modeling a flow of descending signals from higher motor centers. When these two control inputs are tonic-constant and identical, the model has left-right symmetry and basically exhibits ordered coordination with an alternating periodic oscillation. We show that, depending on the intensities of these two control inputs and on the difference between them that introduces asymmetry into the model, the model can reproduce several behaviors observed in the clinical study. Bifurcation analysis of the model clarifies two possible mechanisms for the generation of disordered coordination in the model: one is the spontaneous symmetry-breaking bifurcation in the model with the left-right symmetry. The other is related to the degree of asymmetry reflecting the difference between the two control inputs. Finally, clinical implications by the model's dynamics are briefly discussed.

Ataxia↗
PubMed2003

Classification of dynamics of a model of motor coordination and comparison with Parkinson's disease data.

In our recent reports motor coordination of human lower limbs has been investigated during pedaling a special kind of ergometer which allows its left and right pedals to rotate independently. In particular, relative phase between left and right rotational-velocity waveforms of the pedals and their amplitude modulation have been analyzed for patients with Parkinson's disease (PD). Several patients showed peculiar interlimb coordination different from the regular anti-phase pattern of normal subjects. We have reported that these disordered patterns could be classified into four groups. Moreover, it has been demonstrated that a mathematical model could reproduce most of the disordered patterns. Such a model includes a schematization of the central pattern generator with two identical half-centers mutually coupled and two tonic control signals from higher motor centers, each of which inputs to one of the half-centers. Depending on the intensities of the tonic signals and on the differences between them, the model could generate a range of dynamics comparable to the clinically observed disordered patterns. In this paper, we explore the dynamics of the model by varying the intensities of the tonic signals in the model. Using the same method used for classifying the clinical data, the dynamics of the model are classified into several groups. The classified groups for the simulated data are compared with those for the clinical data to look at qualitative correspondence. Our systematic exploration of the model's dynamics in a wide range of the parameter space has revealed global organization of the bifurcations including Hopf bifurcations and cascades of period-doubling bifurcations among others, suggesting that the bifurcations, induced by instability of stable dynamics of the human motor control system, are responsible for the emergence of the disordered coordination in PD patients.

Cluster Analysis↗
PubMed2003

Aortic arch replacement with proximal first technique.

BACKGROUND: Deep hypothermic circulatory arrest (DHCA) without retrograde cerebral perfusion (RCP) has a strict time limit. We modified a surgical technique for anastomosis to shorten the period of DHCA and unilateral cerebral perfusion (UCP). METHODS: Between March 1993 and August 2001, retrospective analysis was done on 23 consecutive patients, who underwent aortic arch replacement with branches. The patients were divided into two groups: DHCA group and UCP group. The DHCA group, in which DHCA alone and without additional cerebral perfusion was performed, comprised of nine patients. Proximal aortic anastomosis was performed first during systemic cooling; then both the brachiocephalic artery and left carotid artery were reconstructed with the branches of the artificial graft during circulatory arrest; thereafter, cerebral and coronary perfusions were resumed. The UCP group, in which DHCA was not used but right hemisphere perfusion during deep hypothermia was performed when the origin of brachiocephalic artery was safely clamped, consisted of 14 patients. RESULTS: Mean time of DHCA was 18.8+/-4.2 minutes and that of right hemisphere perfusion time was 11.0+/-3.8 minutes, respectively. Twenty-one patients survived the surgery (91.3%), and two (8.7%) died during hospitalization. Transient cerebral complication occurred in four patients in the DHCA group and all recovered. Logistic regression analysis revealed that DHCA was the only parameter to significantly influence temporary neurological dysfunction. There was no other significant difference between the two groups. CONCLUSION: With our modified and simple surgical technique for aortic arch repair, we were able to successfully shorten the DHCA time and right hemisphere perfusion time. However, because DHCA was the only parameter to significantly influence temporary neurological dysfunction, some form of continuous cerebral perfusion at deep hypothermia may be a safer method to preserve cerebral function.

Adult↗
PubMed2002

Proton MR spectroscopic study at 3 Tesla on glutamate/glutamine in Alzheimer's disease.

To investigate metabolic changes in Alzheimer's disease (AD), we performed proton MR spectroscopy at 3T Spectra were acquired from the gray matter of the posterior cingulate gyrus and the precuneus, and from the parietooccipital white matter in nine AD patients and 12 controls. In patients, the N-acetyl group (NA)/creatine + phosphocreatine (Cr) ratios were decreased in both regions, and a decrease in the glutamate + glutamine (Glx)/Cr ratio and a correlation between the NA/Cr and Glx/Cr ratios were detected in the gray matter, but not in the white matter. These results suggest that NA and Glx metabolism are simultaneously affected in AD, however, metabolic changes in Glx are more profound in the gray matter than in the white matter.

Aged↗
PubMed2002

Microsomal enzyme induction and clinical aggravation of porphyria: the evaluation of human urinary 6beta-hydroxycortisol/cortisol ratio as the index of hepatic CYP3A4 activity.

The clinical aspect of porphyria has been investigated, and it is well known that porphyrinogens such as estrogens and alcohol or other inducers of P450 isoenzymes exacerbate the porphyric state. However, there can be a delay in diagnosing porphyria and a difficulty in selecting safe medicine for it even today. A 21-year-old woman developed epilepsy, disturbance of mental state, and spastic tetraparesis during the convalescent period after acute viral encephalitis. She was diagnosed with porphyria after the fifth hospitalization. In the course of modifying her anticonvulsant regimen, the authors examined the 6beta-hydroxycortisol/cortisol ratio (6beta-OHF/F) in her urine, which can be the index of hepatic CYP3A4 activity, with electrospray ionization/mass spectrometry/mass spectrometry (ESI/MS/MS). Generalized and partial complex seizures, other neurological signs and symptoms, and laboratory data were improved after modification of her anticonvulsant regimen. This is the first report of evaluating the urinary 6beta-hydroxycortisol/cortisol ratio in a case of porphyria.

Adult↗
PubMed2002

Economic impact of an Escherichia coli O157:H7 outbreak in Japan.

We estimated the economic impact of an outbreak of foodborne diseases occurring from elementary school lunches in 1996 in which 268 persons in Iwate prefecture, Japan were infected with Escherichia coli O157:H7. This study assessed the impact of direct economic losses and indirect economic consequences due to this outbreak. The economic impact of the outbreak was estimated to be about 82,686,000 yen. The laboratory costs, about 21,204,000 yen, showed the highest ratio of the total cost of this outbreak (about 26%). Also, the cost of foodstuffs that were not purchased during the suspension of the lunch service (about 19%), personnel expenses paid to lunch service employees (about 17%), human illness costs (about 15%), and the repair costs of facilities (about 15%) showed up as a high ratio in the total cost, respectively. Because all patients were children, the productivity losses estimated were low as children were considered as dependants with no income. Instead, we estimated the lost income of the mothers of the children. The source of the contamination could not be identified. Therefore, no food industries suffered any setbacks where certain food items could not be used for daily consumption due to the outbreak.

Child↗
PubMedDate not supplied

Complex regional pain syndrome type I associated with amyotrophic lateral sclerosis.

BACKGROUND: (CRPS I [formerly called reflex sympathetic dystrophy]) is a syndrome with pain and signs of autonomic dysfunction after trauma or immobilization; the pathophysiologic mechanisms of CRPS I, however, remain unknown. DESIGN: The authors present a case of CRPS I associated with amyotrophic lateral sclerosis. Along with the motor paresis due to amyotrophic lateral sclerosis, pain, swelling, and signs of autonomic disturbance occurred. CONCLUSIONS: This case supports the hypothesis that immobilization is one of the major contributing factors for CRPS I.

Aged↗
PubMedDate not supplied

Effect of stage 1 sleep on auditory cortex during pure tone stimulation: evaluation by functional magnetic resonance imaging with simultaneous EEG monitoring.

BACKGROUND AND PURPOSE: Responses of the auditory cortex to sound during sleep have been explored with somewhat discrepant results. The purpose of this study was to investigate the effect of stage 1 sleep on signal intensity changes in the auditory cortex in response to pure tone stimulus measured by functional MR imaging. METHODS: Six sleep-deprived subjects were exposed to a series of echo-planar images for 30-40 minutes. No medication was used to help the subjects go to sleep. A long repetition time of 12 seconds and a 1.9-second clustered multisection acquisition were used to minimize the effect of imager acoustic noise from the preceding acquisition and to make it possible to obtain electroencephalographs between image acquisitions. A pure tone stimulus (beep, 1,000-Hz sine waves, 30-millisecond duration, five beeps per second) was alternated with the baseline every 36 seconds. RESULTS: All subjects fell asleep. The effect of habituation evaluated by comparing the percentage of signal intensity change between the first and second half was not significant. The percentage of signal intensity changes in the right and left transverse temporal gyri were 0.49% and 0.43% during wakefulness and 0.05% and 0.07% during stage 1 sleep. The differences between wakefulness and stage 1 sleep were significant. CONCLUSION: Transition to stage 1 sleep coincides with a decrease in functional MR imaging-determined signal intensity changes in the auditory cortex in response to pure tone stimulus. The limited response of the brain at this stage may protect the brain from sound and facilitate deepening of the sleep stage.

Acoustic Stimulation↗