PubMed Health⌕ Search

Biomedical subjects

K Akaboshi

Publications and source records attributed to K Akaboshi.

At least 19 recordsLinked to original sources
PubMed2000

Quantitative EMG and motor unit recruitment threshold using a concentric needle with quadrifilar electrode.

According to Henneman's size principle, small motor units are recruited before large ones. We used the electromyographic (EMG) signal decomposition technique to determine the quantitative relationships between five motor unit action potential (MUAP) parameters (amplitude, duration, area, thickness, and size index) and the recruitment threshold of the motor units recruited up to 50% of the maximum voluntary contraction in the first dorsal interosseous, biceps brachii, rectus femoris, and tibialis anterior muscles of 5 healthy young men. In each muscle, the amplitude, duration, area, and size index had significant, positive high correlations with the motor unit recruitment thresholds. We conclude that the size principle applies to recordings made with concentric needle EMG electrodes under special recording conditions, and therefore that more importance should be attached to the patient's contraction force during EMG examinations in order to evaluate MUAPs for electrodiagnostic purposes.

Adult↗
PubMed2000

Tonic and kinetic motor units revisited: does motor unit firing behavior differentiate motor units?

OBJECTIVE: We tried to differentiate motor unit into two distinct populations, tonic and kinetic, on the basis of the relationship between the mean inter-spike interval and its variability. METHODS: During voluntary isometric contraction myoelectric activity was recorded with a special quadrifilar electrode from first dorsal interosseous, biceps brachii, soleus, and tibialis anterior muscle. Motor unit action potentials (MUAP) were decomposed into individual MUAP trains, by electromyography (EMG) signal decomposition. The variability in the instantaneous firing rate was assessed at two or more levels of contraction in each muscle. RESULTS: We found each muscle tested had a homogeneous population. There were no tonic and kinetic motor units. But there were differences in the variability in the instantaneous firing rate in the 4 muscles tested. CONCLUSION: Motor unit firing behavior in a muscle may be fitted for its function.

Action Potentials↗
PubMed2000

Physiologic decrease of single thenar motor units in the F-response in stroke patients.

OBJECTIVE: To investigate the left-right difference and the reproducibility by the F-wave motor unit number estimation and to compare the motor unit number between the hemiplegic and unaffected side in stroke patients. SETTING: A referral center and institutional practice providing outpatient care. SUBJECTS: Seven healthy volunteers and 15 consecutive stroke patients. DESIGN: Diagnostic statistical test and correlational study. METHOD: Submaximal stimuli were used to evoke a sample of surface motor unit action potentials (S-MUAPs) in the F-waves that are entirely representative of the relative numbers of detected S-MUAPs of different sizes. The average S-MUAP amplitude was calculated from a selected population of F-wave responses for each abductor pollicis brevis (APB) muscle. The motor unit number was calculated by dividing the maximum M-potential negative peak amplitude by the average S-MUAP negative peak amplitude. RESULT: There was no statistical difference between motor unit numbers on either side and between test and retest in this motor unit number estimation method among normal subjects. The motor unit number on the hemiplegic side was significantly lower than on the unaffected side (p < .05, Mann-Whitney test) among stroke patients. CONCLUSION: The motor unit could decrease in the hemiplegic side after a moderate-to-severe hemiplegic stroke and this decrement might be due to the transsynaptic degeneration secondary to an upper motor neuron lesion.

Action Potentials↗
PubMed2000

Rise time or rise rate: which should be a criterion for analysing motor unit action potentials?

We measured the rise time (RT) and rise rate (RR) of motor unit action potentials (MUAPs) when sharp sounds are heard in concentric EMG in the first dorsal interosseus muscle (FDI) and biceps brachii muscle (BIC) of normal subjects. MUAPs from FDI muscle with an RT of less than 500 microseconds were 85%, and those of more than 500 microseconds were 15%. In contrast, MUAPs from BIC muscle with an RT of less than 500 microseconds were 65%, and those of more than 500 microseconds were 35%. Distributions of the RR for FDI and BIC were also determined. MUAPs from FDI muscle with an RR more than 0.3 mV/ms were 98.3%, and those of less than 0.3 mV/ms were 1.7%. In contrast, MUAPs from BIC muscle with an RR of more than 0.3 mV/ms were 93%, and those of less than 0.3 mV/ms were 7%. We conclude it is better to use RR than RT when accepting MUAPs in clinical EMG, because even when sharp sounds are heard, MUAPs do not always have an RT of less than 500 microseconds. The use of RT and the sharpness of MUAPS therefore need to be reconsidered, or RR should be used in clinical EMG by automatic program.

Action Potentials↗
PubMed1999

Relationship between shoulder muscle strength and functional independence measure (FIM) score among C6 tetraplegics.

The degree of disability varies widely among C6 tetraplegic patients in comparison with that at other neurological levels. Shoulder muscle strength is thought to be one factor that affects functional outcome. The aim of this study was to examine the relationship between shoulder muscle strength and the Functional Independence Measure (FIM) motor score among 14 complete C6 tetraplegic patients. The FIM motor score and American Spinal Injury Association (ASIA) motor score of these patients were assessed upon discharge. We evaluated muscle strength of bilateral scapular abduction and upward rotation, shoulder vertical adduction and shoulder extension by manual muscle testing (MMT). The total shoulder strength score was calculated from the summation of those six MMT scores. The relationships among ASIA motor score, total shoulder strength score and FIM motor score were analyzed. The total shoulder strength score was significantly correlated with the FIM motor score and the score of the transfer item in the FIM. In the transfer item of the FIM, the total shoulder strength score showed a statistically significant difference between the Independent and Dependent Group. Shoulder muscle strength appears to be an important factor in the functional abilities of those with C6 complete tetraplegia. Functional variation depends on the strength of shoulder muscles, especially among C6 tetraplegics.

Activities of Daily Living↗
PubMed1998

Ultrastructural evaluation following catheterization of the fallopian tube with a hysteroscopic catheter.

PURPOSE: Our purpose was to assess the morphology and ultrastructural changes in the tubal epithelium following catheterization of the fallopian tube. METHODS: Fallopian tubes were obtained from 20 women who had undergone hysterectomies. Catheterization was performed in 20 tubes using a catheter developed for hysteroscopic tubal embryo transfer. The catheter has a 3-French diameter, tapering to 2 French (0.66 mm) at the tip portion. The 20 contralateral tubes served as controls and were not catheterized. Ultrastructural changes were examined by scanning electron microscopy and transmission electron microscopy. RESULTS: Scanning electron microscopy showed no transformation or defects of the tubal epithelium surface in catheterized or control tubes. Transmission electron microscopy showed no significant differences in the percentage of abnormal desmosomes and the percentage of basement membrane in ciliated and nonciliated cells between catheterized and noncatheterized tubes. No transformation or defects were observed in catheterized or noncatheterized tubes. CONCLUSIONS: These findings suggest that catheterization of the tube using a hysteroscopic catheter caused no acute damage to the tubal epithelium.

Basement Membrane↗
PubMed1998

The effects of gonadotropin-releasing hormone agonist on androstenedione production and follicular development during controlled ovarian hyperstimulation.

PURPOSE: We performed a prospective randomized study to assess the effects of a GnRH agonist (GnRH-a) on follicular development and steroidogenesis during controlled ovarian hyperstimulation (COH). METHODS: Patients undergoing in vitro fertilization (IVF) for tubal infertility received human menopausal gonadotropin (hMG) stimulation with or without the GnRH-a, buserelin, beginning in the midluteal phase of the prior cycle. We analyzed serum hormone levels, follicular development, and outcome of IVF. RESULTS: The mean number of retrieved oocytes was significantly greater, and the implantation rate per embryo was significantly higher, in the GnRH-a/hMG group (n = 101) than in the hMG-only group (n = 97). The concentration of androstenedione (A) and the A/estradiol ratio in the serum were significantly lower in the GnRH-a treatment group throughout the follicular phase. CONCLUSIONS: The concomitant use of GnRH-a during COH prevents atretic change of the follicles and enhances follicular development by reducing androgen accumulation, resulting in a higher developmental competence of the oocytes.

Adult↗
PubMed1996

Functional assessment of patients with spinal cord injury: measured by the motor score and the Functional Independence Measure.

There is some information about the Functional Independence Measure (FIM) score of patients with spinal cord injury (SCI), but there are a few publications dealing with the relationship between the FIM score and the motor score of the American Spinal Injury Association (ASIA). We have studied the relationship of all FIM items with the motor score, and reviewed the disability of patients with spinal cord injury in greater detail. The purpose of this study was to describe the characteristics of impairment and disability in patients with SCI, using the FIM and motor score of the ASIA. The subjects were 100 inpatients with SCI (Frankel A, B). Neurological level, days from the onset, and the FIM were examined. In addition to these items, the ASIA motor scores were calculated for 22 tetraplegic patients. We investigated the relationships among these various respects. We also examined the changes of the physical items of the FIM score (physical FIM) over time for 18 patients. The mean FIM scores of those with tetraplegia with C4, C5, C6, C7, C8 lesions, and those with paraplegia with above T5 levels, and those below T6 were 35, 61, 82, 90, 116, 114 and 114 respectively. The FIM score reached the plateau in approximately 10 months, 6 months and 3 months post-injury, in tetraplegia, paraplegia above T5 and that below T6 respectively. The FIM scores in C6 patients were widely distributed from 56 to 104. On the other hand, the ASIA motor score could subdivide C6 patients and related well to the FIM score. The mean FIM scores for each neurological level were similar to those previously reported, thus they appeared to be plateau scores. With regard to the motor score, we feel that it could reflect the disability of the patients better than considering the neurological levels alone. Also considering the changes in the physical FIM score over time within a year from the onset of the injury, there were differences in the ADL improvement patterns among patients with different neurological levels. It appears that timing of the highest physical FIM improvement for each neurological level can exist. Thus it is important not to delay the start of the rehabilitation of patients with spinal cord injury in proper time.

Activities of Daily Living↗
PubMed1995

Motor unit firing behavior in slow and fast contractions of the first dorsal interosseous muscle of healthy men.

The motor unit recruitment threshold and firing rate were evaluated during slow and fast contraction of the first dorsal interosseous (FDI) muscle by healthy young men. Using a special quadrifilar electrode myoelectric activity was recorded during voluntary isometric contraction. Motor unit action potentials (MUAPs) were decomposed into individual MUAP trains by the electromyography (EMG) signal decomposition technique. Recruitment thresholds of the motor units decreased with the increase in the speed of contraction, and there was no recruitment reversal despite the increase. In terms of rate coding, the firing rates of the motor units increased as the speed of contraction increased; however, a high threshold motor unit always had a lower firing rate than a low threshold motor unit regardless of the contraction speed. At all contraction speeds, recruitment and rate coding may act through the same mechanism. If excitation of the motoneuron pool occurs rather than excitation of an individual motoneuron, a low threshold motor unit is easier to recruit and fire repetitively than a high threshold one. The motor unit firing behavior during fast contraction basically may be the same as during slow contraction.

Action Potentials↗
PubMed1994

Macro-EMG and motor unit recruitment threshold: differences between the young and the aged.

The relationship between macro-EMG (electromyography) and motor unit recruitment threshold was studied in the first dorsal interosseous (FDI) muscle of normal young and aged subjects. During voluntary isometric contraction, motor unit action potentials (MUAP) were collected by a special quadrifilar electrode and decomposed to each MUAP train (MUAPT) using an EMG signal decomposition technique. Macro-EMG was obtained from the electrode shaft, then triggered and averaged for each MUAPT. A positive linear correlation was observed in both the young and aged subjects. However, the correlation coefficients were significantly lower in the aged individuals than in the young individuals.

Action Potentials↗
PubMed1993

Intraventricular cavernous malformation associated with medullary venous malformation.

We reported a case of cavernous malformation (CM) associated with medullary venous malformation in the same area. The CM was located in the trigone of the lateral ventricle in the dominant hemisphere and drained into the longitudinal caudate vein of Schlesinger via deep medullary veins. By a transsylvian transventricular approach, the CM was totally removed with successful preservation of the medullary venous malformation. This approach is available for trigonal lesions, especially in cases with enlarged inferior horn. We stress that CM removal can be conducted with preservation of the adjacent medullary venous malformation.

Cerebral Veins↗
PubMed1992

[Importance of sperm morphology assessment in human in vitro fertilization].

Two hundred eighteen IVF cycles were analyzed in order to clarify the influence of the strictly normal morphology (SNM) of sperm on IVF outcome. SNM was defined according to Kruger et al.'s strict criteria (1988) with our modifications. IVF cycles were divided into 3 groups: %SNM greater than or equal to 40% (69 cycles), 40% less than %SNM greater than or equal to 12% (123 cycles) and %SNM less than 12% (26 cycles). The rates of embryo transfer and pregnancy per cycle and the rate of abortion per pregnancy in the three groups were as follows: 81%, 39%, 19% in %SNM greater than or equal to 40%; 71%, 24%, 30% in 40% greater than %SNM greater than or equal to 12%; and 58%, 7.7%, 50% in %SNM less than 12%. The pregnancy rate per cycle significantly decreased as the %SNM decreased (p less than 0.01), and there was a tendency toward an increase in the abortion rate per pregnancy as the %SNM decreased. The results suggest that %SNM is a useful parameter to use in predicting the IVF outcome.

Abortion, Spontaneous↗
PubMed1991

[A new criterion for hCG administration in human IVF programs: importance of serum LH levels].

A new, simple criterion for hCG administration to induce ovulation for IVF is described. Serum LH levels were measured daily, and hCG was administered, independent of follicle size or estradiol levels, the night of the day when the LH level first exceeded the J level, defined as the minimum value + (the day 3 value-the minimum value) x 1/3. Based on this hCG criterion, the total and ongoing pregnancy percentages per cycle were 35% and 27%, respectively. It appears that the pregnancy rate decreases when hCG is administered one day before or one day after the criterion is met. Pregnancies resulting from hCG administration based on the criterion had a wide range both of dominant follicle diameter (14-21 mm) and estradiol level (229-2,050 pg/ml). The serum LH level is recommended as a useful parameter in timing hCG administration for IVF.

Chorionic Gonadotropin↗