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Biomedical subjects

T Moritani

Publications and source records attributed to T Moritani.

105 records · Page 6Linked to original sources
PubMed1981

Anaerobic threshold determination by blood lactate and myoelectric signals.

This study examined the potential use of myoelectric signal analysis for determination of anaerobic threshold (AT). Ten college students performed incremental exercise on a bicycle ergometer during which blood samples from either the brachial or radial artery were drawn and corresponding intergrated electromyogram (IEMG) and power spectra also were recorded. Blood AT was determined by observing the changes in arterial blood lactate, Po2 Pco2, HCO3-, and pH. EMG AT was determined by the non-linear increase in IEMG and abrupt increase in frequency band width at 70% of the peak frequency (FRQ70%) which could represent the most active frequency band. The results indicated that a significant increase in FRQ70% occurred immediately after the occurrence of blood AT (p less than 0.05). However, no significant increase could be found in peak frequency. Regression analyses revealed that EMG AT Vo2 correlated significantly with blood AT Vo2 (r = 0.921, p less than 0.001) and with gas exchange AT Vo2 (r = 0.921, p less than 0.001). It was concluded that analysis of myoelectric signals, which reflect motor unit recruitment and discharge frequency, could provide a non-invasive estimate of AT.

Adult↗
PubMed1980

Potential for gross muscle hypertrophy in older men.

The time course of strength gain with respect to the contributions of neural factors and hypertrophy was studied in five young men and five older men during the course of 8 weeks progressive strength training. Young and old men showed similar and significant percentage increases in strength. However, the neurophysiological adaptations in response to the training were quite different. Increases in maximal muscle activation (neural factors) played a dominant role throughout the training for old subjects, while young subjects showed strength gains due to neural factors only at the initial stage, with hypertrophy becoming the dominant factor after some 4 weeks of training. Our data suggest that the effect of muscle training in the old may entirely rest on the neural factors presumably acting of various levels of the nervous system which could result in increasing the maximal muscle activation level in the absence of significant hypertrophy.

Adolescent↗
PubMed1979

Neural factors versus hypertrophy in the time course of muscle strength gain.

The time course of strength gain with respect to the contributions of neural factors and hypertrophy was studied in seven young males and eight females during the course of an 8 week regimen of isotonic strength training. The results indicated that neural factors accounted for the larger proportion of the initial strength increment and thereafter both neural factors and hypertrophy took part in the further increase in strength, with hypertrophy becoming the dominant factor after the first 3 to 5 weeks. Our data regarding the untrained contralateral arm flexors provide further support for the concept of cross education. It was suggested that the nature of this cross education effect may entirely rest on the neural factors presumably acting at various levels of the nervous system which could result in increasing the maximal level of muscle activation.

Arm↗
PubMed1978

Reexamination of the relationship between the surface integrated electromyogram (IEMG) and force of isometric contraction.

The integrated electromyogram (IEMG)--force relationships were studied in 26 physically active young men across the entire domain of forces in the elbow flexor group. All possible error factors (fatigue, muscle length, and co-contraction) were controlled to the greatest extent possible. The experimental conditions were more clearly defined than in previous experiments. The results confirm earlier observations of a linear relationship between IEMG and isometric force, under these experimental conditions and using a unipolar lead system. Highly significant correlations were found. Possible methodological error factors were studied. Bipolar recording produced a curvilinear, relationship which may explain some of the discrepancies of results reported in the literature.

Adolescent↗
PubMedDate not supplied

Diffusion-weighted echo-planar MR imaging: clinical applications and pitfalls -- a pictorial essay.

Diffusion-weighted imaging (DWI) provides unique information about various pathological changes of the brain. DWI is sensitive for the detection of hyperacute infarcts, and useful in distinguishing acute or subacute infarcts from chronic infarcts. DWI is useful in differentiating cytotoxic edema from vasogenic or interstitial edema, which may help to determine prognosis. DWI is useful in differentiating cystic or necrotic tumors from abscesses or epidermoids. DWI can discriminate nonenhanced tumor infiltration from vasogenic edema, and differentiate dysmyelination from demyelination.

Brain Diseases↗
PubMedDate not supplied

MR evaluation of talonavicular angle in congenital talipes equinovarus.

The talonavicular relationship in 14 patients with talipes equinovarus was quantified using gradient echo sequences. The angle formed between the short axis of the navicular and the long axis of the talus was measured. There is a significant difference in the talonavicular angle between patients who had posteromedial release (PMR) and those who had posterior release (PR) or casting only (P=.0004). This method provides an objective assessment of residual deformity following surgical and conservative management of talipes equinovarus.

Analysis of Variance↗
PubMedDate not supplied

Spectrum of Epstein-Barr virus infection in Japanese children: a pictorial essay.

Epstein-Barr virus (EBV) infection has been associated with infectious mononucleosis, EBV-associated hemophagocytic syndrome (EBV-AHS), chronic active EBV infection (CAEBV), lymphomas, inflammatory pseudotumor, lymphomatoid granulomatosis, and nasopharyngeal carcinoma. EBV-AHS and CAEBV are more lethal than infectious mononucleosis with imaging findings of gallbladder wall thickening, pleural effusion, cardiomegaly, and hepatomegaly. EBV infection is also associated with benign and malignant tumors.

Burkitt Lymphoma↗
PubMedDate not supplied

Fast MRI in obstetric diagnoses.

This article describes the fast MRI of fetal abnormalities and placental anomalies in evaluation of the usefulness of fast MRI in obstetric diagnoses. Fast MRI provides excellent resolution for imaging fetal and maternal anatomies without the need for sedation. Fast MRI is therefore useful to clarify diagnoses suggested by equivocal ultrasonographic findings and to obtain additional information for prenatal counseling and management.

Congenital Abnormalities↗
PubMedDate not supplied

H-reflex testing to determine the neural basis of movement disorders of neurologically impaired individuals.

The H-reflex is an indirect measure of the excitability levels of alpha motoneurons. The authors have developed an adaptation of H-reflex testing which allows the continuous monitoring of human alpha motoneuron activity during movement. The technique differs from previously used H-reflex testing techniques in that it utilizes a 5 Hz stimulation to elicit the H-reflex. This allows for continuous and concomitant H- and M-wave recordings during a movement. This is an improvement over past single stimulus techniques in that the time and discomfort associated with this type of experimentation is greatly decreased. The repetitive stimulation technique enables H-reflex testing to be used clinically with neurologically impaired patient populations. Thus far, the authors have used the repetitive H-reflex testing procedures to assess alpha motoneuron activation and reciprocal inhibition of antagonist musculature during voluntary movement and anticipatory postural control responses of non-disabled individuals and of individuals with cerebral palsy. This paper describes the methodology involved in this technique and reports the results obtained.

Adolescent↗