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Biomedical subjects

A Ito

Publications and source records attributed to A Ito.

At least 901 records · Page 50Linked to original sources
PubMed1983

Mechanical efficiency of positive work in running at different speeds.

To investigate the possible role of elastic potentiation on mechanical efficiency, three male marathon runners were filmed while running on a treadmill at various steady-state speeds ranging from 7.0-22.0 km X h-1. Kinematic and mechanical energy analyses were performed from the film. Expired air was collected for energy expenditure determination. The analysis disclosed that during contact on the treadmill the knee and ankle joints initially had a phase of negative (flexion) angular velocity, followed by a positive velocity. In the hip joint the stretch-shortening cycle of the extensor muscles occurred primarily during the flight phase. The mean vertical and horizontal forces of the negative and positive phases of the contact period increased linearly with the increase in the running speed. The calculated mechanical efficiency of positive work was high but relatively constant (55.1 +/- 12.7%) across all speeds. The absolute contribution of the extra work, which comes from the stored elastic energy to the positive work, increased with running speed; however, its relative value (0.61 +/- 0.09 J X min-1 X kg-1) remained constant at all measured speeds. It is suggested, therefore, that when the flight phase is included in the mechanical energy calculations, the measured efficiency for the positive work reaches a high but constant value in running at low-to-moderate speeds.

Ankle Joint↗
PubMed1983

Wavelength dependence of inactivation and membrane damage to Saccharomyces cerevisiae cells by monochromatic synchrotron vacuum-uv radiation (145-190 nm).

Using an electron storage ring as a source of radiation, the wavelength dependence of inactivation and membrane damage in yeast cells (Saccharomyces cerevisiae) was investigated in the range from 145 to 254 nm, with special reference to the effects of vacuum-uv radiation. The cells were irradiated on a Millipore filter in a moist chamber filled with water vapor (deoxygenated) at saturation pressure. Fluence-survival curves taken at 5-nm intervals were generally sigmoidal. Action spectra of the two types of effects were nearly identical in shape. The maximum occurred in both spectra at 160 nm, decreasing sharply toward 180 nm. The spectra remarkably resembled the calculated absorption spectrum of (liquid) water in the range from 145 to 170 nm; the spectra had no similarity at all to the absorption spectra of DNA, proteins, or lipids. These data support the theory that inactivation of wet cells by vacuum-uv radiation may be attributable to damage in the cell membrane initiated by the absorption of water molecules. Above 210 nm the spectrum for inactivation paralleled the absorption of DNA. Genetic changes (induction of gene conversion) were also observed above 210 nm. Photoreversion for the induced convertants was detectable only above 220 nm. These characteristics are consistent with the expectation that above 210 nm the site of major lethal damage shifts to DNA.

Absorption↗
PubMed1983

[Experience in treatment of Mycoplasma pneumoniae with acetylspiramycin].

Antibiotics of tetracycline and macrolide groups are mainly used in treatment of Mycoplasma pneumonia. In this study, acetylspiramycin (ASPM), an antibiotic of macrolide group, was given to 15 cases of Mycoplasma pneumoniae who visited this institute during the period from January, 1980 to March, 1981, and its clinical effects and side effects were investigated. The therapeutic effects were evaluated by days to the normal body temperature, to improvement in cough and to improvement in X-ray findings. The increase in serum antibody value was adopted as the diagnostic index of Mycoplasma infection. The patients who entered into this study were 7 males and 8 females, ranged from 19 to 60 years of age with an average of 36.3 years. The daily dose of ASPM was 600 to 1,200 mg (potency), and the mean administration period was 18.1 days. The results obtained were as follows. 1. The temperature fell to the normal within 2 to 7 days. 2. Cough disappeared in 2 days at shortest and in 55 days at longest. The mean period of cough disappearance was 14.5 days. 3. In 10 cases who could be followed up, shadows in X-ray films disappeared in 3 days at shortest and in 40 days at longest. The mean period to shadow disappearance was 18.6 days. 4. As regards clinical effects, marked improvement was obtained in 2 cases, improvement in 9, slight improvement in 4, and no change in 0 (improvement rate: 73.3%). 5. As a side effect, nausea was found in 1 case, but it was improved by discontinuance of administration.

Adult↗
PubMed1983

[Primary lung cancer treated with fast neutron].

Forty-nine patients with primary lung cancer were treated with fast neutron (average energy, 6 MeV) by so-called mixed therapy method at the Institute of Medical Science, University of Tokyo. Control group (Linacx-ray, 10 MV) was not randomized one, however, these patients were treated by the same chief radiotherapist (Dr. Iino) at Shizuoka Prefectural Hospital and its interval was almost the same to neutron group. The crude survival rate did not show any significant difference between them except for 1 year survival of Stage II (p less than 0.05). Radiation pneumonitis and tumor regression were thought to be almost the same. The incidence of pneumothorax (3/49) was somewhat higher than the x-ray group (3/119) but there was no significant difference. We are now planning a new mixed therapy method which has short time interval (less than 3 hours) between neutron and x-ray irradiation in expectation of decrease of shoulder in x-ray surviving fraction curve.

Fast Neutrons↗