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Cell-based therapies have been used as promising treatments for several untreatable diseases. However, cellbased therapies have side effects such as tumorigenesis and immune responses. To overcome these side effects, therapeutic effects of exosomes have been researched as replacements for cell-based therapies. In addition, exosomes reduced the risk that can be induced by cell-based therapies. Exosomes contain biomolecules such as proteins, lipids, and nucleic acids that play an essential role in cell–cell and cell–matrix interactions during biological processes. Since the introduction of exosomes, those have been proven perpetually as one of the most effective and therapeutic methods for incurable diseases. Much research has been conducted to enhance the properties of exosomes, including immune regulation, tissue repair, and regeneration. However, yield rate of exosomes is the critical obstacle that should be overcome for practical cell-free therapy. Three-dimensional (3D) culture methods are introduced as a breakthrough to get higher production yields of exosomes. For example, hanging drop and microwell were well known 3D culture methods and easy to use without invasiveness. However, these methods have limitation in mass production of exosomes. Therefore, a scaffold, spinner flask, and fiber bioreactor were introduced for mass production of exosomes isolated from various cell types. Furthermore, exosomes treatments derived from 3D cultured cells showed enhanced cell proliferation, angiogenesis, and immunosuppressive properties. This review provides therapeutic applications of exosomes using 3D culture methods.
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Both to determine testing frequency in bone vibrator of audiometer for measurement of vibration perception threshold(VPT) and to evaluate factors influencing VPT, ninty seven healthy adults were tested on their second metacarpal head of both hands, at 250Hz, 500Hz, 1,000Hz and so on. Measures of the VPTs at 1,000Hz were excluded in analysis because frequency 1,000Hz was not recognized as a vibration sense. Mean and standard deviation(S.D.) of the VPTs in the both hands measured at 250Hz were 19.9+/-6.7dB, 21.0+/-7.3dB, respectively and at 500Hz were 33.6+/-8.3dB, 34.9+/-8.1dB, respectively. Both mean and S.D. tended to be lower at 250Hz than 500Hz, and mean differences of VPTs between the left and the right hand at the both frequencies appeared statistically significant (p<0.01). VPTs were significantly correlated with each other (p<0.01). Age was positively correlated(p<0.001) with VPTs and education was negatively(p<0.01). Multiple regression analysis showed that age was the only factor influenced on VPT. These results suggest that, when using the bone vibrator of audiometer for measurement of VPT, the frequency 250Hz as a testing frequency may be more useful than frequency 500Hz, and VPT should be measured on both hands.
Assuntos
Adulto , Humanos , Educação , Mãos , Cabeça , VibraçãoRESUMO
To assess the hearing conservation by the hearing protection devices in the field, 1,237 healthy female weavers of 16 to 24 year old were surveyed from April 1982 to January 1983. By reviewing the charts, their working durations, hearing threshold shift levels and whether wearing the ear plugs or not were checked. The hearing threshold levels were measured at 4,000 Hz by audiometry AA-30A, RION Japan. They were divided into two groups: an experimental group with ear plug and the control group without it. The threshold shift level above 40dB in controls was 44.6% in left and 40.9% in right ear and that in experimental group 8.0% in left and 6.6% in right ear. The distribution of threshold shift levels between control and experimental group was significantly different in both ears, but that between left and right ear not significantly different in both groups. The longer the working durations were, the more the proportion of high threshold shift levels was and the larger the differences in the proportion of above 40dB between both groups were.