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Biomedical subjects

I Nakajima

Publications and source records attributed to I Nakajima.

At least 55 records · Page 3Linked to original sources

Study for verification testing of the helmet-mounted display in the Japanese Experimental Module.

Our purpose is to propose a research and development project in the field of telemedicine. The proposed Multimedia Telemedicine Experiment for Extra-Vehicular Activity will entail experiments designed to support astronaut health management during Extra-Vehicular Activity (EVA). Experiments will have relevant applications to the Japanese Experimental Module (JEM) operated by National Space Development Agency of Japan (NASDA) for the International Space Station (ISS). In essence, this is a proposal for verification testing of the Helmet-Mounted Display (HMD), which enables astronauts to verify their own blood pressures and electrocardiograms, and to view a display of instructions from the ground station and listings of work procedures. Specifically, HMD is a device designed to project images and data inside the astronaut's helmet. We consider this R&D proposal to be one of the most suitable projects under consideration in response to NASDA's open invitation calling for medical experiments to be conducted on JEM.

Data Display↗

Telehealth in the Pacific: current status and analysis report (1999-2000).

From the summer of 1999 to the spring of 2000, we undertook an on-site investigation of the management and operational status of telehealth in the Pacific. The writers also gathered additional materials upon returning to Japan to provide as detailed a report as possible on the current status and analysis of telemedicine in the Pacific. Following the collapse of the Soviet Union, various regions around the world has sought a gentler alternative to "deterrence by arms." The writers of this paper believe one such means is telemedicine. We believe telemedicine services may help offset the emotional stress and sense of inequality experienced by "islanders and civilians living around military bases," which the financial benefits of the so-called "base-economy" alone has never been able to remedy. There are numerous medical support activities currently operating in the Pacific region, and telecommunications is the most effective tool for connecting and unifying such a vast region. We believe that projects for this region must have a clear focus and objective and be able to demonstrate concrete results in order to win subsidies or aid.

Developing Countries↗

Organization of extracellular matrix components during differentiation of adipocytes in long-term culture.

Scanning electron microscopy (SEM) observation showed that fully differentiated spherical adipocytes were embraced by a network of collagens and fibroblastic preadipocytes. The properties of both the collagen networks and the preadipocytes allow the adipocytes to be interconnected, forming a fat-cell cluster, which can anchor to the bottom of a culture dish. In this network structure, collagen fibrils and fibrillar bundles were closely arranged and stratified. We found that immunostained collagens appeared to form extracellular network structures, which can be observed by SEM. The extracellular network of fibronectin was the first to develop among the extracellular matrix (ECM) components, though it became degraded with the progress of adipocyte differentiation. The type I collagen network was the last to develop and remained well organized through the late stage of adipocyte differentiation. The extracellular networks of type III, V, and VI collagen developed by the mid-stage and remained in the late stage of adipocyte differentiation. The network structures of type IV collagen and laminin became degraded during the differentiation process and localized at the surface of spherical cells. In addition to these basement membrane components, types III, V, and VI collagens also showed pericellular spherical staining patterns. These results demonstrated that the constitution and distribution of the ECM are altered during adipocyte differentiation, suggesting that the organization of each ECM component into a suitable structure is a requirement for the differentiation and maintenance of unilocular adipocytes.

Adipocytes↗

Molecular characteristics and site specific distribution of the pigment of the silky fowl.

Silky fowl, a breed of chicken, is hyperpigmented in its various internal tissues. The pigment was extracted from various tissues of two strains of Silky fowl to determine its molecular structure and internal distribution. Analysis by infrared spectroscopy showed two spectrum patterns of the pigment in Silky fowl; one is from ovary and testis, the other is from periosteum and feather. The difference between the two spectra is possibly due to the sulfur contents of melanin. Especially, the spectra of the pigments from feather and periosteum shared the characteristics of synthesized melanin spectrum in common, which indicates that the melanocytes dispersed in these tissues were functionally the same. According to our quantitative analysis, the tissues examined were classified significantly in the order of the pigment content (p<0.05): periosteum > gonads (ovary or testis) = trachea > or = heart, liver, gizzard, cecum, muscles (Pectoralis and Supracoracoideus) and skin. In addition, the specific regions of embryonic neural crest derived cells, such as cardiac artery and various parts of cephalic tissues, were found to be locally hyperpigmented. These data suggest that hyperpigmentation (fibromelanosis) in Silky fowl chicken occurs in a tissue- and organ-specific manner, which is strongly related to neural crest cell development. It is hypothesized that neural crest cells of the bird, containing melanocyte progenitors, acquire unusual ability to differentiate into melanocytes excessively, and to extend the distribution of their descendant along the destinations of neural crest derivatives.

Animals↗

Cephalometric comparisons of craniofacial and upper airway structures in young children with obstructive sleep apnea syndrome.

We studied 15 children of preschool age who had obstructive sleep apnea syndrome to evaluate their dentofacial morphology in relation to the pharyngeal airway space. We found that (1) sleep apnea was often associated with mandibular retrognathia, (2) the lower incisors tended to exhibit a retrocline, (3) there were no significant differences in angular and linear measurements in the cranial base between patients with sleep apnea and a control group of 30 nonapneic children, and (4) the apneic children had a narrower epipharyngeal airway space than did the controls. These findings suggest that obstructive sleep apnea is probably caused by both adenoidal hypertrophy and abnormal development of the facial skeleton. We highly recommend cephalometric analysis as a valuable tool for conducting the presurgical evaluation of sleep apnea in children of preschool age.

Adenoids↗