Biomedical subjects

K Toyokawa

Publications and source records attributed to K Toyokawa.

12 recordsLinked to original sources

PubMed2005

Exogenous hyaluronic acid enhances porcine parthenogenetic embryo development in vitro possibly mediated by CD44.

Exogenous hyaluronic acid (HA) has been reported to improve early embryo development in vitro in pigs and cows. Although early embryo development in vitro is improved by exogenous HA, the mechanism mediating the action of HA is not clearly defined. In the present study, two possible HA actions on early embryo development were proposed to understand interactions between HA and the embryos using porcine parthenotes. We hypothesized that improvement of early embryo development mediated by HA would be caused by embryo-derived growth factors due to the high molecular weight of HA or cellular response through its receptor (CD44). We examined the effects of HA molecular weight on parthenogenetic embryo development, permeability of HA into the zona pellucida, expression of CD44 in porcine parthenotes at various stages, and blocking interactions between HA and CD44 by monoclonal anti-CD44 antibody (mCD44Ab). As a result, although development of porcine parthenotes to the blastocyst stage was significantly enhanced by exogenous HA with various molecular weights, there was no difference in blastocyst formation among the various molecular weights (P < 0.05). Immunofluorescence revealed that exogenous HA was accessible to CD44 through the zona pellucida, irrespective of the oocyte activation and that CD44 was also expressed in both oocytes and parthenotes at all developmental stages. In addition, development of parthenotes was partially blocked by mCD44Ab. In conclusion, we demonstrated that exogenous HA enhanced development of porcine parthenotes in vitro. This improvement mediated by exogenous HA on parthenogenetic embryo development was possibly caused by cellular response via CD44.

Animals↗

PubMed2001

Epidemiology of suicidal ideation and help-seeking behaviors among the elderly in Japan.

This study offers an analysis of the elderly (over 65 years of age) among a general community population in terms of the percentages of: (i) persons with recurring thoughts of death and/or of committing suicide, and (ii) people who have consulted others, including medical professionals, with regard to these problems. Among 433 elderly over the age of 65 in one community in a town in Aomori Prefecture, 358 agreed to participate in the project. Forty-four participants (12.3%) responded that they had either 'thoughts of death' or 'thoughts of suicide', and these thoughts had continued for more than 2 weeks in 12 participants (3.4%). Only 15 of the 44 suicidal elderly responded that they had consulted someone about their problems. Although there are many elderly people exhibiting a subclinical depressive state with recurring thoughts of death or thoughts of suicide, the number of people who consult family members, professionals, or others is very low. This suggests the importance of community networking through educational activities so that people can more readily talk to and support one another.

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PubMed2001

Influence of thoracic radiotherapy on exhaled nitric oxide levels in patients with lung cancer.

BACKGROUND: To determine the physiological role of exhaled nitric oxide (NO) in patients with lung cancer. METHODS: We investigated changes in exhaled NO levels in 29 patients undergoing thoracic radiation therapy with or without chemotherapy. The exhaled NO level was assessed using a chemiluminescence analyzer. RESULTS: The level of exhaled NO was higher in patients with lung cancer before treatment than in controls. With radiotherapy, the exhaled NO level decreased for patients undergoing 40 Gy irradiation and post-radiotherapy. However, five patients showed elevated levels of exhaled NO three times or more than that before radiotherapy. Three of these patients showed signs of radiation pneumonitis. However, none of the other patients showed signs of radiation pneumonitis (p = 0.002). CONCLUSION: Radiation therapy can lower exhaled levels of NO and the levels of exhaled NO may be a useful index for the early prediction of radiation pneumonitis.

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PubMed2001

[Assessment of exhaled NO concentration in monitoring radiation pneumonitis in patient who underwent thoracic radiotherapy for lung cancer].

To monitor radiation pneumonitis, we assessed the exhaled nitrogen oxide (NO) level in patient with lung cancer. A 73-year-old man with idiopathic interstitial pneumonitis underwent thoracic radiotherapy without chemotherapy for squamous cell lung cancer (T2N1M0). He showed elevation of exhaled NO level at 30 Gy-50 Gy, after a decrease at 10-20 Gy. He also showed an abnormal shadow on CT examination at 50 Gy. Although exhaled NO may have had the benefit of predicting radiation pneumonitis before severe clinical symptom appeared, he died three months after radiotherapy because of worsening of the radiation pneumonitis.

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PubMed1977