Tetsuji Tokunaga's research while affiliated with Nagai Internal Medicine Clinic and other places

Publications (4)

Article
The fecal microbiota and short-chain fatty acids (SCFAs) play important roles in the human body. This study examined how hyperbaric conditions affect the fecal microbiota and fecal SCFAs. Fecal samples were obtained from 12 divers at three points during deep-diving training (before the diving training, at 2.1 MPa, and after decompression). At 2.1 M...
Article
Full-text available
Introduction Acute acoustic trauma, which is a kind of sensorineural hearing loss, is caused by acoustic overstimulation. Hyperbaric oxygen therapy (HBOT) is reported to be effective against acute acoustic trauma. Objective We aimed to evaluate the efficacy of HBOT against acoustic hearing loss based on our 20 years of experience with such cases. M...
Article
Full-text available
We aimed to determine whether the composition of the fecal microbiota changes under hyperbaric conditions. In this study, we collected fecal samples from 6 healthy divers at three points during deep diving training (before, 2.1 MPa, end). The frequency of Clostridium cluster XVIII tended to be increased after compression. The frequencies of Clostri...

Citations

... T-RFLP analysis showed a reduced ratio of clostridial cluster XIVa in the SCC patients and clostridial cluster IX in the RCC patients, although these changes were not seen in RCR and SCR patients. Clostridial cluster XIVa includes most butyrate producers that belong to the Firmicutes phylum in the human colon and clostridial cluster IX propionate-producing bacteria [28][29][30]. SCFAs such as butyrate or propionate are known to have an important role in preserving gut barrier functions and exerting immunomodulatory and anti-inflammatory properties [29,31]. The antiproliferative, apoptotic and differentiating properties of the various SCFAs are linked to the degree of induced histone hyperacetylation [32]. ...
... A few studies investigated the efficacy of HBOT in AAT injuries: Ylikoski et al. demonstrated significantly better audiometric results both in low and high frequencies in patients with AAT injuries who were treated with early-onset HBOT (within 3-4 days after injury), compared with those who did not receive HBOT at all [Ylikoski et al., 2008]. Furthermore, Oya et al. [2019] showed that a combination of oral steroids and HBOT significantly improved audiometric results together with alleviation of subjective symptoms (i.e., aural fullness and tinnitus), even when treatment was given 3-4 weeks after initial injury. However, the latter study did not compare between patients receiving only steroid treatment and patients treated with steroids and HBOT, and therefore the exact contribution of HBOT in AAT injury is not clear. ...
... 28 Several of the Firmicutes increased with HBOT in our trial are known producers of secondary bile acids, 29 and in healthy volunteers hyperbaric conditions have been observed to increase bile acid producing Firmicutes. 30 The specific microbes most affected by HBOT, which allowed for this proportional increase in Firmicutes, included known mucinophiles with an association between A muciniphila and HBOT response status. Akkermansia is associated with risk of inflammatory bowel disease development, 31 but data are conflicting on whether A muciniphila is pathogenic or protective against colitis. ...