Kurashiki University of Science & the Arts

The Mekong River in Cambodia is inhabited by approximately ten species of freshwater pufferfish of the family Tetraodontidae. However, limited information is available regarding the toxin profile of these fish. In this study, to obtain sufficient information on the intra-body distribution of toxins in Cambodian freshwater pufferfish, one species of Pao freshwater pufferfish (Pao sp. A) were collected from Phnom Penh (PNH) in November 2019 (n = 23) and from Kratie (KTI) in March 2023 (n = 21). Toxin analyses of these samples revealed that individuals from both regions possessed saxitoxins (STXs) and contained no tetrodotoxin. Pao sp. A specimens from PNH possessed high STXs levels in the skin, muscle, liver, and gonads, whereas those from KTI showed relatively low levels of STXs concentrated in the skin. STXs amount in the ovaries in PNH individuals increased exponentially with increasing the gonadosomatic index (GSI). We also clarified that STXs concentration in the skin became increasingly higher as KTI individuals grew. These results suggest that differences in living regions may affect the intra-body distribution of STXs in Pao freshwater pufferfish, with maturation and/or growth contributing as well.

Similar to human medicine, attempts have been made in veterinary medicine to assess the severity of respiratory disorders using methods other than respiratory function evaluation; however, such approaches remain insufficient.

Medical records at a single small animal private referral center for emergency care were reviewed to identify dogs with respiratory disorders diagnosed by radiography during 2016-2019. The variables of screening test evaluated in this study included patient characteristics, physical examination, and blood test findings. The cases were also divided into Survivors, which were defined as dogs surviving over 7 days from the first consultation day, and Non-survivors, including the dogs euthanized and died naturally within 7 days from the consultation day. In univariate analysis, heart rates, body temperature, white blood count (WBC), glucose, blood urea nitrogen (BUN), phosphate and lactate were significantly different between Survivors and Non-survivors. Multiple logistic regression model with these significant variables revealed that only phosphate was associated with a poor prognosis.

This study has demonstrated several parameters of physical examination and blood test, especially plasma phosphate concentration, could be related with mortality in canine respiratory disorders. Although further studies are needed, these parameters may enable more accurate assessment of the severity of respiratory disorders in dogs by combining with the conventional assessments of respiratory functions including oxygenation and ventilation.

We have previously shown that a single dose of a TREK-1 channel activator, ostruthin, exhibited antidepressant and anxiolytic effects in acute behavioral test models in mice. To assess the potential clinical application, it is essential to evaluate the effects of long-term administration of ostruthin in a chronically stressed mouse model, which is considered to be similar to the clinical condition of major depression in humans. Here, we tested the effects of a single and a 7-day administration of ostruthin on mice that were subjected to chronic unpredictable mild stress (CUMS). A single administration of ostruthin showed antidepressive effects in the tail suspension and forced swim tests of CUMS-treated mice. Unexpectedly, the 7-day administration exhibited only insignificant antidepressive and anxiolytic effects. The 7-day regimen did not affect food intake or body-weight gain, suggesting the absence of apparent cytotoxicity. The mice receiving the 7-day administration had significantly lower blood concentrations of ostruthin compared to those receiving a single dose, suggesting an upregulation of drug-metabolizing activities. These findings suggest that there is a need for stable TREK-1 channel activators that are not affected by drug metabolism.