An almost nontoxic tetrodotoxin analog, 5,6,11-trideoxytetrodotoxin, as an odorant for the grass puffer.

Toxic puffers contain the potent neurotoxin, tetrodotoxin (TTX). Although TTX is considered to serve as a defense substance, previous behavioral studies have demonstrated that TTX acts as an attractive pheromone for some toxic puffers. To elucidate the physiological mechanism of putative pheromonal action of TTX, we examined whether grass puffers Takifugu alboplumbeus can detect TTX. Electroolfactogram (EOG) results suggest that the olfactory epithelium (OE) of grass puffers responded to a type of TTX analog (5,6,11-trideoxyTTX), although it did not respond to TTX. We also examined the attractive action of 5,6,11-trideoxyTTX on grass puffers by recording their swimming behavior under dark conditions. Grass puffers preferred to stay on the side of the aquarium where 5,6,11-trideoxyTTX was administered, and their swimming speed decreased. Additionally, odorant-induced labeling of olfactory sensory neurons by immunohistochemistry against neural activity marker (phosphorylated extracellular signal regulated kinase; pERK) revealed that labeled olfactory sensory neurons were localized in the region surrounding "islets" where there was considered as nonsensory epithelium. 5,6,11-trideoxyTTX has been known to accumulate in grass puffers, but its toxicity is much lower (almost nontoxic) than TTX. Our results suggest that toxic puffers may positively use this TTX analog, which has been present in their body with TTX but whose function was unknown, as an odorant for chemical communication or effective TTX accumulation.

[Cancer Patient Response Conference by Co-Medical Staff].

Often, co-medical staff are asked questions or consultations that are difficult to answer from cancer patients. However, as for the reply contents, each co-medical staff responded in various ways, there was no place to discuss an appropriate reply. At our hospital, we decided to hold a"Cancer Patient Response Conference"to enable us to respond appropriately regardless of years of service or occupation. This time, we investigated the effect of"Cancer Patient Response Conference"on the approach at Ishikiriseiki Hospital. As a result, it is possible for the co-medical staff to respond to empathy of the patient's feelings and to confirm the understanding of the patient, but it seemed that the response from the attending physician was good for the question about the life expectancy and the treatment effect etc. However, it was suggested that collaborative staff sharing patient problems and information at"Cancer Patient Response Conference"will be useful for future cancer patient response.