Pharmacokinetics of L-theanine and the effect on amino acid composition in mice administered with L-theanine.

L-theanine, an amino acid component of the tea leaves of Camellia sinensis, is sold in Japan as a supplement for good sleep. Although several studies in humans and mice have reported the effects of L-theanine on brain function, only a few reports have comprehensively clarified the disposition of theanine administered to mice and its effects on concentrations of other blood amino acids. In this study, we aimed to determine the changes in the blood levels of L-theanine administered to mice and amino acid composition of the serum. L-theanine were administered to four-week-old Std-ddY male mice orally or via tail vein injection. L-theanine and other amino acids in serum prepared from blood collected at different time points post-dose were labeled with phenylisothiocyanate and quantified. The serum concentration of orally administered L-theanine peaked 15 min after administration. The area under the curve for tail vein injection revealed the bioavailability of L- theanine to be approximately 70%. L-theanine administration did not affect any amino acid levels in the serum, but a significant increase in the peak area overlapping the Glycine (Gly) peak was observed 30 min after administration. L-theanine administered to mice was rapidly absorbed and eliminated, suggesting that taking L-theanine as a supplement is safe without affecting its own levels or serum levels of other amino acids. However, considering that Gly, similar to L-theanine, is used as a dietary supplement for its anxiolytic effects and to improve sleep, determining the effects of L-theanine administration on Gly is important and needs further research.

Pharmacist perceptions of a "good death" and differences in perception between patients with cancer, oncologists, and oncology nurses: a questionnaire survey.

BACKGROUND: For pharmacists expected to encounter the deaths of many of their patients in the near future, it is important to understand the perception of a "good death" for patients with cancer who are likely to be aware of the circumstances of their poor prognosis. In this study, we clarified pharmacists' perceptions of a "good death" and considered the differences in perception among patients with cancer, oncologists, and oncology nurses. METHODS: From April to June 2022, an anonymous questionnaire survey was conducted on pharmacists working in hospitals and pharmacies and on members of the Japanese Society for Pharmaceutical Palliative Care and Sciences. The questionnaire consisted of 57 questions, called attributes, developed by Miyashita et al. to investigate the perception of "good death" in Japanese cancer medicine. The importance of those attributes was investigated using a 7-point Likert scale. RESULTS: Three thousand four hundred thirty-two pharmacists were made aware of this survey, and 207 participated in the survey. The responses of pharmacists to the 57 questions were very similar to those of the oncologists. Among them, "Fighting against disease until one's last moment" and "Not making trouble for others" had very low importance, which was the most significantly different from the responses of patients with cancer. "Fighting against disease until one's last moment" tended to be significantly underestimated by pharmacists engaged in patient guidance and interview compared to that by pharmacists not engaged in the duty (p = 0.02). Also, when we compared pharmacists with or without qualifications related to cancer and palliative care, there was no significant difference in the importance of "Fighting against disease until one's last moment." However, the importance of "Not making trouble for others" for qualified pharmacists was significantly underestimated (p = 0.04). CONCLUSION: Since pharmacists understand the limits of chemotherapy, they may want to be close to the patient but may not strongly agree with the "Fighting against cancer" component that patients with cancer prefer. It may be necessary to reconsider better ways of approaching the wishes and satisfaction of patients with cancer under the care of medical professionals in the field of oncology.

Expression levels of human P-glycoprotein in in vitro cell lines: correlation between mRNA and protein levels for P-glycoprotein expressed in cells.

The purpose of this study was to investigate the correlation between mRNA and protein levels for P-glycoprotein (P-gp) expressed in various cell lines to validate the estimation of P-gp activity from its mRNA levels. P-gp expression levels in various cell monolayers, normal, P-gp-induced, P-gp-highly induced, (multidrug resistance, MDR) MDR1-knockdown (A2-2) and MDR1-knockdown (B2-2) Caco-2 cells and MDCKII/MDR1 cells, were quantified by real-time quantitative polymerase chain reaction (PCR) and western blot analysis. Both mRNA and protein levels of P-gp were lowest in the MDR1-knockdown (B2-2) Caco-2 cells, followed by the MDR1-knockdown (A2-2) Caco-2, normal Caco-2, P-gp-induced Caco-2 and P-gp-highly induced Caco-2 cells, and highest in the MDCKII/MDR1 cells. Except for the MDCKII/MDR1 cells, the protein levels of P-gp in all Caco-2 cell lines showed a linear correlation with its mRNA levels; however, although the MDR1 mRNA level in MDCKII/MDR1 cells was much higher than in the P-gp-highly induced Caco-2 cells, the protein levels were almost the same in both cells. From these findings, it was suggested that P-gp activity in MDCKII/MDR1 cells could not be estimated from its mRNA levels.