Electron Microscopic Radioautographic Study on Protein Synthesis in Mitochondria of Binucleate Hepatocytes of Aging Mice

ArticleTheScientificWorldJOURNAL. 7:1008-1023 (2007)journal articl

RNA Synthesis in the Tracheal Epithelial Cells of Aging Mice as Revealed by Electron Microscopic Radioautography

For the purpose of studying the aging changes of macromolecular synthesis in the tracheal epithelial cells of experimental animals, we studied 10 groups of aging mice during development and aging from fetal day 19 to postnatal month 24. They were injected with 3H-uridine, a precursor for RNA synthesis, sacrificed and the tracheal tissues were taken out, fixed and processed for light and electron microscopic radioautography. On many radioautograms the localization of silver grains demonstrating RNA synthesis in tracheal epithelial cells in respective aging groups were analyzed qualitatively and quantitatively. The number of mitochondria per cell, the number of labeled mitochondria with silver grains and the number of silver grains in each cell in respective aging groups were analyzed quantitatively in relation to the aging of animals. The results revealed that the RNA synthetic activity as expressed by the incorporations of RNA precursor, i.e., the number of silver grains in cell nuclei, cell organelles, changed due to the aging of animals. The number of mitochondria, the number of labeled mitochondria and the mitochondrial labeling index labeled with silver grains were counted in each tracheal epithelial cell. It was demonstrated that the number of mitochondria increased from embryonic day 19 to postnatal newborn day 1, 3, 9, 14, adult month 1, 2, reaching the maximum and kept plateau, while the number of labeled mitochondria increased from embryonic day 19 to postnatal adult month 2, reaching the maximum but the labeling indices showing RNA synthesis increased from embryonic day 19 to postnatal newborn day 14 and adult month 1 and decreased to year 2, indicating the aging changes. Based upon our findings, available literature on macromolecular synthesis in mitochondria of various cells are reviewed

Electron Microscopic Radioautographic Study on Protein Synthesis in Hepatocyte Mitochondria of Aging Mice

For the purpose of studying the aging changes of intramitochondrial protein synthesis in mouse hepatocytes, 10 groups of aging mice, each consisting of 3 individuals (total 30), from fetal day 19 to postnatal month 24, were injected during development with 3H-leucine, a protein precursor, sacrificed 1 h later, and the liver tissues processed for electron microscopic (EM) radioautography. On EM radioautograms obtained from each animal, the number of mitochondria, the number of labeled mitochondria, and the mitochondrial labeling index labeled with silver grains due to 3H-leucine showing protein synthesis in each mononucleate hepatocytes were counted and the averages in respective aging groups were compared. From the results, it was demonstrated that the numbers of mitochondria, the numbers of labeled mitochondria, and the labeling indices of intramitochondrial protein syntheses in mononucleate hepatocytes of mice at various ages from embryonic day 19 to postnatal month 24 increased and decreased due to development and aging of animals

Cognitive and Emotional Changes in Peer Educators of Type 2 Diabetes Patients After Starting Peer-Support Activities

Background: Diabetes self-management education through peer support has beneficial effects, especially in regions with limited medical resources. To ensure peer educators continue to provide peer-led education programs, it is important that they remain motivated to instruct patients. Here, to explore measures to enhance peer-educators’ motivation toward such programs, we examined the cognitive and emotional changes in Filipino type 2 diabetics after 7-month activities as peer educators. Methods: We individually performed semi-structured interviews with 13 peer educators with 20 years of age or above in August 2017 (immediately before starting their peer-education activities) and in March 2018 (7 months after the start). The first interview was performed after the peer educators had received 2-day training of diabetes self-management. In both interviews, we asked the peer educators about their feelings toward peer-led educational activities (e.g., satisfaction, difficulty, reward, confidence, and challenges). Their replies about their own cognition and emotions were interpreted and integrated, and then analyzed qualitatively. Results: Four and seven categories were extracted from the first and second interviews, respectively. The category “Cognition of patients’ active learning attitudes and of positive changes in patients’ physical conditions and behavior” observed in the second interview led to “Cognition of growth as a peer educator” and “Satisfaction with supporting patients as a peer educator.” These two feelings gave the peer educators’ “Increased motivation to continue the activities as a peer educator.” This motivation was also associated with “Active collaboration among peer educators,” which was affected by “Difficulties and concerns in working as a peer educator.” Conclusion: To sustain diabetic peer-led education programs, we suggest that interventions be implemented that increase peer educators’ motivation toward their activities and stimulate their awareness of the importance of collaborating with one another. Such collaboration should help to overcome the difficulties they may face in providing peer-led education

A radioprotective agonist for p53 transactivation

Inhibiting p53-dependent apoptosis by inhibitors of p53 is an effective strategy for preventing radiation-induced damage in hematopoietic lineages, while p53 and p21 also play radioprotective roles in the gastrointestinal epithelium. We previously identified some zinc(II) chelators, including 8-quinolinol derivatives that suppress apoptosis in attempts to discover compounds that target the zinc-binding site in p53. We found that 5-chloro-8-quinolinol (5CHQ) has a unique p53-modulating activity that shifts its transactivation from proapoptotic to protective responses including enhancing p21 induction and suppressing PUMA induction. This p53-modulating activity also influenced p53 and p53-target gene expression in unirradiated cells without inducing DNA damage. The specificity of 5CHQ for p53 and p21 was demonstrated by silencing the expression of each protein. These effects seems to be attributable to the sequence-specific alteration of p53 DNA-binding, as evaluated by chromatin immunoprecipitation and electrophoretic mobility shift assays. In addition, 5-chloro-8-methoxyquinoline itself had no antiapoptotic activity, indicating that the hydroxyl group at the 8-position is required for its antiapoptotic activity. We applied this remarkable agonistic activity to protecting the hematopoietic and gastrointestinal system in mouse irradiation models. The dose-reduction factors of 5CHQ in total-body and abdominally irradiated mice were about 1.2 and 1.3, respectively. 5CHQ effectively protected mouse epithelial stem cells from a lethal dose of abdominal irradiation. Furthermore, the specificity of 5CHQ for p53 in reducing the lethality induced by abdominal irradiation was revealed in Trp53-KO mice. These results indicate that the pharmacological upregulation of radioprotective p53-target genes is an effective strategy for addressing the gastrointestinal syndrome

Association between mental health and bone mass among community-dwelling adults: Nagasaki Islands Study on bone health

Osteoporosis and its related fractures are important public health issues. This study examined the association between the Kessler Psychological Distress Scale (K6) and low bone mass in middle-aged community-dwelling men and women. A crosssectional study was nested in a prospective observational study of 1,101 participants (median age: 57 [49-62] years in men and 58 [50-62] years in women) residing in a rural city in western Japan. Participants were recruited during medical check-ups in 2016 and 2017 from the community-dwelling population. The bone mass of the calcaneus was evaluated using quantitative ultrasound. Of the participants, 56 men (14.9%) and 144 women (19.9%) had a bone mass of less than 70% of the mean of young adults. Univariate analysis revealed that there was a trend toward lower body mass index (BMI) and higher prevalence of low bone mass with an increase in K6 scores in men but not in women. Logistic regression analysis, adjusting for possible confounders(age, BMI, smoking, drinking habits, exercise habits, diabetes, hyperlipidemia, and hypertension), showed significant associations between the K6 scores and low bone mass (odds ratio (OR) = 2.66 for the men with 5 to 12 points of K6, OR = 7.51 for men with ≥ 13 of K6, not for women). We showed an association between psychological distress and low bone mass independent of cofounders among community-dwelling middle-aged men but not women. This suggests that healthy mental health in middle-aged men may be a possible target for the prevention of consequent osteoporosis or fragile bone fractures