Authors:Pai-Feng Hsiao, Shao-Kuang Chang, Tien-Huan Hsu, Kuang-Po Li and Chi-Chung Chou
The recommended use of doxycycline (DC) to broiler chicken is 100 mg/L via the drinking water and a 7-day withdrawal time (WDT). However, study of a higher dosage is desirable because of the possible increase of antimicrobial resistance and disease spectrum. Tissue DC residues exceeding the current maximum residue levels (MRL) was our major concern. Therefore, serum concentration and tissue depletion of DC hyclate after administration of 200 mg/L of DC in the drinking water for five consecutive days were studied. The steady-state DC concentration (8.3 ± 0.9 μg/mL) was reached on the third day of medication. The elimination constant (0.05 ± 0.01 1/h), half-life (14.9 ± 1.4 h), area under concentration versus time curve (81.0 ± 9.9 h·μg/mL) and mean residence time (22.7 ± 2.5 h) were obtained using a non-compartmental pharmacokinetic model. It was determined that the current 7-day WDT regulation was still legitimate for the kidney and liver as well as for the breast and leg muscles, which were estimated by linear regression analysis of the 99% upper distribution limit. The unregulated heart and gizzard were considered safe even when the lowest MRL of muscle (100 ng/g) was applied. While at the present time the extra-label use of drugs is only allowed under specific conditions, in the future it may become necessary to increase the general dosage of DC, and the current results suggest a safe range of DC hyclate in chicken; however, skin/fat tissue residues warrant further studies.
Authors:Li Kuang, Wo Wang, Yan Huang, Xiaorong Chen, Zhen Lv, Jun Cao, Ming Ai and Jianmei Chen
Background and aims
Internet addiction (IA) is common among young students. This study aimed to examine the influence and mechanisms of IA and susceptible personality traits on the impact of suicidal ideation in adolescent students in China.
This cross-sectional study (09/2012–09/2015) used stratified cluster sampling with “school type” for stratification; 136,266 students from 63 schools completed the questionnaire. Logistic regression analysis was performed to estimate the effect of IA (Young's Internet Addiction Test) and susceptible personality (Barratt impulsiveness scale, Buss & Perry Aggression Questionnaire; and Eysenck Personality Questionnaire-R Short Scale) on suicidal ideation (Scale of Suicidal Ideation).
Suicidal ideation was observed in 20,218 (14.77%) of the students, and IA was detected in 28,836 (21.16%) subjects. Compared with those without IA, students with IA had a higher prevalence of suicidal ideation (P < 0.0001). No planning impulsiveness had a predictive effect on suicidal ideation in the impulsive personality trait, while in the aggressive personality trait, hostility and self-aggression had a predictive effect on suicidal ideation (all P < 0.0001). High psychoticism and neuroticism were impact factors for suicidal ideation, but extroversion was a protective factor (all P < 0.0001).
These results highlight the importance of assessing personality traits and reducing IA as a possible means of lessening suicidal ideation. Susceptible personality (such as high psychoticism, high neuroticism, and low extroversion) play a prominent role in influencing the probability of having suicidal behavior among those recently exposed to IA.
IA and susceptible personality traits were significantly correlated with suicidal and self-harm ideation among adolescent students.