METHODS: Eighteen post-weaning female Sprague Dawley rats were divided into the following groups: (i) a control group that received vehicle (distilled water and Tween 80); (ii) a group treated with 10 mg/kg body weight (BW) of Genistein (Gen 10); and (iii) a group treated with a higher dose of Genistein (Gen 100). The rats were treated daily for three weeks from postnatal day 22 (P22) to P42. After the animals were sacrificed, blood samples were collected, and the uteri and ovaries were harvested and subjected to light microscopy and immunohistochemical study.
RESULTS: A reduction of the mean weekly BW gain and organ weights (uteri and ovaries) were observed in the Gen 10 group compared to the control group; these findings were reversed in the Gen 100 group. Follicle stimulating hormone and estrogen levels were increased in the Gen 10 group and reduced in the Gen 100 group. Luteinizing hormone was reduced in both groups of Genistein-treated animals, and there was a significant difference between the Gen 10 and control groups (p<0.05). These findings were consistent with increased atretic follicular count, a decreased number of corpus luteum and down-regulation of estrogen receptors-a in the uterine tissues of the Genistein-treated animals compared to the control animals.
CONCLUSION: Post-weaning exposure to Genistein could affect the development of the reproductive system of ovarian-intact experimental rats because of its action on the hypothalamic-pituitary-gonadal axis by regulating hormones and estrogen receptors.
DESIGN: This study was designed as a retrospective cohort study.
SETTING AND PARTICIPANTS: In this study, we analysed the prescription databases of tertiary hospitals in Malaysia. This study included patients aged ≥18 years with at least one opioid prescription (buprenorphine, morphine, oxycodone, fentanyl, dihydrocodeine or tramadol) between 1 January 2011 and 31 December 2016. These patients had no opioid prescriptions in the 365 days prior, and were followed up for 365 days after the initial opioid prescription.
MAIN OUTCOME MEASURES: The main outcome measures were the number of short-term (<90 days) and long-term opioid users (≥90 days), initial opioid prescription period and daily dose.
RESULTS: There were 33 752 opioid-naïve patients who received opioid prescriptions (n=43 432 prescriptions) during the study period. Of these, 29 824 (88.36%) were short-term opioid users and 3928 (11.64%) were long-term opioid users. The majority of these short-term (99.09%) and long-term users (96.18%) received an initial daily opioid dose of <50 mg/day with a short-acting opioid formulation. Short-term opioid users were predominantly prescribed opioids for 3-7 days (59.06%) by the emergency department (ED, 60.56%), while long-term opioid users were primarily prescribed opioids for ≥7 days (91.85%) by non-ED hospital departments (91.8%). The adjusted model showed that the following were associated with long-term opioid use: increasing opioid daily doses, prescription period ≥7 days and long-acting opioids initiated by non-EDs.
CONCLUSIONS: The majority of opioid-naïve patients in tertiary hospital settings in Malaysia were prescribed opioids for short-term use. The progression to long-term use among opioid-naïve patients was attributed to the prescription of higher opioid doses for a longer duration as well as long-acting opioids initiated by non-ED hospital departments.