ABSTRACT
Background Preterm birth-related complications are the leading cause of death in newborns and children under the age of 5 years. Maternal heat exposure has been associated with both sleep status during pregnancy and the increased risk of preterm birth. However, whether sleep status could mediate the association between heat exposure and preterm birth remains unclear. Objective To evaluate the association between maternal heat exposure in early pregnancy and preterm birth, and to further explore potential mediation effect of sleep status on the association between heat exposure and preterm birth. Methods A birth cohort was established in Guangzhou Panyu Maternal Child Health Hospital (Guangzhou Panyu District He Xian Memorial Hospital) from 2017 until now. Pregnant women (with gestational age between 8 and 13 weeks) were included in this study when they presented to the hospital for their first prenatal care visit and signed an informed consent. Then they were followed up until delivery. A total of 3 268 pregnant women were included for the final analysis. Questionnaires were distributed to collect the demographic characteristics, lifestyles, and sleep status of pregnant women. Daily meteorological data during the study period were collected from meteorological monitoring stations in Guangzhou and the average ambient mean temperature of four weeks before the survey was calculated and assigned for each pregnancy. The 75th, 80th, 85th, 90th, and 95th percentiles (P75, P80, P85, P90, and P95) of the average ambient temperature of all pregnant women were used as the thresholds to define heat exposure. Logistic regression was used to evaluate the effects of heat exposure in different definitions on preterm birth and sleep status (sleep duration, night sleep timing, and wake up timing). The mediation effects of sleep status on the relationship between heat exposure and preterm birth were also analyzed. Results Among all the included participants, 165 newborns were preterm births with an incidence rate of 5.0%. Heat exposures with thresholds of P90 and P95 increased the risk of preterm birth, with ORs (95%CIs) of 1.66 (1.04-2.57) and 1.90 (1.03-3.33), respectively (P<0.05). Heat exposures with thresholds of P75, P80, P85, P90, and P95 decreased the sleep duration (<9 h vs. ≥9 h, control group: ≥9 h), and the ORs (95%CIs) were 1.51 (1.25-1.83), 1.44 (1.17-1.77), 1.35 (1.08-1.70), 1.43 (1.09-1.87), and 1.45 (1.00-2.13), respectively. Heat exposures with P75 and P80 thresholds resulted in earlier wake up timing (<8: 00 vs. ≥8: 00, control group: <8: 00), with ORs (95%CIs) of 0.77 (0.63-0.93) and 0.76(0.61-0.93), respectively. No significant association was observed between heat exposure and night sleep timing. The mediation analyses showed that under heat exposure with P90 threshold, a statistically significant mediation effect was observed for sleep duration, and the proportion mediated was 6.07% (95%CI: 0.17%-25.00%) (P<0.05). No significant mediation effect was observed for night sleep timing and wake up timing. Conclusion An elevated risk of preterm birth after heat exposure in early pregnancy may be partly mediated through reducing sleep duration.
ABSTRACT
@#Objective To analyze peri-implant alveolar bone loss with radiography. Methods 38 implants were inserted in 27 cases. The peri-implant alveolar bone was observed and measured with intraoral radiography at time of insertion, functional loading, and 3, 6, 12 months after functional loading. Results The mean peri-implant alveolar bone loss was 0.35 mm immediately after functional loading, 0.57 mm, 0.67 mm,1.01 mm at 3,6,12 months later. There was not significant difference of bone loss between maxilla and mandible, neither of submerged and non-submerged implants. ITI implants performed significantly less bone loss than Replace Select within 3 months after functional loading (P<0.01). Conclusion Osseointegration will successfully be obtained on implants involved. The peri-implant alveolar bone loss with ITI is less than that with Replace Select. The bone loss is not different between submerged and non-submerged implants.
ABSTRACT
<p><b>OBJECTIVE</b>To summarize operation key points, prevention and management of complications in vascularized autotransplantation of submandibular gland for treatment of severe keratoconjunctivitis sicca.</p><p><b>METHODS</b>23 patients with severe keratoconjunctivitis sicca were treated by this procedure. Postoperative (99m)Tc images, follow-up studies, and management of complications were performed.</p><p><b>RESULTS</b>The transplantations were successful in 19 cases, whose symptoms of xerophthalmia disappeared. The patients could stop applying artificial tears. In 4 patients the transplanted glands did not survive. Epiphora occurred in 5 cases. They were successfully treated by reducing the size of the graft. Obstruction of the Wharton's duct took place in one case and was treated by reconstructing the duct. When the superficial temporal vein was too small, venous bridging was applied. To select a relevant vein for anastomosis, blood oozing from the three veins was carefully inspected prior cutting off the gland when the external maxillary artery was preserved and was infused with heparin after the gland had been freed.</p><p><b>CONCLUSIONS</b>If every point has been properly managed, the successful rate of operation could be warranted.</p>