Prenatal exposure to PM2.5 components and the risk of different types of preterm birth and the mediating effect of pregnancy complications: a cohort study.

OBJECTIVES: This study aims to reveal the single and mixed associations of PM2.5 and its components with very, moderately, and late preterm births and to explore the potential mediating role of pregnancy complications in PM2.5-induced preterm birth. STUDY DESIGN: This was a retrospective cohort study. METHODS: We enrolled 168,852 mothers and matched the concentrations of PM2.5 and its five components (OM, SO42-, BC, NO3-, and NH4+) based on their geographical location. Next, we used generalized linear models, quantile g-computation, and mediation analysis to evaluate the associations of PM2.5 and its components with very, moderately, and late preterm births and the mediating role of pregnancy complications. RESULTS: Prenatal exposure to PM2.5 and its components was associated with preterm birth, and the association was strongest in the third trimester. Preterm birth was associated with co-exposure to a mixture of PM2.5 components in the third trimester, and the contributions of NO3-, NH4+, and BC to the risk of preterm birth were positive. Meanwhile, pregnancy complications mediated PM2.5-induced preterm birth. Moreover, very and moderately preterm births were associated with PM2.5 and its components in the second and third trimesters, and very and late preterm births were associated with co-exposure to a mixture of PM2.5 components in the third trimester. CONCLUSIONS: Later exposure to PM2.5 during pregnancy will cause earlier preterm birth. Targeted and positive interventions for anthropogenic sources of specific PM2.5 components and pregnancy complications are helpful for preterm birth prevention.

[Evaluation of the impact of the Japanese encephalitis vaccine included in an expanded immunization program on the reported incidence rate of Japanese encephalitis in Gansu province-based on interrupted time series].

Objective: To evaluate the impact of the Japanese encephalitis vaccine included in an expanded immunization program on the reported incidence rate of Japanese encephalitis in Gansu province. Methods: Information on the reported incidence rate of Japanese encephalitis in Gansu province from 1987 to 2019 was collected through the National Population Health Science Data Center and the China Disease Prevention and Control Information System. In addition, the trend of Japanese encephalitis reported incidence rate in Gansu province before and after the inclusion of the Japanese encephalitis vaccine in the expanded immunization program was analyzed using an interrupted time-series design. Results: The annual reported incidence rate of Japanese encephalitis in Gansu province from 1987 to 2019 was 0.448/per 100 000. However, after the inclusion of the Japanese encephalitis vaccine in the expanded immunization program in Gansu province in 2008, the amount of change in the level of Japanese encephalitis reported incidence rate was -2.223/per 100 000 (t=-2.90, P=0.007), the amount of change in the slope of Japanese encephalitis reported incidence rate was 0.082 (t=2.87, P=0.008) with the slope of Japanese encephalitis reported incidence rate as 0.071 (ß1+ß3=0.071). Conclusions: The Japanese encephalitis vaccine has achieved good prevention and control effects in Gansu province in the short term after its inclusion in the expanded immunization program, but outbreaks of Japanese encephalitis have still occurred. Therefore, in the future, Gansu province should promptly adjust the immunization strategy of the Japanese encephalitis vaccine, and strengthen the vaccination of the adult population, especially the rural adult population in the southeastern region of Gansu province, based on the continued focus on the works on Japanese encephalitis vaccination for children and adolescents.

Distribution and regulation of alpha(2)-adrenoceptors in rat dorsal root ganglia.

Using in situ hybridization with riboprobes the distribution of alpha(2A)-, alpha(2B)- and alpha(2C)-adrenoceptor mRNAs were studied in normal rat dorsal root ganglia and after unilateral peripheral nerve injury (total nerve transection) or inflammation. The most common adrenoceptor mRNA was of the alpha(2C) subtype (almost 80% of all neuron profiles) followed by the alpha(2A) subtype (almost 20%), whereas alpha(2B)-adrenoceptor mRNA was only found in small numbers of neuron profiles. The most dramatic effect of peripheral nerve injury was observed for the alpha(2A)-adrenoceptor mRNA, which increased to 45% of all neuron profiles. In contrast, alpha(2C) adrenoceptor mRNA showed a small decrease in this situation. Carrageenan-induced peripheral inflammation did not affect the percentage of alpha(2A)- or alpha(2C)-adrenoceptor mRNA-positive profiles. These findings suggest that, if any of the alpha(2) adrenoceptor, the alpha(2A) subtype represents the most likely candidate in DRG neurons to be involved in sympathetically maintained pain.

[Studies on transdermal delivery system of dihydroetorphine hydrochloride].

A transdermal delivery system of dihydroetorphine hydrochloride (DHE-TDS) was developed. The DHE-TDS mainly composed of polyvinyl alcohol, polyvinyl pyrrolidone and lactose. Tests on rabbits showed only slight skin irritation according to federal hazardous substances act. By giving DHE-TDS to rabbits, DHE release was shown to be governed by first-order mechanism. When DHE-TDS was given to Wistar rats, a relatively stable blood drug concentration was observed from 4-32 h after drug administration. Writhing tests showed that one dose of DHE-TDS would maintain the narcotic action on rats for at least 48 h.

[Studies on preparation and characteristics of cisplatin chitosan microspheres].

In this paper, the preparation, drug content, size and size distribution, appearance and morphology, release characteristics in vitro and degradation characteristics of cisplatin chitosan microspheres (CDDP-DAC-MS) were studied. CDDP-DAC-MS were prepared by emulsion-crosslink technique. The CDDP-DAC-MS was shown to have rough spherical surface under scanning electron microscopy. The average diameter of the microspheres was 74.80 microns and CDDP content was 20.83% +/- 0.36%. CDDP-DAC-MS swelled slightly in saline after 1 h. Within the test period, the release of CDDP from CDDP-DAC-MS in saline solution could be described by first-order equation. The microspheres were sterilized by 60Co radiation. After 28 d of hepatic artery embolization with CDDP-DAC-MS in dogs, pathological photomicrograph showed that CDDP-DAC-MS could still be observed.

[Studies on hepatic arterial embolization with cisplatin-chitosan-microspheres in dogs].

Cisplatin-chitosan-microspheres (CDDP-DAC-MS) was chosen as a model preparation. Pharmacokinetics, targeting and embolization effects and alteration of liver function were studied after hepatic arterial embolization in dogs with CDDP-DAC-MS, and the platinum content in plasma and liver was determined by flameless atomic absorption spectrophotometry (FAAS). The result of clinical trial was also reported. After the CDDP-DAC-MS and CDDP solution were respectively infused into hepatic artery of dogs through a 5F catheter, the plasma concentration of platinum and AUC of CDDP-DAC-MS group was lower than that of CDDP solution group, but the platinum content in hepatic tissue was 2.92 times as much as that when CDDP solution was given after 24 h. Angiograms revealed a remarkable decrease in the number of arterioles in liver, and histopathologic specimens showed nodular necrosis and hepatic cell degeneration in embolized region. The levels of GPT, GOT and ALP rose transiently after embolization and recovered to normal within 3 weeks. The clinical therapy in six liver cancer patients was successful. It would appear that CDDP-DAC-MS may be a good chemoembolization agent.