Determination of the Dose-Response Relationship of Epidural Dexmedetomidine Combined with Ropivacaine for Labor Analgesia.

Background: The safety and efficacy of dexmedetomidine for epidural labor analgesia have been reported in numerous literatures, but the optimal dose has not been fully determined. The objective of this study was to determine the dose-response relationship of epidural dexmedetomidine (combined with ropivacaine) for labor analgesia. Methods: A total of 120 full-term laboring parturients requesting epidural labor analgesia were enrolled in the study from July 5, 2020 to September 22, 2021. The parturients were randomly assigned to receive 0, 0.1, 0.2, 0.3, 0.4 or 0.5 µg/mL dexmedetomidine combined with 0.075% ropivacaine epidurally. An effective dose was defined as numerical rating scale (NRS) pain score ≤3 at 30-minutes of epidural drug injection. The dose-response relationship of dexmedetomidine (with ropivacaine) for epidural labor analgesia was performed using probit regression. The median effective dose (ED50) and the 95% effective dose (ED95) values for epidural dexmedetomidine combined with 0.075% ropivacaine with 95% confidence intervals (CIs) were derived by interpolation. Results: The estimated values of ED50 and ED95 with 95% CIs for epidural dexmedetomidine (combined with 0.075% ropivacaine) were 0.085 (0.015 to 0.133) µg/mL and 0.357 (0.287 to 0.493) µg/mL, respectively. No differences were found among groups for sensory block level, number of parturients with Bromage score >0, total dosage of analgesics, cesarean delivery rate, fetal birth weight, Apgar score at 1-minute, Apgar score at 5-minutes and adverse effects. Compared with other groups, group dexmedetomidine 0.5 µg/mL had a longer duration of the first stage of labor. Conclusion: The ED50 and ED95 values of dexmedetomidine for epidural labor analgesia was 0.085 and 0.357 µg/mL under the conditions of this study. Dexmedetomidine is a suitable adjuvant for epidural labor analgesia.

Breeding and preliminarily phenotyping of a congenic mouse model with alopecia areata.

In the current study, the alopecia areata gene was introduced into the C57BL/6 (B6) mouse through repeated backcrossing/intercrossing, and the allelic homozygosity of congenic AA(tj)mice (named B6.KM-AA) was verified using microsatellites. The gross appearance, growth characteristics, pathological changes in skin, and major organs of B6.KM-AA mice were observed. Counts and proportions of CD4⁺ and CD8⁺ T lymphocytes in peripheral blood were determined by flow cytometry. Results show that congenic B6.KM-AA mice were obtained after 10 generations of backcrossing/intercrossing. B6.KM-AA mice grew slower than B6 control mice and AA skin lesions were developed by four weeks of age. The number of hair follicles was reduced, but hair structures were normal. Loss of hair during disease progression was associated with CD4⁺ and CD8⁺ T lymphocytes infiltration peri-and intra-hair follicles. No pathological changes were found in other organs except for the skin. In the peripheral blood of B6.KM-AA mice, the percentage of CD4⁺ T cells was lower and percentage of CD8⁺ T cells higher than in control mice. These findings indicate that B6.KM-AA mice are characterized by a dysfunctional immune system, retarded development and T-cell infiltration mediated hair loss, making them a promising new animal model for human alopecia areata.

An investigation of the ability of elemene to pass through the blood-brain barrier and its effect on brain carcinomas.

OBJECTIVES: Elemene is a chemical extracted from plants. It has demonstrated anti-tumour capability. Although widely studied, there has been little reported regarding its tissue distribution. Our aim was to rectify this. METHODS: The tissue distribution of elemene was studied after intragastric or intravenous administration in rats. The effectiveness of elemene in treating brain tumours was studied using the G-422 tumour cell model in mice. KEY FINDINGS: Elemene had a higher concentration in the lungs, spleen and livers than other tissues of normal rats after intragastric and intravenous administration, while the concentration in the gastrointestinal tract was greater after intragastric administration. Elemene molecules were also detected in the rats' brain tissue. Elemene had a therapeutic effect on mice inoculated with G-422 cells both intracranially and subcutaneously. The best life-extending rate and the best tumour-inhibiting rate of elemene were 64.43% and 34.46%, respectively, when 80 mg/kg elemene was used for treatment. CONCLUSIONS: The results from the tissue distribution study showed that elemene can pass through the blood-brain barrier. The therapeutic experiments showed that elemene is effective in treating cerebral malignancy.