Effect of deuteration on the single dose pharmacokinetic properties and postoperative analgesic activity of methadone

Although methadone is effective in the management of acute pain, the complexity of its absorption-distribution-metabolism-excretion profile limits its use as an opioid of choice for perioperative analgesia. Because deuteration is known to improve the pharmacokinetic, pharmacodynamic and toxicological properties of some drugs, here we characterized the single dose pharmacokinetic properties and post-operative analgesic efficacy of d₉-methadone.The pharmacokinetic profiles of d₉-methadone and methadone administered intravenously to CD-1 male mice revealed that deuteration leads to a 5.7- and 4.4-fold increase in the area under the time-concentration curve and maximum concentration in plasma, respectively, as well as reduction in clearance (0.9 ± 0.3 L/h/kg vs 4.7 ± 0.8 L/h/kg). The lower brain-to-plasma ratio of d₉-methadone compared to that of methadone (0.35 ± 0.12 vs 2.05 ± 0.62) suggested that deuteration decreases the transfer of the drug across the blood-brain barrier. The estimated LD₅₀ value for a single intravenous dose of d₉-methadone was 2.1-fold higher than that for methadone. Moreover, d₉-methadone outperformed methadone in the efficacy against postoperative pain by primarily activating peripheral opioid receptors. Collectively, these data suggest that the replacement of three hydrogen atoms in three methyl groups of methadone altered its pharmacokinetic properties, improved safety, and enhanced its analgesic efficacy.     

Relationship between tRNA-derived fragments and human cancers

tRNA-derived fragments, a class of small noncoding RNAs (sncRNAs), have been identified in numerous studies in recent years. tRNA-derived fragments are classified into two main groups, including tRNA halves (tiRNAs) and tRNA-derived small RNA fragments (tRFs), according to different cleavage positions of the precursor or mature tRNAs. Instead of random tRNA degradation debris, a growing body of evidence has shown that tRNA-derived fragments are precise products of specific tRNA modifications and play important roles in biological activities, such as regulating protein translation, affecting gene expression, and altering immune signaling. Recently, the relations between tRNA-derived fragments and the occurrence of human diseases, especially cancers, have generated wide interest. It has been demonstrated that tRNA-derived fragments are involved in cancer cell proliferation, metastasis, progression and survival. In this review, we will describe the biogenesis of tRNA-derived fragments, the distinct expression and function of tRNA-derived fragments in the development of cancers, and their emerging roles as diagnostic and prognostic biomarkers and precise targets of future treatments.     

人肠道病毒71型及柯萨奇病毒A组16型VP1蛋白的真核表达

目的：克隆人肠道病毒71型（EV71）及柯萨奇病毒A组16型（CA16）的VP1蛋白编码基因，构建相应真核表达质粒在体外进行重组表达，检测其细胞内定位，为EV71及CA16的疫苗研究提供基础。方法：通过PCR扩增分别获取EV71及CA16的VP1编码序列，插入pcFlag载体，分别构建EV71及CA16 VP1与FLAG标签融合的真核表达质粒；瞬时转染人胚肾293T细胞及横纹肌肉瘤RD细胞，Western blot法检测融合蛋白的表达，免疫荧光检测融合蛋白的细胞内定位情况。结果：测序表明两种来源VP1蛋白的重组表达质粒构建正确；分别转染两种不同的细胞后，均可通过Western blot检测到相应蛋白表达；免疫荧光检测显示两种毒株的VP1均表达在细胞质中。结论：外源融合表达EV71或CA16 VP1蛋白的真核表达质粒构建成功；所构建质粒分别转染细胞后，均可在细胞质内检测到VP1融合蛋白的表达。     

Engraftable neural crest stem cells derived from cynomolgus monkey embryonic stem cells

Neural crest stem cells (NCSCs), a population of multipotent cells that migrate extensively and give rise to diverse derivatives, including peripheral and enteric neurons and glia, craniofacial cartilage and bone, melanocytes and smooth muscle, have great potential for regenerative medicine. Non-human primates provide optimal models for the development of stem cell therapies. Here, we describe the first derivation of NCSCs from cynomolgus monkey embryonic stem cells (CmESCs) at the neural rosette stage. CmESC-derived neurospheres replated on polyornithine/laminin-coated dishes migrated onto the substrate and showed characteristic expression of NCSC markers, including Sox10, AP2α, Slug, Nestin, p75, and HNK1. CmNCSCs were capable of propagating in an undifferentiated state in vitro as adherent or suspension cultures, and could be subsequently induced to differentiate towards peripheral nervous system lineages (peripheral sympathetic neurons, sensory neurons, and Schwann cells) and mesenchymal lineages (osteoblasts, adipocytes, chondrocytes, and smooth muscle cells). CmNCSCs transplanted into developing chick embryos or fetal brains of cynomolgus macaques survived, migrated, and differentiated into progeny consistent with a neural crest identity. Our studies demonstrate that CmNCSCs offer a new tool for investigating neural crest development and neural crest-associated human disease and suggest that this non-human primate model may facilitate tissue engineering and regenerative medicine efforts.     

Replacing HMG/FSH by low-dose HCG to complete corifollitropin alfa stimulation reduces cost per clinical pregnancy: a randomized pragmatic trial

Research questionThe cost of IVF treatment remains high, among other factors because of the medication needed for ovarian stimulation. This study investigated the effect of using low-dose human chorionic gonadotrophin (HCG) for the second phase of follicular maturation after corifollitropin alfa induction, to replace the more expensive, either recombinant or human menopausal gonadotrophin (HMG), on the cost of ovarian stimulation.DesignOne hundred and five patients were randomly divided into two groups: patients in the HCG group (n = 50) received low-dose HCG from Day 7 until the diameter of at least three follicles reached 17 mm or more, while patients in the FSH group (n = 55) received conventional ovarian stimulation with highly purified HMG injections.ResultsThe clinical pregnancy rate in the HCG group was 38% higher than in the FSH group (number needed to treat, NNT = 13). The cost per pregnancy needed for ovarian stimulation was reduced from €4902 in the FSH group to €2684 in the HCG group. Hence, the cost of ovarian stimulation medication to obtain 10 pregnancies using the conventional FSH protocol is sufficient to attain 18 pregnancies when applying the low-dose HCG protocol.ConclusionThis study provides evidence that using HCG instead of HMG/FSH for ovarian stimulation results in a significant reduction in the cost of IVF with, at least, an equivalent pregnancy rate.     

输卵管妊娠治疗方式及其对未来生育影响的研究进展

输卵管妊娠是一种临床常见的妇科急腹症。输卵管妊娠如能在包块尚未破裂前早期诊断，其相关的病死率大大降低。输卵管妊娠的治疗方式有很多，无论哪种治疗方式，都会导致患者生育功能的下降。临床中对于有生育要求的患者，选择哪种治疗方式更好地保护患者的生育功能并减少并发症仍是有争议的话题。近年有学者做了大量研究比较输卵管妊娠不同治疗方式的并发症及其对患者未来生育前景的影响，甚至提出更新的治疗方式以弥补传统治疗方式的不足。现就输卵管妊娠的治疗方式、并发症及对未来生育的影响的研究进展进行综述。     

胎膜早破孕妇生殖道感染情况及对妊娠结局影响

目的 研究胎膜早破孕妇生殖道感染情况及对妊娠结局的影响。方法 选择2014年5月至2015年1月住院分娩的胎膜早破孕妇70例为早破组,同期无胎膜早破70例为对照组,检测两组生殖道病原微生物感染情况,并比较两组的妊娠结局。结果 早破组生殖道感染阳性率高于对照组,且剖宫产率,母体发生产后出血,绒毛膜羊膜炎,胎儿窘迫及新生儿窒息发生率均高于对照组,差异均有统计学意义(P<0.05)。结论 生殖道感染是胎膜早破最常见的诱因,积极筛查及治疗孕妇生殖道感染可以减少相关产科并发症的发生。