青霉素杂质谱分析方法的优化与转换

目的建立青霉素杂质谱HPLC分析方法,并将其转换成UPLC/UHPLC方法。方法以青霉素混合降解溶液为样品;首先分析《中国药典》(2010年版,ChP2010)方法甲醇-缓冲盐二元流动相色谱系统的缺陷;再利用实验设计理念,以响应曲面法(response surface methodology,RSM)的中心组合设计(central composition design,CCD)对色谱系统进行优化,满意度函数法确定最优色谱条件,并优化梯度洗脱条件;最后,利用软件对HPLC方法的流速、进样体积和梯度时间进行几何缩放,并通过色谱柱的选择,将其分别转换为UPLC方法和UHPLC方法。结果新HPLC方法:色谱柱为Capcell Pak C18 MGII(4.6mm×250mm,5μm),流速:1.0m L/min,进样体积:20μL;UPLC方法:色谱柱为Cortecs C18(2.1mm×100mm,1.6μm),流速:0.35m L/min,进样体积:2.0μL;UHPLC方法:Cortecs C18(4.6mm×150mm,2.76μm),流速:0.8mL/min,进样体积:10μL。3种方法的检测波长均为225nm,柱温均为34℃;流动相A均为磷酸盐缓冲液(取磷酸二氢钾10.6g,加水至1000mL,用磷酸调pH至3.4)-甲醇(72:14,V/V),流动相B均为乙腈;均为梯度洗脱,但梯度洗脱表不同。结论 3个色谱系统的分离效果(出峰顺序和个数)相似。新HPLC方法可以分离出更多的降解杂质,并明显改善了青霉素峰的拖尾,缩短了分析时间。     

Room4Birth – The effect of giving birth in a hospital birthing room designed with person-centred considerations: A Swedish randomised controlled trial

ObjectiveTo evaluate if a birthing room designed with person-centred considerations improves labour and birth outcomes for nulliparous women when compared to regular birthing rooms.MethodsA randomised controlled trial was conducted at a Swedish labour ward between January 2019 and October 2020. Nulliparous women in spontaneous labour were randomised either to a birthing room designed with person-centred considerations (New room) or a Regular room. The primary outcome was a composite of four variables: vaginal non-instrumental birth; no oxytocin augmentation; postpartum blood loss < 1000 ml; and a positive childbirth experience. To detect a difference of 8% between the groups, 1274 study participants were needed, but the trial was terminated early due to consequences of the Covid-19 pandemic.ResultsA total of 406 women were randomised; 204 to the New room and 202 to the Regular room. There was no significant difference in the primary outcome between the groups (42.2% versus 35.1%; odds ratio: 1.35, 95% Confidence Interval 0.90–2.01; p = 0.18). Participants in the New room used epidural analgesia to a lower extent (54.4% versus 65.3%, relative risk: 0.83, 95% Confidence Interval 0.71–0.98; p = 0.03) and reported to a higher degree that the room contributed to a sense of safety, control, and integrity (p=<0.001).ConclusionsThe hypothesis that the New room would improve the primary outcome could not be verified. Considering the early discontinuation of the study, results should be interpreted with caution. Nevertheless, analyses of our secondary outcomes emphasise the experiential value of the built birth environment in improving care for labouring women.     

Blinded sample size reestimation for negative binomial regression with baseline adjustment

In randomized clinical trials, it is standard to include baseline variables in the primary analysis as covariates, as it is recommended by international guidelines. For the study design to be consistent with the analysis, these variables should also be taken into account when calculating the sample size to appropriately power the trial. Because assumptions made in the sample size calculation are always subject to some degree of uncertainty, a blinded sample size reestimation (BSSR) is recommended to adjust the sample size when necessary. In this article, we introduce a BSSR approach for count data outcomes with baseline covariates. Count outcomes are common in clinical trials and examples include the number of exacerbations in asthma and chronic obstructive pulmonary disease, relapses, and scan lesions in multiple sclerosis and seizures in epilepsy. The introduced methods are based on Wald and likelihood ratio test statistics. The approaches are illustrated by a clinical trial in epilepsy. The BSSR procedures proposed are compared in a Monte Carlo simulation study and shown to yield power values close to the target while not inflating the type I error rate.     

A new conditional performance score for the evaluation of adaptive group sequential designs with sample size recalculation

In standard clinical trial designs, the required sample size is fixed in the planning stage based on initial parameter assumptions. It is intuitive that the correct choice of the sample size is of major importance for an ethical justification of the trial. The required parameter assumptions should be based on previously published results from the literature. In clinical practice, however, historical data often do not exist or show highly variable results. Adaptive group sequential designs allow a sample size recalculation after a planned unblinded interim analysis in order to adjust the sample size during the ongoing trial. So far, there exist no unique standards to assess the performance of sample size recalculation rules. Single performance criteria commonly reported are given by the power and the average sample size; the variability of the recalculated sample size and the conditional power distribution are usually ignored. Therefore, the need for an adequate performance score combining these relevant performance criteria is evident. To judge the performance of an adaptive design, there exist two possible perspectives, which might also be combined: Either the global performance of the design can be addressed, which averages over all possible interim results, or the conditional performance is addressed, which focuses on the remaining performance conditional on a specific interim result. In this work, we give a compact overview of sample size recalculation rules and performance measures. Moreover, we propose a new conditional performance score and apply it to various standard recalculation rules by means of Monte-Carlo simulations.     

Novel Compounds Identified by Structure-Based Prion Disease Drug Discovery Using In Silico Screening Delay the Progression of an Illness in Prion-Infected Mice

The accumulation of abnormal prion protein (PrP^Sc) produced by the structure conversion of PrP (PrP^C) in the brain induces prion disease. Although the conversion process of the protein is still not fully elucidated, it has been known that the intramolecular chemical bridging in the most fragile pocket of PrP, known as the “hot spot,” stabilizes the structure of PrP^C and inhibits the conversion process. Using our original structure-based drug discovery algorithm, we identified the low molecular weight compounds that predicted binding to the hot spot. NPR-130 and NPR-162 strongly bound to recombinant PrP in vitro, and fragment molecular orbital (FMO) analysis indicated that the high affinity of those candidates to the PrP is largely dependent on nonpolar interactions, such as van der Waals interactions. Those NPRs showed not only significant reduction of the PrP^Sc levels but also remarkable decrease of the number of aggresomes in persistently prion-infected cells. Intriguingly, treatment with those candidate compounds significantly prolonged the survival period of prion-infected mice and suppressed prion disease-specific pathological damage, such as vacuole degeneration, PrP^Sc accumulation, microgliosis, and astrogliosis in the brain, suggesting their possible clinical use. Our results indicate that in silico drug discovery using NUDE/DEGIMA may be widely useful to identify candidate compounds that effectively stabilize the protein.Electronic supplementary materialThe online version of this article (10.1007/s13311-020-00903-9) contains supplementary material, which is available to authorized users.     

How effective are lead-rubber aprons in protecting radiosensitive organs from secondary ionizing radiation?

IntroductionThe purpose of this experiment was to explore the direction of scattered secondary ionizing radiation to a patient. A left lateral radiographic examination of the elbow was deemed appropriate due to its close proximity to radiosensitive organs and record dose limiting opportunities upon wearing a lead-rubber apron.MethodsAn anthropomorphic phantom and lead-rubber apron (Pb 0.35 mm) was used with a 15 cc ionization chamber (model 10,100 AT TRIAD) to measure scattered radiation to radiosensitive organs. Dose readings were recorded before and after in order to quantify dose reduction. Pearson's correlation, linear regression, t-test and one way analysis of variance (ANOVA) statistics were used to affirm how likely dose limitation was attributed to chance (p < 0.05).ResultsThe lead-rubber apron offered dose reduction to most radiosensitive organs. Notably, ionizing radiation was significantly reduced to the left breast 0.0083 μGy (98%), right breast 0.0000 μGy (99.9%) and spleen 0.0262 μGy (99.9%). No empirical benefit was recorded for testes and ovaries. Interestingly, the thyroid recorded an increase in dose (0.1733 μGy; p = 0.01). This was later mitigated using a thyroid collar but identifies increased stochastic risks if lead-aprons are worn alone. Scattered radiation was also reduced to both eyes, which were not directly covered.ConclusionLead-rubber aprons are generally utilized to limit ionizing radiation, yet this article offers insight whereby increases to ionizing radiation to the thyroid are plausible when wearing a lead-rubber apron alone. Whilst these findings cannot be generalized to other radiographic examinations it provides insight into a potential increase risk of scatter to a radiosensitive organ.Implications for practiceThis paper has implications because it identifies that lead-rubber has an impact on scattered ionizing radiation to radiosensitive organs for a lateral elbow examination. Further, it identifies the potential for ionizing radiation to be increased to the thyroid upon wearing a lead-rubber apron alone.