Recent advances in lipid nanoparticles for delivery of nucleic acid,mRNA, and gene editing-based therapeutics

Lipid nanoparticles (LNPs) are becoming popular as a means of delivering therapeutics, including those based on nucleic acids and mRNA. The mRNA-based coronavirus disease 2019 vaccines are perfect examples to highlight the role played by drug delivery systems in advancing human health. The fundamentals of LNPs for the delivery of nucleic acid- and mRNA-based therapeutics, are well established. Thus, future research on LNPs will focus on addressing the following: expanding the scope of drug delivery to different constituents of the human body, expanding the number of diseases that can be targeted, and studying the change in the pharmacokinetics of LNPs under physiological and pathological conditions. This review article provides an overview of recent advances aimed at expanding the application of LNPs, focusing on the pharmacokinetics and advantages of LNPs. In addition, analytical techniques, library construction and screening, rational design, active targeting, and applicability to gene editing therapy have also been discussed.     

Central cardiovascular and oxygen variables during haemorrhage in the pig

Background: We evaluated the ability of the standards issued by the Danish Society of Anaesthesiologists to reflect a blood loss.
Methods: In 9 pigs bled (0–24 ml kg^-1) and retransfused (to 28 ml kg^-1) during halothane anaesthesia, central cardiovascular, thoracic electrical impedance (TI), oxygen, acid-base and temperature variables were recorded.
Results: With the recommendation for minor surgery (mean arterial pressure (MAP) and heart rate (HR)), the correlation to the blood loss was 0.74 ( P < 0.001) and with that for major surgery (MAP, HR, central venous pressure (CVP) and rectal temperature (Temp_r)) it was 0.79 ( P < 0.001). With the recommendation for extensive surgery (MAP, HR, CVP, pulmonary artery catheter variables and the central-peripheral temperature difference (ΔTemp_r-t)), the correlation was 0.84 ( P < 0.001). Non-invasive monitoring (MAP, HR, ΔTemp_r-t TI and near-infrared spectroscopy of the brain (S_invosO₂)) was only slightly better than basal monitoring (r=0.76, P < 0.001). However, adding arterial base excess (BE), TI and peripheral temperature (Temp_t) to the recommendation for major surgery resulted in a correlation of 0.87 ( P < 0.001), while adding BE and TI to the recommendation for extensive surgery raised correlation to only 0.88 ( P < 0.001).
Conclusion: When the recommendations were followed the correlation to the blood loss ranged from 0.74–0.84. However, with the recording of MAP, HR, CVP, ΔTemp_r-t, BE and TI a correlation of 0.87 was achieved, indicating that a pulmonary artery catheter may not be in need for patients undergoing surgical procedures with expected haemorrhage.     

A computer program for calculating the acid-base parameters in samples of blood using a mini-computer

Summary A computer program is presented and evaluated, which calculates all acid-base parameters from data provided by either the indirect Astrup method or the direct method using empirical formulae derived from the Siggaard-Andersen curve nomogram. The program is implemented on a PDP 8 in a multi-user FOCAL environment and can be adapted to other electronic calculators.     

DNA错配修复基因甲基化在肝细胞癌发生发展中的作用

目的探讨DNA错配修复基因(MMR)hMLH1,hMSH2和hMSH3甲基化在肝细胞癌(HCC)发生发展中的作用。方法采用甲基化特异性聚合酶链反应(MSP)法对38例新鲜HCC组织,相应非肿瘤肝组织,2例正常的捐肝组织及6种肝癌细胞系的hMLH1,hMSH2和hMSH3基因启动子CpG岛甲基化进行检测;培养6种肝癌细胞系,MSP法检测加入5-aza-2‘-deoxycytidine前后hMSH2基因在HCC中的甲基化状态改变;逆转录．聚合酶链反应(RT-PCR)方法检测加入5-aza-2’-deoxycytidine前后hMSH2在肝癌细胞株中的mRNA表达改变。结果HCC标本中13．2％(5／38)发生了hMLH1启动子甲基化,68．4％(26／38)发生了hMSH2启动子甲基化;相应的非肿瘤肝组织中hMLH1,hMSH2启动子甲基化阳性率分别为2．6％(1／38),55．3％(21／38);2例正常肝组织中未发现甲基化;6株肝癌细胞系中有5株发生了hMSH2启动子甲基化,而未发现有MLH1启动子甲基化。所有标本中均未发现有hMSH3启动子甲基化。5-aza-2‘-deoxycytidine处理细胞株后,可部分或完全逆转hMSH2启动子甲基化,各细胞株的mRNA均有不同程度的表达增加。结论hMSH3基因启动子CpG岛甲基化与HCC的发生发展关系不大。hMSH2基因甲基化与mRNA表达密切相关,是基因表达调节的一种重要方式。hMLH1和hMSH2基因启动子CpG岛的高甲基化在HCC中是一个常见的基因改变,DNA错配修复基因尤其是hMSH2基因启动子甲基化在HCC的发生中起了重要作用,是早期事件,其可能为临床诊断HCC提供新的检测指标。     

Quantitative displacement of blood acid base equilibrium in acutely water depleted dogs

Summary Dogs were water depleted 2% of their body weight by the intraperitoneal injection of a hyperosmotic solution of saline and glucose (550 mOsm/l). During a 3-h experiment these water-depleted (WD) animals showed a significant decrease in blood pH, base excess (BE) and plasma bicarbonate (Bic_p) and an increase in both hematocrit (Ht) and blood buffer capacity (BBC). These changes were quantitatively time-dependent. The rate change of pH, BE, and Bic_p were –0.072 units h^–1, –4.7 mEq/l h^–1, and 2.9 mEq/l h^–1, respectively. As control dogs showed no significant time-dependent changes in their blood acid-base status, the observed modifications in the experimental dogs were ascribed to water depletion. Increased endogenous acid production related to tissue hypoxia is suggested to be the mechanism that could explain the increased fixed acid accumulation observed in the water-depleted animals.     

PEG-Hemoglobin as a resuscitation solution in the treatment of hypovolemic shock in the anesthetized rat

This study was designed to determine the advantages of using the hemoglobin-based oxygen carrier, polyethylene glycol conjugated bovine hemoglobin (PEG-Hb), as an additive to Ringer's lactate solution (RLS) for the treatment of acute hemorrhage in anesthetized female rats. Different compositions of PEG-Hb and RLS were administered intravenously in a paradigm that provided 30 ml/kg of resuscitation fluid following an episode of 15 min of hypotension. Hypotension was achieved by the removal of blood (1 ml/min) from the femoral vein until the mean arterial pressure was lowered to or below 50 mmHg and subsequently maintained until resuscitation. Short-term cardiovascular assessment showed that resuscitation fluids containing PEG-Hb resulted in higher mean arterial pressure, aortic blood flow, renal blood flow, and less dramatic shifts in arterial base excess and respiratory blood gases than plain RLS. The long-term survival experiment showed lower lactate dehydrogenase, alkaline phosphatase, and serum glutamic pyruvic transaminase levels in most groups resuscitated with solutions containing PEG-Hb, but no differences in survival (100%) were observed. The data suggest that the addition of PEG-Hb to RLS improves its resuscitative effects. Specifically, a solution of 50% RLS:50% PEG-Hb appeared to have the most favorable cardiovascular and metabolic effects in this anesthetized rat hypovolemic shock resuscitation model. Presumably, the improved effects seen with the addition of PEG-Hb were due to its innate plasma expansion and oxygen-delivery capabilities.     

单源双能量CT扫描单能谱成像技术基物质图像在痛风结节中的应用

目的探讨单源双能量CT扫描单能谱成像技术基物质图像在痛风结节诊断中的应用价值。方法选取本院2017年1月至2019年1月收治的77例高度怀疑痛风患者,均进行单源双能量扫描及尿酸基图和钙基图的分拆、重建,同时结合常规能量扫描进行诊断。以美国风湿病协会制定的痛风诊断标准为基准,计算单源双能量CT诊断痛风结节的敏感度、特异度与准确率。结果根据美国风湿病协会制定的痛风诊断标准,77例患者中57例患者确诊为痛风结节。共56例患者经单源双能量CT扫描检测到痛风结节,其中11例为单关节受累,45例为多关节受累。单源双能量CT诊断痛风的敏感度为91.23%,特异度为80.00%,准确率为87.18%;常规CT诊断痛风的敏感度为77.19%,特异度为60.00%,准确率为72.73%。单源双能量CT诊断痛风的敏感度、准确率显著高于常规CT(P<0.05)。单源双能量CT共检出痛风结节131处,直径0.1~14.7cm;常规CT共检出痛风结节104处,直径0.4~14.7cm,0.1~0.3cm痛风结节未能显示。结论单源双能量CT扫描操作简单、费用低,可利用单能谱成像技术基物质图像上的结晶标记颜色鉴别尿酸和非尿酸结晶沉积,痛风结节诊断的敏感度与准确率较高,且可检出较小痛风结节,值得在痛风的临床诊断中推广应用。     

Postural adaptation during arm raising in children with and without unilateral cerebral palsy

Postural sway during arm movements were related to the size of the base of support (BOS) and the limits of stability (LOS) of children with unilateral cerebral palsy (USCP) and typically developing (TD) children. For half of the trials the mechanical disturbance due to the rapid arm movement was increased by attaching small weights at the wrists. The participants stood with both feet on a large force plate, which recorded the displacements of the center of pressure (CoP). The results showed that in the children with USCP the LOS forward and toward the non-dominant (more-affected) side were smaller than in the TD children whereas the LOS backward and toward the dominant (less-affected) side did not differ between the two groups. When rapidly moving the arms the children with USCP swayed over a larger portion of their base of support in the forward direction and toward their more-affected side. In addition, the maximal sway toward the more-affected side during arm movement exceeded the LOS while balance was maintained. These effects increased when the movements were performed with the weights at the wrists. These results show that an area of permissible sway, which was not spontaneously explored during the leaning task, was required to maintain balance during the supra-postural task. Training to enlarge the LOS that includes weight shifts toward the more-affected side might reduce the area of the BOS that is self-perceived as less secure.