Evaluation of four-dimensional cone beam computed tomography ventilation images acquired with two different linear accelerators at various gantry speeds using a deformable lung phantom

We evaluated four-dimensional cone beam computed tomography (4D-CBCT) ventilation images (VI_CBCT) acquired with two different linear accelerator systems at various gantry speeds using a deformable lung phantom.The 4D-CT and 4D-CBCT scans were performed using a computed tomography (CT) scanner, an X-ray volume imaging system (Elekta XVI) mounted in Versa HD, and an On-Board Imager (OBI) system mounted in TrueBeam. Intensity-based deformable image registration (DIR) was performed between peak-exhale and peak-inhale images. VI_CBCT- and 4D-CT-based ventilation images (VI_CT) were derived by DIR using two metrics: one based on the Jacobian determinant and one on changes in the Hounsfield unit (HU). Three different DIR regularization values (λ) were used for VI_CBCT. Correlations between the VI_CBCT and VI_CT values were evaluated using voxel-wise Spearman’s rank correlation coefficient (r).In case of both metrics, the Jacobian-based VI_CBCT with a gantry speed of 0.6 deg/sec in Versa HD showed the highest correlation for all the gantry speeds (e.g., λ = 0.05 and r = 0.68). Thus, the r value of the Jacobian-based VI_CBCT was greater or equal to that of the HU-based VI_CBCT. In addition, the ventilation accuracy of VI_CBCT increased at low gantry speeds.Thus, the image quality of VI_CBCT was affected by the change in gantry speed in both the imaging systems. Additionally, DIR regularization considerably influenced VI_CBCT in both the imaging systems. Our results have the potential to assist in designing CBCT protocols, incorporating VI_CBCT imaging into the functional avoidance planning process.     

Escherichia coli Heat-Labile Enterotoxin Binds to Glycosylated Proteins with Lactose by Amino Carbonyl Reaction

The binding of Escherichia coli heat-labile enterotoxin (LT) type I to glycosylated proteins with lactose (Galβ1-4Glc) by amino carbonyl reaction was studied by the Western blot assay and by the microtiter well binding assay. LT bound to a lactose-α-lactalbumin amino carbonyl product (Lac-LA), whereas cholera toxin did not. The binding ability of Lac-LA was abolished by β-galactosidase treatment, indicating that the terminal galactose is essential for the binding of LT. The binding of LT to Lac-LA was inhibited by galactose and lactose, and most effectively inhibited by lactulose (Galβ1-4Fru), which is a structural analog of the Amadori rearrangement product of the amino carbonyl reaction between lactose and an ε-amino group of a lysine residue (lactuloselysine). The results suggest that LT recognizes the portion of lactuloselysine in Lac-LA. LT also bound to a melibiose (Galα1-6Glc)-α-lactalbumin amino carbonyl product (Mel-LA), but the binding ability of Mel-LA was weaker than that of Lac-LA, suggesting that the β1-4 linked terminal galactose is dispensable but preferable for the binding. Furthermore, LT bound to the amino carbonyl products of lactose with β-lactoglobulin, caseins, bovine serum albumin, and ovalbumin. These results indicate that LT binds to the amino carbonyl products between proteins and sugars containing the terminal galactose, such as lactose.     

失眠障碍患者脑部CT影像学变化与学习记忆功能变化、临床特征相关性分析

摘要 目的：探讨失眠障碍患者脑部CT影像学变化与学习记忆功能变化、临床特征相关性。方法：回顾性选择2018年6月至2021年6月来我院诊治的失眠障碍患者50例,选择同期来我院体检的健康人群30例。两组受试者均使用飞利浦64排CT进行扫描,检测计算额角指数与海马指数,对比两组受试者的额角指数、海马指数,对比两组受试者的临床记忆评分、睡眠质量评分、WCST评分,分析两组受试者的临床症状,分析观察组患者额角指数、海马指数与临床记忆评分、睡眠指数评分、WCST评分、临床症状评分的相关性。结果：观察组的额角指数、海马指数明显较对照组低（P<0.05）。观察组的临床记忆评分明显较对照组低（P<0.05）。观察组的睡眠质量评分明显较对照组低（P<0.05）。观察组的完成测验数、选择错误率、完成第一个应答数、持续错误率、错误应答数明显较对照组高,完成分类数、概念化水平百分比明显较对照组低（P<0.05）。观察组的躯体感觉评分及心理感觉评分明显较对照组高（P<0.05）。额角指数、海马指数与临床记忆评分呈正比,与睡眠质量评分、临床症状评分呈反比,与WCST评分中的完成分类数、概念化水平百分比呈正比,与WCST评分中的完成测验数、选择错误率、完成第一个应答数、持续错误率、错误应答数呈反比（P<0.05）。结论：脑部CT影像学结果发现,失眠障碍存在学习记忆功能变化,与患者的临床特征相关性、睡眠质量存在存在一定相关性。     

抑郁症患者的脑CT灌注成像特征与认知功能的相关性

摘要 目的：探讨抑郁症患者的脑CT灌注成像特征与认知功能的相关性。方法：选取我院2020年1月到2023年1月收治的90例抑郁症患者作为研究对象,将其分为观察组,另选取同期来我院体检的90名健康志愿者作为对照组。收集所有受检者脑CT灌注成像检查数据,分析抑郁症患者的脑CT灌注成像特征,并建立受试者工作特征（ROC）曲线分析脑CT灌注成像对抑郁症的诊断效能。随后对观察组和对照组受检者均进行认知功能评估,其中包括连线检测（TMT）、视觉再生测验（VRT）、言语流畅性测验（VF）、数字广度测验（DST）以及数字符号测验（SDMT）,并分析脑CT灌注成像与抑郁症认知功能的相关性。结果：观察组与对照组受检者rCBV、rCBF、MTT、TIP、右枕叶、左枕叶、右颞叶、左颞叶、右顶叶、左顶叶CT值对比无明显差异（P＞0.05）,观察组与对照组受检者右额叶、左额叶CT值对比差异显著,观察组明显低于对照组（P＜0.05）;90例抑郁症患者经过汉密尔顿抑郁量表（HAMD）评估后分数均＞20分,确定存在抑郁症状,脑CT灌注成像与HAMD评分诊断抑郁症的准确性、灵敏度、特异性、阳性预测值和阴性预测值对比无明显差异（P＞0.05）,脑CT灌注成像的曲线下面积为83.89,最佳诊断着色界限值为82.53%,HAMD评分的曲线下面积为84.26,最佳诊断着色界限值为87.57%;观察组与对照组受检者连线提笔数、连线错误数、视觉再生检测结果对比无明显差异（P＞0.05）,观察组与对照组受检者连线、言语流畅性、数字广度、数字符号检测结果对比差异显著（P＜0.05）;Spearman相关分析结果表明：连线提笔数、连线错误数、视觉再生与脑CT灌注参数均无明显相关性（P＞0.05）,连线、言语流畅性、数字广度、数字符号与rCBV、rCBF、MTT、TIP、右枕叶、左枕叶、右颞叶、左颞叶、右顶叶、左顶叶CT值无明显相关性（P＞0.05）,连线与右额叶、左额叶CT值呈负相关（P＜0.05）,言语流畅性、数字广度、数字符号与右额叶、左额叶CT值呈正相关（P＜0.05）。结论：抑郁症患者的脑CT灌注成像与健康群体呈现差异,其中右额叶、左额叶差异情况最为显著,提示抑郁症患者可能存在大脑额叶功能改变,另外,抑郁症患者的大脑额叶功能与认知功能变化具有明显相关性。     

Retroviral Oligonucleotide Distributions Correlate with Biased Nucleotide Compositions of Retrovirus Sequences,Suggesting a Duplicative Stepwise Molecular Evolution

A computer-assisted analysis was made of 24 complete nucleotide sequences selected from the vertebrate retroviruses to represent the ten viral groups. The conclusions of this analysis extend and strengthen the previously made hypothesis on the Moloney murine leukemia virus: The evolution of the nucleotide sequence appears to have occurred mainly through at least three overlapping levels of duplication: (1) The distributions of overrepresented (3–6)-mers are consistent with the universal rule of a trend toward TG/CT excess and with the persistence of a certain degree of symmetry between the two strands of DNA. This suggests one or several original tandemly repeated sequences and some inverted duplications. (2) The existence of two general core consensuses at the level of these (3–6)-mers supports the hypothesis of a common evolutionary origin of vertebrate retroviruses. Consensuses more specific to certain sequences are compatible with phylogenetic trees established independently. The consensuses could correspond to intermediary evolutionary stages. (3) Most of the (3–6)-mers with a significantly higher than average frequency appear to be internally repeated (with monomeric or oligomeric internal iterations) and seem to be at least partly the cause of the bias observed by other researchers at the level of retroviral nucleotide composition. They suggest a third evolutionary stage by slippage-like stepwise local duplications. Received: 3 January 1996 / Accepted: 27 March 1996     

Effects of forskolin and cholera toxin on cyclic AMP release in a neurotensin-secreting rat C-cell line

The effects of forskolin and cholera toxin on the regulation of cAMP release were studied in a neurotensin-secreting rat C-cell line. The interaction of these agents with norepinephrine, a potent neurotensin secretagogue, was also investigated. Forskolin stimulated cAMP release 10(2)-10(3) fold while it increased neurotensin release 2-3 fold. Cholera toxin caused a 10(2)-10(3) fold increase in cAMP release and had no effect on neurotensin release. We conclude that the 44-2 C-cells provide a new model for studying the regulation of the concomitant (via forskolin) or independent (via cholera toxin) secretion of cyclic AMP and/or neurotensin.     

Proteolytic fragmentation of myosin: location of SH-1 and SH-2 thiols.

The heavy chain fragmentation pattern of native myosin when digested by proteolytic enzymes is influenced by such conditions as the nature of the proteolytic agent, ionic strength and presence or absence of divalent cations. HMM and S-1 produced by digestion of 14CNEM-labelled myosin under various conditions were analyzed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis. Purified samples of these species were digested under controlled conditions by chymotrypsin and trypsin and a comparison of the observed heavy chain fragmentation patterns led to a sequential arrangement of the proteolytic fragments. The main features of this arrangement are the following: a 21K molecular weight tryptic peptide is found at the N-terminal side of myosin heavy chain. Adjacent to it is a 48K peptide, then a 19.5K peptide containing the two SH-1 and SH-2 thiols. These three peptides constitute the heavy chain of S-1. Adjacent to this S-1 heavy chain is a tryptic (and also chymotryptic) 40K peptide. The rest of the HMM heavy chain on the C-terminus is a sequence susceptible to both chymotrypsin and trypsin attack yielding an undefined number of small peptides.     

Quantification of atherosclerotic plaque activity and vascular inflammation using [18-F] fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT)

Conventional non-invasive imaging modalities of atherosclerosis such as coronary artery calcium (CAC) and carotid intimal medial thickness (C-IMT) provide information about the burden of disease. However, despite multiple validation studies of CAC, and C-IMT, these modalities do not accurately assess plaque characteristics, and the composition and inflammatory state of the plaque determine its stability and, therefore, the risk of clinical events. [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG) imaging using positron-emission tomography (PET)/computed tomography (CT) has been extensively studied in oncologic metabolism. Studies using animal models and immunohistochemistry in humans show that FDG-PET/CT is exquisitely sensitive for detecting macrophage activity, an important source of cellular inflammation in vessel walls. More recently, we and others have shown that FDG-PET/CT enables highly precise, novel measurements of inflammatory activity of activity of atherosclerotic plaques in large and medium-sized arteries. FDG-PET/CT studies have many advantages over other imaging modalities: 1) high contrast resolution; 2) quantification of plaque volume and metabolic activity allowing for multi-modal atherosclerotic plaque quantification; 3) dynamic, real-time, in vivo imaging; 4) minimal operator dependence. Finally, vascular inflammation detected by FDG-PET/CT has been shown to predict cardiovascular (CV) events independent of traditional risk factors and is also highly associated with overall burden of atherosclerosis. Plaque activity by FDG-PET/CT is modulated by known beneficial CV interventions such as short term (12 week) statin therapy as well as longer term therapeutic lifestyle changes (16 months). The current methodology for quantification of FDG uptake in atherosclerotic plaque involves measurement of the standardized uptake value (SUV) of an artery of interest and of the venous blood pool in order to calculate a target to background ratio (TBR), which is calculated by dividing the arterial SUV by the venous blood pool SUV. This method has shown to represent a stable, reproducible phenotype over time, has a high sensitivity for detection of vascular inflammation, and also has high inter-and intra-reader reliability. Here we present our methodology for patient preparation, image acquisition, and quantification of atherosclerotic plaque activity and vascular inflammation using SUV, TBR, and a global parameter called the metabolic volumetric product (MVP). These approaches may be applied to assess vascular inflammation in various study samples of interest in a consistent fashion as we have shown in several prior publications.     

下肢动脉阻塞性病变多层螺旋CT 低剂量扫描成像初探

目的:探讨低剂量CT扫描在下肢动脉脉阻塞性病变诊断中的应用价值.方法:选择127段经DSA确诊的不同部位下肢动脉阻塞性病变行低剂量CT扫描,并采用MPR,VR,MIP等重建方法获得各下肢动脉CTA图像,将CTA图像与DSA图像的诊断结果利用统计学软件SAS8.1行加权Kappa一致性检验,检验水准为:Kaapa.系数大于0.75.结果:所得CTA图像与DSA图像诊断结果的一致性检验的kappa系数为0.8058,两种诊断结果的一致性为优.结论:采用低剂量扫描条件获得高质量的CTA图像在下肢动脉阻塞性病变的诊断上有肯定的价值.