Tamoxifen induces resistance to activated protein C

Introduction

The estrogen antagonist tamoxifen (TAM) increases the thrombotic risk similar to estrogen containing oral contraceptives (OC). In OC users this risk is attributed to alterations of hemostasis resulting in acquired resistance to activated protein C (APC). TAM-induced APC resistance has not been reported yet.

Materials and Methods

Blood samples were collected prospectively from women with breast cancer before (n = 25) and monthly after start of adjuvant TAM treatment (n = 75). APC resistance was evaluated on basis of the effect of APC on the endogenous thrombin generation potential. To detect increased in vivo APC generation APC plasma levels were measured using a highly sensitive oligonucleotide-based enzyme capture assay. Routine hemostasis parameters were measured additionally.

Results

APC sensitivity decreased by 41% (p = 0.001) compared to baseline after one month of TAM application and remained significantly decreased during the study period. Free protein S increased (p = 0.008) while other analyzed procoagulant factors, inhibitors, and activation markers of coagulation decreased or did not change significantly. In five patients the APC concentration increased to non-physiological levels but an overall significant increase of APC was not observed.

Conclusions

This is the first study showing acquired APC resistance under TAM therapy. Acquired APC resistance might explain the increased thrombotic risk during TAM treatment. Observed changes of hemostasis parameters suggest different determinants of TAM-induced APC resistance than in OC-induced APC resistance. The presence of acquired APC resistance in TAM patients warrants further evaluation if these patients may benefit from antithrombotic prophylaxis in the presence of additional thrombotic risk factors.     

Cortical circumferential profile of SPECT cerebral perfusion in Alzheimer''s disease

We developed a semiautomatic method termed “cortical circumferential profiling” for objective analysis of cerebral cortex function in emission tomographic neuroimaging studies. This method treats cortex as a continuous ring near the outer brain edge. A computer algorithm samples the cortex at 60 contiguous, equiangular locations, using 1-cm² samples. These values are plotted as a function of cortical angle to produce the cortical circumferential profile. This method was used in a study of regional cerebral perfusion in 15 patients with Alzheimer's disease and 8 elderly control subjects using N-isopropyl [I-123]-iodoamphetamine. Cortical circumferential profiling decreases variability, examines the entire cortex within slices at preselected levels above the orbital-meatal line, and facilitates intrasubject and intersubject comparisons.     

Synaptic analysis of amacrine cells with neuropeptide Y-like immunoreactivity in turtle retina

Neuropeptide Y-like immunoreactivity has been localized previously within three classes of amacrine cells in the turtle retina. We have used the avidin-biotin with horseradish peroxidase technique to label these neurons for examination at the ultrastructural level to answer the following questions. Where are the synaptic contacts of these neurons made? What types of neurons are involved pre- and postsynaptically? What is the intracellular distribution of the immunoreactivity? Processes with neuropeptide Y-like immunoreactivity were located primarily within three regions of the inner plexiform layer: stratum 1, stratum 3, and at the border between strata 4 and 5. In all three regions the processes with neuropeptide Y-like immunoreactivity received synaptic contacts from both unlabeled amacrine and bipolar cells, but the majority of the synaptic input in all three regions was from unlabeled amacrine cells. Processes with neuropeptide Y-like immunoreactivity were presynaptic to unlabeled amacrine cells in all three regions, but also formed contacts onto unlabeled bipolar cells in the region between strata 4 and 5. The immunoreactivity within these cells gave rise to a diffuse reaction product that was distributed throughout the cytoplasm and within large vesicles. This localization of neuropeptide Y-like immunoreactivity within large vesicles suggests that this peptide may play a neuromodulatory role. Such a role would be consistent with previous studies of neuropeptides in the turtle retina.     

Digital PCR detection of EGFR somatic mutations in non-small-cell lung cancer formalin fixed paraffin embedded samples

BackgroundDigital PCR (dPCR) is proposed to replace real time PCR and Sanger sequencing for detection and quantification of rare mutations, frequently unnoticed in the mass of tumoral cells. Screening of endothelial growth factor receptor (EGFR) mutations is mandatory before treatment with EGFR-targeted therapy with small-molecule tyrosine kinase inhibitors, which has been approved for the treatment of advanced non-small-cell lung cancer (NSCLC).ObjectiveIn order to establish a cost-effective method for detection of mutations, we optimized dPCR identification of EGFR mutations in exons 18–21, and determined dPCR sensitivity, limits of detection (LoD) and quantification (LoQ).MethodsFor clinical validation, we compared the performance of dPCR and castPCR in 57 NSCL formalin fixed paraffin embedded samples and 10 lung cancer-free formalin fixed paraffin embedded samples.ResultsEGFR mutations DEL19, p.L858R, p.G719X, p.L861Q and p.T790 M were detected by dPCR in 27 samples versus 11 detected by castPCR (p = 0.014). LoD was determined as 100 molecules of DNA/uL and LoQ as 1%. Most of the samples (87%) identified by competitive Allele-Specific TaqMan (castPCR) as wild-type and by dPCR as mutated, presented less than 10% mutated DNA molecules (mean 4.57%). Accuracy of dPCR was 94.44%, as measured with the assay recommended by the College of American Pathologists.ConclusionThese results indicated higher sensibility and specificity of dPCR for screening EGFR mutations in NSCLC biopsies, compared to castPCR.     

Quantitative Analysis of Hepatic Microcirculation in Rabbits After Liver Ischemia-Reperfusion Injury Using Contrast-Enhanced Ultrasound

Previous studies have shown that contrast-enhanced ultrasound (CEUS) can be used quantitatively to analyze microcirculation blood perfusion in hepatocellular carcinoma patients. However, limited data have described the application of CEUS in hepatic microcirculation after liver ischemic-reperfusion injury (IRI). The purpose of this study was to explore the use of CEUS quantitatively to assess liver microcirculation after liver IRI. We randomly sorted 45 New Zealand rabbits into 3 groups (15 in each). Group A was a control group in which the rabbits underwent laparotomy alone. In groups B and C, hepatic blood was blocked for 30 min. Simultaneously, rabbits in group C underwent left lateral lobe resection. After 30 min of ischemia, CEUS was conducted after 0 h, 1 h, 6 h and 24 h of reperfusion in the 3 groups. Time-intensity curves (TICs) for CEUS were constructed and quantitative parameters (maximum intensity [IMAX], rise time [RT], time to peak [TTP] and mean transit time [mTT]) were obtained. In addition, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were computed to estimate liver function before the operation and at 0 h, 1 h, 6 h and 24 h after reperfusion, respectively. Pathologic changes in the liver after reperfusion were also observed. Simultaneously, the correlations between serum transaminase and a variety of quantitative analysis parameters were analyzed. In groups B and C, the IMAX value decreased; whereas RT, TTP, mTT and serum ALT and AST levels increased significantly in comparison with those in group A after 0 h and 1 h of reperfusion. The pathology revealed that erythrocytes were destroyed and microcirculation was disturbed. Then, at 6 h of reperfusion, the IMAX continued to decrease. Additionally, the levels of RT, TTP, mTT and serum ALT and AST increased in comparison with those at 1 h of reperfusion. The pathologic analysis revealed inflammatory cell aggregation and leukocyte infiltration. After 24 h of reperfusion, the IMAX was reduced in comparison with that of the 6-h group. The levels of RT, TTP, mTT and serum ALT and serum AST were increased in comparison with that of the 6-h group. These findings were in accordance with the pathologic analysis. In addition, serum transaminase had a negative correlation with IMAX (p < 0.001) and a positive correlation with RT, TTP and mTT (all p < 0.001). So, in conclusion, the quantitative analysis of CEUS can be used to assess hepatic microcirculation after liver IRI.     

声触诊组织成像量化技术评估正常人群冈上肌腱弹性变化

目的 探讨声触诊组织成像量化技术（VTIQ）评估正常人冈上肌腱弹性变化的价值。方法 对120名健康志愿者行二维超声及VTIQ检查,根据年龄将其分为组1（20~39岁）、组2（40~59岁）及组3（≥ 60岁）。测量冈上肌腱最大厚度及其浅层、深层剪切波速度（SWV）,比较不同性别、年龄组及优势手与非优势手侧冈上肌腱厚度及浅层与深层SWV值的差异。结果 同一性别内优势手侧与非优势手侧、不同性别间非优势手侧及优势手侧冈上肌腱厚度值差异均无统计学意义（P均>0.05）。3组间优势手侧及非优势手侧冈上肌腱厚度值差异均有统计学意义（P均<0.05）;组3优势手侧及非优势手侧冈上肌腱厚度均大于组1及组2（P均<0.05）,组1与组2差异均无统计学意义（P均>0.05）。3组组内优势手侧与非优势手侧冈上肌腱厚度值差异均无统计学意义（P均>0.05）。3组间优势手侧及非优势手侧冈上肌腱浅层、深层SWV值差异均有统计学意义（P均<0.001）;3组组内优势手侧冈上肌腱浅层、深层SWV值与非优势手侧差异均无统计学意义（P均>0.05）,但优势手侧及非优势手侧冈上肌腱深层SWV值大于浅层（P均<0.05）。组3男性冈上肌腱浅层及深层SWV均高于女性（P均<0.05）,其余2组差异均无统计学意义（P均>0.05）。结论 肌腱退行性变时,不仅在形态学上表现为厚度增加,在力学特征上还可表现为肌腱软化。VTIQ可间接评价冈上肌腱弹性变化。     

声触诊组织量化技术无创评价慢性肝病的初步研究

目的探讨声触诊组织量化(VTQ)技术无创评价肝纤维化程度的临床应用价值。方法 62例肝纤维化患者(S1~S3期组)、36例肝硬化患者(S4期组)及50例健康志愿者(对照组),应用VTQ技术定量检测肝实质剪切波速度。结果对照组、S1~S3期组及S4期组患者剪切波速度分别为(1.11±0.19)m/s、(1.62±0.41)m/s及(2.48±0.53)m/s,三者比较差异有统计学意义(P﹤0.05)。S1~S3期组ROC曲线下面积为0.801,S4期组ROC曲线下面积为0.956。剪切波速度以1.30m/s为界值,诊断S1~S3期的敏感性为81%,特异性为79%;以1.81m/s为界值,诊断S4期的敏感性为92%,特异性为85%。结论 VTQ可无创测量肝实质剪切波速度,客观反映肝组织的弹性模量,有望为定量评估肝纤维化和肝硬化提供一种客观、准确的新方法。     

声触诊组织量化技术无创评价肝纤维化的临床研究

目的 研究声触诊组织量化(VTQ)技术评价肝纤维化程度的临床价值.方法 使用VTQ技术对271例肝穿刺活检或肝脏手术前后1个月内的患者进行肝硬度测量.男207例,女64例,平均年龄(54.00±12.67)岁.使用ACUSON S2000超声诊断仪测量受检者肝右叶VTQ值5~lO次.肝纤维化病理分期根据Scheuer方案分为S0～S4期.以病理诊断为金标准,评价VTQ技术预测肝纤维化程度的价值及其最佳界限值.结果 271例患者中病理诊断为SO~S4期的病例数分别为28例、29例、41例、52例和121例,VTQ平均值分别为(1.26±0.31)m/s、(1.28±0.28)m/s、(1.31±0.31)m/s、(1.54±O.44)m/s和(1.93±0.50)m/s.SO期与S1期、S1期与S2期的VTQ值之间差异无统计学意义.无或轻度肝纤维化(即S0、S1和S2期)、重度肝纤维化(即S3期)和肝硬化(即S4期)两两之间VTQ值差异均有统计学意义.S≥S3期时,BOC曲线下面积为0.821(95%CI:0.771～0.871);S=S4期时,ROC曲线下面积为0.828(95%CI:0.779~0.877).以1.43 m/s为界值,诊断S≥S3期的敏感度为76%,特异度为77%;以1.52 m/s为界值,诊断S=S4期的敏感度为80%,特异度为73%.结论 VTQ技术是一种间接无创评价肝纤维化的新方法,具有广阔的应用前景.