Factors affecting the transduction of pluripotent hematopoietic stem cells: long-term expression of a human adenosine deaminase gene in mice

An amphotropic retroviral vector, LgAL(delta Mo + PyF101) containing a human adenosine deaminase (ADA) cDNA was used to optimize procedures for the lasting genetic modification of the hematopoietic system of mice. The highest number of retrovirally infected cells in the hematopoietic tissues of long-term reconstituted mice was observed after transplantation of bone marrow (BM) cells that had been cocultured in the presence of both interleukin-1 alpha (IL-1 alpha) and IL-3. A significantly lower number was detected when IL-1 alpha was omitted from such cocultures. The yield of cells that generate spleen colony-forming cells (CFU-S) in the BM of lethally irradiated recipients (MRA-CFU-S) significantly improved on inclusion of the adherent cell fraction of cocultures in the transplant. Retroviral integration patterns in MRA-CFU-S-derived spleen colonies showed that an MRA-CFU-S can produce many CFU-S during BM regeneration. Expression of hADA was detected in the circulating white blood cells of long-term reconstituted animals, demonstrating that the LgAL(delta Mo + PyF101) vector is capable of directing the sustained expression of hADA, and in approximately 35% of the transduced MRA-CFU-S-derived spleen colonies. These results should facilitate the development of gene therapy protocols for the treatment of severe combined immunodeficiency caused by a lack of functional ADA.     

Noise-Induced Variability of Immuno-PET with Zirconium-89-Labeled Antibodies: an Analysis Based on Count-Reduced Clinical Images

Purpose

Positron emission tomography (PET) with Zirconium-89 (Zr-89)-labeled antibodies can be used for in vivo quantification of antibody uptake. Knowledge about measurement variability is required to ensure correct interpretation. However, no clinical studies have been reported on measurement variability of Zr-89 immuno-PET. As variability due to low signal-to-noise is part of the total measurement variability, the aim of this study was to assess noise-induced variability of Zr-89 -immuno-PET using count-reduced clinical images.

Procedures

Data were acquired from three previously reported clinical studies with [⁸⁹Zr]antiCD20 (74 MBq, n?=?7), [⁸⁹Zr]antiEGFR (37 MBq, n?=?7), and [⁸⁹Zr]antiCD44 (37 MBq, n?=?13), with imaging obtained 1 to 6 days post injection (D0–D6). Volumes of interest (VOIs) were manually delineated for liver, spleen, kidney, lung, brain, and tumor. For blood pool and bone marrow, fixed-size VOIs were used. Original PET list mode data were split and reconstructed, resulting in two count-reduced images at 50 % of the original injected dose (e.g., 37 MBq_74inj).Repeatability coefficients (RC) were obtained from Bland-Altman analysis on standardized uptake values (SUV) derived from VOIs applied to these images.

Results

The RC for the combined manually delineated organs for [⁸⁹Zr] antiCD20 (37 MBq_74inj) increased from D0 to D6 and was less than 6 % at all time points. Blood pool and bone marrow had higher RC, up to 43 % for 37 MBq_74inj at D6. For tumor, the RC was up to 42 % for [⁸⁹Zr]antiCD20 (37 MBq_74inj). For [⁸⁹Zr]antiCD20, (18 MBq_74inj), [⁸⁹Zr]antiEGFR (18 MBq_37inj), and [⁸⁹Zr]antiCD44 (18 MBq_37inj), measurement variability was independent of the investigated antibody.

Conclusions

Based on this study, noise-induced variability results in a RC for Zr-89-immuno-PET (37 MBq) around 6 % for manually delineated organs combined, increasing up to 43 % at D6 for blood pool and bone marrow, assuming similar biodistribution of antibodies. The signal-to-noise ratio leads to tumor RC up to 42 %.

     

Clinical effects of antiplatelet drugs and statins on D‐dimer levels

Background

Acute pulmonary embolism may be ruled out by combining nonhigh clinical probability and a normal D‐dimer level. Both antiplatelet drugs and HMG‐CoA reductase inhibitors (statins) have been associated with effects on thrombus formation, potentially influencing D‐dimer levels in this setting, leading to a higher rate of false‐negative tests. Therefore, we determined whether D‐dimer levels in patients with suspected pulmonary embolism are affected by concomitant use of antiplatelet drugs and/or statins and evaluated whether the effect of antiplatelet drugs or statins might affect diagnostic accuracy.

Materials and methods

We performed a posthoc analysis in the YEARS diagnostic study, comparing age‐ and sex‐adjusted D‐dimer levels among users of antiplatelet drugs, statins and nonusers. We then reclassified patients within the YEARS algorithm by developing a model in which we adjusted D‐dimer cut‐offs for statin use and evaluated diagnostic accuracy.

Results

We included 156 statins users, 147 antiplatelet drugs users and 726 nonusers of either drugs, all with suspected pulmonary embolism . Use of antiplatelet drugs did not have a significant effect, whereas statin use was associated with 15% decrease in D‐dimer levels (95% CI, ?28% to ?0.6%). An algorithm with lower D‐dimer thresholds in statin users yielded lower specificity (0.42 compared to 0.33) with no difference in false‐negative tests.

Conclusions

We conclude that use of statins but not of antiplatelet agents is associated with a modest decrease in D‐dimer levels. Adjusting D‐dimer cut‐offs for statin use did, however, not result in a safer diagnostic strategy in our cohort.

     

孟根乌森乌日乐对小鼠的急性毒性研究

目的：了解孟根乌森乌日乐的急性毒性作用剂量及给药后的急性毒性反应和死亡分布情况,确定孟根乌森乌日乐的半数致死量（ LD50）。方法用孔氏综合法（改进寇氏法）分为14．30,9．28,6．04,3．92,2．55,1．66 g? kg－16个剂量组,以0．4 mL／10 g的量灌胃给药1次。实验后观察14 d,记录体重变化及不良反应情况。结果孟根乌森乌日乐小鼠半数致死量为5．1597 g? kg－1（95％CI：3．6652～7．2637 g? kg－1）。14 d内未出现明显不良反应症状且体重有增长趋势。结论孟根乌森乌日乐的急性毒性实验的半数致死量为临床用药量的100倍,提示单次口服较为安全。     

五种布鲁氏菌核酸检测试剂盒检测性能的评价北大核心CSCD

目的比较5种布鲁氏菌核酸实时荧光PCR检测试剂盒的一致性和检出能力,为临床实验室选择检测方法和布鲁氏菌的诊断提供参考依据。方法选用经病原学检测确定为布鲁氏菌阳性的血液样本38份,健康人的血液样本24份,潘氏变形杆菌、溶藻弧菌、河弧菌、铜绿假单胞菌、肺炎克雷伯菌DNA各1份,使用5种试剂盒(编号A-E)分别进行核酸检测,比较5种试剂盒临床样本检测的一致性;选择1份阳性样本核酸用无RNA酶水梯度稀释得到5个浓度(浓度1:4453.13 fg/μL,浓度2:1113.28 fg/μL,浓度3:278.32 fg/μL,浓度4:69.58 fg/μL,浓度5:17.40 fg/μL),每个浓度使用5种试剂盒(编号A-E)分别进行3次检测,比较5种试剂盒的阳性检出率及批内重复性。结果5种试剂盒检测67份DNA样品的符合率稍有不同,试剂盒ABDE的符合率均为100%,试剂盒C的符合率为98.51%。批内重复性显示5种试剂盒在浓度1、浓度2、浓度3水平重复检测DNA的Ct值变异系数均<5%;在浓度1与浓度4梯度区间,试剂盒的阳性检出能力比较显示试剂盒A、B、D较高,为11/12,试剂盒C和E较低,为8/12。结论5种试剂盒的真实性和可靠性较好,灵敏度和符合率稍有差别,特异度均为100%;重复性较好,检测性能良好。部分试剂盒对弱阳性样本的检出能力不强,该类样本可使用多种试剂盒复核,以保障结果的准确性。     

Direct videoscopic approach to the descending thoracic aorta for aortic arch endograft delivery: evaluation in a porcine model.

PURPOSE: To examine the feasibility of a direct videoscopic approach to the descending thoracic aorta for endograft delivery to the aortic arch. METHODS: A double purse-string suture was placed on the aorta of 3 pigs via a thoracoscopic approach. Subsequently, the aorta was cannulated in the center of the purse-string. A 22-F delivery catheter was advanced under fluoroscopic control over a guidewire via a trocar into the proximal aorta. After deployment of a tubular endograft, the catheter was withdrawn from the aorta while simultaneously tightening the purse-string suture, without aortic cross clamping. The outcome was evaluated by post implant angiography and autopsy results. RESULTS: The procedure was successfully completed in all animals, with a mean total procedure time of 126 minutes (range 118-137). Mean endograft implantation time from needle puncture to catheter extraction was 27 minutes (range 21-37). Hemostasis was obtained in all animals after withdrawal of the delivery catheter and tightening the purse-string suture. The mean blood loss was 143 mL (range 80-220). Autopsy proved all purse-string sutures to be adequately placed and all endografts deployed in the correct position. CONCLUSION: A direct videoscopic approach to the descending thoracic aorta proved a feasible technique for endograft delivery to the aortic arch in a porcine model.     

Frequency of major hemorrhage in patients treated with unfractionated intravenous heparin for deep venous thrombosis or pulmonary embolism: a study in routine clinical practice

BACKGROUND: The rate of major hemorrhage during the initial treatment with unfractionated heparin (UFH) in patients with deep venous thrombosis (DVT) and pulmonary embolism (PE) in routine clinical practice is understudied. In recent clinical trials an overall average of 3.8% was reported. However, the incidence of this complication in routine patient care might be higher owing to less strict patient selection and lack of standardization in the administration of heparin. We have determined major bleeding rates during heparin treatment for DVT or PE in routine practice and compared these rates with data from clinical trials. METHODS: Data on the occurrence of major hemorrhage were retrieved according to strict criteria from the records of patients who had received continuous intravenous UFH therapy to treat objectively documented DVT or PE in 3 hospitals. RESULTS: After exclusion of 29 patients because of lack of objective diagnosis of DVT or PE and 25 patients because of initial treatment with low-molecular-weight heparin, 424 consecutive patients were available for detailed analysis. Among them, 17 patients (4.0%; 95% confidence interval, 2.1%-5.9%) experienced major hemorrhage during UFH treatment, which in most patients occurred at the end of planned heparin therapy; one of the hemorrhages was fatal. Six patients (1.4%; 95% confidence interval, 0.3%-2.5%) developed clinically suspected recurrent venous thromboembolism (fatal in 1 case) during UFH treatment or within 7 days' cessation. CONCLUSIONS: Administration of continuous intravenous UFH in patients with DVT or PE in routine clinical practice leads to a major bleeding rate of 4.0%. This rate is comparable to the rate of major bleeding in patients who received UFH in clinical trials. Our findings are relevant to the discussion of major bleeding rates in patients with DVT and PE treated in daily clinical practice with subcutaneous low-molecular-weight heparin and newer antithrombotic drugs.     

Epstein-Barr virus (EBV)-associated lymphoproliferations in severe combined immunodeficient mice transplanted with Hodgkin's disease lymph nodes: implications of EBV-positive bystander B lymphocytes rather than EBV-infected Reed-Sternberg cells

To establish an in vivo model for the study of Hodgkin's disease and Reed-Sternberg (RS) cells, 25 lymph node tissue samples involved by Hodgkin's disease were grafted into severe combined immunodeficiency (SCID) mice. Ten Epstein-Barr virus (EBV)-associated tumors were obtained in SCID mice. EBV-positive tumors growing in SCID mice were correlated with the presence of EBV-positive nonneoplastic B cells in patient tumors (90% v 26.6%; P<.01) and was independent of the EBV status of RS cells. Our results suggested that EBV-positive tumors growing in SCID mice originated from normal EBV-positive small lymphocytes (bystander B lymphocytes). We also compared the characteristics of these tumors with those obtained after transplantation of 15 non-Hodgkin's lymphoma and four reactive lymph nodes. The latent period to observe a growing tumor in SCID mice was similar between the two groups (12.86 +/- 5.59 weeks for Hodgkin's disease v 13.6 +/- 5.36 weeks for non-Hodgkin's lymphoma and reactive lymph nodes). The relatively high number of EBV-positive small lymphocytes detected in Hodgkin's disease and T-cell lymphoma compared with B-cell lymphoma may account for the greater percentage of EBV- positive tumors obtained in SCID mice. Our results show that SCID mice do not provide the growth conditions that are required for in vivo growth of RS cells. We noted in some SCID tumors, the presence of binucleated and/or multinucleated giant cells resembling RS cells. However, the presence of such cells was not restricted to mice grafted with lymph nodes involved by Hodgkin's disease. We postulate that in previous reports, cells resembling RS cells were just binucleated EBV- positive lymphoma blastoid cells rather than actual RS cells.