植入型心律转复除颤器而非乙胺碘呋酮可降低充血性心力衰竭患者死亡风险

问题：与安慰剂组相比，充血性心力衰竭（CHF）患者服用乙胺碘呋酮或使用植入型心律转复除颤器（ICD），能否降低全因死亡率？     

丹酚酸A对小鼠脑缺血再灌注致学习记忆功能障碍的改善作用及作用机制

本实验采用脑缺血再灌注损伤造成小鼠学习记忆功能障碍模型。通过跳台和避暗实验法研究了丹酚酸对记忆获得功能障碍的改善作用。结果表明丹酚酸Ａ３，１０ｍｇ·ｋｇ－１ｉｖ可以减轻脑缺血再灌注导致的小鼠学习记忆功能障碍状态。并使小鼠脑缺血再灌注后脑组织中脂质过氧化产物ＭＤＡ含量明显降低。体外实验表明丹酚酸Ａ１０－８～１０－７’ｍｏｌ·Ｌ－１可以抑制大鼠脑组织匀浆脂质过氧化反应和羟自由基（·ＯＨ）的生成，表现出较强的抗氧化作用，提示丹酚酸改善脑缺血再灌注损伤的主要机制可能与其抗氧化作用有关。     

Retention of glycoprotein Ib/IX receptors on external surfaces of thrombin-activated platelets in suspension

The present study has evaluated the hypothesis stating that glycoprotein (GP) Ib/IX, the receptor for von Willebrand factor (vWF), is downregulated and cleared from exposed surfaces to channels of the open canalicular system (OCS) on platelets activated by thrombin in suspension. Cryosections of resting and thrombin-activated platelets fixed at intervals of 1 to 30 minutes after stimulation by thrombin and stained with antiglycocalicin antibody and protein A gold showed no decrease in the density of GPIb/IX receptors on the platelet surface or increase on linings of the OCS at any interval after stimulation by thrombin. Thin sections of platelets exposed to thrombin in suspension followed by settling onto a plastic chamber for intervals of 1 to 30 minutes revealed retention of GPIb/IX receptors on exposed surfaces detected by vWF, anti-vWF, and protein A gold throughout the 30-minute period of study. Results of this investigation indicate that GPIb/IX receptors remain on the surface of platelets activated by thrombin in suspension, are not cleared to the OCS, and retain the ability to bind vWF for at least 30 minutes.     

Immunoglobulin and T cell receptor gene configuration in acute lymphoblastic leukemia of infancy

We examined immunoglobulin (Ig) heavy chain, K light chain, and T cell receptor (TCR) gamma and beta gene configuration in the leukemic cells from a series of infants aged less than 1 year with acute lymphoblastic leukemia (ALL). Each of these 11 cases demonstrated leukemic cell surface antigens that have been correlated with a B cell precursor phenotype. Of the 11, lymphoblasts of 4 retained the germline configuration of both Ig and TCR loci, whereas 7 had rearranged the Ig heavy chain gene. Two of these seven showed light chain gene rearrangement. TCB beta chain rearrangement had occurred in only one of the 11 patients' tumors. No TCR gamma chain rearrangements were identified. These results are in contrast to earlier studies of B cell precursor ALL in children in which Ig heavy chain gene rearrangements were evident in every case and approximately 40% showed Ig light chain rearrangement as well. In addition, 45% of cases of B cell precursor ALL of children had rearranged their gamma TCR genes, and 20% had rearranged beta. These data suggest that ALL in infancy represents an earlier stage of B cell development than is found in B cell precursor ALL of children. ALL in the infant age group has been associated with the worst prognosis of all patients with ALL. This study suggests that the disease in infants differs not only clinically, but also at the molecular genetic level, from the disease in children.     

Temperature-Controlled Irrigated Tip Radiofrequency Catheter Ablation:

Temperature-Controlled Irrigated Tip Ablation. Introduction : In patients with ventricular tachycardias due to structural heart disease, catheter ablation cures < 60% partly due to the limited lesion size after conventional radiofrequency ablation. Irrigated tip radiofrequency ablation using power control and high infusion rates enlarges lesion size, hut has increased risk of cratering. The present study explores irrigated tip catheter ablation in temperature- controlled mode, target temperature 60°C, using an irrigation rate of 1 mL/min, comparing this to conventional catheter technique, target temperature 80°C.
Methods and Results : In vivo anesthetized pigs were ablated in the left ventricle. In vitro strips of porcine left ventricular myocardium were ablated in a tissue bath. Lesion volume was significantly larger after irrigated tip ablation both in vivo (544 ± 218 vs 325 ± 194 mm³, P < 0.01) and in vitro (286 ± 113 vs 179 ± 23 mm³, P < 0.01). The incidence of cratering was not significantly different between the two groups. In vivo, no coagulum formation on part of the catheter tip was seen after irrigated tip ablation as opposed to 52% of the applications with conventional ablation (P < 0.05).
Conclusion : We conclude that temperature-controlled radiofrequency ablation with irrigated tip catheters using low target temperature and low infusion rate enlarges lesion size without increasing the incidence of cratering and reduces coagulum formation of the tip.     

Post‐Transplantation Immunoadsorption Can Be Withheld in ABO‐Incompatible Kidney Transplant Recipients

After ABO‐incompatible kidney transplantation, postoperative plasma exchange (PE) or immunoadsorption (IA) is performed per protocol or depending on postoperative A/B‐titers to prevent acute rejection. However, the need for postoperative PE or IA is not known. Since 2006, 30 consecutive patients received three standard postoperative IAs. Starting from 2009, the last 46 patients received only preoperative IA. Preoperative desensitization consisted of rituximab, tacrolimus, mycophenolate mofetil, prednisone and intravenous immunoglobulins. Antigen‐specific IA was performed pre‐operatively with the Glycosorb device. Biopsy‐proven acute rejections either antibody‐mediated (AMR) or mixed cellular and antibody‐mediated (MAR) within 3 months were recorded. The postoperative titer in patients with postoperative IA did not exceed 1:16 (IgG 1:4 [<2–16] median and range). The postoperative IgG titer was not significantly different after abandoning postoperative IA, although three patients had titers of 1:32 and one patient even 1:128. Rejections tended to be more frequent in the group with postoperative IA: 6 AMR and 3 MAR were recorded in 30 patients, vs. 4 AMR and 1 MAR in the 46 patients without postoperative IA (30 vs. 11%, P = 0.067). Baseline characteristics differed however: in the group with postoperative IA the vast majority had blood group O (87 vs. 52%, P = 0.003). Also, the IgG titer on the day of transplantation was higher (1:4 [<2–16] vs. 1:2 [<2–32], P = 0.007). All 14 patients with AMR and MAR rejections had postoperative IgG titers ≤1:16. Postoperative removal of A/B‐antibodies can be safely removed from the ABOi transplantation protocol using strict preoperative criteria for antibody lowering.     

Head and neck MR imaging in the pediatric patient

Magnetic resonance (MR) imaging studies of the head and neck (excluding the brain) were obtained in 49 children believed to have lesions of the head and neck. Seven children had normal images; in the remaining 42, lesions were divided into four categories: midline lesions, lesions of symmetric paired structures, facial lesions, and nasopharyngeal and oropharyngeal lesions. All entities were well delineated by MR imaging. The imaging planes and sequences chosen depended on the suspected abnormality. Midline lesions were best imaged in the sagittal plane, lesions of paired structures and the face in the axial or coronal planes, and nasopharyngeal and oropharyngeal lesions in the axial or sagittal planes. Intracranial extension of head and neck neoplasms was best evaluated in the coronal plane. Surface coils provided better resolution and were thus more useful in evaluating small superficial lesions; head or body coils were more useful in defining the extent of large lesions. T2-weighted images provided better differentiation between normal and tumor tissue in patients with head and neck neoplasms.