添加谷氨酰胺的全胃肠外营养对造血干细胞移植术后常见并发症的防治作用

目的:严重的黏膜损伤是诱发造血干细胞移植后出现并发症的一常见原因,已有证据显示谷氨酰胺能降低接受化疗患儿黏膜炎的发生率。观察谷氨酰胺对异基因外周造血干细胞移植患者并发症及恢复的影响。方法:选择于2002-03/2006-11在河南省血液病研究所接受同胞异基因外周造血干细胞移植的48例血液系统肿瘤患者。所有患者及其家属对治疗和实验均知情同意,并经医院伦理委员会批准。所有患者移植前均处于完全缓解状态,营养中等或良好,心、肝、肾功能正常,将48例患者随机分为标准化全胃肠外营养液组(标准组,n=13)和加用谷氨酰胺的全胃肠外营养液组(谷氨酰胺组,n=35)。待患者中性粒细胞升至1.0×109L-1,且无任何感染指征,进行异基因外周造血干细胞移植。造血干细胞输注后第1天开始给予全胃肠外营养与胃肠外营养联合谷氨酰胺双肽,至中性粒细胞≥1.0×109L-1,且无消化道症状时停用。观察两组患者中性粒细胞恢复时间、出层流室时间以及关于感染、急性移植物抗宿主病等情况有无差异。结果:48例患者均进入结果分析。两组患者营养物质的摄入基本相同,谷氨酰胺组有6例发生黏膜炎,标准组有11例,差异显著(P<0.05);谷氨酰胺组有1例发生严重腹泻,标准组有5例,差异显著(P<0.05);谷氨酰胺组有3例发生临床感染,标准组有7例,差异显著(P<0.05);标准组中性粒细胞≥0.5×109L-1的持续时间短于谷氨酰胺组(P>0.05);谷氨酰胺组抗生素治疗时间及无菌病房居住时间较标准组短(P<0.05);两组急性移植物抗宿主病发生率差异无统计学意义(P>0.05)。结论:添加谷氨酰胺的全胃肠外营养可改善异基因造血干细胞移植患者的营养状态,减少感染及肠损害,减少急性移植物抗宿主病的发生,有利于异基因移植患者恢复。     

Defective T suppressor-inducer cell function in human immune deficiency virus-seropositive hemophilia patients

In human immune deficiency virus (HIV)-seropositive hemophilia patients, a low number of CD4 + lymphocytes is found, as well as a low CD4+/CD8+ ratio. In previous studies, it has been shown that antigen- specific T-helper cell (CD4+) function was present and no excessive antigen-specific T-suppressor cell (CD8+) function could be demonstrated. In this report, we studied another activity of CD4+ cells, namely the capacity to induce T-suppressor cell activity. The results clearly show a selective dysfunction of CD4+ suppressor-inducer (Tsi) cell function. Since these HIV-seropositive hemophilia patients showed the presence of activated B cells in the peripheral circulation refractory to antigen-specific T-helper cell signals and secreting specific antibodies spontaneously, we raised the hypothesis that the activated B cells in the patients activate the Tsi cells in vivo. This constant activation leads to a functional exhaustion of the Tsi cell pool.     

Recovery of T cell subsets after autologous bone marrow transplantation is mainly due to proliferation of mature T cells in the graft

In 22 patients with malignancies, treated with high-dose chemoradiotherapy and autologous bone marrow transplantation (BMT), peripheral blood T cell subsets and functions were studied. In ten cytomegalovirus (CMV)-negative patients, CD4+ and CD8+ T cells (representing T cells of the helper/inducer phenotype and T cells of the suppressor/cytotoxic phenotype, respectively), recovered slowly and simultaneously. In 12 CMV-positive patients, however, CD8+ T cells recovered more rapidly than CD4+ T cells and rose to increased counts. No T cells with an immature phenotype (CD1+, OKT6+) were observed. Lymphocyte stimulation by herpes simplex virus infected fibroblasts (and by CMV-infected fibroblasts in CMV-positive patients) in contrast remained high and even increased after BMT in both groups. These data indicate that T cell recovery after autologous BMT is mainly due to proliferation of mature T cells present in the BM graft and not to generation of new T cells from T cell precursors.     

Thrombolytic therapy is indicated for patients over 75 years of age with st-elevation acute myocardial infarction: antagonist viewpoint

From the available data, one cannot conclude whether thrombolytic therapy is beneficial or detrimental in patients older than age 75 years with acute myocardial infarction. Data favor the use of primary percutaneous transluminal coronary angioplasty rather than thrombolysis in eligible patients older than age 75 years with acute myocardial infarction to reduce mortality, recurrent myocardial infarction, stroke, and intracranial hemorrhage. High-risk elderly patients with acute myocardial infarction, such as those with a large anterior myocardial infarction complicated by heart failure and hypotension, those with persistent ischemic pain or marked ST-segment changes, those with hemodynamic instability, and those at high risk for stroke or bleeding complications, should, especially, be treated with percutaneous transluminal coronary angioplasty.     

Prevalence of left ventricular diastolic dysfunction in obese persons with and without diabetes mellitus

Forty obese diabetic patients (mean age 48 +/- 9 years) and 93 obese nondiabetic patients (mean age 43 +/- 9 years) underwent Doppler and tissue Doppler echocardiographic evaluation of left ventricular diastolic function before gastric bypass surgery. Moderate or severe left ventricular diastolic dysfunction was present in 24 of 40 obese diabetics (60%) and in 21 of 93 obese nondiabetics (23%) (p <0.001).     

Clusterin promotes amyloid plaque formation and is critical for neuritic toxicity in a mouse model of Alzheimer's disease

Studies have shown that clusterin (also called apolipoprotein J) can influence the structure and toxicity of amyloid-beta (Abeta) in vitro. To determine whether endogenous clusterin plays a role in influencing Abeta deposition, structure, and toxicity in vivo, we bred PDAPP mice, a transgenic mouse model of Alzheimer's disease, to clusterin(-/-) mice. By 12 months of age, PDAPP, clusterin(-/-) mice had similar levels of brain Abeta deposition as did PDAPP, clusterin(+/+) mice. Although Abeta deposition was similar, PDAPP, clusterin(-/-) mice had significantly fewer fibrillar Abeta (amyloid) deposits than PDAPP mice expressing clusterin. In the absence of clusterin, neuritic dystrophy associated with the deposited amyloid was markedly reduced, resulting in a dissociation between fibrillar amyloid formation and neuritic dystrophy. These findings demonstrate that clusterin markedly influences Abeta structure and neuritic toxicity in vivo and is likely to play an important role in Alzheimer's disease pathogenesis.     

Cross-platform validation of neurotransmitter release impairments in schizophrenia patient-derived NRXN1-mutant neurons

Heterozygous NRXN1 deletions constitute the most prevalent currently known single-gene mutation associated with schizophrenia, and additionally predispose to multiple other neurodevelopmental disorders. Engineered heterozygous NRXN1 deletions impaired neurotransmitter release in human neurons, suggesting a synaptic pathophysiological mechanism. Utilizing this observation for drug discovery, however, requires confidence in its robustness and validity. Here, we describe a multicenter effort to test the generality of this pivotal observation, using independent analyses at two laboratories of patient-derived and newly engineered human neurons with heterozygous NRXN1 deletions. Using neurons transdifferentiated from induced pluripotent stem cells that were derived from schizophrenia patients carrying heterozygous NRXN1 deletions, we observed the same synaptic impairment as in engineered NRXN1-deficient neurons. This impairment manifested as a large decrease in spontaneous synaptic events, in evoked synaptic responses, and in synaptic paired-pulse depression. Nrxn1-deficient mouse neurons generated from embryonic stem cells by the same method as human neurons did not exhibit impaired neurotransmitter release, suggesting a human-specific phenotype. Human NRXN1 deletions produced a reproducible increase in the levels of CASK, an intracellular NRXN1-binding protein, and were associated with characteristic gene-expression changes. Thus, heterozygous NRXN1 deletions robustly impair synaptic function in human neurons regardless of genetic background, enabling future drug discovery efforts.

Schizophrenia is a devastating brain disorder that affects millions of people worldwide and exhibits a strong genetic component. In a key discovery, deletions or duplications of larger stretches of chromosomal DNA that lead to copy number variations (CNVs) were identified two decades ago (1, 2). CNVs occur unexpectedly frequently, are often de novo, and usually affect multiple genes depending on the size of the deleted or duplicated stretch of DNA. Strikingly, the biggest genetic risk for schizophrenia was identified in three unrelated CNVs: a duplication of region 16p11.2 and deletions of 22q11.2 and of 2p16.3 (3–9). Of these CNVs, 16p11.2 and 22q11.2 CNVs affect more than 20 genes, whereas 2p16.3 CNVs impact only one or more exons of a single gene, NRXN1, which encodes the presynaptic cell-adhesion molecule neurexin-1 (4, 7, 9–12). NRXN1 CNVs confer an approximately 10-fold increase in risk of schizophrenia, and additionally strongly predispose to other neuropsychiatric disorders, especially autism and Tourette syndrome (13, 14). Moreover, genome-wide association studies using DNA microarrays identified common changes in many other genes that predispose to schizophrenia with smaller effect sizes (15–21). Viewed together, these studies indicate that variations in a large number of genes are linked to schizophrenia. Among these genetic variations, heterozygous exonic CNVs of NRXN1 are rare events, but nevertheless constitute the most prevalent high-risk single-gene association at present.Neurexins are central regulators of neural circuits that control diverse synapse properties, such as the presynaptic release probability, the postsynaptic receptor composition, and synaptic plasticity (22–28). To test whether heterozygous NRXN1 mutations might cause functional impairments in human neurons, we previously generated conditionally mutant human embryonic stem (ES) cells that enabled induction of heterozygous NRXN1 deletions using Cre-recombinase (29). We then analyzed the effects of the deletion on the properties of neurons induced from the conditionally mutant ES cells using forced expression of Ngn2, a method that generates a relatively homogeneous population of excitatory neurons that are also referred to as induced neuronal (iN) cells (30). These experiments thus examined isogenic neurons without or with a heterozygous NRXN1 loss-of-function mutation that mimicked the schizophrenia-associated 2p16.3 CNVs, enabling precise control of the genetic background. The heterozygous NRXN1 deletion produced a robust but discrete impairment in neurotransmitter release without major changes in neuronal development or morphology (29). These results were exciting because they suggested that a discrete impairment in neurotransmitter release could underlie the predisposition to schizophrenia conferred by the 2p16.3 CNV, but these experiments did not reveal whether the NRXN1 mutation induces the same synaptic impairment in schizophrenia patients (31).The present project was initiated to achieve multiple overlapping aims emerging from the initial study on human NRXN1 mutations (29). First, we aimed to validate or refute the results obtained with neurons generated from engineered conditionally mutant ES cells with neurons generated from patient-derived induced pluripotent stem (iPS) cells containing NRXN1 mutations (Fig. 1A). This goal was pursued in order to gain confidence in the disease-relevance of the observed phenotypes. Second, we wanted to test whether the observed phenotype is independent of the laboratory of analysis (i.e., whether it is sufficiently robust to be replicated at multiple sites) (Fig. 1A). This goal was motivated by the observation of limited reproducibility in some studies of the phenotypes of patient-derived neurons. We hypothesized that this lack of reproducibility is due to variations in experimental conditions rather than an experimental failure, and designed our studies to demonstrate robustness of the findings through replication. Third, we aimed to generate reagents that could be broadly used by the scientific community for investigating the cellular basis of neuropsychiatric disorders (32). This goal was prompted by the challenges posed by the finding that many different genes appear to be linked to schizophrenia. Fourth, we aimed to definitively establish or exclude the possibility that human neurons are uniquely sensitive to a heterozygous loss of NRXN1 compared with mouse neurons (Fig. 1B). The goal here was to test whether at least as regards to NRXN1, mouse and human neurons exhibit fundamental differences. Fifth and finally, we hoped to gain further insights into the mechanisms by which NRXN1 mutations predispose to schizophrenia, an obviously needed objective given our lack of understanding of this severe disorder. As described in detail below, our data provide advances toward meeting these goals, establishing unequivocally that heterozygous NRXN1 deletions in human but not in mouse neurons cause a robust impairment in neurotransmitter release that is replicable in multiple laboratories.Open in a separate windowFig. 1.Overall study design illustrating the experimental approach to analyze human heterozygous NRXN1 loss-of-function mutations, to achieve cross-laboratory and cross-platform validation of observed phenotypes, and to perform cross-paradigm evaluations of these phenotypes in human and mouse neurons. (A) Experimental strategy for analyzing the functional effects of heterozygous NRXN1 loss-of-function mutations in human patient-derived neurons and for validating the observed phenotypes in a cross-laboratory and cross-platform comparison. PBMCs from schizophrenia patients with NRXN1 deletions and from control individuals were reprogrammed into iPS cells by Rutgers University (RUCDR Infinite Biologics). iPS cells that passed QC were shipped to Stanford and to FCDI for expansion, banking, and transdifferentiation into induced neurons. The indicated subsequent analyses were carried out at Stanford University and at Rutgers University. FCDI manufactured industry-scale human induced neurons that were shipped to Rutgers for analysis, whereas Stanford generated induced neurons at an academic single-laboratory scale for analysis. (B) Experimental strategy to evaluate the conservation of NRXN1-deletion phenotypes observed in human neurons in mouse neurons (cross-paradigm evaluation). Human and mouse stem cells that carried heterozygous engineered conditional NRXN1/Nrxn1 deletions were transdifferentiated into neurons by Ngn2 expression and analyzed using similar approaches to ensure comparability. In this approach, isogenic human and mouse neurons without or with NRXN1/Nrxn1 deletions were compared to test whether side-by-side analysis of human and mouse neurons prepared by indistinguishable approaches yields similar phenotypes.     

Association Between Maximal Activated Clotting Time and Major Bleeding Complications During Transradial and Transfemoral Percutaneous Coronary Intervention

Objectives

This study sought to determine whether higher maximal activated clotting time (ACT) during transradial (TR) percutaneous coronary intervention (PCI) is associated with greater bleeding risk.

CRT plus ICD in congestive heart failure. Use of cardiac resynchronization therapy and an implantable cardioverter-defibrillator in heart failure patients with abnormal left ventricular dysfunction

Cardiac resynchronization therapy (CRT) significantly improves functional status, exercise duration, left ventricular (LV) ejection fraction, death from progressive congestive heart failure (CHF), and hospitalization for CHF in patients with moderate-to-severe CHF, an abnormal LV ejection fraction, and a QRS duration on the electrocardiogram of 120 msec or more. In these patients, CRT reduces all-cause mortality, though not significantly. However, CRT plus. an implantable cardioverter-defibrillator (ICD) significantly reduces all-cause mortality. Compared with placebo, ICD therapy significantly reduced all-cause mortality by 33% in patients with class II or III CHF, an abnormal LV ejection fraction, and a QRS duration on the electrocardiogram of 120 msec or more.