Nitric Oxide Modulates Metabolic Processes in the Tumor Immune Microenvironment

The metabolic requirements and functions of cancer and normal tissues are vastly different. Due to the rapid growth of cancer cells in the tumor microenvironment, distorted vasculature is commonly observed, which creates harsh environments that require rigorous and constantly evolving cellular adaption. A common hallmark of aggressive and therapeutically resistant tumors is hypoxia and hypoxia-induced stress markers. However, recent studies have identified alterations in a wide spectrum of metabolic pathways that dictate tumor behavior and response to therapy. Accordingly, it is becoming clear that metabolic processes are not uniform throughout the tumor microenvironment. Metabolic processes differ and are cell type specific where various factors promote metabolic heterogeneity within the tumor microenvironment. Furthermore, within the tumor, these metabolically distinct cell types can organize to form cellular neighborhoods that serve to establish a pro-tumor milieu in which distant and spatially distinct cellular neighborhoods can communicate via signaling metabolites from stroma, immune and tumor cells. In this review, we will discuss how biochemical interactions of various metabolic pathways influence cancer and immune microenvironments, as well as associated mechanisms that lead to good or poor clinical outcomes.     

Mitochondrial Glycerol-3-Phosphate Acyltransferase-Dependent Phospholipid Synthesis Modulates Phospholipid Mass and IL-2 Production in Jurkat T Cells

Changes in glycerophospholipid metabolism with age and disease can have a profound effect on immune cell activation and effector function. We previously demonstrated that glycerol‐3‐phosphate acyltransferase‐1, the first and rate limiting step in de novo glycerophospholipid synthesis, plays a role in modulating murine T cell function. The resultant phenotype is characterized by decreased IL‐2 production, increased propensity toward apoptosis, and altered membrane glycerophospholipid mass similar to that of an aged T cell. Since T cells in previous experiments were harvested from GPAT‐1^?/? mice, questions remained as to what extent the macro environment of the model influenced the observed cellular phenotype. Therefore, we generated and phenotypically characterized a mitochondrial glycerol‐3‐phosphate acyltransferase (GPAM) deficient Jurkat T cell. Furthermore, this line was used to probe possible mechanisms by which GPAT‐1/GPAM regulates T cell function. We report here that many of the key dysfunctional characteristics of murine GPAT‐1^?/? T cells are recapitulated in the GPAMKD Jurkat T cell. We found striking decreased IL‐2 production along with altered phospholipid mass and increased incidence of apoptosis. Since PtdOH is an indirect downstream product of GPAM, we attempted to rescue IL‐2 production with PtdOH supplementation; however, this addition did not return IL‐2 production to normal levels. Interestingly, we did find significantly decreased Zap‐70 phosphorylation following stimulation, suggesting that GPAM deficiency may alter membrane based stimulatory signaling. These data show for the first time that GPAM deficiency results in an inherent defect in Jurkat T cell function and glycerophospholipid composition and that this defect cannot be rescued by addition of exogenous PtdOH.     

TSP的DNA算法

由于Adleman和Lipton的开创性工作,最近DNA计算引起了人们的极大兴趣,他们提出的分子算法解决了图形的表示方法,但是没有给出如何处理图中节点的弧线的信息。本文的目的是通过提出在图中城市间的距离用简单的弧线代表,延伸了Adleman和Lipton提出的基本的分子算法。并提出只有当算法步骤由当前的需要人工干预被可执行的可在试管中操作的DNA链代替,解决计算难题的真正可行DNA计算可以实现。该算法的创新之处在于表示城市和路径的DNA链长度的设计,能使我们在合理的范围内寻找旅行商问题的解,较大地简化了问题的复杂度。     

l-Carnitine and Long-Chain Acylcarnitines are Positively Correlated with Ambulatory Blood Pressure in Humans: The SABPA Study

The prevalence of hypertension in sub-Saharan Africa is increasing rapidly, and treatment remains challenging. Although the use of l-carnitine in treatment has received much attention, studies reporting on physiological l-carnitine levels in hypertensives are limited. Our aim was to determine physiological levels of l-carnitine and acylcarnitines in African and Caucasian men, and to investigate associations between ambulatory blood pressure (BP) and carnitine levels. Participants included 101 African and 101 Caucasian teachers. Ambulatory BP measurements were conducted, and l-carnitine and acylcarnitine levels determined. African men showed significantly higher systolic BP (p < 0.001), diastolic BP (p < 0.001) and l-carnitine levels (p = 0.01). In both ethnic groups, partial regression analyses revealed a positive association between BP and l-carnitine, although in Caucasians it was with systolic (r = 0.20, p = 0.045), and in Africans with diastolic BP (r = 0.23, p = 0.023). After adjusting for confounders, an independent positive association between systolic (R ² = 0.37, β = 0.12, p = 0.041) and diastolic BP (R ² = 0.39, β = 0.14, p = 0.018) and l-carnitine and long-chain acylcarnitines (R ² = 0.38, β = 0.17, p = 0.005 and R ² = 0.39, β = 0.15, p = 0.011) were found, independent of ethnicity. Physiological l-carnitine levels were not only higher in Africans than in Caucasians but also above the expected reference range. Despite promising results on l-carnitine (and its short-chain derivatives) in hypertension treatment regimens, our findings paradoxically show that elevated BP is significantly associated with higher physiological l-carnitine and long-chain acylcarnitine levels.     

220kV变电站金属材料腐蚀原因分析

对宁晋220 kV变电站周围的大气环境和渡河水质情况进行分析,介绍变电站常用各种材质在大气环境下的腐蚀机理.由汶河水质特性分析得出宁晋变电站腐蚀成因.     

生化防护服防护性能分析与探讨

介绍了生化防护服的防护原理,生化防护服必须具备的防护性能以及应具备的良好的服用性能;指出了今后生化防护服的研发方向。     

猪肉蛋白和牛肉蛋白对生长期大鼠生理功能的影响

目的：研究长期摄入猪肉蛋白和牛肉蛋白对生长期大鼠生长性能、生理功能的影响。方法：30 只雄性Sprague-Dawley（SD）大鼠随机分为3 组,分别饲喂添加酪蛋白、猪肉蛋白和牛肉蛋白作为蛋白质来源的半合成饲料,实验期为90 d,观察其对大鼠生理指标的影响。结果：相对于酪蛋白组,猪肉蛋白组和牛肉蛋白组大鼠的生长速率变缓,脂肪沉积减少（P＜0.05）,但有较高的谷丙转氨酶和谷草转氨酶活力（P＜0.05）。猪肉蛋白和牛肉蛋白可降低大鼠血清中的甘油三酯浓度（P＜0.05）,牛肉蛋白还可降低总胆固醇和血糖浓度（P＜0.05）,猪肉蛋白则对其没有显著影响（P＞0.05）。猪肉蛋白组和牛肉蛋白组的大鼠有较低的血清游离氨基酸水平（P＜0.05）。结论：长期摄入猪肉蛋白和牛肉蛋白会对大鼠机体代谢产生不同的影响,这与蛋白质来源及其消化和吸收有关。猪肉蛋白和牛肉蛋白有控制大鼠体质量增长的作用,牛肉蛋白还可以降低大鼠肝脏代谢水平,具有降血脂的功能。     

二甲基甘氨酸钠对肉鸡生长发育及抗氧化能力的影响

研究食品抗氧化剂二甲基甘氨酸钠（N,N-dimethylglycine sodium salt,Na-DMG）对肉鸡器官指数、血液生理生化指标及抗氧化功能的影响。选用1 日龄爱拔益加（Arbor Acres,AA）肉鸡720 只,随机分成6 组,每组6 个重复,对照组饲喂基础日粮,实验组在基础日粮中添加300、500、1 000、1 500、2 000 mg/kg二甲基甘氨酸钠。结果表明：日粮中添加2 000 mg/kg的二甲基甘氨酸钠可显著提高肉鸡的脾脏指数（P＜0.05）;与对照组相比,添加剂量为1 000 mg/kg的二甲基甘氨酸钠组肉鸡生长前期血液中三碘甲状腺原氨酸（triiodothyronine,T3）的含量显著提高（P＜0.05）,二甲基甘氨酸钠对肉鸡生长后期血液中的生理生化指标无显著影响（P＞0.05）;二甲基甘氨酸钠对肉鸡血清和肝脏的总抗氧化能力影响较为显著。肉鸡生长后期,添加剂量在500 mg/kg以上的二甲基甘氨酸钠组肉鸡的血清中T-AOC活力显著提高（P＜0.05）;1 000 mg/kg以上的二甲基甘氨酸钠则能显著提高肉鸡肝脏的T-AOC活力（P＜0.05）。二甲基甘氨酸钠可有效促进肉鸡胰腺的发育,增强肉鸡的免疫功能,并能显著提高肉鸡的抗氧化能力,且以1 000～2 000 mg/kg的添加剂量效果最佳。     

间歇升温对香蕉李贮藏中生理生化变化的影响

以香蕉李为试材,研究了不同的间歇升温对低温下贮藏的李果实生理生化的影响。结果显示:对照果在冷藏20d时,呼吸强度和乙烯释放量逐渐增加,相对电导率明显上升;说明冷害已经开始启动,而且随着贮藏时间的延长,冷害指数显著增大,冷害程度明显加剧,果实正常后熟过程受阻。经过间歇升温的果实,果皮逐渐由绿变黄,再由黄转红而逐渐完成后熟过程。间歇升温到10℃虽然对冷害症状有所缓解,但李果实更易成熟老化,可溶性固形物含量快速下降,呼吸强度明显高于冷害果,膜透性增加最快,贮藏后期老化的果实更易发生冷害。而间歇升温到18℃的李果实呼吸强度、膜透性、贮藏初期的乙烯释放量明显受到抑制,可溶性固形物含量较高,冷害指数显著下降,说明间歇升温到18℃能有效地抑制李果实冷害的发生,延缓了李果实的衰老进程,保持了李果实良好的贮藏品质。     

减压对金铃大枣贮藏过程中生理生化变化的影响

在(-1±0.5)℃的条件下,以常压贮藏为对照,进行金铃大枣的减压贮藏实验。在贮藏过程中,测定了枣果的VC含量、可溶性固形物(TSS)含量、多聚半乳糖醛酸酶(PG)活性、丙二醛(MDA)含量及相对电导率,研究了减压贮藏对枣果生理生化变化的影响。结果表明,减压贮藏可以显著抑制枣果的成熟和衰老,但对保持枣果VC含量的效果不显著。