The effect of amino acid infusion on leg protein turnover assessed by L-[15N]phenylalanine and L-[1-13C]leucine exchange

A stable isotope technique depending on the use of [15N]phenylalanine and [1-13C]leucine to assess exchange was utilized to measure the components of protein turnover of the human leg and the effects of amino acid infusion. Eight healthy subjects (28.5 +/- 2.5 years) were studied when post-absorptive in the basal state and again during infusion of a mixed amino acid solution (55 g l-1, 1.52 ml kg-1 h-1). During the basal period leucine oxidation by the leg was 4.4 +/- 2.0 nmol 100 g-1 min-1 and this increased threefold during amino acid infusion (13.6 +/- 3.1 nmol 100 g-1 min-1, mean +/- SEM, P = 0.003). Amino acid infusion abolished the net negative balance between incorporation of leucine into, and release from, protein (basal, -31.8 +/- 5.8; during infusion, +3.1 +/- 7.1 nmol 100 g-1 P = 0.001). Phenylalanine exchange showed a similar pattern (basal, -13.7 +/- 1.8; during infusion, -0.8 +/- 3.0 nmol 100 g-1 min-1, P = 0.003). Basal entry of leucine into leg protein (i.e. protein synthesis) was 70.0 +/- 10.8 nmol 100 g-1 min-1 and this increased during amino acid infusion to 87.3 +/- 14.1 nmol 100 g-1 min-1 (P = 0.11). Phenylalanine entry to protein also increased with amino acid infusion (29.1 +/- 4.5 vs. 38.3 +/- 5.8 nmol 100 g-1 min-1, P = 0.09). Release from protein of leucine (101.8 +/- 9.1 vs. 84.2 +/- 9.1 nmol 100 g-1 min-1, P = 0.21) and of phenylalanine (42.8 +/- 4.2 vs. 39.1 +/- 4.2 nmol 100 g-1 min-1, P = 0.50) was unchanged by amino acid infusion. The results suggest that, in the post-absorptive state in man, infusion of mixed amino acids, without additional energy substrates; reverses negative amino acid balance by a mechanism which includes stimulation of muscle protein synthesis but which does not alter protein breakdown. Interpretation of the results obtained concurrently on whole-body protein turnover suggests that the increase in muscle protein synthesis contributes substantially to the whole-body increase, but the fall in whole-body breakdown with exogenous amino acids is independent of changes in muscle.     

腹主动脉瘤先兆破裂及破裂的CT征象(附10例分析)

目的探讨腹主动脉瘤先兆破裂及破裂在多层螺旋CT中的表现。方法收集10例临床证实腹主动脉瘤的患者的CT扫描资料进行回顾性分析。结果腹主动脉瘤先兆破裂的CT征象:动脉瘤大小增加、附壁血栓和环状钙化的管壁出现局部连续中断及高密度新月征;腹主动脉瘤破裂的CT征象:腹膜后血肿和动脉包含征。结论 CT可显示腹主动脉瘤先兆破裂及破裂的CT征象,及时做出诊断。     

Haptoglobin: a review of the major allele frequencies worldwide and their association with diseases

Haptoglobin (Hp) is a plasma alpha(2)-glycoprotein which binds free haemoglobin, thus preventing oxidative damage. The complex is rapidly removed from the circulation by a specific receptor (CD163) found on macrophages. Three major subtypes, Hp1-1, Hp2-1 and Hp2-2 are the product of two closely related genes HP(1) and HP(2). The frequency of the HP(1) and HP(2) genes varies worldwide depending on racial origin: the HP(1)frequency varying from about 0.07 in parts of India to over 0.7 in parts of West Africa and South America. Both HP(1) and HP(2) have been linked to susceptibility to various diseases. Such associations may be explained by functional differences between the subtypes in the binding of Hb and its rate of clearance from the plasma. However, there are also corresponding negative reports for disease associations. The conflicting evidence on disease association and the lack of association between disease and particular populations, despite the wide range of HP(1) and HP(2) gene frequencies across the world, may indicate that any associations are marginal.     

Heavy metal concentrations in soils as determined by laser-induced breakdown spectroscopy (LIBS), with special emphasis on chromium

Soil is unanimously considered as one of the most important sink of heavy metals released by human activities. Heavy metal analysis of natural and polluted soils is generally conducted by the use of atomic absorption spectroscopy (AAS) or inductively coupled plasma optical emission spectroscopy (ICP-OES) on adequately obtained soil extracts. Although in recent years the emergent technique of laser-induced breakdown spectroscopy (LIBS) has been applied widely and with increasing success for the qualitative and quantitative analyses of a number of heavy metals in soil matrices with relevant simplification of the conventional methodologies, the technique still requires further confirmation before it can be applied fully successfully in soil analyses. The main objective of this work was to demonstrate that new developments in LIBS technique are able to provide reliable qualitative and quantitative analytical evaluation of several heavy metals in soils, with special focus on the element chromium (Cr), and with reference to the concentrations measured by conventional ICP spectroscopy. The preliminary qualitative LIBS analysis of five soil samples and one sewage sludge sample has allowed the detection of a number of elements including Al, Ca, Cr, Cu, Fe, Mg, Mn, Pb, Si, Ti, V and Zn. Of these, a quantitative analysis was also possible for the elements Cr, Cu, Pb, V and Zn based on the obtained linearity of the calibration curves constructed for each heavy metal, i.e., the proportionality between the intensity of the LIBS emission peaks and the concentration of each heavy metal in the sample measured by ICP. In particular, a triplet of emission lines for Cr could be used for its quantitative measurement. The consistency of experiments made on various samples was supported by the same characteristics of the laser-induced plasma (LIP), i.e., the typical linear distribution confirming the existence of local thermodynamic equilibrium (LTE) condition, and similar excitation temperatures and comparable electron number density measured for all samples. An index of the anthropogenic contribution of Cr in polluted soils was calculated in comparison to a non-polluted reference soil. Thus, the intensity ratios of the emission lines of heavy metal can be used to detect in few minutes the polluted areas for which a more detailed sampling and analysis can be useful.     

氢杨梅素改善高脂饮食诱导的肥胖小鼠肝脏脂肪沉积及机制（英文）

有文献报道, SIRT1-AMPK信号通路可能在DHM改善肝脏细胞甘油三酯蓄积、胰岛素抵抗等作用中发挥作用。为此,本课题拟进一步观察DHM对高脂饮食诱导的肥胖小鼠肝脏脂肪沉积的影响,并探讨其可能机制。C57BL/6J小鼠采用普通饲料和高脂饲料喂养,同时分别用或不用低剂量(125 mg/kg)或高剂量(250 mg/kg)的DHM处理16周。实验期间,每两周检测体重一次。16周后,眼眶静脉取血并处死动物,同时取肩胛下、附睾与腹股沟的脂肪并用电子秤进行称重,并记录脂肪重量。全自动生化分析仪检测:血清甘油三酯(triglyceride,TG)、血清总胆固醇(totalcholesterol,TC)、血清高密度脂蛋白(high-densitylipoprotein,HDL)、血清低密度脂蛋白(low-densitylipoprotein,LDL)。取肝脏甲醛固定、HE和油红O染色检测肝脏脂肪沉积情况;比色法检测肝脏MDA和SOD含量; Realtime PCR检测相关指标的基因表达:IL-6、IL-8、TNF-α、乙酰辅酶A羧化酶(acetyl-Co A carboxylase, ACC)、固...     

心脏过表达人源PRKAG2(G100S)转基因小鼠模型的建立

目的 建立心脏过表达人源PRKAG2 (G100S)的转基因小鼠模型,为进一步研究该人源基因点突变对小鼠心脏发育、形态和功能维持的作用奠定基础.方法 克隆人源基因PRKAG2并构建点突变质粒,将人源PRKAG2 (G100S)插入α肌球蛋白重链(α-MHC)启动子下游,构建转基因表达载体.选用C57BL/6J小鼠为遗传背景,通过显微注射法建立人源PRKAG2(G100S)转基因小鼠模型,利用特异引物PCR法鉴定转基因小鼠的基因型.采用实时荧光定量PCR(qPCR)和蛋白质印迹法检测人源PRKAG2 (G100S)的表达.结果 经过回交繁育后建立了2个品系的心脏特异表达人源PRKAG2(G100S)的转基因小鼠品系F2代,并通过qPCR、蛋白质印迹法检测,确认了转基因小鼠心脏组织中人源PRKAG2(G100S)在rmRNA和蛋白水平存在过表达,且该突变能在转基因小鼠中稳定传代.结论 本研究成功建立了心脏特异表达人源PRKAG2(G100S)转基因小鼠模型,人源PRKAG2 (Gl00S)基因在心脏组织的过度表达在小鼠心脏发育和功能维持中的作用需要进一步深入研究与探讨.     

钴对小鼠卵母细胞成熟和体外受精的影响

[目的]研究钴的生殖毒性.[方法]采用卵母细胞体外培养和体外受精的方法.[结果]氯化钴降低体内(0 h)第一极体释放率和卵母细胞存活率(P＜0.01),降低卵母细胞(24 h)的体外受精率(P＜0.01),且有剂量依赖性增加,随着体外培养时间的延长,2个剂量组的第一极体释放率与各自0 h相比有显著提高,除了6.0 mg·kg-1组外,48 h后3.0 mg·kg-1剂量组的IVF率与24 h时相比显著提高,3.0 mg·kg-1和6.0 mg·kg-1两组的IVF率在48 h和72 h时与对照组比差异均有显著性(P＜0.05,P＜0.01).[结论]实验结果提示,氯化钴能够抑制卵母细胞的体内成熟,降低卵母细胞的体外受精能力,具有明显的生殖毒性.     

医疗设备紧急修理工艺初探

本文从传统故障检测方法入手，另辟蹊径，发掘速诊、急修工艺内涵，通过故障表象揭露本质，把难捉膜难下手的故障进行系统总结，先简单后复杂，先容易后困难。创造性地发展了医疗设备维修工艺为临床提供及时、高效、经济的服务。对医疗设备管理、维修人员有较高的参考价值。     

Causes and Prevention of Diabetic Foot Skin Breakdown

As the number of persons with diabetes increases, there is an increased incidence of foot skin breakdown and lower extremity amputations. Approximately 44%–85% of those amputations can be prevented. Prevention requires an understanding of the causes of diabetic foot skin breakdown and the measures necessary for prevention. As rehabilitation nurses, we care for patients with strokes, hip fractures, spinal cord injuries, or joint replacements, who are diabetic and are at risk for foot skin breakdown. We also care for patients with amputations who are at risk for skin breakdown of the remaining foot. This article identifies the causes of foot skin breakdown, such as neuropathy, peripheral vascular disease, trauma, and infection. Discussion includes patients who are at risk, the foot areas at risk, preventive measures, and patient and family education for the prevention of foot skin breakdown in the diabetic patient.     

Mechanical and thermal effects in striated muscle irradiated by ns-laserpulses

The therapeutic application of laser light is required to minimize defects in the non-irradiated tissue. The primary mechanism of interaction is determined by the duration of laser action. In the case of continuous wave laser light a tissue layer surrounding the irradiated volume is thermally affected. With the pulses of a Q-switched laser (duration some ns) tissue cutting will be obtained by the laser-induced breakdown. To be able to distinguish between thermal and mechanical effects by histological examination, experiments were performed with laser pulse durations of 8ns and 100μs under the same conditions with a Nd-YAG laser at 1064nm. The beam was focused through air below the tissue surface. The beam geometry in the focal region was identical for both cases. The defective region after irradiation could be divided into four zones surrounding a crater. In the μs-experiments the zones corresponded to the temperature distribution in the tissue, so the changes were all classified as thermal. In the ns-experiments, in general larger craters were found. Increasing the number of pulses to 200 the picture is similar to that produced with μs-pulses. These results show that a few ns-pulses suffice to form a crater. Additional ns-pulses lead to heat accumulation and produce thermal lesions like those of the μs-case.