Basic metabolism: proteins

Proteins serve a range of physiological functions in health and in disease. Their overall structure is determined predominantly by the sequence of amino acids when they are synthesized, which in turn is a derivative of the sequence of nucleotides in the corresponding segment of DNA. There is a constant turnover of body protein, the rate of which exceeds dietary protein intake and therefore suggests a degree of recycling. Some amino acids that enter the body protein pool can be synthesized (‘non-essential’ amino acids) while others can only be obtained through dietary means (‘essential’ amino acids). During critical illness and significant trauma there appears to be dysregulation such that synthesis of some non-essential amino acids is limited, while there is an increase in amino acid oxidation. Modification of dietary intake to address the potential imbalance in illness is probably insufficient in isolation to prevent muscle wasting.     

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.     

Dihydromyricetin improves liver fat deposition in high-fat diet-induced obese mice

It has been reported that the histone/protein deacetylase SIRT1-AMP-activated protein kinase (SIRT1-AMPK) signaling pathway may play a role in the effects of dihydromyricetin (DHM) on improving triglyceride (TG) accumulation and insulin resistance in liver cells. Therefore, we aimed to further observe the effect of DHM on liver fat deposition in high-fat diet (HFD)-induced obese mice and explore its possible mechanism. C57BL/6J mice were fed with a normal diet (ND) and HFD and were treated with or without low-dose (125 mg/kg) or high-dose (250 mg/kg) DHM for 16 weeks, respectively. During the experiment, body weight was checked every 2 weeks. After 16 weeks, the orbital vein was bled, the animals were sacrificed, and the subscapular, epididymal, and inguinal fat were collected and weighed with an electronic scale. An automatic biochemical analyzer was used to determine the levels of serum triglyceride (TG), serum total cholesterol (TC), serum high-density lipoprotein (HDL), and serum low-density lipoprotein (LDL). The livers were stained with hematoxylin-eosin staining (H&E) and Oil Red O to detect liver fat deposition. A colorimetric method was used to detect liver MDA and SOD contents. Quantitative real-time PCR (qRT-PCR) was used to detect the gene expressions of related indicators, such as interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), acetyl-CoA carboxyl acetyl-CoA carboxylase (ACC), sterol regulatory element-binding protein-1c (SREBP-1), fatty acid synthetase (FAS), peroxisome proliferator activation receptor alpha (peroxisome proliferator-activated receptor-alpha, PPARα), palmitoyltransferase 1 (carnitine palmitoyltransferase 1, CPT1), SIRT1, and AMPK. Western blotting analysis was used to detect the protein expression levels of SIRT1, AMPK, SIRT1-AMPK, ACC, SREBP-1, FAS, PPARα, and CPT1. Results showed that compared with the ND group, the weight and body fat of the mice in the HFD group were increased significantly. The levels of TG, TC, and LDL were increased, the level of HDL was decreased, the volume of hepatocytes was increased, the number of lipid droplets, fat deposition, MDA, IL-6, IL-8, TNF-α, SREBP-1c, FAS, ACC1, SIRT1, and AMPK protein levels were significantly increased, and the SOD activity, PPARα, CPT1, SIRT1 mRNA, AMPK mRNA, PPARα, CPT1 levels were significantly decreased. DHM could significantly reverse the changes of the above indexes in HFD mice, while DHM had no significant effect on the above indexes in ND mice. Collectively, our findings revealed that DHM improved liver fat deposition in HFD-induced obese mice, and the mechanism might be related to inhibition of oxidative stress, inflammation, lipid synthesis, and promotion of lipid decomposition.     

LIBS快速评价产品质量属性的研究进展及在中药的应用前景

激光诱导击穿光谱技术（LIBS）是一种基于原子发射光谱的元素分析技术，具有“快速、实时、无损、原位”等优势。本文介绍LIBS快速分析的特征；系统综述了该技术在工业、农业、医药、环境、艺术与考古、远程遥感领域快速评价产品质量属性的应用进展，展望了LIBS技术未来的发展空间及中药的应用前景。     

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.     

Organizational and individual factors associated with breakdown of residential placements for people with intellectual disabilities

Background People with intellectual disabilities (IDs) whose behaviour challenges services are at increased risk of placement breakdown. Most previous research has tended to focus on the role of individual characteristics in predicting breakdown. A small number of studies have suggested that service variables may impact on intervention effectiveness and hence placement breakdown. Method This study used a non‐experimental group comparison design to investigate potential differences between two groups of residential homes, one of which had experienced placement breakdown, and one of which had successfully maintained placements in the community. Results More residents in the breakdown group had inappropriate sexual behaviours but there were no other differences. Services in the breakdown group had more limited procedural guidance for staff, weaker training, supervision and team meetings and less external professional support. Conclusion Placement characteristics may be an important determinant of community placement success for people with IDs and challenging behaviour. Those selecting and funding residential placements for such people should attend to the technical competence of the placement (in terms of its use of procedural guidance, training and professional advice) and to the extent of support for staff (in terms of training, supervision and team meetings).