State of the art of bacterial chemotaxis

Bacterial chemotaxis is a biased movement of bacteria toward the beneficial chemical gradient or away from a toxic chemical gradient. This movement is achieved by sensing a chemical gradient by chemoreceptors. In most of the chemotaxis studies, Escherichia coli has been used as a model organism. E. coli have about 4–6 flagella on their surfaces, and the motility is achieved by rotating the flagella. Each flagellum has reversible flagellar motors at its base, which rotate the flagella in counterclockwise and clockwise directions to achieve “run” and “tumble.” The chemotaxis of bacteria is regulated by a network of interacting proteins. The sensory signal is processed and transmitted to the flagellar motor by cytoplasmic proteins. Bacterial chemotaxis plays an important role in many biological processes such as biofilm formation, quorum sensing, bacterial pathogenesis, and host infection. Bacterial chemotaxis can be applied for bioremediation, horizontal gene transfer, drug delivery, or maybe some other industry in near future. This review contains an overview of bacterial chemotaxis, recent findings of the physiological importance of bacterial chemotaxis in other biological processes, and the application of bacterial chemotaxis.     

快速流程模式下肝切除患者围手术期不同营养支持的比较

目的：比较快速流程（FT）模式下肝切除患者围手术期不同营养支持方法的疗效。
　　方法：将104例拟行肝切除患者随机均分为2组,分别接受肠内营养（EN）与肠外营养（PN组）,所有患者均采用FT围手术期处理。比较两组患者手术前后体质量（WT）、血红蛋白（HB）、总蛋白（TP）、白蛋白（ALB）及总淋巴细胞计数（TLC）变化,以及术后肛门排气排便时间、住院天数、消化道不良反应和并发症发生率。
　　结果：PN组术后7d各项营养指标较术前3d均明显降低,而EN组内只有TP及ALB较术前降低,但降幅均明显小于PN组（均P<0.05）;EN组术后肛门排气排便时间较PN组明显提前,术后不良反应发生率低于PN组（均P<0.05）;两组术后住院时间及并发症发生率差异无统计学意义（均P>0.05）。
　　结论：FT模式下肝切除患者围手术期应用EN支持有利于改善营养状况及免疫功能,促进术后康复。     

Arteriolar responses to vasodilator stimuli and elevated P(O2) in renin congenic and Dahl salt-sensitive rats

OBJECTIVES: Angiotensin II suppression leads to impaired vascular relaxation in normotensive animals on a high-salt diet. The goal of this study was to determine whether normal vascular reactivity could be restored by transferring the chromosomal region carrying the Dahl salt-resistant (R) renin gene into the Dahl salt-sensitive (SS) genetic background in a strain of renin congenic rats (RGRR). METHODS: Male RGRR and SS rats were fed low-salt (0.4%) and high-salt (4%) diets for 4 weeks. The responses of cremaster muscle arterioles to acetylcholine (ACh), sodium nitroprusside (SNP), and elevated PO2 were assessed using video microscopy. RESULTS: ACh-induced dilation was significantly enhanced in RGRR on a high-salt diet compared to SS rats, while dilation to the NO donor SNP was similar in both strains. A high-salt diet significantly enhanced arteriolar constriction in response to elevated PO2, in both SS and RGRR rats. CONCLUSIONS: These data suggest that transfer of the chromosomal region containing the renin gene is crucial in the recovery of ACh-induced dilation of arterioles in RGRR rats vs. SS rats, and that factors in the SS genetic background contribute to an enhanced sensitivity to elevated PO2, independent of genes on chromosome 13.     

Nutritional state and energy balance in cirrhotic patients with or without hypermetabolism: Multicentre prospective study by the ‘Nutritional Problems in Gastroenterology’ Section of the Italian Society of Gastroenterology (SIGE)

BACKGROUND AND AIMS: A total of 334 stable, compensated cirrhotic patients admitted to 10 Italian Gastroenterology Units were included in a prospective study to evaluate nutritional state and energy balance in liver cirrhosis. MATERIALS AND METHODS: Nutritional state and calorie intake were examined in the total population, while adequacy of calorie intake versus measured total energy expenditure was evaluated in a comparable subpopulation and in 40 matched controls, by computing the energy balance. RESULTS: Our data demonstrated that: (i) malnutrition was present in 25% of the total patients and significantly correlated with the Child's group (A=16%; B=25%; C=44%); (ii) the type of malnutrition is influenced by mBEE: normometabolic patients exhibit a significant (p<0.005) reduction of mid-arm fat area while both hypermetabolic and hypometabolic patients show a significant (p<0.005) decline in kg of free fat mass; (iii) normometabolic and hypometabolic patients have a negative energy balance, due to a high level of physical activity (127+/-14 kJ) in the first group and a reduced energy intake/kg body weight (102+/-12 kJ) in the second; (iv) hypermetabolic patients have a positive energy balance due to decreased daily physical activity/kg body weight (108+/-28 kJ); (v) malnourished and normometabolic patients eat a significantly (p<0.05) reduced percentage of protein whereas malnourished and hypermetabolic patients eat a significantly increased percentage of fat (p<0.05). CONCLUSION: Although multivariate regression analysis confirms that the Child-Pugh's score is a better independent predictor of malnutrition, the measure of REE, TEE, calorie intake and energy balance need to be routinely performed in cirrhotic patients, in order to recognise hypermetabolic and hypometabolic patients (approximately 30%) in whom the nutritional and metabolic parameters are indispensable as a basis for designing and prescribing personalised nutritional strategies that can treat muscle malnutrition and thus improve the morbidity and mortality rates.     

Comparison of a Mediterranean to a low-fat diet intervention in adults with type 1 diabetes and metabolic syndrome: A 6–month randomized trial

Background and aims

The metabolic syndrome (MS) is an emerging complication in patients with type 1 diabetes (T1D), with no preventive or therapeutic treatment reported yet. We wanted to compare the impact of two 6-month nutritional interventions, based on a Mediterranean (MED) or a low-fat diet, on waist circumference, anthropometric and metabolic outcomes in patients with both T1D and the MS.

A C-Peptide-Based Model of Pancreatic Insulin Secretion in Extremely Preterm Neonates in Intensive Care

Background:

Model-based glycemic control relies on sufficiency of underlying models to describe underlying patient physiology. In particular, very preterm infant glucose-insulin metabolism can differ significantly from adults, and is relatively unstudied. In this study, C-peptide concentrations are used to develop insulin-secretion models for the purposes of glycemic control in neonatal intensive care.

Methods:

Plasma C-peptide, insulin, and blood glucose concentrations (BGC) were retrospectively analyzed from a cohort of 41 hyperglycemic very preterm (median age 27.2 [26.2-28.7] weeks) and very low birth-weight infants (median birth weight 839 [735-1000] g). A 2-compartment model of C-peptide kinetics was used to estimate insulin secretion. Insulin secretion was examined with respect to nutritional intake, exogenous and plasma insulin concentration, and BGC.

Results:

Insulin secretion was found to be highly variable between patients and over time, and could not be modeled with respect to age, weight, or protein or dextrose intake. In 13 of 54 samples exogenous insulin was being administered, and insulin secretion was lower. However, low data numbers make this result inconclusive. Insulin secretion was found to increase with BG, with a stronger association in female infants than males (R² = .51 vs R² = .13, and R² = .26 for the combined cohort).

Conclusions:

A sex-based insulin secretion model was created and incorporated into a model-based glycemic control framework. Nutritional intake did not predict insulin secretion, indicating that insulin secretion is a complex function of a number of metabolic factors.     

不同透析方式对患者微炎症状态和营养状况的临床观察

目的 探讨常规血液透析和高通量血液透析两种不同治疗方式对维持性血液透析患者微炎症状态和营养状况的影响.方法 选取50例维持性血液透析患者随机分成常规透析(CHD)和高通量透析(HFHD)两组,分别测定两组患者入组后首次透析(透析前)和治疗3个月后(透析前)的血浆白蛋白(Alb)、血清C反应蛋白(CRP)、白细胞介素-6(IL-6)的水平进行比较,同时比较治疗前后体重指数、肱三头肌皮肤皱褶厚度(TSF)、上臂围(MAC)和上臂肌围(MAMC)的变化.结果 CHD组治疗3个月后对IL-6、CRP清除差异无统计学意义(P＞0.05),对Alb的影响差异无统计学意义(P＞0.05);HFHD组治疗3个月后对IL-6、CRP清除差异有统计学意义(P＜0.05),对Alb的提升差异有统计学意义(P＜0.05);HFHD组治疗3个月后TSF、MAC测量值升高,但是差异无统计学意义(P＞0.05),两组治疗后对BMI、MAMC的测量值差异无统计学意义.结论 高通量透析与常规透析相比对IL-6和CRP等微炎症细胞因子的清除能力更显著,对改善微炎症状态有积极作用;且与常规透析相比对营养状态的改善也有一定帮助作用.     

The management of perioperative nutrition in patients with end stage liver disease undergoing liver transplantation

Malnutrition is found in almost 100% of patients with end stage liver disease (ESLD) awaiting transplantation and malnutrition before transplantation leads to higher rates of post-transplant complications and worse graft survival outcomes. Reasons for protein energy malnutrition include several metabolic alterations such as inadequate intake, malabsorption, and overloaded expenditure. And also, stress from surgery, gastrointestinal reperfusion injury, immunosuppressive therapy and corticosteriods use lead to delayed bowl function recovery and disorder of nutrients absorption. In the pretransplant phase, nutritional goals include optimization of nutritional status and treatment of nutrition-related symptoms induced by hepatic decompensation. During the acute post-transplant phase, adequate nutrition is required to help support metabolic demands, replenish lost stores, prevent infection, arrive at a new immunologic balance, and promote overall recovery. In a word, it is extremely important to identify and correct nutritional deficiencies in this population and provide an adequate nutritional support during all phases of liver transplantation (LT). This study review focuses on prevalence, nutrition support, evaluation, and management of perioperative nutrition disorder in patients with ESLD undergoing LT.     

血液透析患者营养状况与逆流行病学现象的探讨

目的 了解维持性血液透析患者(MHD)的营养状况,探讨其存在的逆流行病学现象,为进一步提出针对性营养干预策略提供依据.方法 采用主观综合性营养评估法(SGA)、人体测量、生化指标测定方法综合评估113例维持性血液透析患者的营养状态.结果 根据SGA评分,55.75％(63例)的患者营养状况良好;营养不良患者占44.25％(50例),其中39.82％(45例)为轻-中度营养不良,4.42％(5例)为重度营养不良.营养不良组患者肱三头肌皮褶厚度(TSF)、动静脉瘘对侧上臂周径(MAC)、上臂肌围(MAMC)低于营养良好组,差异有统计学意义(P＜0.01).营养不良组总胆固醇(CH)、三酰甘油(TG)、低密度脂蛋白(LDL)、血清白蛋白(Alb)、前白蛋白(PA)、血肌酐(Scr)、尿素氮(BUN)、钙(Ca)、磷(P)较营养良好组低,其中TG、PA、Scr、BUN差异有统计学意义(P＜0.05,P＜0.01),而高密度脂蛋白(HDL)和甲状旁腺素(PTH)较营养良好组偏高,但差异无统计学意义.结论 MHD患者营养不良发生比例偏高,且MHD患者营养不良是导致其逆流行病学现象的原因之一,建议根据MHD患者具体的病理生理特点来调整治疗标准.