Non-linear dynamics of heart rate variability during incremental cycling exercise

Within the last years complex models of cardiovascular regulation and exercise fatigue have implemented heart rate variability (HRV) as a measure of autonomic nervous system. Using detrended fluctuation analysis (DFA) to assess heart rate correlation properties, the present study examines the influence of exercise intensity on total variability and complexity in non-linear dynamics of HRV. Sixteen cyclists performed a graded exercise test on a bicycle ergometer. HRV time domain measures and fractal correlation properties were analyzed using short-term scaling exponent alpha1 of DFA. Amplitude and complexity of HRV parameters decreased significantly. DFA-alpha1 increased from rest to low exercise intensity and showed an almost linear decrease from higher intensities until exhaustion. These findings support a qualitative change in self-organized heart rate regulation from a complex autonomic control at rest and low intensities towards a breakdown of the interaction in control mechanisms with non-autonomic heart rate control dominating at high intensities.     

SGLT2抑制剂达格列净对2型糖尿病肾病患者血糖波动的影响

目的 探究SGLT2抑制剂达格列净对2型糖尿病肾病患者的血糖波动的影响。方法 选取2020年8月至2022年3月(含随访时间)中国科学技术大学附属第一医院(安徽省立医院)内分泌科收治的101例血糖控制不佳,且既往未使用钠葡萄糖协同转运蛋白2(SGLT2)抑制剂的2型糖尿病肾病住院患者,不含达格列净治疗作为对照组(n＝51),含达格列净治疗作为观察组(n＝50),比较两组患者治疗前后血糖波动及尿白蛋白肌酐比(UACR)的差异。结果 治疗1个月后,两组患者平均血糖(MBG)、血糖变异度(CV)、平均血糖标准差(SDBG)、平均血糖波动幅度(MAGE)、日间血糖平均绝对差(MODD)、高血糖(动态血糖值>10mmol/L)和低血糖(动态血糖值<3.1mmol/L)发生率均较治疗前下降,差异具有统计学意义(P<0.05),且观察组较对照组下降幅度大(P<0.05);两组患者治疗1、3、6个月后UACR也均较治疗前下降,差异具有统计学意义(P<0.05),观察组治疗后UACR较对照组下降幅度大(P<0.05)。结论 SGLT2抑制剂达格列净在控制2型糖尿病肾病患者的血糖方面更为稳定,且较少出现低血糖等不良反应,同时还可以有效降低UACR。     

血糖波动对糖尿病大鼠理化指标及甲状腺功能的影响

目的观察持续高血糖及血糖波动对糖尿病（DM）大鼠理化指标及甲状腺功能的影响,探讨血糖波动对DM大鼠甲状腺组织损伤的程度及可能的损伤机制。方法用高糖高脂饲料叠加腹腔注射STZ建立DM大鼠模型,并分为持续性高血糖组、血糖波动组,另设正常对照组（C组）,每组各10只。12周后检测血生化、甲状腺功能并处死,取双侧甲状腺称重,计算甲状腺的重量指数（mg/100g）。结果持续高血糖组与血糖波动组糖化血红蛋白A1c（HbA1c）相近（P＞0.05）。血糖波动组甘油三酯（TG）、空腹血糖（FPG）、总胆固醇（TC）明显低于持续高血糖组,差异均有统计学意义（均P＜0.05）。持续高血糖组和血糖波动组的游离三碘甲状腺原氨酸（FT3）、游离甲状腺素（FT4）、甲状腺重量指数均明显低于正常组,且差异有统计学意义（均P＜0.05）;持续高血糖组、血糖波动组之间差异无统计学意义（P＞0.05）。各组间促甲状腺素（TSH）差异无统计学意义（P＞0.05）。结论无论血糖波动,还是持续高血糖均可降低DM大鼠FT3、FT4水平,糖代谢紊乱可能是导致DM大鼠甲状腺损伤的机制。     

糖化血红蛋白控制理想的2型糖尿病视网膜病变与血糖波动的关系

目的 动态血糖监测（CGM）评估血糖波动,探讨糖化血红蛋白（HbA1c）<7.0%的2型糖尿病患者视网膜病变（DR）与血糖波动的关系。方法 选择2014年5月至2018年1月在合肥市第二人民医院内分泌科住院的168例HbA1c<7.0%的2型糖尿病患者为研究对象,根据DR病变程度,将108例无DR的患者纳为NDR组,60例DR患者纳为DR组。对受试者进行连续72 h的CGM,计算平均血糖（MBG）、血糖水平标准差（SDBG）、有效波动平均幅度（MAGE）,同时检测HbAlc、血压、体质指数,评估HbA1c控制理想的2型糖尿病视网膜病变与血糖波动之间的相关性。结果 DR组患者病程（8.33±0.82）年、收缩压（138.20±11.84）mmHg、舒张压（86.53±8.57）mmHg、SDBG（2.73±0.54）、MAGE（3.98±0.70）mmol/L,均高于NDR组,差异有统计学意义（P<0.05）。logistic回归分析显示,病程、MAGE是2型糖尿病患者发生DR的危险因素（P<0.05）。结论 HbAlc<7.0%的2型糖尿病患者DR与糖尿病病程、血糖波动及血压有关。     

Ames波动试验和GADD45a-GFP GreenScreen两种快速筛选方法评价大黄素和芫花素的遗传毒性

目的 使用Ames波动试验和GADD45a-GFP GreenScreen两种快速筛选方法,对有毒中药芫花和了哥王的主要单体成分大黄素和芫花素的遗传毒性进行评价。方法 （1）Ames波动试验：在非代谢活化（-S9）和代谢活化（+S9）条件下使用鼠伤寒沙门菌TA100开展基于96孔液态培养法的细菌回复性突变试验,大黄素和芫花素（终质量浓度范围均为0.1~10 μg/mL）与菌液充分混合后在37℃下培养72 h。（2）GADD45a GreenScreen高通量筛选试验：在非代谢活化（-S9）和代谢活化条件下（+S9）将表达GADD45a基因的TK细胞（GenM-T01和GenM-C01）与大黄素（0.13~32.0 μg/mL）和芫花素（0.07~16.0 μg/mL）分别作用48 h（-S9）和3 h（+S9）,之后通过酶标仪和流式细胞仪检测绿色荧光蛋白（enhanced green fluorescent protein,EGFP）的荧光强度。结果 有无代谢活化条件下,10 μg/mL大黄素均可诱导TA100的回复性突变率显著性升高（P<0.05、P<0.001）;代谢活化条件下,10 μg/mL芫花素可诱导TA100的回复性突变率显著性升高（P<0.001）,16.0 μg/mL芫花素诱导TK6细胞表达的GADD45a-EGFP荧光强度也超过了遗传毒性阈值（1.3倍）。结论 当前研究提示大黄素和芫花素为可疑遗传毒性,需要开展深入研究明确其遗传毒性及机制。Ames波动试验和GADD45a GreenScreen是良好的高通量筛选备选试验,可极大优化浩繁的药物的毒性筛选工作,尤其适宜诸如中药等成分和配伍复杂的药物。     

Mediterranean Diet Pyramid: A Proposal for Italian People

Bread was a staple in the traditional Mediterranean diet of the early 1960s, as well as nowadays; however, it was a stone ground sourdough bread in Nicotera and probably in the Greek cohorts of the Seven Countries Study. In the present review, the nutritional characteristics of this food are analyzed in relation to its protective effects on coronary heart disease, metabolic diseases and cancer. According to our traditions, cultural heritage and scientific evidence, we propose that only cereal foods with low glycemic index (GI) and rich in fiber have to be placed at the base of the Mediterranean diet pyramid, whereas refined grains and high GI starchy foods have to be sited at the top.     

Taking a Low Glycemic Index Multi-Nutrient Supplement as Breakfast Improves Glycemic Control in Patients with Type 2 Diabetes Mellitus: A Randomized Controlled Trial

Dietary therapy is the mainstay of treatment for diabetes. This study examined the effect of a low glycemic index (GI) multi-nutrient supplement, consumed in place of breakfast, on glycemic control in patients with type 2 diabetes mellitus (T2DM). A total of 71 participants were randomized at a 2:1 ratio into either a breakfast replacement group or a normal breakfast group for a 12-week interventional study. The primary outcome measure was change in hemoglobin A1c (HbA1c). Nutrition status and somatometry were studied as secondary outcomes. The breakfast replacement group displayed a −0.2% absolute reduction in HbA1c (95% CI (confidence interval), −0.38% to −0.07%, p = 0.004), while the HbA1c of the control group increased 0.3% (95% CI, 0.1% to 0.5%, p = 0.005). The baseline Mini Nutritional Assessment score for both groups was 26.0 and no significant changes occurred following intervention. However, there was a statistically significant difference in body mass index between the treatment and control groups (p = 0.032) due to the weight gain in the control group (increased 0.5 kg, 95% CI was 0.2 to 0.9, p = 0.007). These data suggest that breakfast replacement with a low GI multi-nutrient supplement can improve glycemic and weight control in T2DM.     

Pre-Exercise Nutrition: The Role of Macronutrients,Modified Starches and Supplements on Metabolism and Endurance Performance

Endurance athletes rarely compete in the fasted state, as this may compromise fuel stores. Thus, the timing and composition of the pre-exercise meal is a significant consideration for optimizing metabolism and subsequent endurance performance. Carbohydrate feedings prior to endurance exercise are common and have generally been shown to enhance performance, despite increasing insulin levels and reducing fat oxidation. These metabolic effects may be attenuated by consuming low glycemic index carbohydrates and/or modified starches before exercise. High fat meals seem to have beneficial metabolic effects (e.g., increasing fat oxidation and possibly sparing muscle glycogen). However, these effects do not necessarily translate into enhanced performance. Relatively little research has examined the effects of a pre-exercise high protein meal on subsequent performance, but there is some evidence to suggest enhanced pre-exercise glycogen synthesis and benefits to metabolism during exercise. Finally, various supplements (i.e., caffeine and beetroot juice) also warrant possible inclusion into pre-race nutrition for endurance athletes. Ultimately, further research is needed to optimize pre-exercise nutritional strategies for endurance performance.     

Association between weight cycling and risk of developing diabetes in adults: A systematic review and meta-analysis

Aims/IntroductionIn this meta‐analysis, we aimed to explore the association between bodyweight cycling (weight fluctuation) and the risk of developing diabetes.Materials and MethodsWe analyzed data from eligible cohort studies that assessed the association between weight cycling in adults and the risk of developing diabetes from online databases PubMed, Cochrane Library and EMBASE databases (1966 to April 2020). We pooled data using relative risks (RRs) with a random effects model.ResultsA total of 14 studies involving 253,766 participants, including 8,904 diabetes events, were included. One study included eight independent reports, resulting in 21 reports in 14 studies. Summary analysis showed that individuals who suffered weight cycling had a higher risk of diabetes (RR 1.23. 95% confidence interval 1.07–1.41; P = 0.003). However, the association between weight cycling and the risk of developing diabetes was not observed in obese participants (body mass index ≥30 kg/m²; P = 0.08).ConclusionsThe present meta‐analysis showed that weight cycling was a strong independent predictor of new‐onset diabetes. Future studies are required to detect the causal links between weight cycling and the risk of developing diabetes.