甲状腺功能亢进症患者植物神经功能的昼夜周期改变

目的 研究甲状腺功能亢进症(甲亢)患者植物神经功能的昼夜周期改变.方法 记录33例初发甲亢患者(甲亢组)和35例健康体检者(对照组)的24 h动态心电图,并通过心率变异性的时域和频域分析来评价心脏植物神经功能状态.结果 甲亢组所有NN间期的标准差(SDNN);以5 min为间隔将24 h连续记录分为288段,先计算每段的平均NN间期,然后计算288个NN间期平均值的标准差(SDANN);以5 min为间隔将24 h连续记录分为288段,先计算每段的NN间期标准差,然后计算288个NN间期标准差的平均值(ASDNN);所有相邻NN间期差值的均方根(rMSSD)显著低于对照组[(82.3±29.0)ms比(139.4±40.2)ms;(75.0±27.4)ms比(130.3±43.9)ms;(29.9±14.9)ms比(57.3±14.4)ms;(19.8±10.9)ms比(29.5±9.4)ms](P＜0.01或＜0.05).甲亢组总功率(TP)、高频功率(HF)、低频功率(LF)和极低频功率(VLF)显著低于对照组[(566.1±573.2)ms2/Hz比(1894.2±984.3)ms2/Hz、(68.1±88.9)ms2/Hz比(232.7±155.5)ms2/Hz、(127.4±163.0)ms2/Hz比(551.3±390.6)ms2/Hz、(330.3±300.6)ms2/Hz比(1073.2±570.2)ms2/Hz](P＜0.01).短时频域分析甲亢组VLF在全天大多数时间均显著高于对照组(P＜0.05),LF主要在白天显著高于对照组(P＜0.05),HF在全天散在时间高于对照组(P＜0.05);两组LF/HF在全天绝大多数时间差异无统计学意义(P＞0.05).结论 甲亢患者心脏变时性低,交感神经张力在全天均增高,而迷走神经张力虽有相应增高,但以白天增高为主,夜间接近正常水平.

Abstract：

Objective To investigate the circadian change of autonomic nervous system in hyperthyroidism (HT) patients. Methods Recording 24 h dynamic electrocardiography from 33 HT patients( HT group) and 35 controls (control group). The cardiac autonomic nervous function was evaluated by the time domain and frequency domain analysis of heart rate variability( HRV). Results Comparing with control group, the SDNN, SDANN, ASDNN and rMSSD were significantly lower in HT group[ (82.3 ± 29.0)ms vs. (139.4±40.2 ) ms, ( 75.0 ± 27.4) ms vs. ( 130.3 ± 43.9) ms, (29.9 ± 14.9 ) ms vs. (57.3 ± 14.4) ms,( 19.8 ± 10.9 ) ms vs. (29.5 ± 9.4) ms ] (P ＜ 0.01 or ＜ 0.05 ), the long term total power (TP), high frequency (HF), low frequency (LF) and very low frequency (VLF) were significantly lower in HT group [ (566.1±573.2) ms2/Hz vs. ( 1894.2 ± 984.3)ms2/Hz, (68.1 ± 88.9 ) ms2/Hz vs. (232.7 ± 155.5 ) ms2/Hz, ( 127.4 ±163.0) ms2/Hz vs. (551.3 ± 390.6) ms2/Hz, (330.3 ± 300.6) ms2/Hz vs. (1073.2 ± 570.2) ms2/Hz] (P ＜0.01 ). Comparing with control group, short term VLF was higher in HT group during most time in 24 hours (P＜ 0.05 ). Short term LF was higher in HT group mainly in day time (P＜ 0.05 ). Short term HF was higher in HT group occasionally in the whole day (P＜0.05). Short term LF/HF didn't show significant difference between HT group and control group at most time points (P＞0.05).Conclusion In HT patients, cardiac chronotropic property is impaired, sympathetic activity increases in whole day, vagal activity increases correspondently but the increase in day is more marked than that in night.     

心率变异性在脑力负荷评价中的应用

目的探讨用心率变异性(HRV)来评价脑力负荷的可行性。方法受试者在计算机前输入随机数字,模拟脑力劳动。采用Holter8800型动态心电图分析仪连续记录其心电信号,并将心电信号转变为数字信号,应用Holter分析软件分析HRV频域指标:总功率(TP)、低频(LF)、高频(HF)、LFHF。结果输入数字的速度随时间的延长而逐渐增加,输入正确率却逐渐下降。输入速度与HRV的TP和LF呈明显的正相关(r值分别为0.851和0.827,P<0.05),并呈现剂量-反应关系,而HF和LFHF与输入速度之间没有明显相关。休息和脑力劳动开始时HRV各指标的值分别为:TP:(2745.4±1301.6)、(686.2±420.7)ms2Hz;HF:(670.6±393.8)、(202.6±171.7)ms2Hz;LF:(870.5±553.7)、(206.0±187.9)ms2Hz。脑力劳动时HRV各指标与休息时相比,均明显降低,这是一个总的趋势。然后它们在低水平上随着负荷量(强度和时间)的增加而波动且有逐渐升高的趋势。结论心率变异性可以用作脑力劳动负荷的评价指标,但其变化规律有待于进一步的研究。     

Sympathetic predominance in young male white-collar workers with mild to moderate hypertension

In order to investigate the difference in diurnal variation of autonomic control between young male mild to moderate hypertensive and normotensive white-collar workers, we accessed heart rate variability with ambulatory blood pressure for over 24 hours including work and sleep periods. Both mean systolic and diastolic blood pressures (SBP and DBP) were significantly (p<0.01) higher in hypertensives (HT, n=11) than normotensives (NT, n=11) in all phases, whereas heart rate was not different between them in any phase. Blood pressures during work period (on-duty) were significantly higher than those during non-work period (off-duty) in both NT and HT. High frequency (HF; 0.15-0.40 Hz) power showed a circadian pattern in phase with the sleep-wake cycle. Both HF and low frequency (LF; 0.05-0.15 Hz) powers in HT were significantly lower than that in NT during the sleep period (p<0.05). LF/HF ratio showed a circadian pattern that was almost opposite of the pattern in HF power. Twenty-four-hour average LF/HF in HT was higher than that in NT (p<0.05). Especially during on-duty, LF/HF in HT was significantly higher than in NT (p<0.05). The increase of SBP and LF/HF from off-duty period to on-duty period (deltaSBP and deltaLF/HF) showed significant positive correlation (r=0.67, P<0.05) in HT group, suggesting that the SBP elevation during on-duty in HT may be coupled with sympathetic activation. These results suggest that HT showed significantly reduced parasympathetic control during sleep and an increased sympathetic activity especially during on-duty as compared with NT. Our findings imply that persistence of sympathodominant states together with reduced vagal activity in young mild to moderate hypertensive workers may be related to future cardiovascular disorders.     

Heart rate variability (HRV) analysis in radio and TV broadcasting stations workers

Objectives

The aim of the study was to assess the mechanism of cardiovascular impairments in workers exposed to UHF-VHF radio frequency electromagnetic fields (EMF).

Materials and Methods

Heart rate variability (HRV) was analysed using 512 normal heart beats registered at rest. The analysis concerned time-domain (STD R-R) and frequency-domain (VLF, LF, HF) parameters of HRV. Fifty nine workers (group I) with low-level and 12 workers (group II) with high-level exposure were examined. The mean age of the subjects was 47±9 years and 41±14 years, and mean exposure duration 19.1±8.8 years and 13±4 years, in groups I and II, respectively. The groups were divided according to: E_max, E_dose, E_mean for frequencies UHF, VHF and UHF+VHF: The control group consisted of 42 non-exposed subjects, aged 49±8 years. Statistical analysis comprised one-way analysis of variance, covariance analysis and logistic regression models.

Results

In the exposed groups, the heart rate was higher than in the control one. Standard deviation of R-R intervals (STD R-R) was found to be significantly (p = 0.0285) lower in group I (42.5±24.7 ms) compared to the control group (62.9±53.5 ms). The risk of lowered STD R-R was significantly increased (OR = 2.37, p = 0.023) in group II. Both exposed groups presented significantly higher VLF and LF values than the control group (p = 0.005 and p = 0.0025, respectively). The EMF-exposed groups were characterised by the dominance of the sympathetic system (LF/HF 1.3±0.35).

Conclusions

The results indicate that exposure to radiofrequency EMF may affect the neurovegetative regulation.     

依托咪酯或丙泊酚对老年冠心病非心脏手术围插管期心率变异性的影响

目的 研究依托咪酯和丙泊酚对老年冠心病患者行非心脏手术时在全身麻醉诱导气管插管期间心率变异性(HRV)的影响.方法将90例择期行中上腹部手术的老年冠心病患者随机分成依托咪酯组(E组)和丙泊酚组(P组),每组各45例.分别于麻醉前、麻醉诱导后及气管插管后用心率变异功率谱分析技术观察两组患者的HRV变化.结果麻醉诱导后,E组总功率(TP)和HRV低频(LF)[(756±535)ms2/Hz和(316±301)ms2/Hz],P组LF、HRV高频(HF)、LF/HF及TP[(187±168)ms2/Hz、(89±48)ms2/Hz、2.3±1.6和(616±462)ms2/Hz]均较麻醉前显著降低(P<0.05);组间比较,麻醉诱导后,E组LF、HF、LF/HF及TP均显著高于P组(P<0.05).气管插管后,两组LF、HF、LF/HF及TP均较麻醉前显著升高(P<0.05);组间比较,气管插管后两组HRV各指标比较差异均无统计学意义(P>0.05).结论丙泊酚在麻醉诱导时对老年冠心病自主神经功能的抑制作用强于依托咪酯;而对于气管插管引起的心血管反应而言依托咪酯和丙泊酚药效相似.     

Autonomic nervous system activity and the state and development of obesity in Japanese school children

OBJECTIVE: The autonomic nervous system (ANS) plays an important role in regulating energy expenditure and body fat content; however, the extent to which the ANS contributes to pediatric obesity remains inconclusive. The aim of this study was to evaluate whether sympathetic and/or the parasympathetic nerve activities were altered in an obese pediatric population. We further examined a physiological association between the duration of obesity and the sympatho-vagal activities to scrutinize the nature of ANS alteration as a possible etiologic factor of childhood obesity. RESEARCH METHODS AND PROCEDURES: Forty-two obese and 42 non-obese healthy sedentary school children were carefully selected from 1080 participants initially recruited to this study. The two groups were matched in age, gender, and height. The clinical records of physical characteristics and development of the obese children were retrospectively reviewed to investigate the onset and progression of obesity. The ANS activities were assessed during a resting condition by means of heart rate variability power spectral analysis, which enables us to identify separate frequency components, i.e., total power (TP), low-frequency (LF) power, and high-frequency (HF) power. The spectral powers were then logarithmically transformed for statistical testing. RESULTS: The obese children demonstrated a significantly lower TP (6.77 +/- 0.12 vs. 7.11 +/- 0.04 ln ms(2), p < 0.05), LF power (6.16 +/- 0.12 vs. 6.42 +/- 0.05 ln ms(2), p < 0.05), and HF power (5.84 +/- 0.15 vs. 6.34 +/- 0.07 ln ms(2), p < 0.01) compared with the non-obese children. A partial correlation analysis revealed that the LF and HF powers among 42 obese children were negatively associated with the duration of obesity independent of age (LF: partial r = -0.55, p < 0.001; HF: partial r = -0.40, p < 0.01). The obese children were further subdivided into two groups based on the length of their obesity. All three spectral powers were significantly reduced in the obese group with obesity of >3 years (n = 18) compared to the group with obesity of <3 years. DISCUSSION: Our data indicate that obese children possess reduced sympathetic as well as parasympathetic nerve activities. Such autonomic depression, which is associated with the duration of obesity, could be a physiological factor promoting the state and development of obesity. These findings further imply that preventing and treating obesity beginning in the childhood years could be an urgent and crucial pediatric public health issue.     

噪声对作业工人心率变异性的影响

目的 研究噪声对作业工人心率变异性(heart rate variability, HRV)的影响。
方法 选取某公司动力车间单纯接触噪声的作业人员96人为噪声接触组, 同时选取同一单位不接触噪声的工作人员95人为对照组, 两组均进行24 h动态心电图检查, 测量或计算24 h平均心率(HR)和HRV时域指标24 h全部窦性RR间期的标准差(SDNN)、24 h内全部窦性RR间期差值的均方根(RMSSD)、24 h内相邻两个正常窦性RR间期差值大于50 ms的个数所占的百分数(PNN50), 及频谱指标高频功率(HF)、低频功率(LF)、极低频功率(VLF), 比较接触组与对照组各指标的差异, 并分析接触组HRV各指标与工龄、年龄、性别、HR的相关性。
结果 接触组SDNN、PNN50、LF、VLF低于对照组, HR高于对照组(P < 0.05);接触组中SDNN、PNN50、LF、VLF与工龄及HR呈负相关(r=-0.582~-0.283, P < 0.05), 与性别无相关性(P>0.05), SDNN、PNN50、LF与年龄呈负相关(r=-0.233~-0.211, P < 0.05)。
结论 噪声作业工人心率变异性降低, 提示长期的噪声接触可引起作业工人自主神经功能紊乱。
     

Adiponectin levels during low- and high-fat eucaloric diets in lean and obese women

OBJECTIVE: Adiponectin influences insulin sensitivity (S(I)) and fat oxidation. Little is known about changes in adiponectin with changes in the fat content of eucaloric diets. We hypothesized that dietary fat content may influence adiponectin according to an individual's SI. RESEARCH METHODS AND PROCEDURES: We measured changes in adiponectin, insulin, glucose, and leptin in response to high-fat (HF) and low-fat (LF) eucaloric diets in lean (n = 10) and obese (n = 11) subjects. Obese subjects were further subdivided in relation to a priori SI. RESULTS: We found significantly higher insulin, glucose, and leptin and lower adiponectin in obese vs. lean subjects during both HF and LF. The mean group values of these measurements, including adiponectin (lean, HF 21.9 +/- 9.8; LF, 20.8 +/- 6.6; obese, HF 10.0 +/- 3.3; LF, 9.5 +/- 2.3 ng/mL; mean +/- SD), did not significantly change between HF and LF diets. However, within the obese group, the insulin-sensitive subjects had significantly higher adiponectin during HF than did the insulin-resistant subjects. Additionally, the change in adiponectin from LF to HF diet correlated positively with the obese subjects' baseline SI. DISCUSSION: Although in lean and obese women, group mean values for adiponectin did not change significantly with a change in fat content of a eucaloric diet, a priori measured SI in obese subjects predicted an increase in adiponectin during the HF diet; this may be a mechanism that preserves SI in an already obese group.     

The changing pattern of poisoning with psychoactive drugs in Croatia

The aim of this study was to analyse the frequency of poisoning with psychoactive drugs (benzodiazepines, antidepressants and neuroleptics) over the last 15 years in Croatia. The analysis was based on poisoning incidents reported over the phone (hot line) to the Zagreb Poison Control Center and included two periods: 1985-1991 (period I) and 1992-1999 (period II). The data were analysed separately for children and adults. Each phone call was counted as one poisoning incident. Child poisoning with neuroleptics was significantly higher in period II than in period I and so was the adult poisoning with antidepressants, amytriptyline, and combined psychoactive drugs. The frequency of total psychoactive drug poisoning was significantly higher in adults than in children in both periods. From 1992, the frequency of adult poisoning with antidepressants considerably increased as one of the many consequences of war-related stress. The results indicate a need for careful psychiatric evaluation and more critical use of antidepressants in affected individuals.     

An international prospective cohort study of mobile phone users and health (COSMOS): Factors affecting validity of self-reported mobile phone use

This study investigates validity of self-reported mobile phone use in a subset of 75 993 adults from the COSMOS cohort study. Agreement between self-reported and operator-derived mobile call frequency and duration for a 3-month period was assessed using Cohen’s weighted Kappa (κ). Sensitivity and specificity of both self-reported high (≥10 calls/day or ≥4 h/week) and low (≤6 calls/week or <30 min/week) mobile phone use were calculated, as compared to operator data. For users of one mobile phone, agreement was fair for call frequency (κ = 0.35, 95% CI: 0.35, 0.36) and moderate for call duration (κ = 0.50, 95% CI: 0.49, 0.50). Self-reported low call frequency and duration demonstrated high sensitivity (87% and 76% respectively), but for high call frequency and duration sensitivity was lower (38% and 56% respectively), reflecting a tendency for greater underestimation than overestimation. Validity of self-reported mobile phone use was lower in women, younger age groups and those reporting symptoms during/shortly after using a mobile phone. This study highlights the ongoing value of using self-report data to measure mobile phone use. Furthermore, compared to continuous scale estimates used by previous studies, categorical response options used in COSMOS appear to improve validity considerably, most likely by preventing unrealistically high estimates from being reported.     

Opuntia ficus indica's effect on heart-rate variability in high-level athletes

Opuntia ficus indica (OFI) has many physiological effects, but a relationship between OFI and heart-rate variability (HRV) has never been established. The aim of this study was to describe the effects of a diet supplement of OFI on HRV in athletes. The first day, heart rate (HR) was measured at rest in supine (SU) and standing (ST) positions to analyze HRV in 10 athletes, followed by a randomized assignment to an OFI (5) or placebo (5) group. The next day, the athletes repeated the HRV test. One month later the crossover protocol was applied. In OFI, the high-frequency-activity HF(SU) (1,773 +/- 2,927 vs. 5,856 +/- 8,326 ms(2), p < .05), HF(ST) (295 +/- 313 vs. 560 +/- 515 ms(2), p < .05), and low-frequency LF(SU) (1,621 +/- 1,795 vs. 6,029 +/- 9,007 ms(2), p < .01) increased. HR(SU) (66 +/- 13 vs. 57 +/- 11 beats/min, p < .01) and HR(ST) (87 +/- 11 vs. 76 +/- 9 beats/min, p < .01) decreased. A diet supplement of OFI increases HF and LF activities and decreases HR.     

多感知音乐疗法对心率变异性的影响

目的:探讨音乐疗法对心率变异性的影响。方法:对20名受试者进行音乐疗法实验,用3种方法分析治疗前、中、后心率变异性各种参数的变化。结果:随着治疗时间的增加,受试者主观感觉明显放松。心率变异性的VLF、LF、HF成分在音乐治疗后明显增加,而LF/HF无明显变化规律。音乐治疗后的近似熵也普遍低于音乐治疗前。结论:轻松的音乐可以增加副交感神经系统的活性,对心率变异性的影响显著。     

Effects of dinner composition on postprandial macronutrient oxidation in prepubertal girls

OBJECTIVE: To see whether a fat-rich (50%) evening meal promoted fat oxidation and a different spontaneous food intake on the following day at breakfast than a meal with a lower fat content (20%) in 10 prepubertal obese girls. RESEARCH METHODS AND PROCEDURES: The postabsorptive and postprandial (10.5 hours) energy expenditure after a low-fat (LF) (20% fat, 68% carbohydrate, 12% protein) and an isocaloric (2.1 MJ) and isoproteic high-fat (HF; 50% fat, 38% carbohydrate, 12% protein) meal were measured by indirect calorimetry. RESULTS: Fat oxidation was not significantly different after the two meals [LF, 31 +/- 9 vs. HF, 35 +/- 9 g/10.5 hours, p = not significant (NS)]. The girls oxidized 1.8 +/- 0.9 times more fat than that ingested (11.1 grams) with the LF meal vs. 0.3 +/- 0.3 times more fat than that ingested (27.1 grams) with the HF meal (p < 0.001). Carbohydrate oxidation was significantly higher after an LF than an HF meal (39 +/- 12 vs. 29 +/- 9 g/10.5 hours, p < 0,05). At breakfast, the girls spontaneously ingested a similar amount of energy (1.5 +/- 0.7 vs. 1.5 +/- 0.6 MJ, p = NS) and macronutrient proportions (fat, 23% vs. 26%, p = NS; protein, 9% vs. 10%; carbohydrate, 68% vs. 64%,) independently of their having eaten an HF or an LF dinner. DISCUSSION: An HF dinner did not stimulate fat oxidation, and no compensatory effect in spontaneous food intake was observed during breakfast the following morning. Cumulated total fat oxidation after dinner was higher than total fat ingested at dinner, but a much larger negative fat balance was observed after the LF meal. Spontaneous energy and nutrient intakes at breakfast were similar after LF and HF isocaloric, isoproteic dinners. This study points out the lack of sensitivity of short-term fat balance to subsequently readjust fat intake and emphasizes the importance of an LF meal to avoid transient positive fat imbalance.     

Insoluble cereal fiber reduces appetite and short-term food intake and glycemic response to food consumed 75 min later by healthy men

BACKGROUND: Insoluble fiber consumption is associated with reduced risk of obesity and diabetes, but its mechanisms of action are unknown. OBJECTIVE: The objective was to describe the effect of insoluble fiber on appetite, short-term food intake, and blood glucose (BG) before and after a meal 75 min later in healthy men. DESIGN: In a crossover design, high-fiber (HF; 33 g insoluble fiber) cereal, low-fiber (LF) cereal, white bread (WB), and water control were administered to young men after an overnight fast. Caloric treatments had similar energy, macronutrient content, volume, and weight. In the first experiment, subjective appetite and BG were measured at 15-min intervals before and after an ad libitum meal at 75 min. In the second experiment, a preset pizza meal (850 kcal) was consumed at 75 min. Appetite and blood glucose were measured for 150 min at fasting and at 15-min intervals before and after the fixed meal. RESULTS: In experiment 1, ad libitum food intake was lower after the HF cereal and WB than after the LF cereal and water (937 +/- 86, 970 +/- 65, 1109 +/- 90, 1224 +/- 89 kcal, respectively; P < 0.001). Appetite was lower (P < 0.05) after the HF cereal than after the WB but not different from the LF cereal. The BG area under the curve (AUC) did not differ among the HF cereal, WB, and LF cereal from 0 to 75 min, but the postmeal BG increased after the WB and LF cereal but not after the HF cereal. In experiment 2, the HF cereal, but not the LF cereal or WB, increased fullness before and prevented an increase in the BG AUC after the preset meal (P < 0.05). CONCLUSION: A serving of 33 g insoluble fiber reduced appetite, lowered food intake, and reduced glycemic response to a meal consumed 75 min later.     

Adaptation to a high-fat diet leads to hyperphagia and diminished sensitivity to cholecystokinin in rats

Rats fed high-fat (HF) diets exhibit reduced sensitivity to some peptide satiety signals. We hypothesized that reduced sensitivity to satiety signals might contribute to overconsumption of a high-energy food after adaptation to HF diets. To test this, we measured daily, 3-h intake of a high-energy, high-fat (HHF, 22.3 kJ/g) test food in rats fed either low-fat (LF) or HF, isoenergetic (16.2 kJ/g) diets. During testing, half of each group received the HHF test food (LF/HHF; HF/HHF), whereas the other half received their respective maintenance diet (LF/LF; HF/HF). Rats fed a HF diet ate more of the HHF food during the 3-h testing period than LF-fed rats (HF/HHF = 7.7 +/- 0.3 g vs. LF/HHF = 5.5 +/- 0.2 g; P = 0.003). Rats tested on their own maintenance diets had similar intakes (HF/HF = 3.2 +/- 0.2 g vs. LF/LF = 3.7 +/- 0.3 g), which were lower (P < or = 0.008) than intakes of rats tested on HHF. HHF-tested rats did not differ in body weight by the end of wk 2 of testing. In a subsequent short-term choice preference test, rats exhibited an equal relative preference for HHF irrespective of their maintenance diets (HF = 63.1%, LF = 68.1%, P = 0.29). Finally, we examined the effect of intraperitoneal NaCl or cholecystokinin (CCK)-8 (100 and 250 ng/kg) injection on 1-h food intake. Both doses of CCK significantly suppressed food intake in LF-fed rats but not HF-fed rats. These results demonstrate that chronic ingestion of a HF diet leads to short-term overconsumption of a high-energy, high-fat food compared with LF-fed cohorts, which is associated with a decreased sensitivity to CCK.     

Differential effects of amino acid and ketoacid on protein metabolism in humans

We examined the effects of insulin, amino acid (AA), and branched-chain ketoacid (KA) availability on leucine kinetics in eight healthy volunteers (age = 22 +/- 2 y, body mass index = 24 +/- 1 kg) by using the euglycemic insulin clamp and [1-14C] leucine turnover techniques. Four experimental conditions were studied: study I, hyperinsulinemia; study II, hyperinsulinemia with maintenance of basal plasma AA and branched-chain KA concentrations; study III, hyperinsulinemia with hyperaminoacidemia and basal plasma branched-chain KA concentrations; and study IV, hyperinsulinemia plus basal plasma AA concentrations and elevated branched-chain KA levels. Basal endogenous leucine flux (ELF) averaged 1.20 +/- 0.05 (mumol.kg-1.min-1, mean +/- SE); basal leucine oxidation (LOX) was 0.25 +/- 0.01; and basal non-oxidative leucine disposal (NOLD) was 0.95 +/- 0.04. ELF significantly decreased in study I (0.77 +/- 0.06 mumol.kg-1.min-1, P < 0.01 versus basal). When plasma AA and branched-chain KA were either maintained at their basal levels (study II) or increased above baseline values (studies III and IV), ELF declined further (0.64 +/- 0.05, 0.66 +/- 0.02, and 0.66 +/- 0.03 mumol.kg-1.min-1, respectively; all Ps < 0.01 versus basal and P < 0.01 versus study I). LOX declined in study I (0.12 +/- 0.02 mumol.kg-1.min-1, P < 0.01 versus basal) but increased significantly in studies II, III, and IV (0.31 +/- 0.04, 0.37 +/- 0.03, and 0.40 +/- 0.03 mumol.kg-1.min-1, respectively, all Ps < 0.01 versus basal, P < 0.05 study IV versus study II, and P < 0.05 study III versus study II). NOLD declined in study I (0.65 +/- 0.05 mumol/kg.min, P < 0.01 versus basal), whereas neither the maintenance of basal plasma AA/branched-chain KA levels (study II; 0.89 +/- 0.2 mumol.kg-1.min-1) nor the elevation of plasma branched-chain KA concentration (study IV; 0.96 +/- 0.1 mumol.kg-1.min-1) increased NOLD above baseline level. A stimulation of NOLD was observed only when plasma AA levels were increased (study III; 1.23 +/- 0.03 mumol/kg.min, P < 0.01 versus basal). In conclusion, the present data do not support the concept of a direct anabolic action of ketoanalogs but do provide additional evidence for the pivotal role of AA availability in the stimulation of whole-body protein synthesis.     

Body water distribution in severe obesity and its assessment from eight-polar bioelectrical impedance analysis

OBJECTIVE: To measure body water distribution and to evaluate the accuracy of eight-polar bioelectrical impedance analysis (BIA) for the assessment of total body water (TBW) and extracellular water (ECW) in severe obesity. DESIGN: Cross-sectional study. SETTING: Obesity clinic. SUBJECTS: In all, 75 women aged 18-66 y, 25 with body mass index (BMI) between 19.1 and 29.9 kg/m(2) (ie not obese), 25 with BMI between 30.0 and 39.9 kg/m(2) (ie class I and II obese), and 25 with BMI between 40.0 and 48.2 kg/m(2) (ie class III obese). METHODS: TBW and ECW were measured by (2)H(2)O and Br dilution. Body resistance (R) was obtained by summing the resistances of arms, trunk and legs as measured by eight-polar BIA (InBody 3.0, Biospace, Seoul, Korea). The resistance index at a frequency of x kHz (RI(x)) was calculated as height (2)/R(x). RESULTS: ECW : TBW was similar in women with class III (46+/-3%, mean+/-s.d.) and class I-II obesity (45+/-3%) but higher than in nonobese women (39+/-3%, P<0.05). In a random subsample of 37 subjects, RI(500) explained 82% of TBW variance (P<0.0001) and cross-validation of the obtained algorithm in the remaining 38 subjects gave a percent root mean square error (RMSE%) of 5% and a pure error (PE) of 2.1 l. In the same subjects, RI(5) explained 87% of ECW variance (P<0.0001) and cross-validation of the obtained algorithm gave a RMSE% of 8% and a PE of 1.4 l. The contribution of weight and BMI to the prediction of TBW and ECW was nil or negligible on practical grounds. CONCLUSIONS: ECW : TBW is similar in women with class I-II and class III obesity up to BMI values of 48.2 kg/m(2). Eight-polar BIA offers accurate estimates of TBW and ECW in women with a wide range of BMI (19.1-48.2 kg/m(2)) without the need of population-specific formulae.     

医专大学生手机使用行为、手机依赖综合征与睡眠质量的相关研究

目的 分析医专大学生手机使用行为、手机依赖综合征对睡眠质量的影响。方法 采用自编一般资料及手机使用情况调查表、大学生手机成瘾倾向量表(MPATS)、匹兹堡睡眠质量指数(PSQI)对医专1073名大学生进行问卷调查。结果 医专大学生手机依赖综合征检出率为13.14%;手机依赖者比非手机依赖者更多地选择社交软件,非手机依赖者使用打电话、看电子书的频率比手机依赖者高,差异具有统计学意义(P<0.05);每天手机使用时间越长,每周睡前使用手机次数越多,睡眠质量越差(P<0.05);手机依赖者睡眠质量显著低于比非手机依赖者(P<0.05);多元逐步回归结果显示,每天手机使用时间、手机依赖量表总分均是睡眠质量的影响因素。结论 每天手机使用时间越长,每周睡前使用手机次数越多,手机依赖越严重,睡眠质量越差。     

Heart rate variability and left ventricular diastolic function in anorexia nervosa

PURPOSE: To investigate the cardiac effects of starvation in a group of adolescents with anorexia nervosa (AN). METHODS: Twenty-five patients with AN (range 13-20 years), compared with 25 age-matched thin and 25 age-matched control women with body mass index > 20 Kg/m(2), underwent a complete clinical evaluation, including echocardiogram and 24-hour electrocardiogram monitoring to evaluate heart rate variability (HRV) indices. RESULTS: Compared to both thin and control women, patients with AN had greater HRV time domain indices (SDNN: 246.5 +/- 32.4 vs. 170.4 +/- 24 ms and vs. 181 +/- 21.2 ms, p <.001), and in the frequency domain a lower LF/HF ratio (4.2 +/- 1.3 vs. 6.7 +/- 1.2 and vs. 6.8 +/- 1.3 ms, p <.001). AN patients showed reduced left ventricular mass with normal systolic function and typical diastolic patterns, characterized by a lower peak velocity transmitral flow in late diastole (peak A: 35.9 +/- 8.5 vs. 45.2 +/- 7.3 cm/sec and vs. 46.6 +/- 6.3 cm/sec, p <.01), a comparable peak velocity in early diastole (peak E: 92.7 +/- 12.1 vs. 83 +/- 6.2 and vs. 86.8 +/- 9.1 cm/sec, ns) and, subsequently, a greater E/A ratio (2.8 +/- 0.7 vs. 1.8 +/- 0.3 and vs. 1.9 +/- .5, p <.01) than thinness and control groups. Moreover, SDNN was also positively related to E/A ratio (r =.54, p <.01). CONCLUSIONS: Our findings demonstrate a cardiovascular vagal hyperactivity in AN, which appears to influence the ventricular diastolic dynamics. HRV and diastolic function analysis may represent useful tools in monitoring anorexia-induced cardiac modifications.     

Consumption of flavonoids in onions and black tea: lack of effect on F2-isoprostanes and autoantibodies to oxidized LDL in healthy humans

BACKGROUND: Oxidative damage to lipids in vivo may be involved in the development of atherosclerosis and cancer. Onions and black tea are foods rich in flavonoids, predominantly the flavonoid quercetin, which is a potent in vitro inhibitor of membrane lipid peroxidation and LDL oxidation. OBJECTIVE: Our objective was to investigate the effects of consuming a high-flavonoid (HF) diet enriched with onions and black tea on indexes of oxidative damage in vivo compared with a low-flavonoid (LF) diet. DESIGN: Thirty-two healthy humans were studied in a randomized crossover design. Indexes of oxidative damage used were plasma F2-isoprostanes (a biomarker of lipid peroxidation in vivo) and the titer of antibodies to malondialdehyde (MDA)-modified LDL. RESULTS: There were no significant differences in the intake of macronutrients or assessed micronutrients, plasma F2-isoprostane concentrations, and MDA-LDL autoantibody titer between the HF and LF dietary treatments. In the men, however, plasma concentrations of the F2-isoprostane 8-epi-prostaglandin F2alpha were slightly higher after the HF treatment phase than after the LF treatment [0.31 +/- 0.029 nmol/L (111 +/- 10.4 ng/L) compared with 0.26 +/- 0.022 nmol/L (92 +/- 7.8 ng/L); P = 0.041]. In all subjects, plasma quercetin concentrations were significantly higher after the HF treatment phase than after the LF treatment: 221.6 +/- 37.4 nmol/L compared with less than the limit of detection of 66.2 nmol/L. CONCLUSION: Flavonoid consumption in onions and tea had no significant effect on plasma F2-isoprostane concentrations and MDA-LDL autoantibody titer in this study and thus does not seem to inhibit lipid peroxidation in humans.