A critical body residue approach for predicting persistent bioaccumulative toxicant effects on reproduction and population dynamics of meiobenthic copepods

Critical body residues (CBRs) are the measured tissue toxicant concentrations yielding a median dose-response on a dry-weight or lipid-normalized basis. They facilitate management decisions for species protection using tissue analysis. Population CBR is the mean dose yielding 50% population suppression and was predicted here in Amphiascus tenuiremis for fipronil sulfide (FS) using lifetables and the Leslie matrix. Microplate bioassays (ASTM E-2317-14) produced biomass sufficient for dry mass and lipid-normalized CBR estimates of reproduction (fertility) and population growth suppression. Significant FS toxic effects were delayed naupliar development (at ≥0.10?μg?L(-1)), delayed copepodite development (at 0.85?μg?L(-1)), decreased reproductive success (at ≥ 0.39?μg?L(-1)), and decreased offspring production (at 0.85?μg?L(-1)). A reproductive median effective concentration (EC50) of 0.16?μg?L(-1) (95% CI: 0.12-0.21?μg?L(-1)) corresponded to an adult all-sex CBR and lipid-normalized CBR of 0.38?pg FS?·?μg(-1) dry weight (95% CI: 0.27-0.52?pg FS?·?μg(-1)) or 2.8?pg FS?·?μg(-1) lipid (95% CI: 2.2-3.6?pg FS?·?μg(-1)), respectively. Copepod log bioconcentration factor (BCF)?=?4.11?±?0.2. Leslie matrix projections regressed against internal dose predicted fewer than five gravid females in a population by the third generation at 0.39 and 0.85?μg FS?·?L(-1) (i.e., 9.6-10.2?μg FS?·?μg(-1) lipid), and 50% population suppression at a CBR of 1.6?pg FS?·?μg(-1) lipid. This more integrative population CBR as a management tool would fall 1.75 times below the CBR for the single most sensitive endpoint-fertility rate.     

Lower oxidation of a high molecular weight glucose polymer vs. glucose during cycling

We previously reported no difference in the oxidation rate of a high molecular weight glucose polymer (GP) vs. maltodextrin (8?kDa) during exercise; however, the ingestion rate (1.8?g·min(-1)) was above the glucose absorption-oxidation maxima (～1.0?g·min(-1)), possibly masking either faster gastric emptying of the GP and delivery to the circulation observed at rest or physical properties of the GP that might slow intestinal absorption. Therefore, we asked whether GP oxidation could be differentially affected when ingested at a lower rate (0.8?g·min(-1)). Eight cyclists performed three 150-min rides at 50% peak power while ingesting solutions containing 8% GP (500-750?kDa, 21 mosm·kg(-1)), 8% glucose (469 mosm·kg(-1)), or water. The exogenous carbohydrate oxidation rate was determined using stable isotope methodology and indirect calorimetry. Glucose and GP were oxidized on average at 0.54?g·min(-1) (coefficient of variation (CV) 37%) and 0.41?g·min(-1) (CV 60%), respectively, which equated to a moderate (effect size) reduction of 24% (90% confidence limits:?±22%) with GP. The endogenous carbohydrate oxidation rate with glucose (1.04?g·min(-1); CV 68%) was not clearly different from GP (15%; 90% confidence limits:?±24%) and total carbohydrate oxidation rate was not affected. Plasma glucose concentration was 8.3% lower (±7.0%, moderate) and nausea 0.4 units higher (±0.4 units, moderate) with GP vs. glucose. To conclude, the oxidation rate of GP when ingested below the glucose absorption-oxidation maxima is slower than glucose. Further work could determine the physical properties of the carbohydrate and (or) physiological mechanism determining this response. Meanwhile, utility of the glucose polymer over glucose or maltodextrin in energy beverages appears limited.     

Cellular responses in skeletal muscle to a season of ice hockey

We hypothesized that a season of ice hockey would result in extensive remodeling of muscle. Tissue sampled from the vastus lateralis of 15 players (age = 20.6 ± 0.4 years; mean ± SE) prior to (PRE) and following (POST) a season was used to characterize specific adaptations. Measurement of representative metabolic pathway enzymes indicated higher maximal activities in POST than in PRE (p < 0.05) for succinic dehydrogenase (3.26 ± 0.31 vs. 3.91 ± 0.11 mol mg protein(-1) min(-1)), citrate synthase (7.26 ± 0.70 vs. 8.70 ± 0.55 mol mg protein(-1) min(-1)), and phosphofructokinase (12.8 ± 1.3 vs. 14.4 ± 0.96 mol mg protein(-1) min(-1)) only. The season resulted in an increase in Na+-K+-ATPase concentration (253 ± 6.3 vs. 265 ± 6.0 pmol g(-1) wet weight), a decrease (p < 0.05) in maximal activity of the sarcoplasmic reticulum Ca2+-ATPase (107 ± 4.2 micromol g protein(-1) min(-1) vs. 92.0 ± 4.6 micromol g protein(-1) min(-1)), and no change in the distribution (%) of fibre types. A smaller (p < 0.05) cross-sectional area (CSA) for both type I (-11.7%) and type IIA (-18.2%) fibres and a higher (p < 0.05) capillary count/CSA for type I (+17.9%) and type IIA (+17.2%) were also found over the season. No changes were found in peak oxygen consumption (51.4 ± 1.2 mL kg(-1) min(-1) vs. 52.3 ± 1.3 mL kg(-1) min(-1)). The results suggest, based on the alterations in oxidative and perfusion potentials and muscle mass, that the dominant adaptations are in support of oxidative metabolism, which occurs at the expense of fibre CSA and possibly force-generating potential.     

Hydration status and fluid and sodium balance in elite Canadian junior women's soccer players in a cool environment

Dehydration can impair mental and on-field performance in soccer athletes; however, there is little data available from the female adolescent player. There is a lack of research investigating fluid and electrolyte losses in cool temperatures. Therefore, the purpose of this study was to investigate the pretraining hydration status, fluid balance, and sweat sodium loss in 34 female Canadian junior elite soccer athletes (mean age ± SD, 15.7 ± 0.7 years) in a cool environment. Data were collected during two 90 min on-field training sessions (9.8 ± 3.3 °C, 63% ± 12% relative humidity). Prepractice urine specific gravity (USG), sweat loss (pre- and post-training body mass), and sweat sodium concentration (regional sweat patch method) were measured at each session. Paired t tests were used to identify significant differences between training sessions and Pearson's product moment correlation analysis was used to assess any relationships between selected variables (p ≤ 0.05). We found that 45% of players presented to practice in a hypohydrated state (USG > 1.020). Mean percent body mass loss was 0.84% ± 0.07% and sweat loss was 0.69 ± 0.54 L. Although available during each training session, fluid intake was low (63.6% of players consumed <250 mL). Mean sweat sodium concentration was 48 ± 12 mmol·L?1. Despite low sweat and moderate sodium losses, players did not drink enough to avoid mild fluid and sodium deficits during training. The findings from this study highlights the individual variations that occur in hydration management in athletes and thus the need for personalized hydration guidelines.     

An exploratory study of sodium, potassium, and fluid nutrition status of tube-fed nonambulatory children with severe cerebral palsy

Children with severe cerebral palsy (CP) often have lower mineral intakes than healthy children. It is unknown if their lower nutrient intakes are adequate to meet their needs. The objective of this study was to examine the sodium, potassium, phosphate, and fluid status of primarily tube-fed nonambulatory children with severe CP. The design consisted of a cross-sectional exploratory study and a clinical trial of sodium supplementation. Nutritional status was determined among primarily tube-fed children (aged 2 to 17 years) with CP based on blood and urine samples, anthropometry, and 3-day food records. Mineral and fluid status was evaluated by a nephrologist blind to nutrient intakes. Twenty children supplied food records, blood samples, and anthropometric measurements, and 16 supplied urine samples. Six (37.5%) of those who provided urine samples were considered possibly dehydrated, as urine osmolality was >600 mmol·kg(-1). Six (60%) of the 10 children with satisfactory fluid status (low urine osmolality) were considered to have a possible dietary sodium deficiency based on a very low urine sodium concentration (<20 mmol·L(-1)). Those considered to have a possible dietary sodium deficiency had a significantly lower sodium intake (48% ± 15% Adequate Intake (AI)) compared with those considered sodium sufficient (73% ± 20% AI) (p = 0.031). One child was considered possibly phosphorus deficient, but none was assessed as likely potassium deficient. The conclusion was that sodium deficiencies were likely prevalent among the children. The findings from this small observational study suggest that sodium intakes for tube-fed children with CP should be maintained near the AI for their age. Hydration status of children receiving hypercaloric formulas should be monitored.     

Malleability of human skeletal muscle sarcoplasmic reticulum to short-term training

This study investigated the hypothesis that adaptations would occur in the sarcoplasmic reticulum in vastus lateralis soon after the onset of aerobic-based training consistent with reduced Ca2?-cycling potential. Tissue samples were extracted prior to (0 days) and following 3 and 6 days of cycling performed for 2 h at 60%-65% of peak aerobic power (VO?(peak)) in untrained males (VO?(peak) = 47 ± 2.3 mL·kg?1·min?1; mean ± SE, n = 6) and assessed for changes (nmol·mg protein?1·min?1) in maximal Ca2?-ATPase activity (V(max)), Ca2?-uptake, and Ca2?-release (phase 1 and phase 2) as well as the sarcoplasmic (endoplasmic) reticulum Ca2?-ATPase (SERCA) isoforms. Training resulted in reductions (p < 0.05) in SERCA1a at 6 days (-14%) but not at 3 days. For SERCA2a, reductions (p < 0.05) were also noted only at 6 days (-7%). For V(max), depressions (p < 0.05) were found at 6 days (172 ± 11) but not at 3 days (176 ± 13; p < 0.10) compared with 0 days (192 ± 11). These changes were accompanied by a lower (p < 0.05) Ca2?-uptake at both 3 days (-39%) and 6 days (-48%). A similar pattern was found for phase 1 Ca2?-release with reductions (p < 0.05) of 37% observed at 6 days and 23% (p = 0.21) at 3 days of training, respectively. In a related study using the same training protocol and participant characteristics, microphotometric determinations of V(max) indicated reductions (p < 0.05) in type I at 3 days (-27%) and at 6 days (-34%) and in type IIA fibres at 6 days (-17%). It is concluded that in response to aerobic-based training, sarcoplasmic reticulum Ca2?-cycling potential is reduced by adaptations that occur soon after training onset.     

牛血铅成分分析标准物质的研制

目的 研制牛血铅成分分析国家一级标准物质.方法 根据<一级标准物质技术规范(JJG1006-1994)>和ISO 17511要求,按照剂量.效应关系,选择2头雄性健康牛,以醋酸铅为饲料添加物,按每天2～5 mg/ks体重剂量喂养,制作牛血铅模型.当牛血铅分别达到90～100、190～200、280～300μg/L时,采集牛血,分装于密封性良好的耐低温管中,辐射后冷冻保存.进行均匀性检验、稳定性监测及放置室温时间检验.选用核素稀释质谱法(isotopic dilution mass spectrometry,ID-MS)为研制物质铅含量赋值.通过对美国NIST SRM 955b两个浓度样品铅含量的表达验证赋值方法.结果 铅含量分别为90～100、190～200、280～300 μg/L的低、中、高浓度组研制物质均匀性单因素方差分析F值分别为0.61、1.64、0.28,P值均大于0.05,说明3组研制物质均匀.经过14个月监测,3组浓度相对标准偏差分别为0.85%、1.05%和0.49%;与14个月前比较,t值分别为0.787、1.132、0.854,P值均大于0.05,表明研制物质14个月时间数值稳定.3组牛血铅的特性量值±不确定度分别为(102.4±5.5)、(181.2±4.0)、(304.5±3.9)μg/L.通过对美国NIST SRM 955b两个浓度样品铅含量的准确重现,说明赋值方法和程序正确.置常温下4 d内测定,结果稳定.结论 该络合型牛血铅成分分析研制物质的各项指标均达到国家一级标准物质的要求.     

Independent and combined effects of carbohydrate and caffeine ingestion on aerobic cycling performance in the fed state

The purpose of this study was to examine the independent and combined effects of carbohydrate and caffeine ingestion on performance and various physiological parameters during aerobic cycling (～1 h). Ten male cyclists (28 ± 9 years, 73 ± 6 kg, 66 ± 9 mL·kg(-1)·min(-1) maximal oxygen consumption) performed 20 min of steady-state (SS) cycling (60% peak power (W(max))) followed by a simulated 20-km time trial (TT) under placebo (PLA), carbohydrate (CHO), caffeine (CAF), and combined CAF-CHO conditions, all of which were performed in the fed state. CAF-CHO improved TT performance by 3.4% ± 2% (84 ± 57 s) compared with PLA (p < 0.05), whereas no differences were detected among CHO, CAF, and PLA. The SS respiratory exchange ratio was elevated in CHO (0.92 ± 0.03), CAF (0.96 ± 0.07), and CAF-CHO (0.95 ± 0.02) compared with PLA (0.89 ± 0.03) (p < 0.05). Post-SS and post-TT blood glucose levels were also elevated in CAF-CHO (88.3 ± 16.7 mg·dL(-1) and 111.2 ± 33.5 mg·dL(-1), respectively) compared with PLA (74.5 ± 9.8 mg·dL(-1) and 85.4 ± 17.6 mg·dL(-1), respectively) (p < 0.05). Treatment conditions did not differentially impact SS pulmonary ventilation, oxygen consumption, heart rate, peak quadriceps muscle strength, rating of perceived exertion, or blood lactate. CAF and CHO improved TT performance when taken together but not independently. Although the present work did not yield any definitive physiological mechanisms for the performance findings, these data suggest that cyclists in the fed state should ingest carbohydrate and caffeine together to improve time trial performance.     

中国膳食暴露评估模型软件开发及验证

目的 开发具有我国自主知识产权的膳食暴露评估模型软件,并按国际通用标准对其概率评估模型进行合理性和计算正确性验证.方法 基于我国膳食调查及食品污染物监测数据,采用统计分析系统(SAS)编程技术建立膳食暴露评估模型计算模块和人机对话界面.使用全国2～7岁儿童膳食暴露概率评估模型的结果与点估计及江苏省金湖地区2～7岁儿童双份饭研究结果相比较的方法验证模型的合理性.通过随机抽取10 000人天的膳食暴露数据与@Risk软件计算结果相比较的方法验证软件外部计算的正确性;以模型计算的2～3岁儿童食物消费量及铅污染残留浓度数据的均数漂移为指标验证本软件内部计算的正确性.结果 成功开发了包括多种膳食暴露评估模型并具有易于操作用户界面的中国膳食暴露评估模型软件.在合理性验证方面,概率评估模型结果低于点估计,其中黄瓜的乙酰甲胺磷膳食暴露点估计为4.78 μg·kg~(-1)·d~(-1),概率评估的P99.9为0.39μg·kg~(-1)·d~(-1);同时概率评估高于双份饭结果,儿童铅膳食暴露概率评估P95为11.08μg·kg~(-1)·d~(-1),双份饭P95为5.75μg·kg~(-1)·d~(-1).在计算正确性验证方面,概率评估模型计算结果与@Risk结果接近,乙酰甲胺磷膳食暴露概率评估计算的P95为4.27μg·kg~(-1)·d~(-1),@Risk计算的P95为4.24 μg·kg~(-1)·d~(-1);消费量及污染物的均数漂移表现为以零为中心的随机误差分布,漂移范围为0.05%～11.9%.结论 开发的中国膳食暴露评估模型软件计算正确,结果合理,对提升我国膳食暴露评估技术水平具有现实意义.     

Effect of training load on simulated team sport match performance

This study examined the effect of training load on running performance and plasma markers of anaerobic metabolism, muscle damage, and inflammation during a simulated team sport match performance. Seven team sport athletes (maximal oxygen uptake, 47.6 ± 4.2 mL·kg(-1)·min(-1)) completed a 60-min simulated team sport match before and after either 4 days of HIGH or LOW training loads. Venous blood samples were taken pre-match, immediately post-match, and 2 h post-match for interlukin-6, monocyte chemoattractant protein-1 (MCP-1), creatine kinase (CK), lactate dehydrogenase, C-reactive protein, xanthine oxidase (XO), and hypoxanthine. Following HIGH training load, sprint velocity decreased (p < 0.001) and total distance covered was reduced (HIGH 5495 ± 670 m, LOW 5608 ± 674 m, p = 0.02) was observed during the simulated match protocol compared with the LOW match simulation. Decreased performance capacity was accompanied by a significant increase in serum CK concentration (HIGH 290 ± 62 U·L(-1), LOW 199 ± 33 U·L(-1), p = 0.005). The HIGH training also resulted in a decreased post-match hypoxanthine and MCP-1 and an increase in XO concentration 2 h post-match. Four days of increased training load reduced running performance during the match simulation and altered the metabolic and inflammatory response to high-intensity intermittent exercise.     

Characterization of Salmonella enterica isolates from turkeys in commercial processing plants for resistance to antibiotics, disinfectants, and a growth promoter

Salmonella enterica isolates from turkeys in two commercial processing plants (1 and 2) were characterized for susceptibility to antibiotics, disinfectants, and the organoarsenical growth promoter, 4-hydroxy-3-nitrophenylarsonic acid (3-NHPAA, roxarsone), and it's metabolites, NaAsO(2) (As(III)) and Na(2)HAsO(4) ? 7H(2)O (As(V)). The 130 Salmonella serovars tested demonstrated a low incidence of resistance to the antibiotics gentamicin (GEN), kanamycin (KAN), sulfamethoxazole (SMX), streptomycin (STR), and tetracycline (TET). Isolates resistant to antibiotics were most often multidrug resistant. Serovars Hadar and Typhimurium were resistant to KAN, STR, and TET and GEN, SMX, and STR, respectively. All isolated Salmonella serovars were resistant to the disinfectant chlorhexidine with minimum inhibitory concentrations (MICs; 1-8?μg/mL), and they were susceptible to triclosan and benzalkonium chloride. The didecyldimethylammonium chloride component was the most active ammonium chloride tested. No cross-resistance was observed between antibiotics and disinfectants. The MICs for 3-NHPAA (4096?μg/mL) were consistent between processing Plant 1 and Plant 2, but MICs for the 3-NHPAA metabolites (As(III) and As(V)) were higher in Plant 1 than in Plant 2. In Plant 1, 76% of the isolates had MICs >256?μg/mL for As(III) and 92% of the isolates had MICs >1024?μg/mL for As(V). In Plant 2, all of the isolates had MICs ≤256?μg/mL for As(III) and 90% of the isolates had MICs ≤1024?μg/mL for As(V). Only 4 Salmonella serovars were isolated from Plant 1, but 10 serovars were isolated from Plant 2. S. enterica serovar Derby from Plant 1 was highly resistant to As(III) and As(V) with MICs >1024 and >8192?μg/mL, respectively, suggesting previous exposure to high arsenic metabolite concentrations. These levels may have been high enough to kill other Salmonella serovars, thus possibly explaining the lack of serovar diversity observed in Plant 1. The application of a growth promoter may affect the serovar diversity in treated birds.     

高效液相色谱-电感耦合等离子体质谱法测定人尿中6种砷形态化合物

目的建立高效液相色谱-电感耦合等离子体质谱（HPLC?ICP?MS）测定人尿中砷胆碱（AsC）、砷甜菜碱（AsB）、三价砷（As3+）、二甲基砷酸（DMA5+）、甲基砷酸（MMA5+）、五价砷（As5+）等6种砷形态化合物含量的方法。方法优化流动相pH值及无水乙醇含量,以50 mmol·L-1的（NH₄）₂CO₃溶液（含2%无水乙醇、pH=8.5）为流动相,用He模式消除氯离子（Cl-）干扰,通过Hamilton PRP X?100阴离子交换色谱柱对 10倍稀释的人尿砷形态化合物进行分离,与ICP?MS联用,建立6种砷形态化合物的检测方法。结果6种砷形态化合物13 min左右可以得到完全分离,标准曲线线性相关系数为0.999,检出限为0.10~0.20 μg·L-1,定量限为0.30~0.50 μg·L-1。精密度实验显示,加标浓度0.20 μg·L-1时相对标准偏差（RSD）为5.96%~9.07%;加标浓度2.00 μg·L-1时RSD为2.48%~6.38%,加标浓度5.00 μg·L-1时RSD为1.41%~2.57%。准确度实验显示,加标回收率为80%~125%。结论所建立HPLC?ICP?MS测定人尿6种砷形态化合物的方法,快速、准确、灵敏,可应用于人群尿砷的测定。     

某蓄电池厂作业工人血铅、尿铅与指甲铅检测结果分析

目的 通过对某蓄电池厂工作人员血铅、尿铅及指甲铅水平的分析, 探讨三者在职业病诊断中的价值。
方法 留取该企业203名作业工人静脉血标本、尿标本以及指甲标本, 用石墨炉原子吸收光谱法测定血铅、尿铅以及指甲铅水平, 并对数据进行统计学分析。
结果 该企业铅烟时间加权平均浓度(C_TWA)为(0.31 ±0.37) mg/m3, 铅尘C_TWA为(0.28 ±0.50) mg/m3。员工血铅均值为(280.37 ±164.86)μg/L, 异常率为22.7%;尿铅均值为(0.035 ±0.042) mg/L, 异常率为11.3%;指甲铅均值为(1 407.96 ±2 625.26)μg/g。男性工人血铅、尿铅、指甲铅水平均高于女性工人, 差异有统计学意义(P < 0.01或0.05)。不同工龄组工人血铅、尿铅异常率差异均无统计学意义(P>0.05)。血铅、尿铅水平和指甲铅水平均存在相关关系(r=0.544、0.546, P < 0.01)。
结论 该蓄电池厂铅作业工人血铅、尿铅、指甲铅均有异常, 指甲铅和血铅水平有较好的相关性。指甲铅水平可作为职业性慢性铅中毒诊断的一个辅助指标, 值得进一步探讨。
     

Awareness and use of caffeine by athletes competing at the 2005 Ironman Triathlon World Championships

This study assessed the knowledge, prevalence, and quantity of caffeine use by athletes competing at the 2005 Ironman Triathlon World Championships. Caffeine-related questionnaires were self-administered to 140 (105 male and 35 female, 40.3 +/- 10.7 y) athletes representing 16 countries. Fifty of these athletes further consented to immediate post-race blood samples for analysis of plasma caffeine and paraxanthine using high-performance liquid chromatography (HPLC). Seventy-two percent of 70 athletes correctly identified caffeine as being an unrestricted substance in triathlon. The majority of athletes [125 (89%)] were planning on using a caffeinated substance immediately prior to or throughout the race. Cola drinks (78%), caffeinated gels (42%), coffee (usually pre-race) (37%), energy drinks (13%), and NoDoz tablets (9%) were the most popular caffeinated choices. Mean +/- standard deviation (and range) post race plasma caffeine and paraxanthine levels were 22.3 +/- 20 micromol/L (1.7 to 98.4) and 9.4 +/- 6 micromol/L (1.8 to 28.9), respectively. Seven athletes (14%) finished with plasma caffeine levels > or = 40 micromol/L. Plasma values from elite athletes did not differ from age group competitors. Despite the prevalence of its consumption and the training experience of this athletic group, over one quarter of athletes remained either confused or uninformed about caffeine's legality. Levels of plasma caffeine taken immediately post race indicated that athletes typically finish with quantities of caffeine that have been shown to improve endurance performance (i.e., approximately 20 micromol/L or a dose of > or = 3 mg/kg body weight).     

Leucine-protein supplemented recovery feeding enhances subsequent cycling performance in well-trained men

The purpose of this study was to determine whether a practical leucine-protein, high-carbohydrate postexercise feeding regimen could improve recovery, as measured by subsequent cycling performance and mechanistic markers, relative to control feeding. In a crossover, 10 male cyclists performed 2- to 2.5-h interval training bouts on 3 consecutive evenings, ingesting either leucine-protein, high-carbohydrate nutrition (0.1/0.4/1.2/0.2?g·kg(-1)·h(-1); leucine, protein, carbohydrate, fat, respectively) or isocaloric control (0.06/1.6/0.2?g·kg(-1)·h(-1); protein, carbohydrate, fat, respectively) nutrition for 1.5?h postexercise. Throughout the experimental period diet was controlled, energy and macronutrient intake balanced, and protein intake clamped at 1.6?g·kg(-1)·day(-1). The alternate supplement was provided the next morning, thereby isolating the postexercise nutrition effect. Following 39?h of recovery, cyclists performed a repeat-sprint performance test. Postexercise leucine-protein ingestion improved mean sprint power by 2.5% (99% confidence limit,?±2.6%; p = 0.013) and reduced perceived overall tiredness during the sprints by 13% (90% confidence limit,?±9.2%), but perceptions of leg tiredness and soreness were unaffected. Before exercise, creatine-kinase concentration was lowered by 19% (90% confidence limits,?±18%), but lactate dehydrogenase and pressure-pain threshold were unaltered. There was a small reduction in anger (25%?± 18%), but other moods were unchanged. Plasma leucine (3-fold) and essential amino acid (47%) concentrations were elevated postexercise. Net nitrogen balance trended mildly negative in both conditions (mean?± SD: leucine-protein,?-20?± 46?mg·kg(-1) per 24?h; control, -25?± 36?mg·kg(-1) per 24?h). The ingestion of a leucine-protein supplement along with other high-carbohydrate food following intense training on consecutive days enhances subsequent high-intensity endurance performance and may attenuate muscle membrane disruption in well-trained male cyclists.     

食品中玉米赤霉烯酮化学发光酶免疫方法建立

目的建立检测食品中玉米赤霉烯酮(ZEN)快速灵敏化学发光酶免疫方法。方法采用棋盘滴定法确定化学发光检测ZEN最佳工作条件(抗原包被浓度、包被量、一抗和二抗的工作效价、线性范围和检出限等),建立化学发光检测ZEN的方法并对实际样品进行检测,同时将检测结果与液相色谱-串联质谱法(LC-MS/MS)结果进行比较。结果经多次实验,化学发光检测ZEN的工作条件为:玉米赤霉烯酮-牛血清蛋白(ZEN-BSA)最佳包被浓度为0.1μg/mL,包被量为100μL/孔,抗ZEN单克隆抗体的最佳工作效价为1:1600,标准曲线线性范围0.01~50 ng/mL,50%抑制浓度为13.04 ng/mL,ZEN的最低检出浓度为0.007 ng/mL,样品中ZEN的最低检出量为0.15μg/kg,在20~400μg/kg添加水平的回收率范围为66%~115%;用所建方法对23个食品样品进行分析,检测结果与LC-MS/MS结果高度相关(r²=0.98)。结论所建方法准确、灵敏,适用于食品中ZEN污染水平的批量筛选。     

Ingesting a high-dose carbohydrate solution during the cycle section of a simulated Olympic-distance triathlon improves subsequent run performance

The well-established ergogenic benefit of ingesting carbohydrates during single-discipline endurance sports has only been tested once within an Olympic-distance (OD) triathlon. The aim of the present study was to compare the effect of ingesting a 2:1 maltodextrin/fructose solution with a placebo on simulated OD triathlon performance. Six male and 4 female amateur triathletes (age, 25 ± 7 years; body mass, 66.8 ± 9.2 kg; peak oxygen uptake, 4.2 ± 0.6 L·min(-1)) completed a 1500-m swim time-trial and an incremental cycle test to determine peak oxygen uptake before performing 2 simulated OD triathlons. The swim and cycle sections of the main trials were of fixed intensities, while the run section was completed as a time-trial. Two minutes prior to completing every quarter of the cycle participants consumed 202 ± 20 mL of either a solution containing 1.2 g·min(-1) of maltodextrin plus 0.6 g·min(-1) of fructose at 14.4% concentration (CHO) or a sugar-free, fruit-flavored drink (PLA). The time-trial was 4.0% ± 1.3% faster during the CHO versus PLA trial, with run times of 38:43 ± 1:10 min:s and 40:22 ± 1:18 min:s, respectively (p = 0.010). Blood glucose concentrations were higher in the CHO versus PLA trial (p < 0.001), while perceived stomach upset did not differ between trials (p = 0.555). The current findings show that a 2:1 maltodextrin/fructose solution (1.8 g·min(-1) at 14.4%) ingested throughout the cycle section of a simulated OD triathlon enhances subsequent 10-km run performance in triathletes.     

载脂蛋白CⅠ和维生素E结合蛋白与肺结核脂质代谢的相关性

目的：探讨载脂蛋白CⅠ（ApoC1）和维生素E结合蛋白（AFM）与肺结核患者脂质代谢的相关性。方法采用ELISA法检测ApoC1、AFM在31例肺结核患者（肺结核组）和26名正常人（正常对照组）血清中的含量,两组均空腹抽血检测总胆固醇、甘油三酯、高密度脂蛋白、低密度脂蛋白、载脂蛋白A1、载脂蛋白B、脂蛋白A和视黄醇结合蛋白等指标,并分析肺结核组血清差异蛋白质与临床检测指标的相关性。结果肺结核组ApoC1含量为（34.60±4.60）μg/mL,显著低于对照组的（38.43±5.12）μg/mL （t=2.703,P<0.01）;肺结核组AFM含量为（15.69±6.79）μg/mL,高于对照组的（11.95±6.36）μg/mL（t=2.054,P<0.05）,且AFM 与患者的甘油三酯含量存在负相关性（rs=-0.371,P<0.05）;ApoC1与所有临床指标均无相关性。结论 ApoC1和AFM可能参与了肺结核患者的脂质代谢。     

A scientific nutrition strategy improves time trial performance by ≈6% when compared with a self-chosen nutrition strategy in trained cyclists: a randomized cross-over study

We investigated whether an athlete's self-chosen nutrition strategy (A), compared with a scientifically determined one (S), led to an improved endurance performance in a laboratory time trial after an endurance exercise. S consisted of about 1000 mL·h(-1) fluid, in portions of 250 mL every 15 min, 0.5 g sodium·L(-1), 60 g glucose·h(-1), 30 g fructose·h(-1), and 5 mg caffeine·kg body mass(-1). Eighteen endurance-trained cyclists (16 male; 2 female) were tested using a randomized crossover-design at intervals of 2 weeks, following either A or S. After a warm-up, a maximal oxygen uptake test was performed. Following a 30-min break, a 2.5-h endurance exercise on a bicycle ergometer was carried out at 70% maximal oxygen uptake. After 5 min of rest, a time trial of 64.37 km (40 miles) was completed. The ingested nutrition was recorded every 15 min. In S, the athletes completed the time trial faster (128 vs. 136 min; p ≤ 0.001) and with a significantly higher power output (212 vs. 184 W; p ≤ 0.001). The intake of fluid, energy (carbohydrate-, mono-, and disaccharide), and sodium was significantly higher in S compared with A (p ≤ 0.001) during the endurance exercise. In the time trial, only sodium intake was significantly higher in S (p ≤ 0.001). We concluded that a time trial performance after a 2.5-h endurance exercise in a laboratory setting was significantly improved following a scientific nutrition strategy.     

珠海市8～10岁儿童碘营养状况分析

[目的]了解珠海市8～10岁儿童碘营养状况,为制定碘缺乏病防治策略提供基础数据。[方法]以县(区)为单位,按"东、西、南、北、中"5方位抽取随机抽取5所小学;在所抽取小学各随机抽检20名8～10岁儿童尿样,用砷铈催化分光光度法检测其尿碘浓度。[结果]各监测区8～10岁儿童尿碘中位数为200.43～237.81μg/L,50μg/L以下所占比例为1%～3%。全市8～10岁儿童尿碘中位数213.05μg/L,50μg/L以下所占比例为1.67%。[结论]珠海市8～10岁儿童碘营养状态略超过适宜量,处于可接受水平。