离子与脊髓损伤

脊髓损伤后,组织中钙、镁、钾、钠等离子的浓度发生改变,同时,这些离子失衡又加重脊髓损伤。研究脊髓损伤后组织中离子浓度的变化规律,对脊髓损伤的救治具有重要意义。本文就此作一综述。     

绵羊营养研究的新进展(二)

Grace报道了在黑麦草/白三叶草草地上放牧的新西兰罗姆尼羊不同器官和组织中钠、钾、镁、钙、磷、锌、铁、铜和锰的分布。这些矿物质元素的含量与绵羊剪毛后空腹体重的增加和羊毛的生长有关。 Hidiroglou研究饲养在不稳定环境和稳定环境条件下空怀母羊血浆中钙、镁和铁浓度的季节性变化。 Poad研究认为,用萨福克和哥伦比亚公羊杂交的生长羔羊,日粮中的钙量应不超过0.5％,锌不多于19—26ppm。但是,适当提高日粮的钙水平不会招致生长羔羊缺锌症。     

运动对优秀竞走运动员尿电解质排泄的影响

选取 5名优秀竞走运动员 ,研究运动对尿电解质排泄的影响。结果表明 ,运动后尿钾、磷排泄量增加 ,而尿钠排泄量有显著的下降 ,钙与镁的排泄量则无显著变化。提示运动员运动后补充电解质十分必要。     

海洛因依赖者血清中7种微量元素分析

目的　探讨海洛因依赖者血清中钾、钠、氯、钙、镁、磷、铁离子的含量与海洛因依赖的关系。方法　采集 6 0例志愿戒毒的海洛因依赖者血清作为观察组 ,另外采集 90例年龄相似的非药物滥用健康者血清作为对照组 ,分别测定血清中钾、钠、氯、钙、镁、磷、铁离子的含量。结果　观察组血清离子含量分别是 (x±s)mmol/L :钾 :3 9± 0 5、钠 :138 2± 5 5、氯 :10 3 2±5 5、钙 :2 3± 0 2、镁 :1 2± 0 3、磷 :1 4± 0 3;铁 :2 5 2± 4 5 μmol/L ;对照组血清离子含量分别是 (x±S)mmol/L :钾 :3 8± 0 6、钠 :139 1± 5 3、氯 :10 5 2± 5 9、钙 :2 4± 0 3、镁 :1 3± 0 2、磷 :1 3± 0 3;铁 :2 3 9± 4 9μmol/L ;两组比较均无显著性差异 (P >0 0 5 )。结论　海洛因依赖者血清钾、钠、氯、钙、镁、磷、铁离子的含量与非海洛因依赖者无差别     

国内镁剂的应用现状及前景

镁有多种存在形式 ,医学领域的镁多是化合物 ,常用的有硫酸镁 ,门冬氨酸钾镁 ,氧化镁等 ,但对机体起作用的主要是其中的镁离子。镁离子是人体必需的微量元素 ,是仅次于钠、钾、钙的人体第四位阳离子。在细胞内 ,镁离子的重要性仅次于钾离子。镁在生命活动中参于许多生化反应 ,并与多种疾病及其治疗有关。1　镁剂的应用现状1.1　心血管系统　镁对心脏病的治疗机制是多方面的。①抑制心脏传导 ,减少心动过速发生 ;②扩张血管 ,增加冠脉血流 ,降低心脏后负荷 ;③促进心肌产生能量 ;④抑制血小板积聚 ;⑤维持离子和细胞膜结构的稳定[1] 。镁用于…     

精神分裂症患者血清4种宏量元素含量及其相关分析

采用火焰原子吸收法测定精神分裂症患者２８例（首次治疗病人１６例，多次住院治疗病人１２例）和健康对照者１０例血清钠、钾、钙、镁的含量。结果表明，精神分裂症患者血清钙和镁含量显著低于对照组（ｐ＜０．０５），其中首次治疗病人血清镁含量降低程度较多次住院治疗者更明显（ｐ＜０．０５）。相关分析结果，患者组病人血清镁与钙呈负的直线相关，钠与钙、钾与钙呈正的直线相关。     

低氧运动对血清离子浓度的影响及电解质饮料干预的效果

目的:研究在低氧环境下运动对血清离子浓度的影响,及补充电解质饮料--"宝矿力水特"对血清离子浓度变化的干预效果.方法:让受试者分别在运动前、中、后补充电解质饮料--"宝矿力水特",或补充纯净水,或不补充电解质饮料和水三种情况下以70%VO2max负荷进行低氧运动1小时,测定运动前、运动后即刻和运动后半小时、1小时血清中的离子浓度.结果:研究表明,不补充电解质饮料和水的情况下低氧运动后血清总钙、磷、钠显著升高(钙、磷P<0.01,钠P<0.05),而血清钾、氯变化不显著(P>0.05).补充电解质饮料--"宝矿力水特"可以促进运动后血清总钙、磷的恢复和维持血清钠、氯的正常水平.补充纯净水后,由于血液稀释使血清总钙、磷、钠、钾、氯的恢复速度有所延迟.     

运动员减体重期对维生素代谢的改变及其补充

对34名摔跤运动员减体重期维生素代谢的研究表明,运动员减体重期摄入的VA、VB1、VB2、PP、Vc都明显低于运动员供给量标准。血中VA浓度减重前后基本一致,暗适应时间稍延长,24h尿中VB1、VB2、Vc排出量减体重后明显低于减体重前。尿中PP排出量减体重前后基本一样,任意克肌酐尿中VB1、VB2、PP、Vc排出量与24h尿中这几种维生素排出量结果基本一致,进一步说明了结果的可靠性。服用减重营养饼干后,血中VA含量减体重后高于减前,适应时间减体重前后基本一致,但短于普通饼干组。尿中VB1、VB2、PP、Vc排出量减体重后高于减重前,且均高于吃普通饼干对照组。说明减体重营养饼干补充了运动员减体重造成的各种维生素的不足和丢失,满足了运动员减体重对维生素的需要。     

运动员减体重期维生素代谢的改变及其补充

对３４名摔跤运动员减体重期维生素代谢的研究表明,运动员减体重期摄入的ＶＡ、ＶＢ１、ＶＢ２、ＰＰ、ＶＣ都明显低于运动员供给量标准。血中ＶＡ浓度减重前后基本一致,暗适应时间稍延长,２４ｈ尿中ＶＢ１;、ＶＢ２、ＶＣ排出量减体重后明显低于减体重前。尿中ＰＰ排出量减体重前后基本一样,任意克肌酐尿中ＶＢ１、ＶＢ２、ＰＰ、ＶＣ排出量与２４ｈ尿中这几种维生素排出量结果基本一致,进一步说明了结果的可靠性。服用减重营养饼干后,血中ＶＡ含量减体重后高于减前,适应时间减体重前后基本一致,但短于普通饼干组。尿中ＶＢ１、ＶＢ２、ＰＰ、ＶＣ排出量减体重后高于减重前,且均高于吃普通饼干对照组。说明减体重营养饼干补充了运动员减体重造成的各种维生素的不足和丢失,满足了运动员减体重对维生素的需要。     

营养不良膈肌功能与膈肌细胞磷、镁、钠、钾、钙关系的实验研究

[摘要]目的：研究营养不良大鼠膈肌收缩力和肌细胞内磷、镁、钠、钾、钙水平的关系。方法：SD大鼠20只,随机分为对照组（CTL）和营养不良组（ND）。ND组限食半量4周,全部大鼠处死后测膈肌收缩力,肌细胞内磷、镁、钠、钾、钙水平。结果：ND组大鼠体重、膈重均显著低于CTL组（P〈0．01）,不同频率刺激下的膈肌收缩力均显著低于CTL组（P〈0．05）,收缩力与膈重之比两组无显著差异。ND组大鼠膈肌磷、镁显著低于CTL组,两组大鼠膈肌最大颤搐收缩力（Pt）与磷、镁水平呈显著正相关（r=0．63,P〈0．01;r=0．77,P〈0．01）,最大强直性收缩力（Po）与镁呈显著正相关（r=0．076,P〈0．01）。结论：营养不良时膈肌萎缩导致收缩力下降,低磷、低镁可能是膈肌收缩力下降的因素之一。     

Factors related to rapid weight loss practices among international-style wrestlers

PURPOSE: The deaths of three intercollegiate wrestlers in 1997 prompted the NCAA and governing bodies that oversee high school sports to adopt new policies prohibiting unsafe weight loss practices. Similar policies have not yet been adopted for international style wrestling, a style that attracts thousands of youth once the regulated scholastic season is over. Therefore, this study examined the rapid weight loss practices in high school wrestlers participating in international style wrestling. To do this, rapid weight gain (RWG), an index that reflects the degree of rapid weight loss (RWL), was examined. METHODS: Wrestlers (N = 2638) participating in the 1997 and 1998 National wrestling championships were randomly selected to be weighed at matside with electronic scales. The methods wrestlers used to accomplish weight loss were also assessed in a subsample of wrestlers. RESULTS: Wrestlers gained an average of 3.4 kg, which represents a 4.81% gain of body weight. The range across weight classes and age groups was -2.68 kg (-2.1% loss of body weight) to +16.73 kg (13.4% gain of body weight). No differences in RWG existed as a function of the represented state teams. In addition, wrestlers who were older and more successful (i.e., placers) gained significantly more weight that their younger and less successful counterparts (P < 0.001). Excessive running, using saunas, and wearing vapor-impermeable suits were cited as the most common methods used to achieve RWL. CONCLUSION: These results suggest that RWL still exists in international style wrestling, and similar policies to those recently instituted by the NCAA are warranted.     

Weight loss methods of high school wrestlers

PURPOSE: The purpose of this investigation was to assess the weight loss practices of Michigan high school wrestlers at all levels of competition. METHODS: A two-page survey was designed to assess weight loss behaviors of high school wrestlers. It was mailed by the Michigan High School Athletic Association (MHSAA) midway through the wrestling season to all Michigan high schools participating in interscholastic wrestling. RESULTS: Completed surveys were received from 2532 wrestlers. Wrestlers lost an average of 6 pounds during the season. Over 50% of wrestlers lost more than 5 pounds; 27% of wrestlers lost at least 10 pounds; 72% of wrestlers engaged in at least one potentially harmful weight loss method each week of the wrestling season; 52% used at least two methods each week; 12% used at least five methods each week. Weekly use of laxatives, diet pill, or diuretics was reported by 2% of wrestlers. Vomiting to lose weight was done at least weekly by 2% of wrestlers. Wrestlers who engaged in at least one rapid weight loss method per week lost more weight, began wrestling at an earlier age, and reported more binge eating compared with wrestlers who did not report weekly rapid weight loss. CONCLUSION: The majority of Michigan high school wrestlers engaged in at least one potentially harmful weight loss method each week of the wrestling season. Fasting and various methods of dehydration were the primary methods of rapid weight loss. Wrestlers who lost weight each week were more likely to binge eat. Potentially harmful weight loss practices were found to be common at all grades and success levels.     

Weight control in wrestling: eating disorders or disordered eating?

PURPOSE: Several recent studies have pointed out that the weight loss techniques used by wrestlers to make weight are similar to the behavior of bulimics. The purpose of this study was to determine whether an increased risk of bulimia nervosa existed for a group of junior high and high school wrestlers. METHODS: Wrestlers (N = 85) completed the Eating Disorder Inventory (EDI) once during the season, and once during the off-season. A comparison group of nonwrestlers (N = 75) also completed the questionnaire. RESULTS: No significant differences were found between the number of in-season wrestlers and nonwrestlers classified as "at risk" for bulimia nervosa. Significant differences were revealed, however, between in-season wrestlers and nonwrestlers, and between in-season wrestlers and off-season wrestlers, on the Drive for Thinness subscale. In both cases, significantly more in-season wrestlers scored above the "at risk" cutoff on the subscale. CONCLUSIONS: These results indicate that although in-season wrestlers are more weight conscious than nonwrestlers, these feelings and attitudes are transient. All subjects classified as "at risk" also participated in an interview which followed the format of the Eating Disorder Examination. Interviews with in-season wrestlers revealed that their concerns with weight were due entirely to the demands of wrestling, and did not meet the severity level required for a diagnosis of bulimia nervosa.     

Patterns of weight loss and regain in wrestlers: has the tradition changed?

To assess current weight loss practices in wrestlers, 63 college wrestlers and 368 high school wrestlers completed a questionnaire that examined the frequency and magnitude of weight loss, weight control methods, emotions associated with weight loss, dieting patterns, and preoccupation with food. Clear patterns emerged showing frequent, rapid, and large weight loss and regain cycles. Of the college wrestlers, 41% reported weight fluctuations of 5.0-9.1 kg each week of the season. For the high school wrestlers, 23% lost 2.7-4.5 kg weekly. In the college cohort, 35% lost 0.5-4.5 kg over 100 times in their life, and 22% had lost 5.0-9.1 kg between 21 and 50 times in their life. Of the high school wrestlers, 42% had already lost 5.0-9.1 kg 1-5 times in their life. A variety of aggressive methods wer used to lose weight including dehydration, food restriction, fasting, and, for a few, vomiting, laxatives, and diuretics. "Making weight" was associated with fatigue, anger, and anxiety. Thirty to forty percent of the wrestlers, at both the high school and college level, reported being preoccupied with food and eating out of control after a match. The tradition of "making weight" still appears to be integral to wrestling. The potential physiological, psychological, and health consequences of these practices merit further attention.     

Iowa wrestling study: cross-validation of the Tcheng-Tipton minimal weight prediction formulas for high school wrestlers

Previous research by Tcheng and Tipton developed two prediction equations appropriate for the estimation of minimal weight for high school wrestlers. The purpose of this investigation was to cross-validate these equations using densitometric estimates of minimal weight. Skeletal dimension measurements and hydrostatic weighing were completed on 220 Iowa high school wrestlers at various times in and out of season. High concurrent validity (r = 0.93) and small residual errors (less than 0.33 kg) were observed when compared to densitometric estimates. Regression weights were of similar magnitude to those from the previous study. Two new prediction models were tested. Model II enhanced the multiple R over previous equations to 0.962 and decreased the SEE by 25% (0.55 kg). The equation was: Minimal Weight (lbs) = 0.49 x Current Weight (lbs) + 1.65 x Height (inches) + 1.81 x Chest Diameter (cm) + 6.70 x Right Wrist Diameter (cm) + 1.35 x Chest Depth (cm) - 156.56. It was concluded that the Tcheng-Tipton equations or the new models could be used as valid indicators of a minimal weight for scholastic wrestlers.     

Physiological effects of a weight loss regimen practiced by college wrestlers

The effects of weight loss (dehydration) techniques (which mimicked techniques used prior to actual competition) used by intercollegiate wrestlers on selected physiological parameters (strength, anaerobic power, anaerobic capacity, the lactate threshold (LT), and peak aerobic power) were examined in seven intercollegiate wrestlers. During the 36 h weight loss period, subjects lost 3.3 kg (4.9% body weight), all of which occurred during the 12 h prior to weigh-in, using exercise in a rubberized sweat suit. Weight loss resulted in a reduction in upper body but not lower body strength measures (peak torque and average work per repetition). Anaerobic power and anaerobic capacity were significantly reduced in a dehydrated state (81.4 kgm.s-1, normal weight; 63.9 kgm.s-1, weight loss; 1984.3 kgm.40 s-1, normal weight; 1791.4 kgm.40 s-1, weight loss). Analyses of treadmill data revealed the following: 1) velocity was decreased at LT (4.4%) and peak (6.5%) during weight loss (P less than 0.05); 2) VO2 peak was significantly reduced with weight loss (6.7%, P less than 0.05); 3) treadmill time to exhaustion was significantly reduced in the weight loss state (12.4%) (35.7 min, normal weight; 31.3 min, weight loss). It was concluded that typical wrestling weight loss techniques result in deleterious effects on strength, anaerobic power, anaerobic capacity, the lactate threshold, and aerobic power.     

Hemodynamic response to submaximal exercise after dehydration and rehydration in high school wrestlers

Cardiac output (Q), heart rate (HR), stoke volume (SV), and arteriovenous oxygen difference (AVD) were measured in 16 high school wrestlers during submaximal work (65%Vo2 Max) at normal weight (T1), after a four or five percent weight loss (T2), and following one hour of rehydration (T3). Weight losses were accomplished over 48 hours by fluid and food restriction as well as intermittent exercise. An ad libitum volume and commercial glucose-electrolyte solution was used to rehydrate the subjects. At T2 the mean weight loss was 4.6%, with the average plasma deficit estimated to be 4.9%. Under these conditions significantly higher HR and lower SV were observed during standardized exercise. Although Q was 7.8% lower and AVD was 7.3% higher after dehydration, neither change was statistically significant. Following rehydration all dependent variables returned to near T1 levels. It was concluded that despite a short rehydration period, the cardiovascular dynamics of these high school wrestlers rapidly returned to normal during moderately heavy work because of the small plasma changes that accompanied the 48-hour weight loss.     

NCAA rule change improves weight loss among national championship wrestlers

PURPOSE: The present investigation was initiated to examine the weight management practices among wrestlers participating in the NCAA Division I, II, and III wrestling tournaments. Part 1 examined the efficacy of body composition assessment between preseason (PRE) and postseason (POST). Part 2 examined rapid weight loss (RWL) during the 20 h preceding the weigh-in and the rapid weight gained (RWG) during the first day's competition. METHODS: Subjects include 811 competitors from Divisions I, II, and III participating in the NCAA national championship tournaments between 1999 and 2004. Measurements included relative body fatness (% BF) and weight (WT) on the day preceding the tournament and the evening of the first day. Minimal weight (MW) was computed with 5% BF. Retrospectively, MW, % BF, and WT from the previous fall were obtained for comparisons from NCAA records. RESULTS: Part 1: WT and % BF decreased significantly PRE (WT 74.0 +/- 11.1 kg; % BF 12.3 +/- 3.4%) to POST (WT 71.5 +/- 10.4 kg; % BF 9.5 +/- 1.8%), but MW (PRE MW 68.0 +/- 9.2 kg, POST MW 67.9 +/- 9.1 kg) remained unchanged. Heavier wrestlers and Division I and II wrestlers showed the greatest changes in WT and % BF. Part 2: RWL averaged (+/- SD) 1.2 +/- 0.9 kg and relative to weight 1.7 +/- 1.2%. Division I and lighter wrestlers showed the greatest change. RWG averaged 0.9 +/- 0.8 kg, or 1.3 +/- 1.2%. RWG was greater among lighter and Division I and II wrestlers. CONCLUSIONS: Minimal weight estimates PRE appear valid compared with POST. RWL and RWG are reduced significantly over previous investigations with only mat-side weigh-ins. The NCAA weight management program appears effective in reducing unhealthy weight cutting behaviors and promoting competitive equity. Efforts to institute similar programs among younger wrestlers seem warranted.     

Test development for the study of physical performance in wrestlers following weight loss.

This study was conducted to develop a testing protocol which would determine the extent of upper-body power output decrements in subjects following weight loss. Five athletes who had trained via upper-body exercise performed a 6-minute variable intensity arm crank test on an isokinetic ergometer before and after a 3-day, 4.5% body weight loss. Blood samples were drawn from a forearm vein pre- and 1, 3, and 5 min post-arm cranking for assessment of lactate, pH, hemoglobin, and hematocrit. The work performed pre-weight loss was significantly (paired t-test, p less than 0.05) greater than that performed post-weight loss. Repeated measures ANOVA yielded no significant differences in blood variables; however, pre-weight loss lactate values were higher and hemoglobin, hematocrit, and pH values were lower than post-weight loss values. It was concluded that a 4.5% body weight reduction resulted in performance decrements during this arm crank test. Survey information obtained from collegiate wrestlers (n = 14) subsequently tested under this protocol indicates the physical demands of this test approximate the physical demands of actual wrestling competition. It would therefore be appropriate to use this protocol during future testing of wrestlers in weight loss studies.