Why do long-distance runners not have more bone? A vital biomechanical explanation and an estrogen effect

Inanimate structures cannot detect and repair their fatigue damage or microdamage, so to minimize it they need more structural material and strength. Living bone handles this matter differently. Bone modeling drifts adapt bone architecture and strength to the loads on bones in ways that tend to keep strains from exceeding a “modeling threshold” range. Strains (or equivalent features) above that threshold switch mechanically controlled modeling ON. Where strains stay below that threshold, this modeling goes OFF. Repeatedly loading-deloading a bone causes microdamage in it, and basic multicellular unit (BMU)-based bone remodeling normally repairs it. Where strains stay below an operational “microdamage threshold,” remodeling can repair whatever microdamage happens for as long as it happens. Strains above that threshold can cause too much microdamage to repair completely and lead to fatigue fractures of trabeculae or whole bones. The modeling threshold normally lies comforably below the microdamage threshold. Since modeling normally adjusts bone architecture to keep strains from exceeding the modeling threshold, this keeps strains below the microdamage threshold, too, and voluntary activities do not cause more microdamage than remodeling can repair. Therefore, long-distance runners do not need more bone mass and strength than nonrunners of comparable age, sex, and body size.     

新兵训练后功能性闭经女兵的心身症状与激素水平

目的:探讨新人伍女兵功能性下丘脑性闭经(FHA)者与月经正常者激素水平及心理健康状况的差异。方法:在某部队新人伍女兵98人接受了为期近4个月的体能训练之后,有54人出现闭经.其中闭经3个月以上者有35人(研究组)。训练后月经正常、在采血时月经周期处于第5～11天者有26人(对照组)。分别测定她们血清中的促卵泡生成素(FSH)、黄体生成素(LH)、雌二醇(E_2)、孕酮(P)、泌乳素(PRL)、睾酮(T)、ACTH、T_3、T_4的水平,并用SCL-90分别评定她们的心理健康状况。结果:FHA 者血清FSH 值为4.96±1.73 mIU/ml,LH 值为2.63±1.78 mIU/ml,E_2的值为7.23±5.37 pg/ml,对照组血清相应值为10.73±2.30mIU/ml、12.31±2.15mIU/ml、41.67±6.13pg/ml,差异有统计学意义(P<0.01),闭经组低于对照组。FHA 组SCL-90的躯体化、人际敏感、抑郁、焦虑及其他因子分大于2的比率分别为:51.4%、42.9%、48.6%、51.4%及37.1%;而对照组这5项分值大于2的比率分别为15.4%、15.4%、19.2%、21.3%及11.5%,两组间这5个因子大于2的人数差异有统计学显著意义(P<0.05),闭经组高于对照组。结论:诊断为FHA 的女兵与月经正常女兵的激素水平有差异,闭经组心身症状的发生率也高于对照组。     

51例闭经的临床分析和治疗探讨

目的 探讨闭经的病因、治疗方法及疗效。方法 对1989年2月－2001年2月间我院妇科内分泌治疗的51例闭经患者的临床资料进行回顾性分析,并根据患者的临床症状及血清激素水平特征归类讨论。结果 51例闭经患者,未婚8例,女婚43例,其中3例结婚时间短于半年,37例为不孕症者,占72．5％。多囊卵巢综合征（PCOS）21例（41．2％）;卵巢早衰（POF）18例（35．3％）;高催乳素血症（HPRL）6例;垂体微腺瘤4例;高雄激素血症（HT）2例。通过内分泌药物治疗后观察,PCOS患者的妊娠率为58．8％;POF患者中仅有1例妊娠;HPRL6例患者中有5例妊娠;垂体微腺瘤3例（已婚）中有2例妊娠;高雄激素血症的2例患者中1例妊娠。结论 闭经患者经过适当的治疗,除POF外其妊娠率效果较为满意。     

闭经的细胞遗传学研究

目的： 研究原发性及继发性闭经患者的染色体核型,探讨各种异常核型的分布情况。方法：取外周血做淋巴细胞培养,制备染色体,采用Ｇ显带分析或常规染色体检查。结果：被检的４９３ 例患者中,２６８ 例为原发性闭经。异常染色体核型占４１．８ ％（１１２／２６８）,其中以４５,Ｘ及其各种嵌合型最多,占６５．２％ （７３／１１２）。４６,ＸＹ是原发性闭经另一类常见的异常核型,占２２．３ ％（２５／１１２）。２２５ 例继发性闭经中,异常核型占９．８％ （２２／２２５） ,其中Ｘ单体占２２．７％ （５／２２）。１５．２％ （５／３３）的Ｘ单体患者（ 原发性和继发性闭经）有月经初潮。结论：性染色体异常是导致原发性闭经的主要原因之一,亦是高促性腺素继发性闭经的主要病因。Ｘ 单体及其嵌合型是闭经的主要异常核型。Ｙ染色体的存在也可引起闭经。     

Leptin and Its Emerging Role in Children and Adolescents

Leptin is an adipocyte-secreted hormone which plays a key role in energy homeostasis. Recent “proof of concept” studies involving leptin administration to humans support its critical role in regulating energy homeostasis, neuroendocrine and immune function as well as insulin resistance in states of energy/ caloric deprivation. Moreover, interventional studies in leptin deficient children and observational studies in normal girls and boys support a role for leptin as a permissive factor for the initiation of puberty in children. The potential clinical usefulness of leptin in several disease states in children and adolescents, including hypothalamic amenorrhea, eating disorders and syndromes of insulin resistance is still under investigation.     

闭经患者的外周血淋巴细胞染色体观察

目的：探讨闭经患者与染色体异常的关系.方法：选择闭经患者139例（其中原发性闭经91例,继发性闭经48例）,对其进行外周血淋巴细胞染色体检查.结果：原发闭经组,性染色体数目和（或）结构异常者28例,常染色体异常1例.继发闭经组,性染色体数目和（或）结构异常者4例,常染色体异常1例.结论：结合临床体征和染色体检查,不仅为闭经患者寻找病因提供理论依据,而且有利于指导闭经患者的治疗.     

Chemotherapy-induced amenorrhea: influence on disease-free survival and overall survival in receptor-positive premenopausal early breast cancer patients.

BACKGROUND: The aim of this study was to evaluate the influence of early chemotherapy-induced amenorrhea (CIA) on disease-free survival and overall survival in premenopausal patients with receptor-positive early breast cancer treated with adjuvant chemotherapy without any hormonotherapy. PATIENTS AND METHODS: Retrospectively, we reviewed data from 130 premenopausal patients with localized hormone-sensitive breast cancer. These patients were treated between 1985 and 1995 at the same institution. They all underwent a loco-regional treatment and adjuvant chemotherapy. Early CIA was defined as an amenorrhea arising during the first year following the beginning of chemotherapy. Predictors of early CIA were examined. The survival analyses were done using the Kaplan-Meier method and Cox analysis. RESULTS: Median follow-up was 9 years. Mean age was 42.9 +/- 5 years. Ninety-two per cent of patients had histologically-proven positive axillary nodes. Adjuvant chemotherapy contained no anthracycline in 63%. Early CIA occurred during or after adjuvant chemotherapy in 57% of the patients. It was definitive in 91%. In our study, age was the only CIA predictor in univariate analysis. Women who experienced early CIA tend to have a longer disease-free survival, but the difference was not significant. This trend was lost in multivariate analysis, most probably due to the small sample size. The overall survival was not different. CONCLUSION: Although not statistically significant, our results on a very selected population of patients suggest that a chemotherapy-induced amenorrhea might have its own therapeutic effect besides the cytotoxic action of chemotherapy.     

军地融合共建新型医疗联合体探讨——以福建中医药大学附属第三人民医院为例

目的 探讨绝经前乳腺癌化疗致闭经(CIA)的影响因素,了解化疗后卵巢功能的变化规律及CIA与绝经的关系。 方法 回顾性收集300例接受化疗(至少4个周期)的绝经前乳腺癌的临床资料,记录患者的年龄、病理类型、肿块分期、腋窝淋巴结转移数、激素受体、人表皮生长因子受体-2(HER-2)、化疗方案、放疗、内分泌治疗、靶向治疗、月经变化等情况和血清性激素水平[卵泡剌激素(FSH),黄体生成素(LH),雌二醇(E2)]并进行分析。采用ROC曲线、Fisher精确概率检验及卡方检验分析各因素与CIA之间的关系。使用Kaplan-Meier生存分析统计CIA发生时间与性激素水平达到绝经时间的差异。 结果 204 例患者出现CIA,年龄与CIA发生具有明显相关性,曲线下面积为0.899(P<0.001,95%CI:0.863～0.935),年龄影响CIA的最佳临界值为43 岁。CIA的发生与病理类型、肿块分期、腋窝淋巴结转移数、雌激素受体(ER)、孕激素受(PR)、HER-2状态无关、化疗方案、是否放疗、曲妥珠单抗靶向治疗、内分泌治疗无关(P>0.05)。CIA患者中,年龄≤45 岁者更易恢复月经(91.4% vs 35.8%,P<0.001),月经恢复的中位时间为6.7 月(3.0～11.3 月); 绝经更多见于年龄>45 岁者(1.4% vs 50.0%,P<0.001)。Kaplan-Meier分析显示,CIA的发生时间明显早于性激素水平达到绝经的时间(2.6月 vs 13.6月,P<0.001); 在46～50岁、>50岁两个年龄组中,CIA均明显早于性激素水平达绝经的时间[(2.6月 vs 17.2月,P<0.001),(1.9月 vs 12.1月,P<0.001)]。 结论 年龄是CIA发生、月经恢复的独立且具有预测意义的重要影响因素。绝经多发生在确诊乳腺癌时年龄>45岁的患者,月经恢复多见于≤45岁患者。CIA的发生明显早于性激素水平达绝经状态,这一时间间隔对乳腺癌患者出现CIA后绝经状态的判断具有重要的参考价值,对合理选择内分泌治疗药物具有重要的临床意义。