卒中型高血压大鼠心肌线粒体Ca~（2＋），Mg~（2＋）—ATPase及膜流动

本文比较了卒中型自发往高血压鼠（ＳＨＲｓｐ）和京都Ｗｉｓｔａｒ正常血压鼠（ＷＫＹ）心肌线粒体Ｃａ￣（２＋），Ｍｇ￣（２＋）－ＡＴＰａｓｅ活力及膜流动性。用定磷法测得ＷＫＹ和ＳＨＲｓｐ的Ｃａ￣（２＋），Ｍｇ￣（２＋）－ＡＴＰａｓｅ活力（２５℃）分别为０．２８７±０．０１６及０．２１８±０．０１７μｍｏｌ／（ｍｉｎ．ｍｇ）（－ｘ±Ｓｘ）。ＳＨＲｓｐ心肌线粒体Ｃａ￣（２＋），Ｍｇ￣（２＋）－ＡＴＰａｓｅ活力降低２４．７％，两组比较有显著差异（Ｐ＜０．０１，ｎ＝９）．以ＤＰＨ标记心肌线粒体膜，测得ＷＫＹ和ＳＨＲｓｐ的荧光偏振值分别为０．１８７±０．００３及０．１８１±０．００３（Ｐ＞０．０５，ｎ＝６）。     

穿心莲提取液减轻心肌缺血－再灌注过程中钙超负荷的机制探讨

本文采用整体犬急性心肌缺血－再灌注模型以探讨穿心莲提取液减轻钙超负荷的机制。结扎冠脉左前降支上１／３处９０ｍｉｎ后再灌注６０ｍｉｎ较持续结扎１５０ｍｉｎ，缺血中心区心肌细胞内Ｃａ２＋增加（Ｐ＜０．０５）、Ｎａ＋明显增加（Ｐ＜０．０１），心肌细胞膜Ｃａ２＋－ＡＴＰａｓｅ活性明显降低（Ｐ＜０．０１），心肌组织ＭＤＡ含量显著增高（Ｐ＜０．０１）。而在再灌注前４５ｍｉｎ静脉给予穿心莲提取液，则见其缺血中心区心肌细胞内Ｃａ２＋降低（Ｐ＜０．０５）、Ｎａ＋明显降低（Ｐ＜０．０１），心肌细胞膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ、Ｃａ２＋－ＡＴＰａｓｅ活性明显增加（Ｐ＜０．０１）。心肌组织ＭＤＡ含量显著降低（Ｐ＜０．０１）。说明穿心莲提取液减轻心肌缺血－再灌注过程中钙超负荷与减轻氧自由基危害、保护心肌细胞膜ＡＴＰａｓｅ活性、降低钠超负荷有关。     

H~＋－Ca~（2＋）交换在心肌细胞缺氧复氧过程中所致Ca~（2＋）超负荷的意

多数研究资料表明：在心肌细胞发生氧反常和ｐＨ反常后，Ｈ￣＋一Ｎａ￣＋、Ｎａ￣＋一Ｃａ￣（２＋交换加强是细胞内Ｃａ￣（２＋）超载的重要机制。我们的研究表明，造成细胞Ｃａ￣（２＋）超载的原因，除Ｈ￣＋一Ｎａ￣＋、Ｎａ￣＋一Ｃａ￣（２＋）交换外，尚有Ｈ￣＋一Ｃａ￣（２＋）交换参加．本实验证实，在细胞缺氧１０、２０、３０和４０ｍｉｎ时，经Ｈ￣＋一Ｃａ￣（２＋）交换进入细胞的Ｃａ２＋量占同一时点细胞摄Ｃａ￣（２＋）总量的比率分别为（％）：１０．１±０．５、１２４±０．７、１１．８±０．４和１１．２±０．５、平均值为（％）：１１．４±０．９．当缺氧细胞再复氧后，这一比率显著增加。各时点的比率分别为（％）：２３．７±０．６、２２．３±０．５、２２．１±０．７和２０．５±０．８、平均值为（％）：２２．２±１２。这一结果表明：在ｐＨ反常所致Ｃａ￣（２＋）超载过程中，Ｈ￣＋一Ｃａ￣（２＋）交换的作用不容忽视。     

镁对大鼠缺氧再给氧心肌细胞内游离钙的影响

目的和方法：用ＡＣＡＳ５７０粘附式细胞仪，以荧光素染色法观察镁（Ｍｇ２＋）对体外培养乳鼠心肌细胞内游离钙（Ｃａ２＋）的影响及对缺氧再给氧时细胞内Ｃａ２＋作用。结果：细胞外Ｍｇ２＋降至０３ｍｍｏｌ·Ｌ－１，细胞内Ｃａ２＋荧光强度上升速度加快，达到稳定所需时间延长，出现Ｃａ２＋振荡曲线。增加Ｍｇ２＋浓度可使细胞内Ｃａ２＋降低。Ｍｇ２＋还可以显著减少缺氧再给氧时细胞内Ｃａ２＋，Ｐ＜００１。结论：细胞外低Ｍｇ２＋可导致细胞内Ｃａ２＋增加，Ｍｇ２＋有维持正常心肌细胞内Ｃａ２＋稳定性及拮抗缺氧再给氧时细胞内Ｃａ２＋超载作用     

组织中Ca~（2＋）－ATP酶的图像分析仪测定法

在Ｃａ（２＋）－ＡＴＰ酶含量的测定中，我们尝试用图像分析仪测定组织中Ｃａ（２＋）－ＡＴＰ的含量，并将其结果与显微分光光度法进行了比较。表明两种方法的结果一致（Ｐ＞０．０５），而图像分析仪法操作简便、快速、准确，是测定组织中Ｃａ（２＋）－ＡＴＰ酶含量较理想的方法。我们应用该法测定了晕厥心肌中Ｃａ（２＋）－ＡＴＰ酶含量，缺血组织中Ｃａ（２＋）－ＡＴＰ含量明显低于对照组（Ｐ＜０．０１）。     

去甲肾上腺素对大鼠腹腔巨噬细胞内IP_3、［Ca~（2＋）］_i和Ia抗原表达

本文应用细胞膜放射标记和离子交换层析法测定巨噬细胞（ＭФ）内肌醇－１，４，５－三磷酸（ＩＰ３）、用Ｃａ￣（２＋）指示剂的分光光谱法测定ＭФ内Ｃａ￣（２＋）浓度（［Ｃａ￣（２＋）］）、用ＡＰＡＡＰ桥联酶标法检测ＭФ表面Ｉａ抗原的表达，研究去甲肾上腺素（ＮＥ）对大鼠腹腔的ＭФ内ＩＰ３、［Ｃａ￣（２＋）］ｉ和ＭФ表面ｌａ抗原表达的影响。结果显示ＮＥ（１０￣（－８）ｍｏｌ／Ｌ）可显著增高ＭФ中ＩＰ＿３含量（４４２±２２ｃｐｍ／１０￣６ｃｅｌｌｓ，对照组１０２±８ｃｐｍ／１０￣６ｃｅｌｌｓ，Ｐ＜０．０１）；ＮＥ可使ＭФ内［Ｃａ￣（２＋）］ｉ显著增高（３２２±７８ｎｍｏｌ／Ｌ，对照组９７±１７ｎｍｏｌ／Ｌ，Ｐ＜０．０１）；ＮＥ可显著增高ＭФ表面Ｉ－Ａ、Ｉ－Ｅ抗原的表达（６４±８％、５８±６％，对照组５０±３％，４４±４％，Ｐ＜０．０１）。提示神经递质ＮＥ促进ＭФ表面Ｉａ抗原表达的作用可能是通过第二信使ＩＰ＿３和Ｃａ￣（２＋）介导的。     

牛磺酸对缺血大鼠心肌线粒体Ca2+-Mg2+-ATP酶活性与MDA含量影响

目的和方法：用Ｗｉｓｔａｒ大鼠皮下注射异丙肾上腺素（ＩＳＰ,５ｍｇ／ｋｇ）诱导心肌缺血模型。观测心肌线粒体（Ｍｉｔ）中丙二醛（ＭＤＡ）含量、Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶和Ｃａ２＋－ＡＴＰ酶活性及牛磺酸（Ｔａｕ）的影响。结果：缺血组大鼠心肌Ｍｉｔ中ＭＤＡ升高８７８３％、Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶和Ｃａ２＋－ＡＴＰ酶活性分别降低３７５６％和５０２０％（Ｐ＜０．０１）。Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶活性与ＭＤＡ含量也呈显著负相关（ｒ＝－０．８７,Ｐ＜０．０１）。Ｃａ２＋－ＡＴＰ酶活性与ＭＤＡ含量也呈显著负相关（ｒ＝－０７９,Ｐ＜０．０１）。在注射异丙肾上腺素（ＩＳＰ）前３０ｍｉｎ腹腔注射Ｔａｕ（２００ｍｇ／ｋｇ）则Ｍｉｔ中ＭＤＡ含量、Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶和Ｃａ２＋－ＡＴＰ酶活性均未见显著异常改变。结论：Ｔａｕ可能通过抑制ＭＤＡ的生成实现其保护Ｃａ２＋－ＡＴＰ酶和Ｃａ２＋－Ｍｇ２＋－ＡＴＰ酶活性的作用。     

维拉帕米和Mm^2＋对缺氧及复氧单心肌细胞游离Ca^2＋的影响

本文采用荧光探针Ｆｕｒａ－２结合计算机图像处理技术观察不同时间的缺氧及复氧单心肌细胞内游离Ｃａ＾２＋含量的变化以及Ｃａ＾２＋通道阻滞剂及Ｎａ＾＋－Ｃａ＾２＋交换抑制剂对其的影响。结果显示随着缺氧和缺氧复氧时间的延长，细胞内Ｃａ＾２＋浓度逐渐增加。     

脑缺血和再灌注时Ca~（2＋）／CaMPKII活性的变化及苄丙咯的影响

本文以蒙古沙土鼠双侧颈总动脉结扎造成脑缺血模型，研究了脑缺血和再灌注时大脑Ｃａ￣２＋／ＣａＭＰＫⅡ活性变化及苄丙咯对其活性的影响，实验结果：（１）Ｃａ￣２＋／ＣａＭＰＫⅡ活性随脑缺血时间的延长而逐渐降低，脑缺血１０分钟，酶活性显著低于正常组（Ｐ＜０．０１）；（２）脑缺血１０分钟再灌注２０分钟，酶活性部分恢复，与缺血１０分钟组相比，酶活性有明显上升（Ｐ＜０．０１），但缺血２０分钟再灌注，其活性不再恢复；（３）缺血前２０分钟腹腔注射苄丙咯，在缺血１０分钟时酶活性明显高于对照组（Ｐ＜０．０ｌ）。结果提示Ｃａ￣２＋／ＣａＭＰＫⅡ活性对缺血非常敏感；苄丙咯对该酶活性有一定保护作用。     

α-MSH对EGTA发热的作用

目的：观察α－ＭＳＨ对ＥＧＴＡ发热反应的作用及其可能机制。方法：建立ＥＧＴＡ发热模型；在离体条件下，应用Ｆｕｒａ－２荧光指示剂测定细胞内Ｃａ２＋浓度（［Ｃａ２＋］ｉ）；体外培养下丘脑神经细胞。结果：α－ＭＳＨ能明显抑制ＥＧＴＡ性发热反应（Ｐ＜０．０１）；ＥＧＴＡ可以降低下丘脑神经细胞［Ｃａ２＋］ｉ水平（Ｐ＜０．０１），但α－ＭＳＨ不影响正常下丘脑神经细胞［Ｃａ２＋］ｉ及ＥＧＴＡ对下丘脑神经细胞［Ｃａ２＋］ｉ的作用（Ｐ＞０．０５）；ＥＧＴＡ可刺激体外培养的下丘脑神经细胞释放ＣＲＨ（Ｐ＜０．０５），而α－ＭＳＨ能抑制ＥＧＴＡ的这种作用（Ｐ＜０．０５）。结论：α－ＭＳＨ抑制中枢发热介质ＣＲＨ的产生可能是降低ＥＧＴＡ发热反应的主要机制之一；中枢ＣＲＨ的产生和释放增加可能是ＥＧＴＡ性发热的一个重要因素。     

Pain and Effusion and Quadriceps Activation and Strength

Context:

Quadriceps dysfunction is a common consequence of knee joint injury and disease, yet its causes remain elusive.

Objective:

To determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion affect the magnitude of quadriceps dysfunction.

Design:

Crossover study.

Setting:

University research laboratory.

Patients or Other Participants:

Fourteen (8 men, 6 women; age = 23.6 ± 4.8 years, height = 170.3 ± 9.16 cm, mass = 72.9 ± 11.84 kg) healthy volunteers.

Intervention(s):

All participants were tested under 4 randomized conditions: normal knee, effused knee, painful knee, and effused and painful knee.

Main Outcome Measure(s):

Quadriceps strength (Nm/kg) and activation (central activation ratio) were assessed after each condition was induced.

Results:

Quadriceps strength and activation were highest under the normal knee condition and differed from the 3 experimental knee conditions (P < .05). No differences were noted among the 3 experimental knee conditions for either variable (P > .05).

Conclusions:

Both pain and effusion led to quadriceps dysfunction, but the interaction of the 2 stimuli did not increase the magnitude of the strength or activation deficits. Therefore, pain and effusion can be considered equally potent in eliciting quadriceps inhibition. Given that pain and effusion accompany numerous knee conditions, the prevalence of quadriceps dysfunction is likely high.Key Words: arthrogenic muscle inhibition, central activation failure, voluntary activation, muscles

Key Points

• Knee pain and effusion resulted in arthrogenic muscle inhibition and weakness of the quadriceps.
• The simultaneous presence of pain and effusion did not increase the magnitude of quadriceps dysfunction.
• To reduce arthrogenic muscle inhibition and improve muscle strength, clinicians should employ interventions that target removing both pain and effusion.

Quadriceps weakness is a common consequence of traumatic knee joint injury^1,2 and chronic degenerative knee joint conditions.^3,4 Arthrogenic muscle inhibition (AMI), a neurologic decline in muscle activation, results in quadriceps weakness and hinders rehabilitation by preventing gains in strength.⁵ The inability to reverse AMI and restore muscle function can lead to decreased physical abilities,⁶ biomechanical deficits,⁷ and possibly reinjury.⁵ Furthermore, researchers^8,9 have suggested that quadriceps weakness resulting from AMI may place patients at risk for developing osteoarthritis in the knee. In light of the substantial influence of quadriceps AMI on these clinically relevant outcomes, we need to improve our understanding of the factors that contribute to this neurologic decline in muscle activity so efforts to target and reverse it can be implemented and gains in strength can be achieved more easily.Joint injury and disease are accompanied by numerous sequelae (ie, pain, swelling, tissue damage, inflammation), so ascertaining which one ultimately leads to neurologic muscle dysfunction is difficult. Whereas a joint effusion can result in AMI,^10–12 the effects of pain are less understood despite many clinicians attributing AMI to pain. Using techniques that introduce knee pain without accompanying injury may provide insights into the role of pain in eliciting AMI.The degree of knee joint damage may play a role in the quantity of AMI that manifests. Hurley et al^13,14 demonstrated that quadriceps AMI, measured using an interpolated-twitch technique, was greater in patients with extensive traumatic knee injury (eg, fractured tibial plateau, ruptured medial collateral ligament, and medial meniscectomy) than patients with isolated joint trauma (ie, isolated anterior cruciate ligament [ACL] rupture). Similarly, patients with more knee joint symptoms (ie, greater number of symptoms and increased severity of symptoms) may present with greater magnitudes of quadriceps inhibition. Recently, investigators¹⁵ have suggested that patients with more pain display less quadriceps strength, supporting this tenet. Given that effusion and pain often present simultaneously with joint injuries and diseases, such as ACL injury and osteoarthritis, examining both the isolated and cumulative effects of these sequelae appears warranted to determine if they influence the magnitude of muscle inhibition.Experimental joint-effusion and pain models are safe and effective experimental methods that allow for the isolated examination of their effects on muscle function. The effusion model, whereby sterile saline is injected directly into the knee joint capsule,⁷ produces a clinically relevant magnitude of the joint effusion that may be present with traumatic injury. Effusion is thought to activate group II afferents responding to stretch or pressure,^16–18 which in turn may facilitate group Ib interneurons and result in quadriceps AMI.⁵ The pain model involves injecting hypertonic saline into the infrapatellar fat pad to produce anteromedial knee pain similar to that described in patients with patellofemoral pain syndrome.¹⁹ Pain is considered to initiate AMI through activation of group III and IV afferents that act as nocioceptors to signal damage or potential damage to joint structures.^16–18 The firing of these afferents then may lead to facilitation of group Ib interneurons, the flexion reflex, or the gamma loop, ultimately resulting in quadriceps inhibition.²⁰ Thus, these models allow us to create symptoms that are associated with knee injury and have the added benefit of providing a way to examine their effects in isolation.Therefore, the purpose of our study was to determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion would affect the magnitude of quadriceps dysfunction. We hypothesized that pain alone would result in quadriceps inhibition and that the magnitude of inhibition would be greater when effusion and pain were present simultaneously.     

即早基因c-fos与脑血管病及学习记忆

即早基因c-fos是广泛存在于原核细胞和真核细胞的高度保守基因.在正常情况下,c-fos基因参与细胞生长、分化、信息传递、学习和记忆等生理过程,而在病理情况下c-fos基因表达及调控变化与多种疾病的发生和发展有关.C-fos在中枢神经系统的某些部位可有基础水平的表达,但表达很低,当受到如脑缺血、脑出血、痫性发作、应激等刺激后,其在数十分钟内做出反应,在对外界刺激-转录耦联的信忠传递过程中起着核内第三信使的重要作用.     

Opportunities and challenges in the prevention and control of cancer and other chronic diseases: children's diet and nutrition and weight and physical activity

OBJECTIVE: The purpose of this article is to review the role of behavioral research in disease prevention and control, with a particular emphasis on lifestyle- and behavior-related cancer and chronic disease risk factors--specifically, relationships among diet and nutrition and weight and physical activity with adult cancer, and tracking developmental origins of these health-promoting and health-compromising behaviors from childhood into adulthood. METHOD: After reviewing the background of the field of cancer prevention and control and establishing plausibility for the role of child health behavior in adult cancer risk, studies selected from the pediatric published literature are reviewed. Articles were retrieved, selected, and summarized to illustrate that results from separate but related fields of study are combinable to yield insights into the prevention and control of cancer and other chronic diseases in adulthood through the conduct of nonintervention and intervention research with children in clinical, public health, and other contexts. RESULTS: As illustrated by the evidence presented in this review, there are numerous reasons (biological, psychological, and social), opportunities (school and community, health care, and family settings), and approaches (nonintervention and intervention) to understand and impact behavior change in children's diet and nutrition and weight and physical activity. CONCLUSIONS: Further development and evaluation of behavioral science intervention protocols conducted with children are necessary to understand the efficacy of these approaches and their public health impact on proximal and distal cancer, cancer-related, and chronic disease outcomes before diffusion. It is clear that more attention should be paid to early life and early developmental phases in cancer prevention.