cathepsin L及其抑制剂cystatin C在急性脱髓鞘动物模型中的表达及意义

在饲料中掺入cuprizone饲育小鼠6周,制备急性脱髓鞘动物模型。进而利用髓鞘荧光染色和原位杂交方法,检测动物胼胝体内髓鞘的脱失以及cathepsin L及其抑制剂cystatin C的表达情况。结果发现,与正常动物比较,cuprizone饲育6周后小鼠胼胝体内髓鞘脱失严重,胼胝体内cathepsin L和cystatin C的表达均显著上调。结果提示,髓鞘损伤后cathepsin L高表达可能有助于髓鞘残骸的清理,其抑制剂cystatin C的表达增强可将蛋白水解程度控制在一定范围内,这对髓鞘再生具有积极的意义。     

CPZ介导急性脱髓鞘小鼠海马中nestin的表达

目的:探讨双环己酮草酰二腙(cuprizone,CPZ)介导急性脱髓鞘小鼠海马中nestin的表达。方法:用掺入0.2%CPZ的普通饲料饲养C57BL/6小鼠6周,制备脱髓鞘模型,然后使用免疫荧光染色、q RT-PCR、Western Blot方法,检测小鼠脑内髓鞘脱失后海马中nestin的表达变化。结果:(1)体重称量结果显示:CPZ组体重明显低于对照组(P0.01);(2)免疫荧光结果显示:CPZ组海马CA区和DG区颗粒细胞层中nestin阳性细胞明显低于对照组分别为:P0.05,P0.01;(3)Western Blot和q RT-PCR实验结果显示:CPZ组海马中nestin蛋白和m RNA含量均明显低于对照组(P0.05)。结论:CPZ介导小鼠急性脱髓鞘后海马内nestin表达降低,提示髓鞘脱失可能会抑制nestin表达。     

Mdivi-1对cuprizone诱导的脱髓鞘性病变小鼠少突胶质细胞的保护作用

目的:探讨线粒体分裂抑制剂1(Mdivi-1)对cuprizone诱导的脱髓鞘性病变模型小鼠少突胶质细胞损伤的作用及其机制。方法:将8周龄雄性C57BL/6小鼠用含0. 2%cuprizone的饲料饲喂,制备脱髓鞘性病变模型。将小鼠随机分为DMSO正常组(腹腔注射DMSO+饲喂正常饲料)、cuprizone模型组(饲喂含cuprizone的饲料)、DMSO+cuprizone模型组(腹腔注射DMSO+饲喂含cuprizone的饲料)和Mdivi-1干预组(腹腔注射Mdivi-1+饲喂含cuprizone的饲料)。通过固蓝染色及PLP、p-Drp1(Ser616)、CFB、C1q、C3b和C5b-9的免疫荧光染色实验检测Mdivi-1对髓鞘和少突胶质细胞的保护作用。结果:饲喂含cuprizone的饲料42 d可成功诱导小鼠脱髓鞘性病变模型,导致大脑胼胝体区髓鞘丢失,诱导Drp1磷酸化水平升高及C1q和CFB补体途径激活,并导致攻膜复合体在少突胶质细胞上组装。给予Mdivi-1可明显减少髓鞘丢失,抑制补体激活和攻膜复合体在少突胶质细胞的组装。结论:Mdivi-1干预可缓解cuprizone诱导的小鼠脱髓鞘病理学改变,其机制可能与抑制补体激活替代途径有关。     

p100基因RNA干扰质粒载体的构建与鉴定

目的:构建p100基因RNA干扰质粒载体,并检测其对多巴胺能的MN9D细胞系中p100蛋白表达的抑制作用。方法:设计并合成2条针对小鼠p100基因的RNA干扰片段,退火后分别连入pSilencerTM3.1-H1质粒并分别命名为Sip100#1、Sip100#2,酶切和测序鉴定正确后,将以上重组质粒及阴性对照质粒分别转染MN9D细胞,运用Western Blot方法检测各组细胞胞浆内p100蛋白的表达水平。结果:(1)酶切和测序结果证实目的寡核苷酸片段已被准确克隆到pSilencerTM3.1-H1质粒;(2)与对照组相比,转染MN9D细胞48 h后Sip100#1组及Sip100#2组p100蛋白的表达水平受到明显抑制,其中Sip100#1组下降58%,差异有统计学意义(P0.01)。结论:本研究成功构建出小鼠p100基因靶向RNAi质粒载体,并能有效抑制MN9D细胞内p100蛋白的表达,为进一步研究p100蛋白所在信号通路对多巴胺能神经细胞的作用提供了工具。     

Cuprizone介导的急性脱髓动物模型髓鞘脱失及再生的机制

本研究通过在饲料中掺入cuprizone饲育小鼠,建立髓鞘可再生的急性脱髓动物模型,并利用髓鞘染色和原位杂交后免疫组化双标技术,检测髓鞘脱失和再生状况以及少突胶质前体细胞的改变。结果表明,给予cuprizone6周后,动物胼胝体严重脱髓鞘,少突胶质前体细胞在髓鞘脱失区域集聚,且增殖活跃;恢复正常饲料饲养4周后,髓鞘基本恢复正常形态。由此推测,在cuprizone介导的急性脱髓动物模型髓鞘脱失和再生过程中,少突胶质前体细胞的增殖活化为髓鞘再生提供了基础。     

星形胶质细胞在cuprizone介导的急性脱髓动物模型中的变化及其意义

目的:利用cuprizone制备髓鞘可再生的急性脱髓鞘动物模型,探讨脱髓鞘疾病髓鞘再生机制。方法:在饲料中掺入cuprizone饲育小鼠,通过调控饲育时间,造成神经脱髓鞘及髓鞘再生,并利用免疫荧光染色和原位杂交方法,检测不同时间点髓鞘的脱失和再生情况以及星形胶质细胞的反应。结果:cuprizone饲育6周后,动物小脑和胼胝体白质内髓鞘脱失严重,星形胶质细胞增殖活跃;在恢复正常饲料后,髓鞘基本恢复正常结构,星形胶质细胞仍处于活化增殖状态。结论:利用cuprizone可制备髓鞘可再生的急性脱髓鞘动物模型,星形胶质细胞的活化增殖对髓鞘再生具有重要作用。     

丙戊酸钠对小鼠原代少突胶质细胞增殖和分化的影响

目的:观察丙戊酸钠(VPA)药物对原代培养的小鼠少突胶质细胞增殖和分化的影响。方法:体外培养并纯化小鼠少突胶质前体细胞,对增殖或诱导分化的细胞分为Control组和VPA组。利用CCK-8试剂检测VPA对少突胶质前体细胞活性的影响,5-溴脱氧尿嘧啶核苷(Brd U)标记检测增殖期细胞并计算所占比例,免疫细胞化学法检测在细胞不同分化阶段时2',3'-环核苷酸3'-磷酸二酯酶(CNP)和髓鞘碱性蛋白(MBP)、髓磷脂脂蛋白(PLP)和髓鞘相关糖蛋白(MAG)等标志性分子的表达情况real time RT-PCR和Western Blot法分别检测细胞增殖和分化时期相关分子的mRNA和蛋白质水平的表达情况。结果:VPA在1 mmol/L时对细胞活性促进作用最显著;免疫细胞化学显示:与Control组相比,VPA处理组Brd U阳性增殖细胞数量显著增加,CNP和MBP阳性细胞数量明显减少; RT-PCR法检测到与Control组相比,VPA处理后少突细胞中血小板衍化生长因子受体α(PDGFRα) mRNA表达水平增加,CNP、MBP和PLP等分化相关分子的mRNA表达水平降低;同时Western Blot方法检测到细胞分化阶段MBP蛋白水平表达显著降低。结论:VPA能够显著促进体外培养小鼠少突前体细胞的增殖,并抑制细胞分化。     

二氢丹参酮Ⅰ(DHTS1)通过抑制双环己酮草酰二腙诱导的小鼠小胶质细胞激活减轻髓鞘损伤

目的探讨二氢丹参酮I(DHTS1)对双环己酮草酰二腙(cuprizone)诱导脱髓鞘保护作用的机制。方法 DHTS1溶解于5 g/L羧甲基纤维素钠(CMC-Na)中,饲喂小鼠含2 g/L cuprizone的饲料制备脱髓鞘模型,给予DHTS1处理,实验动物随机分为CMC-Na正常组、 CMC-Na联合cuprizone处理组、 DHTS1联合cuprizone处理组。通过固蓝(LFB)组织化学染色、免疫荧光组织化学染色检测髓鞘碱性蛋白(MBP)和髓鞘蛋白脂(PLP)的表达判断髓鞘完整性,原位末端转移酶标记技术(TUNEL)检测细胞凋亡;免疫荧光组织化学染色检测小胶质细胞/巨噬细胞特异性蛋白钙离子结合接头蛋白分子1(Iba-1)、 CD86、 CD163的表达确定小胶质细胞极化情况。脂多糖(LPS)极化SIM-A9小胶质细胞, DHTS1处理,实验分为CMC-Na对照组、 DHTS1对照组、 CMC-Na联合LPS处理组和DHTS1联合LPS处理组。流式细胞术检测CD16/32、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)阳性细胞比例。结果与CMC-Na联合cuprizone模型组比较, DHTS1处理明显减少cuprizone诱导的小鼠大脑胼胝体区髓鞘脱失,减少细胞凋亡,减少Iba-1~+阿米巴样小胶质细胞的面积,减少CD86~+细胞数目,增加CD163~+细胞数目。与CMC-Na联合LPS处理组相比, DHTS1明显减少CD16/32~+、 TNF-α~+、 iNOS~+小胶质细胞的百分比。结论 DHTS1可以抑制cuprizone诱导的脱髓鞘和细胞凋亡,可能与DHTS1调节小胶质细胞极化,减轻中枢神经系统炎症反应有关。     

人参皂苷Rb1促进小鼠坐骨神经损伤修复的作用及机制研究

目的 构建小鼠坐骨神经损伤（SNI）模型,探讨人参皂苷Rb1对小鼠坐骨神经损伤修复的促进作用及机制。 方法 选取成年雄性昆明小鼠78只,随机分为假手术组（26只）、模型组（26只）、治疗组（26只）。模型制作采用钳夹损伤法,假手术组仅游离坐骨神经。模型制作后30 min,治疗组腹腔注射10 mg/kg人参皂苷Rb1,模型组与假手术组给予同等体积的生理盐水。采用坐骨神经功能指数（SFI）对小鼠坐骨神经功能进行追踪评价;利用HE染色及生长相关蛋白43(GAP43)免疫荧光染色检测损伤14 d后坐骨神经再生修复情况;利用透射电子显微镜观察损伤节段髓鞘的结构改变。损伤后14 d,检测脑源性神经营养因子(BDNF)、神经生长因子(NGF)mRNA水平的表达变化。模型制作后3 d、7 d,利用Ki67、S100β免疫荧光染色检测施万细胞的增殖、迁移能力;利用Real-time PCR检测炎症相关因子以及施万细胞激活相关转录因子mRNA表达水平;通过Western blotting对Sox10在蛋白水平的变化进行验证。 结果 治疗组SFI评分高于模型组小鼠,神经近端、远端HE染色较均一。透射电子显微镜提示,治疗组髓鞘结构、厚度较模型组明显改善,髓鞘内神经纤维排列较为整齐。免疫荧光染色结果显示,治疗组坐骨神经GAP43+轴突伸长明显优于模型组,BDNF、NGF等营养因子表达升高。进一步检测发现,给予Rb1后损伤节段附近Ki67+细胞增殖、S100β+施万细胞迁移明显增多。Real-time PCR结果显示,治疗组肿瘤坏死因子(TNF)-α、白细胞介素(IL)-1β mRNA表达水平明显下降,施万细胞激活相关转录因子表达水平上升。 结论 10 mg/kg Rb1能降低再生组织环境中炎症因子表达水平,增加BDNF、NGF等营养因子的表达水平,促进施万细胞激活,从而促进小鼠坐骨神经损伤后的神经再生。     

氯化钴对小鼠海马神经元细胞缺氧损伤的影响

目的:研究氯化钴(CoCl_2)对小鼠海马神经元细胞系HT22细胞缺氧损伤的影响。方法:实验分为3组,分别为低浓度氯化钴组(CoCl_2-L)、中浓度氯化钴组(CoCl_2-M)和高浓度氯化钴组(CoCl_2-H)。利用不同浓度CoCl_2处理HT22细胞建立细胞缺氧损伤模型,通过HE染色观察HT22细胞轴突损伤情况,CCK-8法检测HT22细胞体外增殖活性,Western Blot检测HT22细胞中低氧诱导因子-1α(HIF-1α)和tau蛋白的表达情况。结果:HE染色显示CoCl_2可致HT22细胞轴突断裂,CCK8检测显示CoCl_2对HT22细胞的增殖有明显抑制作用。Western Blot结果显示CoCl_2-H组细胞中HIF-1α表达显著上调,tau蛋白表达显著降低。结论:CoCl_2可致轴突损伤,并且上调HT22细胞的HIF-1α表达、降低tau的表达。     

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.     

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.     

Postinfectious immunodeficiency and autoimmunity: pathogenic and clinical values and implications

Autoimmunity is still a mystery of clinical immunology and medicine as a whole. The etiology and pathogenesis of autoimmune disorders remain unclear and, thus, are assessed as a balance between hereditary predisposition, triggering factors and the appearance of autoantibodies and/or self-reactive T cells. Among the immunological armamentarium, molecular mimicry, based on self-reactive T- and B-cell activation by cross-reactive epitopes of infectious agents, is of special value. Hypotheses regarding the possible involvement of molecular mimicry in the development of postinfectious autoimmunity are currently very intriguing. They provide new approaches for identifying etiological agents that are associated with postinfectious autoimmunity, paired microbial- and tissue-linked epitopes targeted for autoimmune reaction determination, postinfectious autoimmunity pathogenesis recognition and specific prevention, and therapy for autoimmune disorder development.     

Beta-endorphin and drug-induced reward and reinforcement

Although drugs of abuse have different acute mechanisms of action, their brain pathways of reward exhibit common functional effects upon both acute and chronic administration. Long known for its analgesic effect, the opioid beta-endorphin is now shown to induce euphoria, and to have rewarding and reinforcing properties. In this review, we will summarize the present neurobiological and behavioral evidences that support involvement of beta-endorphin in drug-induced reward and reinforcement. Currently, evidence supports a prominent role for beta-endorphin in the reward pathways of cocaine and alcohol. The existing information indicating the importance of beta-endorphin neurotransmission in mediating the reward pathways of nicotine and THC, is thus far circumstantial. The studies described herein employed diverse techniques, such as biochemical measurements of beta-endorphin in various brain sites and plasma, and behavioral measurements, conducted following elimination (via administration of anti-beta-endorphin antibodies or using mutant mice) or augmentation (by intracerebral administration) of beta-endorphin. We suggest that the reward pathways for different addictive drugs converge to a common pathway in which beta-endorphin is a modulating element. beta-Endorphin is involved also with distress. However, reviewing the data collected so far implies a discrete role, beyond that of a stress response, for beta-endorphin in mediating the substance of abuse reward pathway. This may occur via interacting with the mesolimbic dopaminergic system and also by its interesting effects on learning and memory. The functional meaning of beta-endorphin in the process of drug-seeking behavior is discussed.     

PTEN与信号转导及肿瘤

ＴＥＮ[1] (ｐｈｏｓｐｈａｔａｓｅａｎｄｔｅｎｓｉｎｈｏｍｏｌｏｇｙｄｅｌｅｔｅｄｏｎｃｈｒｏｍｏｓｏｍｅｔｅｎ)又名ＭＭＡＣ1 [2 ] (ｍｕｔａｔｅｄｉｎｍｕｔｉｐｌｙａｄａｎｃｅｄｃａｎｃｅｒ 1 )和ＴＥＰ1 [3 ] (ＴＧＦ -βｒｅｇｕｌａｔｅｄａｎｄｅｐｉｔｈｅｌｉａｌｃｅｌｌ -ｒｉｃｈｅｄｐｈｏｓｐｈａｔａｓｅ 1 ) (以下均称为ＰＴＥＮ) ,是 1 997年由 3个研究小组先后发现的一个具有双特异磷酸酶活性的抑癌基因。ＰＴＥＮ基因异常广泛存在于人类多种恶性肿瘤 ,如恶性神经胶质瘤、前列腺癌、子宫内膜癌、黑色素瘤等…     

Tobacco and alcohol and the risk of head and neck cancer

Summary We carried out two case-control studies on the relative risk of head and neck cancer in association with tobacco and alcohol consumption. The first study carried out at the ENT Department of the University hospitals of Heidelberg and Giessen (FRG) comprised 200 male patients with squamous cell cancer of the head and neck and 800 control subjects matched for sex, age, and residential area (1:4 matching design). Of the tumour patients, 4.5% had never smoked, in contrast to 29.5% of the control group. The average tobacco and alcohol consumption of the patients was approximately twice as high as in the control subjects. The highest alcohol and tobacco consumption was observed in patients suffering from oropharyngeal cancer. Tobacco and alcohol increased the risk of head and neck cancer in a dose-dependent fashion and acted as independent risk factors. In heavy smokers (> 60 pack-years) a relative risk of 23.4 (alcohol adjusted) was calculated. Combined alcohol and tobacco consumption showed a synergistic effect. The risk ratio increased more in a multiplicative than in an additive manner. Oral and laryngeal cancer were associated with the highest tobacco-associated risk values. The highest ethanol-associated risk values were associated with oropharyngeal and laryngeal cancer. The second study was carried out at the ENT Department of the University of Heidelberg on 164 males with squamous cell carcinoma of the larynx and 656 control subjects matched for sex, age and residential area (1:4 matching design). Of the cases, 4.2% had never smoked, compared with 28.5% of the control subjects. The risk of laryngeal cancer by tobacco consumption was dose dependent, reaching a maximum value of 9.1 (adjusted for alcohol) for a consumption of more than 50 tobacco-years (TY). The relative risk of laryngeal cancer associated with alcohol intake was also dose dependent, reaching a value of 9.0 (adjusted for tobacco) for a mean daily consumption of more than 75 g alcohol. An analysis of subsite specific risks showed that heavy smokers (> 50 TY) carried a nearly ten times higher risk of supraglottic cancer than of glottic cancer. The risk of supraglottic cancer from alcohol consumption was also higher than that of glottic cancer.     

Muscle strength and serum testosterone,cortisol and SHBG concentrations in middle-aged and elderly men and women

Forty healthy males (M) and females (F) divided into two different age groups i.e. M50 years (range 44–57; n= 9), F50 years (range 43–54; n= 9), M70 years (range 64–73; n= 11) and F70 years (range 63–73; n= 11) volunteered as subjects for examination of muscle cross-sectional area (CSA) and maximal voluntary isometric force production characteristics of the leg extensor muscles and serum androgen and sex hormone binding globulin (SHBG) concentrations. The CSA in the male groups was greatly larger (P < 0.01) than in the female groups and both elderly groups demonstrated slightly (n.s.) smaller values in the CSA than the two middle-aged groups. Maximal force of 2854 ± 452 N in M50 was greater (P < 0.05) than that of 2627 ± 752 N recorded for F50 as well as the force of 2787 ± 843 in M70 was greater (P < 0.001) than that of 1849 ± 295 recorded for F70. The force between F50 and F70 differed significantly (P < 0.05) from each other. The maximal rate of force production in M50 was greater (P < 0.01) than in F50 as well as in M70 greater (P < 0.001) than in F70. Both middle-aged groups demonstrated greater (P < 0.05) values than the respective elderly groups of the same sex. The individual values in the CSA correlated with the values in maximal force both in the middle-aged subjects (r= 0.66; P < 0.01) and in the elderly subjects (r= 0.69; P < 0.01). The mean concentration of serum testosterone in M50 was slightly (n.s.) greater than in M70 and in F50 significantly (P < 0.05) greater than in F70. Serum SHBG levels were lower in the males (P < 0.01) than in the females and serum testosterone/SHBG ratio in M70 and in F70 were lower (P < 0.05) than in M50 and in F50, respectively. In the females significant positive correlations were observed between the individual values in serum testosterone concentration and the values both in the CSA (r= 0.46; P < 0.05) and in maximal force (r= 0.62; P < 0.01) as well as between serum testosterone/SHBG ratio and both the CSA (r= 0.55; P < 0.05) and maximal force (r= 0.68; P < 0.01). The present results imply that the decreasing basal level of blood testosterone over the years in aging people, especially in females, may lead to decreasing anabolic effects on muscles thus having an association with age-related declines in the maximal voluntary neuromuscular performance capacity in aging people.     

海洛因成瘾与学习记忆

海洛因成瘾是我国发病最高,危害最大的一种成瘾性疾病,而其中枢机制则是解决临床预防和治疗的关键,至今仍不清楚。既往工作表明,学习记忆功能在海洛因成瘾的中枢机制中居于重要的中心环节。本文在总结既往海洛因成瘾研究工作基础上联系学习记忆功能,试图从系统整合层次分析相关领域研究工作的不足和今后工作的发展方向。